PMC:3567831 / 15020-24241 JSONTXT

{"project":"0_colil","denotations":[{"id":"22761504-18054343-6869","span":{"begin":142,"end":144},"obj":"18054343"},{"id":"22761504-20038476-6870","span":{"begin":757,"end":759},"obj":"20038476"},{"id":"22761504-18202887-6871","span":{"begin":964,"end":966},"obj":"18202887"},{"id":"22761504-18202887-6872","span":{"begin":1881,"end":1883},"obj":"18202887"},{"id":"22761504-17483110-6873","span":{"begin":2097,"end":2098},"obj":"17483110"},{"id":"22761504-16053960-6874","span":{"begin":2100,"end":2101},"obj":"16053960"},{"id":"22761504-9626846-6875","span":{"begin":2567,"end":2569},"obj":"9626846"},{"id":"22761504-16053960-6877","span":{"begin":3491,"end":3492},"obj":"16053960"},{"id":"22761504-17620519-6878","span":{"begin":3494,"end":3496},"obj":"17620519"},{"id":"22761504-20884022-6879","span":{"begin":3724,"end":3726},"obj":"20884022"},{"id":"22761504-22068435-6880","span":{"begin":3768,"end":3769},"obj":"22068435"},{"id":"22761504-20137602-6881","span":{"begin":4425,"end":4427},"obj":"20137602"},{"id":"22761504-12142186-6882","span":{"begin":5380,"end":5382},"obj":"12142186"},{"id":"22761504-16320929-6883","span":{"begin":5839,"end":5841},"obj":"16320929"},{"id":"22761504-15573275-6884","span":{"begin":6221,"end":6223},"obj":"15573275"},{"id":"22761504-18442532-6885","span":{"begin":6738,"end":6740},"obj":"18442532"},{"id":"22761504-15152297-6886","span":{"begin":6961,"end":6963},"obj":"15152297"},{"id":"22761504-17707185-6887","span":{"begin":8368,"end":8370},"obj":"17707185"},{"id":"22761504-17239717-6888","span":{"begin":8666,"end":8667},"obj":"17239717"},{"id":"22761504-10359738-6889","span":{"begin":9015,"end":9017},"obj":"10359738"},{"id":"22761504-17620519-6876","span":{"begin":3285,"end":3287},"obj":"17620519"},{"id":"22761504-18328859-6876","span":{"begin":3285,"end":3287},"obj":"18328859"},{"id":"22761504-18510487-6876","span":{"begin":3285,"end":3287},"obj":"18510487"}],"text":"DISCUSSION\nObstructive HCM is characterized by diastolic dysfunction, dynamic LVOT obstruction and rhythm troubles with risk of sudden death [11]. Generally speaking, the LVOT obstruction is often caused by the basal septum hypertrophy. Moreover, SAM of the mitral valve could result in mitral–septal apposition and incomplete leaflet apposition. As an important phenomenon in the mechanism of pathology, SAM may be caused by, as well as aggravate, the obstruction of LVOT, and would result in mitral valve apparatus distortion and MR. In this group, SAM was present in 100% of the patients preoperatively. Besides, anomalous papillary muscles can also contribute to MR and midcavity obstruction, usually by direct insertion into the mitral valve leaflets [12].\nThe diagnosis of obstructive HCM is often made by echocardiography and/or magnetic resonance imaging. Echocardiography has been considered the standard for diagnosis and assessment of LVOT obstruction [13]. The morphological features are that patients have a hypertrophied interventricular septum and left ventricle (usually \u003e15 mm in adults, or the equivalent relative to body surface area in children and teenagers), but without any other diseases that may cause secondary hypertrophy. Additionally, the patients may also have other characteristics, such as typical symptoms (exertional dyspnea, palpitations and chest discomfort), electrocardiographic changes (arrhythmia) or positive family history of HCM. LVOT obstruction may be demonstrated by LVOT gradient under TTE or TEE.\nThe treatment strategy for obstructive HCM is significantly dependent on the degree of symptoms due to obstruction. The benefits and risks of each procedure should be analysed scientifically on the basis of current evidence. It is commonly accepted that medical therapy remains the first-line treatment in the majority of HCM patients [13], but if the peak instantaneous LVOT gradient is ≥50 mmHg (at rest or with provocation) and the symptoms cannot be managed with medications, septal reduction therapy is strongly recommended to avoid sudden death [5, 6]. In this retrospective study, we found that LVOT gradient was low (\u003c50 mmHg) in six patients (six of 93) at rest but became much higher (\u003e50 mmHg) after provocation. These patients all had drug-refractory symptoms after activity and underwent myectomy with a very good outcome. Therefore, some labile obstructive HCM patients also need surgical intervention. A provocation test is very important for patients in order not to miss the diagnosis of obstructive HCM [14].\nPatients with persistent symptoms, despite optimal medical therapy, are usually considered candidates for septal reduction therapy. The surgical strategy has been often made depending on the patient's preference, physician's experience as well as some special status in a given situation. Compared with ablation, a longer period for recovery will be needed after TAESM because of thoracotomy and cardiopulmonary bypass. However, more and more experienced cardiac surgeons have reported encouraging results about TAESM during past years, which is considered the therapeutic gold standard in many prestigious cardiac centres today, even if alcohol septal ablation develops as another choice for high-risk patients [15–17]. TAESM can be performed safely with very low mortality and excellent long-term survival, which can be equivalent to general population, because the disease course of HCM has been changed thoroughly [6, 16].\nIn our opinion, one of the vital factors that directly determines the outcome of TAESM is the surgeon's clinical experience and anatomical knowledge of the LVOT. In experienced centres, the surgical outcome can be excellent [18]. As is mentioned in the 2011 guideline [1], extended Morrow procedure is a challenging operation in cardiac surgery, so there must be a learning curve before a surgeon can perform it perfectly. During the past 30 years, the largest group of Chinese obstructive HCM patients were treated in our institution. We have experienced a tough learning process and have gradually seen remarkable improvement by borrowing ideas from international communications and clinical exploration. According to our clinical practice, we had a morbidity of ∼7.4%, complete heart block (CHB) of ∼7.4% and MVR of 16.7% between 1996 and 2007. Moreover, the postoperative LVOT gradient was at an average level of 24 mmHg [19]. In the past few years, we have gradually improved the operating skills to tailor resection precisely, by properly increasing the extent of myectomy with precise discrimination, correction/resection of aberrant papillary muscles and mitral subvalvular apparatus abnormalities and using headlamps, long scalpels and forceps. This retrospective study shows that a much better clinical outcome, with a mortality of 0% (0/93), CHB rate of 3.2% (3 of 93), MVR of 10.8% and a mean postoperative LVOT gradient of 14.34 ± 13.44 mmHg, has been obtained since October 2009. Especially for the recent 20 cases, we have obtained results better than the average level, with a postoperative LVOT gradient of 1–9 mmHg.\nAs a significant advantage of TAESM, other associated cardiac diseases can be treated surgically. Patients with or without concomitant surgical procedures can benefit from the operation by means of improved life expectancy and performance status [20]. In this group, concomitant surgical procedures were carried out in 37 patients (39.8%, all for preexisting conditions), including MVP, MVR and CABG. In our clinical practice, coronary angiography was considered a preoperative routine examination for patients over 40, so as to detect coronary atherosclerotic heart disease and myocardial bridge, which might be associated with an unfavourable prognosis in HCM patients and should be treated empirically [21]. So, 18 patients were diagnosed with coronary disease and underwent on-pump CABG immediately after myectomy. All these patients had a good outcome during follow-up.\nAs mitral valve leaflets and subvalvular apparatus abnormalities play an important role in the pathologies of obstructive HCM, surgical management of the mitral valve has been considered a vital part of myectomy [22]. According to the analysis of preoperative echocardiography in this study, SAM was accessed in all and MR in 73 patients (78.5%), of whom 41 were more than moderate level. For many patients, SAM and MR could disappear or diminish automatically after myectomy. However, some patients had mitral valve abnormities, which also need special surgical treatment during the operations, or it would negatively influence the surgical outcome. For them, mitral valve repair or plasty is recommended as the priority choice [23]. According to our practice, MVR can be avoided in most patients with degenerative MR and HCM, and it is indicated only if the mitral valve cannot be repaired because of severe pathological changes such as endocarditis [24] or of other procedures have failed to relieve the LVOT gradient. In this group, SAM disappeared postoperatively including those who had MVP, except only one still had mild SAM but without mitral-septal contact. In this group, MVR was carried out in 10 cases (10 of 93). Six of them had severely damaged mitral valve, which could not be repaired. While for the other four cases, intraoperative TEE showed that the LVOT gradient and SAM had not been resolved perfectly after initial myectomy and MVP, so they had MVR thereafter.\nTAESM can be successfully performed after a history of alcohol ablation treatment. In this group, three cases had histories of alcohol septal ablation performed in the previous 6 months to 4 years. Because the drug-refractory symptoms did not disappear after ablation or recurred later, myectomy was suggested to them when they were readmitted to hospital. They had a successful surgical procedure and uneventful recovery, of whom one had MVR after a failed MVP, the other two had a significant decrease in the LVOT gradient from a preoperative level of 67–133 mmHg (with physiological provocation) to 4–10 mmHg postoperatively. Consequently, a history of alcohol ablation may not adversely affect the surgical outcome of obstructive HCM, but a higher incidence of CHB than in the case of those who underwent only surgical myectomy was observed and reported in another study [10].\nElectrocardiographic changes may be one of the main types of complications after TAESM, including left bundle branch block, intraventricular block and CHB. Unlike RBBB, which is more common after ablation, the left bundle branch block developed in nearly half of the septal myectomy patients [3]. Therefore, those who had complete RBBB preoperatively may have a higher risk of CHB after myectomy. In this retrospective study, three patients (3.2%) developed CHB after myectomy and permanent pacing was needed for them, of whom two had a previous history of complete RBBB. Pacing cannot be regarded as a primary treatment for obstructive HCM [25], but after TAESM, it may be needed with a very low probability in some special patients. Therefore, it is necessary to be alert when surgical myectomy is performed in obstructive HCM patients with RBBB."}

{"project":"TEST0","denotations":[{"id":"22761504-131-137-6869","span":{"begin":142,"end":144},"obj":"[\"18054343\"]"},{"id":"22761504-150-156-6870","span":{"begin":757,"end":759},"obj":"[\"20038476\"]"},{"id":"22761504-100-106-6871","span":{"begin":964,"end":966},"obj":"[\"18202887\"]"},{"id":"22761504-111-117-6872","span":{"begin":1881,"end":1883},"obj":"[\"18202887\"]"},{"id":"22761504-233-238-6873","span":{"begin":2097,"end":2098},"obj":"[\"17483110\"]"},{"id":"22761504-236-241-6874","span":{"begin":2100,"end":2101},"obj":"[\"16053960\"]"},{"id":"22761504-105-111-6875","span":{"begin":2567,"end":2569},"obj":"[\"9626846\"]"},{"id":"22761504-236-242-6876","span":{"begin":3285,"end":3287},"obj":"[\"18510487\", \"17620519\", \"18328859\"]"},{"id":"22761504-198-203-6877","span":{"begin":3491,"end":3492},"obj":"[\"16053960\"]"},{"id":"22761504-201-207-6878","span":{"begin":3494,"end":3496},"obj":"[\"17620519\"]"},{"id":"22761504-63-69-6879","span":{"begin":3724,"end":3726},"obj":"[\"20884022\"]"},{"id":"22761504-39-44-6880","span":{"begin":3768,"end":3769},"obj":"[\"22068435\"]"},{"id":"22761504-78-84-6881","span":{"begin":4425,"end":4427},"obj":"[\"20137602\"]"},{"id":"22761504-149-155-6882","span":{"begin":5380,"end":5382},"obj":"[\"12142186\"]"},{"id":"22761504-228-234-6883","span":{"begin":5839,"end":5841},"obj":"[\"16320929\"]"},{"id":"22761504-213-219-6884","span":{"begin":6221,"end":6223},"obj":"[\"15573275\"]"},{"id":"22761504-79-85-6885","span":{"begin":6738,"end":6740},"obj":"[\"18442532\"]"},{"id":"22761504-218-224-6886","span":{"begin":6961,"end":6963},"obj":"[\"15152297\"]"},{"id":"22761504-233-239-6887","span":{"begin":8368,"end":8370},"obj":"[\"17707185\"]"},{"id":"22761504-137-142-6888","span":{"begin":8666,"end":8667},"obj":"[\"17239717\"]"},{"id":"22761504-70-76-6889","span":{"begin":9015,"end":9017},"obj":"[\"10359738\"]"}],"text":"DISCUSSION\nObstructive HCM is characterized by diastolic dysfunction, dynamic LVOT obstruction and rhythm troubles with risk of sudden death [11]. Generally speaking, the LVOT obstruction is often caused by the basal septum hypertrophy. Moreover, SAM of the mitral valve could result in mitral–septal apposition and incomplete leaflet apposition. As an important phenomenon in the mechanism of pathology, SAM may be caused by, as well as aggravate, the obstruction of LVOT, and would result in mitral valve apparatus distortion and MR. In this group, SAM was present in 100% of the patients preoperatively. Besides, anomalous papillary muscles can also contribute to MR and midcavity obstruction, usually by direct insertion into the mitral valve leaflets [12].\nThe diagnosis of obstructive HCM is often made by echocardiography and/or magnetic resonance imaging. Echocardiography has been considered the standard for diagnosis and assessment of LVOT obstruction [13]. The morphological features are that patients have a hypertrophied interventricular septum and left ventricle (usually \u003e15 mm in adults, or the equivalent relative to body surface area in children and teenagers), but without any other diseases that may cause secondary hypertrophy. Additionally, the patients may also have other characteristics, such as typical symptoms (exertional dyspnea, palpitations and chest discomfort), electrocardiographic changes (arrhythmia) or positive family history of HCM. LVOT obstruction may be demonstrated by LVOT gradient under TTE or TEE.\nThe treatment strategy for obstructive HCM is significantly dependent on the degree of symptoms due to obstruction. The benefits and risks of each procedure should be analysed scientifically on the basis of current evidence. It is commonly accepted that medical therapy remains the first-line treatment in the majority of HCM patients [13], but if the peak instantaneous LVOT gradient is ≥50 mmHg (at rest or with provocation) and the symptoms cannot be managed with medications, septal reduction therapy is strongly recommended to avoid sudden death [5, 6]. In this retrospective study, we found that LVOT gradient was low (\u003c50 mmHg) in six patients (six of 93) at rest but became much higher (\u003e50 mmHg) after provocation. These patients all had drug-refractory symptoms after activity and underwent myectomy with a very good outcome. Therefore, some labile obstructive HCM patients also need surgical intervention. A provocation test is very important for patients in order not to miss the diagnosis of obstructive HCM [14].\nPatients with persistent symptoms, despite optimal medical therapy, are usually considered candidates for septal reduction therapy. The surgical strategy has been often made depending on the patient's preference, physician's experience as well as some special status in a given situation. Compared with ablation, a longer period for recovery will be needed after TAESM because of thoracotomy and cardiopulmonary bypass. However, more and more experienced cardiac surgeons have reported encouraging results about TAESM during past years, which is considered the therapeutic gold standard in many prestigious cardiac centres today, even if alcohol septal ablation develops as another choice for high-risk patients [15–17]. TAESM can be performed safely with very low mortality and excellent long-term survival, which can be equivalent to general population, because the disease course of HCM has been changed thoroughly [6, 16].\nIn our opinion, one of the vital factors that directly determines the outcome of TAESM is the surgeon's clinical experience and anatomical knowledge of the LVOT. In experienced centres, the surgical outcome can be excellent [18]. As is mentioned in the 2011 guideline [1], extended Morrow procedure is a challenging operation in cardiac surgery, so there must be a learning curve before a surgeon can perform it perfectly. During the past 30 years, the largest group of Chinese obstructive HCM patients were treated in our institution. We have experienced a tough learning process and have gradually seen remarkable improvement by borrowing ideas from international communications and clinical exploration. According to our clinical practice, we had a morbidity of ∼7.4%, complete heart block (CHB) of ∼7.4% and MVR of 16.7% between 1996 and 2007. Moreover, the postoperative LVOT gradient was at an average level of 24 mmHg [19]. In the past few years, we have gradually improved the operating skills to tailor resection precisely, by properly increasing the extent of myectomy with precise discrimination, correction/resection of aberrant papillary muscles and mitral subvalvular apparatus abnormalities and using headlamps, long scalpels and forceps. This retrospective study shows that a much better clinical outcome, with a mortality of 0% (0/93), CHB rate of 3.2% (3 of 93), MVR of 10.8% and a mean postoperative LVOT gradient of 14.34 ± 13.44 mmHg, has been obtained since October 2009. Especially for the recent 20 cases, we have obtained results better than the average level, with a postoperative LVOT gradient of 1–9 mmHg.\nAs a significant advantage of TAESM, other associated cardiac diseases can be treated surgically. Patients with or without concomitant surgical procedures can benefit from the operation by means of improved life expectancy and performance status [20]. In this group, concomitant surgical procedures were carried out in 37 patients (39.8%, all for preexisting conditions), including MVP, MVR and CABG. In our clinical practice, coronary angiography was considered a preoperative routine examination for patients over 40, so as to detect coronary atherosclerotic heart disease and myocardial bridge, which might be associated with an unfavourable prognosis in HCM patients and should be treated empirically [21]. So, 18 patients were diagnosed with coronary disease and underwent on-pump CABG immediately after myectomy. All these patients had a good outcome during follow-up.\nAs mitral valve leaflets and subvalvular apparatus abnormalities play an important role in the pathologies of obstructive HCM, surgical management of the mitral valve has been considered a vital part of myectomy [22]. According to the analysis of preoperative echocardiography in this study, SAM was accessed in all and MR in 73 patients (78.5%), of whom 41 were more than moderate level. For many patients, SAM and MR could disappear or diminish automatically after myectomy. However, some patients had mitral valve abnormities, which also need special surgical treatment during the operations, or it would negatively influence the surgical outcome. For them, mitral valve repair or plasty is recommended as the priority choice [23]. According to our practice, MVR can be avoided in most patients with degenerative MR and HCM, and it is indicated only if the mitral valve cannot be repaired because of severe pathological changes such as endocarditis [24] or of other procedures have failed to relieve the LVOT gradient. In this group, SAM disappeared postoperatively including those who had MVP, except only one still had mild SAM but without mitral-septal contact. In this group, MVR was carried out in 10 cases (10 of 93). Six of them had severely damaged mitral valve, which could not be repaired. While for the other four cases, intraoperative TEE showed that the LVOT gradient and SAM had not been resolved perfectly after initial myectomy and MVP, so they had MVR thereafter.\nTAESM can be successfully performed after a history of alcohol ablation treatment. In this group, three cases had histories of alcohol septal ablation performed in the previous 6 months to 4 years. Because the drug-refractory symptoms did not disappear after ablation or recurred later, myectomy was suggested to them when they were readmitted to hospital. They had a successful surgical procedure and uneventful recovery, of whom one had MVR after a failed MVP, the other two had a significant decrease in the LVOT gradient from a preoperative level of 67–133 mmHg (with physiological provocation) to 4–10 mmHg postoperatively. Consequently, a history of alcohol ablation may not adversely affect the surgical outcome of obstructive HCM, but a higher incidence of CHB than in the case of those who underwent only surgical myectomy was observed and reported in another study [10].\nElectrocardiographic changes may be one of the main types of complications after TAESM, including left bundle branch block, intraventricular block and CHB. Unlike RBBB, which is more common after ablation, the left bundle branch block developed in nearly half of the septal myectomy patients [3]. Therefore, those who had complete RBBB preoperatively may have a higher risk of CHB after myectomy. In this retrospective study, three patients (3.2%) developed CHB after myectomy and permanent pacing was needed for them, of whom two had a previous history of complete RBBB. Pacing cannot be regarded as a primary treatment for obstructive HCM [25], but after TAESM, it may be needed with a very low probability in some special patients. Therefore, it is necessary to be alert when surgical myectomy is performed in obstructive HCM patients with RBBB."}

{"project":"2_test","denotations":[{"id":"22761504-18054343-28905035","span":{"begin":142,"end":144},"obj":"18054343"},{"id":"22761504-20038476-28905036","span":{"begin":757,"end":759},"obj":"20038476"},{"id":"22761504-18202887-28905037","span":{"begin":964,"end":966},"obj":"18202887"},{"id":"22761504-18202887-28905038","span":{"begin":1881,"end":1883},"obj":"18202887"},{"id":"22761504-17483110-28905039","span":{"begin":2097,"end":2098},"obj":"17483110"},{"id":"22761504-16053960-28905040","span":{"begin":2100,"end":2101},"obj":"16053960"},{"id":"22761504-9626846-28905041","span":{"begin":2567,"end":2569},"obj":"9626846"},{"id":"22761504-18510487-28905042","span":{"begin":3285,"end":3287},"obj":"18510487"},{"id":"22761504-17620519-28905042","span":{"begin":3285,"end":3287},"obj":"17620519"},{"id":"22761504-18328859-28905042","span":{"begin":3285,"end":3287},"obj":"18328859"},{"id":"22761504-16053960-28905043","span":{"begin":3491,"end":3492},"obj":"16053960"},{"id":"22761504-17620519-28905044","span":{"begin":3494,"end":3496},"obj":"17620519"},{"id":"22761504-20884022-28905045","span":{"begin":3724,"end":3726},"obj":"20884022"},{"id":"22761504-22068435-28905046","span":{"begin":3768,"end":3769},"obj":"22068435"},{"id":"22761504-20137602-28905047","span":{"begin":4425,"end":4427},"obj":"20137602"},{"id":"22761504-12142186-28905048","span":{"begin":5380,"end":5382},"obj":"12142186"},{"id":"22761504-16320929-28905049","span":{"begin":5839,"end":5841},"obj":"16320929"},{"id":"22761504-15573275-28905050","span":{"begin":6221,"end":6223},"obj":"15573275"},{"id":"22761504-18442532-28905051","span":{"begin":6738,"end":6740},"obj":"18442532"},{"id":"22761504-15152297-28905052","span":{"begin":6961,"end":6963},"obj":"15152297"},{"id":"22761504-17707185-28905053","span":{"begin":8368,"end":8370},"obj":"17707185"},{"id":"22761504-17239717-28905054","span":{"begin":8666,"end":8667},"obj":"17239717"},{"id":"22761504-10359738-28905055","span":{"begin":9015,"end":9017},"obj":"10359738"}],"text":"DISCUSSION\nObstructive HCM is characterized by diastolic dysfunction, dynamic LVOT obstruction and rhythm troubles with risk of sudden death [11]. Generally speaking, the LVOT obstruction is often caused by the basal septum hypertrophy. Moreover, SAM of the mitral valve could result in mitral–septal apposition and incomplete leaflet apposition. As an important phenomenon in the mechanism of pathology, SAM may be caused by, as well as aggravate, the obstruction of LVOT, and would result in mitral valve apparatus distortion and MR. In this group, SAM was present in 100% of the patients preoperatively. Besides, anomalous papillary muscles can also contribute to MR and midcavity obstruction, usually by direct insertion into the mitral valve leaflets [12].\nThe diagnosis of obstructive HCM is often made by echocardiography and/or magnetic resonance imaging. Echocardiography has been considered the standard for diagnosis and assessment of LVOT obstruction [13]. The morphological features are that patients have a hypertrophied interventricular septum and left ventricle (usually \u003e15 mm in adults, or the equivalent relative to body surface area in children and teenagers), but without any other diseases that may cause secondary hypertrophy. Additionally, the patients may also have other characteristics, such as typical symptoms (exertional dyspnea, palpitations and chest discomfort), electrocardiographic changes (arrhythmia) or positive family history of HCM. LVOT obstruction may be demonstrated by LVOT gradient under TTE or TEE.\nThe treatment strategy for obstructive HCM is significantly dependent on the degree of symptoms due to obstruction. The benefits and risks of each procedure should be analysed scientifically on the basis of current evidence. It is commonly accepted that medical therapy remains the first-line treatment in the majority of HCM patients [13], but if the peak instantaneous LVOT gradient is ≥50 mmHg (at rest or with provocation) and the symptoms cannot be managed with medications, septal reduction therapy is strongly recommended to avoid sudden death [5, 6]. In this retrospective study, we found that LVOT gradient was low (\u003c50 mmHg) in six patients (six of 93) at rest but became much higher (\u003e50 mmHg) after provocation. These patients all had drug-refractory symptoms after activity and underwent myectomy with a very good outcome. Therefore, some labile obstructive HCM patients also need surgical intervention. A provocation test is very important for patients in order not to miss the diagnosis of obstructive HCM [14].\nPatients with persistent symptoms, despite optimal medical therapy, are usually considered candidates for septal reduction therapy. The surgical strategy has been often made depending on the patient's preference, physician's experience as well as some special status in a given situation. Compared with ablation, a longer period for recovery will be needed after TAESM because of thoracotomy and cardiopulmonary bypass. However, more and more experienced cardiac surgeons have reported encouraging results about TAESM during past years, which is considered the therapeutic gold standard in many prestigious cardiac centres today, even if alcohol septal ablation develops as another choice for high-risk patients [15–17]. TAESM can be performed safely with very low mortality and excellent long-term survival, which can be equivalent to general population, because the disease course of HCM has been changed thoroughly [6, 16].\nIn our opinion, one of the vital factors that directly determines the outcome of TAESM is the surgeon's clinical experience and anatomical knowledge of the LVOT. In experienced centres, the surgical outcome can be excellent [18]. As is mentioned in the 2011 guideline [1], extended Morrow procedure is a challenging operation in cardiac surgery, so there must be a learning curve before a surgeon can perform it perfectly. During the past 30 years, the largest group of Chinese obstructive HCM patients were treated in our institution. We have experienced a tough learning process and have gradually seen remarkable improvement by borrowing ideas from international communications and clinical exploration. According to our clinical practice, we had a morbidity of ∼7.4%, complete heart block (CHB) of ∼7.4% and MVR of 16.7% between 1996 and 2007. Moreover, the postoperative LVOT gradient was at an average level of 24 mmHg [19]. In the past few years, we have gradually improved the operating skills to tailor resection precisely, by properly increasing the extent of myectomy with precise discrimination, correction/resection of aberrant papillary muscles and mitral subvalvular apparatus abnormalities and using headlamps, long scalpels and forceps. This retrospective study shows that a much better clinical outcome, with a mortality of 0% (0/93), CHB rate of 3.2% (3 of 93), MVR of 10.8% and a mean postoperative LVOT gradient of 14.34 ± 13.44 mmHg, has been obtained since October 2009. Especially for the recent 20 cases, we have obtained results better than the average level, with a postoperative LVOT gradient of 1–9 mmHg.\nAs a significant advantage of TAESM, other associated cardiac diseases can be treated surgically. Patients with or without concomitant surgical procedures can benefit from the operation by means of improved life expectancy and performance status [20]. In this group, concomitant surgical procedures were carried out in 37 patients (39.8%, all for preexisting conditions), including MVP, MVR and CABG. In our clinical practice, coronary angiography was considered a preoperative routine examination for patients over 40, so as to detect coronary atherosclerotic heart disease and myocardial bridge, which might be associated with an unfavourable prognosis in HCM patients and should be treated empirically [21]. So, 18 patients were diagnosed with coronary disease and underwent on-pump CABG immediately after myectomy. All these patients had a good outcome during follow-up.\nAs mitral valve leaflets and subvalvular apparatus abnormalities play an important role in the pathologies of obstructive HCM, surgical management of the mitral valve has been considered a vital part of myectomy [22]. According to the analysis of preoperative echocardiography in this study, SAM was accessed in all and MR in 73 patients (78.5%), of whom 41 were more than moderate level. For many patients, SAM and MR could disappear or diminish automatically after myectomy. However, some patients had mitral valve abnormities, which also need special surgical treatment during the operations, or it would negatively influence the surgical outcome. For them, mitral valve repair or plasty is recommended as the priority choice [23]. According to our practice, MVR can be avoided in most patients with degenerative MR and HCM, and it is indicated only if the mitral valve cannot be repaired because of severe pathological changes such as endocarditis [24] or of other procedures have failed to relieve the LVOT gradient. In this group, SAM disappeared postoperatively including those who had MVP, except only one still had mild SAM but without mitral-septal contact. In this group, MVR was carried out in 10 cases (10 of 93). Six of them had severely damaged mitral valve, which could not be repaired. While for the other four cases, intraoperative TEE showed that the LVOT gradient and SAM had not been resolved perfectly after initial myectomy and MVP, so they had MVR thereafter.\nTAESM can be successfully performed after a history of alcohol ablation treatment. In this group, three cases had histories of alcohol septal ablation performed in the previous 6 months to 4 years. Because the drug-refractory symptoms did not disappear after ablation or recurred later, myectomy was suggested to them when they were readmitted to hospital. They had a successful surgical procedure and uneventful recovery, of whom one had MVR after a failed MVP, the other two had a significant decrease in the LVOT gradient from a preoperative level of 67–133 mmHg (with physiological provocation) to 4–10 mmHg postoperatively. Consequently, a history of alcohol ablation may not adversely affect the surgical outcome of obstructive HCM, but a higher incidence of CHB than in the case of those who underwent only surgical myectomy was observed and reported in another study [10].\nElectrocardiographic changes may be one of the main types of complications after TAESM, including left bundle branch block, intraventricular block and CHB. Unlike RBBB, which is more common after ablation, the left bundle branch block developed in nearly half of the septal myectomy patients [3]. Therefore, those who had complete RBBB preoperatively may have a higher risk of CHB after myectomy. In this retrospective study, three patients (3.2%) developed CHB after myectomy and permanent pacing was needed for them, of whom two had a previous history of complete RBBB. Pacing cannot be regarded as a primary treatment for obstructive HCM [25], but after TAESM, it may be needed with a very low probability in some special patients. Therefore, it is necessary to be alert when surgical myectomy is performed in obstructive HCM patients with RBBB."}

{"project":"MyTest","denotations":[{"id":"22761504-18054343-28905035","span":{"begin":142,"end":144},"obj":"18054343"},{"id":"22761504-20038476-28905036","span":{"begin":757,"end":759},"obj":"20038476"},{"id":"22761504-18202887-28905037","span":{"begin":964,"end":966},"obj":"18202887"},{"id":"22761504-18202887-28905038","span":{"begin":1881,"end":1883},"obj":"18202887"},{"id":"22761504-17483110-28905039","span":{"begin":2097,"end":2098},"obj":"17483110"},{"id":"22761504-16053960-28905040","span":{"begin":2100,"end":2101},"obj":"16053960"},{"id":"22761504-9626846-28905041","span":{"begin":2567,"end":2569},"obj":"9626846"},{"id":"22761504-18510487-28905042","span":{"begin":3285,"end":3287},"obj":"18510487"},{"id":"22761504-17620519-28905042","span":{"begin":3285,"end":3287},"obj":"17620519"},{"id":"22761504-18328859-28905042","span":{"begin":3285,"end":3287},"obj":"18328859"},{"id":"22761504-16053960-28905043","span":{"begin":3491,"end":3492},"obj":"16053960"},{"id":"22761504-17620519-28905044","span":{"begin":3494,"end":3496},"obj":"17620519"},{"id":"22761504-20884022-28905045","span":{"begin":3724,"end":3726},"obj":"20884022"},{"id":"22761504-22068435-28905046","span":{"begin":3768,"end":3769},"obj":"22068435"},{"id":"22761504-20137602-28905047","span":{"begin":4425,"end":4427},"obj":"20137602"},{"id":"22761504-12142186-28905048","span":{"begin":5380,"end":5382},"obj":"12142186"},{"id":"22761504-16320929-28905049","span":{"begin":5839,"end":5841},"obj":"16320929"},{"id":"22761504-15573275-28905050","span":{"begin":6221,"end":6223},"obj":"15573275"},{"id":"22761504-18442532-28905051","span":{"begin":6738,"end":6740},"obj":"18442532"},{"id":"22761504-15152297-28905052","span":{"begin":6961,"end":6963},"obj":"15152297"},{"id":"22761504-17707185-28905053","span":{"begin":8368,"end":8370},"obj":"17707185"},{"id":"22761504-17239717-28905054","span":{"begin":8666,"end":8667},"obj":"17239717"},{"id":"22761504-10359738-28905055","span":{"begin":9015,"end":9017},"obj":"10359738"}],"namespaces":[{"prefix":"_base","uri":"https://www.uniprot.org/uniprot/testbase"},{"prefix":"UniProtKB","uri":"https://www.uniprot.org/uniprot/"},{"prefix":"uniprot","uri":"https://www.uniprot.org/uniprotkb/"}],"text":"DISCUSSION\nObstructive HCM is characterized by diastolic dysfunction, dynamic LVOT obstruction and rhythm troubles with risk of sudden death [11]. Generally speaking, the LVOT obstruction is often caused by the basal septum hypertrophy. Moreover, SAM of the mitral valve could result in mitral–septal apposition and incomplete leaflet apposition. As an important phenomenon in the mechanism of pathology, SAM may be caused by, as well as aggravate, the obstruction of LVOT, and would result in mitral valve apparatus distortion and MR. In this group, SAM was present in 100% of the patients preoperatively. Besides, anomalous papillary muscles can also contribute to MR and midcavity obstruction, usually by direct insertion into the mitral valve leaflets [12].\nThe diagnosis of obstructive HCM is often made by echocardiography and/or magnetic resonance imaging. Echocardiography has been considered the standard for diagnosis and assessment of LVOT obstruction [13]. The morphological features are that patients have a hypertrophied interventricular septum and left ventricle (usually \u003e15 mm in adults, or the equivalent relative to body surface area in children and teenagers), but without any other diseases that may cause secondary hypertrophy. Additionally, the patients may also have other characteristics, such as typical symptoms (exertional dyspnea, palpitations and chest discomfort), electrocardiographic changes (arrhythmia) or positive family history of HCM. LVOT obstruction may be demonstrated by LVOT gradient under TTE or TEE.\nThe treatment strategy for obstructive HCM is significantly dependent on the degree of symptoms due to obstruction. The benefits and risks of each procedure should be analysed scientifically on the basis of current evidence. It is commonly accepted that medical therapy remains the first-line treatment in the majority of HCM patients [13], but if the peak instantaneous LVOT gradient is ≥50 mmHg (at rest or with provocation) and the symptoms cannot be managed with medications, septal reduction therapy is strongly recommended to avoid sudden death [5, 6]. In this retrospective study, we found that LVOT gradient was low (\u003c50 mmHg) in six patients (six of 93) at rest but became much higher (\u003e50 mmHg) after provocation. These patients all had drug-refractory symptoms after activity and underwent myectomy with a very good outcome. Therefore, some labile obstructive HCM patients also need surgical intervention. A provocation test is very important for patients in order not to miss the diagnosis of obstructive HCM [14].\nPatients with persistent symptoms, despite optimal medical therapy, are usually considered candidates for septal reduction therapy. The surgical strategy has been often made depending on the patient's preference, physician's experience as well as some special status in a given situation. Compared with ablation, a longer period for recovery will be needed after TAESM because of thoracotomy and cardiopulmonary bypass. However, more and more experienced cardiac surgeons have reported encouraging results about TAESM during past years, which is considered the therapeutic gold standard in many prestigious cardiac centres today, even if alcohol septal ablation develops as another choice for high-risk patients [15–17]. TAESM can be performed safely with very low mortality and excellent long-term survival, which can be equivalent to general population, because the disease course of HCM has been changed thoroughly [6, 16].\nIn our opinion, one of the vital factors that directly determines the outcome of TAESM is the surgeon's clinical experience and anatomical knowledge of the LVOT. In experienced centres, the surgical outcome can be excellent [18]. As is mentioned in the 2011 guideline [1], extended Morrow procedure is a challenging operation in cardiac surgery, so there must be a learning curve before a surgeon can perform it perfectly. During the past 30 years, the largest group of Chinese obstructive HCM patients were treated in our institution. We have experienced a tough learning process and have gradually seen remarkable improvement by borrowing ideas from international communications and clinical exploration. According to our clinical practice, we had a morbidity of ∼7.4%, complete heart block (CHB) of ∼7.4% and MVR of 16.7% between 1996 and 2007. Moreover, the postoperative LVOT gradient was at an average level of 24 mmHg [19]. In the past few years, we have gradually improved the operating skills to tailor resection precisely, by properly increasing the extent of myectomy with precise discrimination, correction/resection of aberrant papillary muscles and mitral subvalvular apparatus abnormalities and using headlamps, long scalpels and forceps. This retrospective study shows that a much better clinical outcome, with a mortality of 0% (0/93), CHB rate of 3.2% (3 of 93), MVR of 10.8% and a mean postoperative LVOT gradient of 14.34 ± 13.44 mmHg, has been obtained since October 2009. Especially for the recent 20 cases, we have obtained results better than the average level, with a postoperative LVOT gradient of 1–9 mmHg.\nAs a significant advantage of TAESM, other associated cardiac diseases can be treated surgically. Patients with or without concomitant surgical procedures can benefit from the operation by means of improved life expectancy and performance status [20]. In this group, concomitant surgical procedures were carried out in 37 patients (39.8%, all for preexisting conditions), including MVP, MVR and CABG. In our clinical practice, coronary angiography was considered a preoperative routine examination for patients over 40, so as to detect coronary atherosclerotic heart disease and myocardial bridge, which might be associated with an unfavourable prognosis in HCM patients and should be treated empirically [21]. So, 18 patients were diagnosed with coronary disease and underwent on-pump CABG immediately after myectomy. All these patients had a good outcome during follow-up.\nAs mitral valve leaflets and subvalvular apparatus abnormalities play an important role in the pathologies of obstructive HCM, surgical management of the mitral valve has been considered a vital part of myectomy [22]. According to the analysis of preoperative echocardiography in this study, SAM was accessed in all and MR in 73 patients (78.5%), of whom 41 were more than moderate level. For many patients, SAM and MR could disappear or diminish automatically after myectomy. However, some patients had mitral valve abnormities, which also need special surgical treatment during the operations, or it would negatively influence the surgical outcome. For them, mitral valve repair or plasty is recommended as the priority choice [23]. According to our practice, MVR can be avoided in most patients with degenerative MR and HCM, and it is indicated only if the mitral valve cannot be repaired because of severe pathological changes such as endocarditis [24] or of other procedures have failed to relieve the LVOT gradient. In this group, SAM disappeared postoperatively including those who had MVP, except only one still had mild SAM but without mitral-septal contact. In this group, MVR was carried out in 10 cases (10 of 93). Six of them had severely damaged mitral valve, which could not be repaired. While for the other four cases, intraoperative TEE showed that the LVOT gradient and SAM had not been resolved perfectly after initial myectomy and MVP, so they had MVR thereafter.\nTAESM can be successfully performed after a history of alcohol ablation treatment. In this group, three cases had histories of alcohol septal ablation performed in the previous 6 months to 4 years. Because the drug-refractory symptoms did not disappear after ablation or recurred later, myectomy was suggested to them when they were readmitted to hospital. They had a successful surgical procedure and uneventful recovery, of whom one had MVR after a failed MVP, the other two had a significant decrease in the LVOT gradient from a preoperative level of 67–133 mmHg (with physiological provocation) to 4–10 mmHg postoperatively. Consequently, a history of alcohol ablation may not adversely affect the surgical outcome of obstructive HCM, but a higher incidence of CHB than in the case of those who underwent only surgical myectomy was observed and reported in another study [10].\nElectrocardiographic changes may be one of the main types of complications after TAESM, including left bundle branch block, intraventricular block and CHB. Unlike RBBB, which is more common after ablation, the left bundle branch block developed in nearly half of the septal myectomy patients [3]. Therefore, those who had complete RBBB preoperatively may have a higher risk of CHB after myectomy. In this retrospective study, three patients (3.2%) developed CHB after myectomy and permanent pacing was needed for them, of whom two had a previous history of complete RBBB. Pacing cannot be regarded as a primary treatment for obstructive HCM [25], but after TAESM, it may be needed with a very low probability in some special patients. Therefore, it is necessary to be alert when surgical myectomy is performed in obstructive HCM patients with RBBB."}

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HCM is characterized by diastolic dysfunction, dynamic LVOT obstruction and rhythm troubles with risk of sudden death [11]. Generally speaking, the LVOT obstruction is often caused by the basal septum hypertrophy. Moreover, SAM of the mitral valve could result in mitral–septal apposition and incomplete leaflet apposition. As an important phenomenon in the mechanism of pathology, SAM may be caused by, as well as aggravate, the obstruction of LVOT, and would result in mitral valve apparatus distortion and MR. In this group, SAM was present in 100% of the patients preoperatively. Besides, anomalous papillary muscles can also contribute to MR and midcavity obstruction, usually by direct insertion into the mitral valve leaflets [12].\nThe diagnosis of obstructive HCM is often made by echocardiography and/or magnetic resonance imaging. Echocardiography has been considered the standard for diagnosis and assessment of LVOT obstruction [13]. The morphological features are that patients have a hypertrophied interventricular septum and left ventricle (usually \u003e15 mm in adults, or the equivalent relative to body surface area in children and teenagers), but without any other diseases that may cause secondary hypertrophy. Additionally, the patients may also have other characteristics, such as typical symptoms (exertional dyspnea, palpitations and chest discomfort), electrocardiographic changes (arrhythmia) or positive family history of HCM. LVOT obstruction may be demonstrated by LVOT gradient under TTE or TEE.\nThe treatment strategy for obstructive HCM is significantly dependent on the degree of symptoms due to obstruction. The benefits and risks of each procedure should be analysed scientifically on the basis of current evidence. It is commonly accepted that medical therapy remains the first-line treatment in the majority of HCM patients [13], but if the peak instantaneous LVOT gradient is ≥50 mmHg (at rest or with provocation) and the symptoms cannot be managed with medications, septal reduction therapy is strongly recommended to avoid sudden death [5, 6]. In this retrospective study, we found that LVOT gradient was low (\u003c50 mmHg) in six patients (six of 93) at rest but became much higher (\u003e50 mmHg) after provocation. These patients all had drug-refractory symptoms after activity and underwent myectomy with a very good outcome. Therefore, some labile obstructive HCM patients also need surgical intervention. A provocation test is very important for patients in order not to miss the diagnosis of obstructive HCM [14].\nPatients with persistent symptoms, despite optimal medical therapy, are usually considered candidates for septal reduction therapy. The surgical strategy has been often made depending on the patient's preference, physician's experience as well as some special status in a given situation. Compared with ablation, a longer period for recovery will be needed after TAESM because of thoracotomy and cardiopulmonary bypass. However, more and more experienced cardiac surgeons have reported encouraging results about TAESM during past years, which is considered the therapeutic gold standard in many prestigious cardiac centres today, even if alcohol septal ablation develops as another choice for high-risk patients [15–17]. TAESM can be performed safely with very low mortality and excellent long-term survival, which can be equivalent to general population, because the disease course of HCM has been changed thoroughly [6, 16].\nIn our opinion, one of the vital factors that directly determines the outcome of TAESM is the surgeon's clinical experience and anatomical knowledge of the LVOT. In experienced centres, the surgical outcome can be excellent [18]. As is mentioned in the 2011 guideline [1], extended Morrow procedure is a challenging operation in cardiac surgery, so there must be a learning curve before a surgeon can perform it perfectly. During the past 30 years, the largest group of Chinese obstructive HCM patients were treated in our institution. We have experienced a tough learning process and have gradually seen remarkable improvement by borrowing ideas from international communications and clinical exploration. According to our clinical practice, we had a morbidity of ∼7.4%, complete heart block (CHB) of ∼7.4% and MVR of 16.7% between 1996 and 2007. Moreover, the postoperative LVOT gradient was at an average level of 24 mmHg [19]. In the past few years, we have gradually improved the operating skills to tailor resection precisely, by properly increasing the extent of myectomy with precise discrimination, correction/resection of aberrant papillary muscles and mitral subvalvular apparatus abnormalities and using headlamps, long scalpels and forceps. This retrospective study shows that a much better clinical outcome, with a mortality of 0% (0/93), CHB rate of 3.2% (3 of 93), MVR of 10.8% and a mean postoperative LVOT gradient of 14.34 ± 13.44 mmHg, has been obtained since October 2009. Especially for the recent 20 cases, we have obtained results better than the average level, with a postoperative LVOT gradient of 1–9 mmHg.\nAs a significant advantage of TAESM, other associated cardiac diseases can be treated surgically. Patients with or without concomitant surgical procedures can benefit from the operation by means of improved life expectancy and performance status [20]. In this group, concomitant surgical procedures were carried out in 37 patients (39.8%, all for preexisting conditions), including MVP, MVR and CABG. In our clinical practice, coronary angiography was considered a preoperative routine examination for patients over 40, so as to detect coronary atherosclerotic heart disease and myocardial bridge, which might be associated with an unfavourable prognosis in HCM patients and should be treated empirically [21]. So, 18 patients were diagnosed with coronary disease and underwent on-pump CABG immediately after myectomy. All these patients had a good outcome during follow-up.\nAs mitral valve leaflets and subvalvular apparatus abnormalities play an important role in the pathologies of obstructive HCM, surgical management of the mitral valve has been considered a vital part of myectomy [22]. According to the analysis of preoperative echocardiography in this study, SAM was accessed in all and MR in 73 patients (78.5%), of whom 41 were more than moderate level. For many patients, SAM and MR could disappear or diminish automatically after myectomy. However, some patients had mitral valve abnormities, which also need special surgical treatment during the operations, or it would negatively influence the surgical outcome. For them, mitral valve repair or plasty is recommended as the priority choice [23]. According to our practice, MVR can be avoided in most patients with degenerative MR and HCM, and it is indicated only if the mitral valve cannot be repaired because of severe pathological changes such as endocarditis [24] or of other procedures have failed to relieve the LVOT gradient. In this group, SAM disappeared postoperatively including those who had MVP, except only one still had mild SAM but without mitral-septal contact. In this group, MVR was carried out in 10 cases (10 of 93). Six of them had severely damaged mitral valve, which could not be repaired. While for the other four cases, intraoperative TEE showed that the LVOT gradient and SAM had not been resolved perfectly after initial myectomy and MVP, so they had MVR thereafter.\nTAESM can be successfully performed after a history of alcohol ablation treatment. In this group, three cases had histories of alcohol septal ablation performed in the previous 6 months to 4 years. Because the drug-refractory symptoms did not disappear after ablation or recurred later, myectomy was suggested to them when they were readmitted to hospital. They had a successful surgical procedure and uneventful recovery, of whom one had MVR after a failed MVP, the other two had a significant decrease in the LVOT gradient from a preoperative level of 67–133 mmHg (with physiological provocation) to 4–10 mmHg postoperatively. Consequently, a history of alcohol ablation may not adversely affect the surgical outcome of obstructive HCM, but a higher incidence of CHB than in the case of those who underwent only surgical myectomy was observed and reported in another study [10].\nElectrocardiographic changes may be one of the main types of complications after TAESM, including left bundle branch block, intraventricular block and CHB. Unlike RBBB, which is more common after ablation, the left bundle branch block developed in nearly half of the septal myectomy patients [3]. Therefore, those who had complete RBBB preoperatively may have a higher risk of CHB after myectomy. In this retrospective study, three patients (3.2%) developed CHB after myectomy and permanent pacing was needed for them, of whom two had a previous history of complete RBBB. Pacing cannot be regarded as a primary treatment for obstructive HCM [25], but after TAESM, it may be needed with a very low probability in some special patients. Therefore, it is necessary to be alert when surgical myectomy is performed in obstructive HCM patients with RBBB."}