PMC:6019327 / 27131-28099 JSONTXT

{"project":"2_test","denotations":[{"id":"28506916-12681994-29307090","span":{"begin":203,"end":205},"obj":"12681994"},{"id":"28506916-12681994-29307090","span":{"begin":203,"end":205},"obj":"12681994"},{"id":"28506916-15734621-29307091","span":{"begin":336,"end":338},"obj":"15734621"},{"id":"28506916-15734621-29307091","span":{"begin":336,"end":338},"obj":"15734621"},{"id":"28506916-16221266-29307092","span":{"begin":339,"end":341},"obj":"16221266"},{"id":"28506916-16221266-29307092","span":{"begin":339,"end":341},"obj":"16221266"},{"id":"T66656","span":{"begin":203,"end":205},"obj":"12681994"},{"id":"T25073","span":{"begin":203,"end":205},"obj":"12681994"},{"id":"T45741","span":{"begin":336,"end":338},"obj":"15734621"},{"id":"T73790","span":{"begin":336,"end":338},"obj":"15734621"},{"id":"T46585","span":{"begin":339,"end":341},"obj":"16221266"},{"id":"T3178","span":{"begin":339,"end":341},"obj":"16221266"},{"id":"T52662","span":{"begin":203,"end":205},"obj":"12681994"},{"id":"T60294","span":{"begin":203,"end":205},"obj":"12681994"},{"id":"T91936","span":{"begin":336,"end":338},"obj":"15734621"},{"id":"T2296","span":{"begin":336,"end":338},"obj":"15734621"},{"id":"T63313","span":{"begin":339,"end":341},"obj":"16221266"},{"id":"T53782","span":{"begin":339,"end":341},"obj":"16221266"}],"text":"PV anatomy is highly variable between patients (Figure 2). Four distinct PV ostia are present in approximately 60% of patients, whereas variant anatomy is observed in 40% of patients undergoing ablation.67 In approximately 80% of cases, the anterior part of the ostium of the left PVs is common, separated from the appendage by a ridge.68,69 The most frequent type of variant anatomy is a left common PV, and the second most frequent variant anatomy is a right middle PV. Anomalous PVs can also be observed arising from the roof of the atrium. The orifices of the left PVs are located more superior than those of the right PVs. The right superior (RS) PV and the left superior (LS) PV project forward and upward, whereas the right inferior (RI) PV and the left inferior (LI) PV project backward and downward. The RSPV lies just behind the superior vena cava (SVC) or RA, and the left PVs are positioned between the left atrial appendage (LAA) and the descending aorta."}