Genetic Determinants of Ablation Outcome
Because many genetic determinants of AF have been identified, a logical question would be to ask whether genetics can help predict the outcome of an ablation procedure.35 At the present time, however, whether genetics will help predict outcomes remains an unanswered question. Although there have been a number of studies exploring the relation between a genetic variant or single nucleotide polymorphism (SNP) and AF ablation outcome, these studies have been challenged by small sample sizes, testing of a limited number of SNPs, and variable endpoints.
One recent study pooled ablation data from three different sites consisting of 991 individuals of European ancestry.36 They tested representative SNPs at the top three loci (PITX2, ZFHX3, and KCNN3) identified for AF in genome-wide association studies and related these SNPs to ablation outcome. The primary finding was that an SNP, rs2200733, at the chromosome 4q25 or the PITX2 locus for AF was associated with a 1.4-fold increased risk of late AF recurrence. In contrast, another recent study found differing results in a large Korean population of 1068 individuals undergoing catheter ablation for AF.37 This second study tested a similar set of SNPs, representing the PITX2, ZFHX3, and KCNN3 loci, yet they did not observe any long-term difference in AF recurrence after an ablation.
It is possible that the different outcomes noted in these two studies are due to a racial difference in the genetic influence on ablation outcome, although future studies will be necessary to resolve this issue. Larger, prospective, multiethnic studies that test a comprehensive number of SNPs will be necessary before genetic data can be considered clinically useful when considering AF ablation procedures.