Predictors of atrial fibrillation occurrence in patients with hypertrophic cardiomyopathy

Abstract

Abstract Introduction Patients with hypertrophic cardiomyopathy (HCM) are at increased risk of dysrhythmias, especially atrial fibrillation (AF). Purpose The aim of this study was to evaluate the incidence of AF in HCM patients (P) and to determine predictors of AF. Methods Retrospective analysis of HCM P at a single tertiary center. Baseline clinical, echocardiographic and cardiovascular magnetic resonance (CMR) characteristics were collected. On follow up AF was identified by electrocardiogram and/or 24 hours Holter monitoring. Results 61P (59% male) were included, with a mean age of 58±2 years. 27.9% had angina (all of them CCS 2), 34.4% were in NYHA II and 14.8% in NYHA III, 8.2% had syncope and 39.3% had palpitations. A family history of sudden cardiac death (SCD) or cardiomyopathy was present in 40.4% of the cases. The mean HCM risk SCD score was 3.35±0.28%. On echocardiography left atrium (LA) diameter was 44.86±0.87mm, LA volume (LAvol) was 89.97±5.39mL (indexed LAvol 46.05±2.55mL/m2), interventricular septum (IVS) was 16.83±0.663mm, left ventricle (LV) mass was 290.94±13.897g and maximum wall thickness (MWT) was 20.59±0.596mm. 77% P had LA enlargement. 88.5%P had late gadolinium enhancement (LGE) in CMR with a median number of 5±7 segments involved. AF developed in 23P (37.7%), with a mean age of 58±3 years. Predictors of AF development were NYHA III (p=0.007), risk score (p=0.007), LA diameter (p=0.007), LAvol (p=0.005) and indexed LAvol (p=0.002), MWT (p=0.0015), LGE in more than 5 segments (p=0.029) and LGE in the inferior basal and inferior median IVS (p=0.033 and p=0.042). The only independent predictor was LAvol (p=0.0012), with an area under the curve of 0.755 and a cut off of 85.9mL being the best predictor (p=0.004). Combining LAvol >85.9mL with LGE involving >5 segments and LAvol >85.9mL with LGE in inferior basal IVS (IBIVS) a statistically significant difference between groups was achieved (p=0.009 in the combined predictor LAvol + LGE >5 segments and p=0.002 in the combined predictor LAvol + LGE in IBIVS) (figure 1 and figure 2). In a multivariable analysis including these 2 combined predictors and LAvol alone the only independent predictor was the combination of LAvol + IBIVS involvement. Conclusion AF is frequent in patients with HCM and develops in younger ages than in general population. NYHA III, risk score, LA diameter, LAvol, MWT, LGE >5 segments and LGE in IBIVS and in IMIVS were predictors of AF, with LAvol being the independent predictor. The combination of LAvol with LGE >5 segments and LAvol with LGE in IBIVS presented stronger predictor value comparing with these characteristics alone. Funding Acknowledgement Type of funding source: None