Calculated Risk for Sudden Cardiac Death in Patients with Apical Versus Nonobstructive Nonapical Hypertrophic Cardiomyopathy

There are limited and conflicting data regarding the prognosis of patients with apical hypertrophic cardiomyopathy (HC) and their risk for sudden cardiac death (SCD). We used data from a single tertiary center for comparing the clinical course and the calculated risk for SCD in patients with nonobstructive apical HC (apical HC) versus patients with nonobstructive, nonapical HC (NONA HC). The 5-year SCD risk was calculated based on the HC risk-SCD tool. A total of 109 patients were included in the cohort of whom 44 (40%) patients were diagnosed with apical HC. The majority of patients were males with a median age at diagnosis of 40 years (interquartile range 26, 59 years). Patients with apical HC had a significant lower calculated 5-year risk for SCD compared with patients with NONA HC (2.65 ± 2.2% vs 4.00 ± 3.5%, respectively, p = 0.017), primarily due to a lower incidence of familial SCD (20% vs 43% respectively, p = 0.014). Only 9% of patients with apical HC had a calculated risk of >6% (implantable cardioverter-defibrillator recommended), as compared with 23% of patients with NONA HC. During a median follow-up of 1,018 days (interquartile range 546, 1449 days), apical HC patients tended to develop less malignant ventricular arrhythmia episodes compared with NONA HC patients (0% vs 7.7%, respectively, p = 0.060). In conclusion, apical HC patients have a lower calculated risk of SCD compared with NONA HC patients, mainly due to a lower incidence of family history of SCD. Thus, apical HC should be considered a form of HC less prone to SCD.