Helical distribution of hypertrophy in patients with hypertrophic cardiomyopathy: prevalence and clinical implications.

Recently a novel pattern of helical distribution of hypertrophy has been described in patients with hypertrophic cardiomyopathy (HCM). Our aim was to determine its prevalence and potential implications in an unselected cohort. One-hundred- and eight consecutive patients diagnosed with HCM by cardiac magnetic resonance (CMR) were included (median clinical follow up of 1718 days). All clinical and complementary test information was prospectively collected. The presence of a helical pattern was assessed by a simple measurement of the maximal left ventricle (LV) wall thickness (LVWT) for each of the 17 classical LV segments and it was classified in one of three types according to its extension. A helical distribution was detected in 58% of patients, and was associated to a higher incidence of left ventricular outflow tract obstruction (LVOT; 35% vs. 10%; p = 0.005) and systolic anterior motion of the mitral valve (SAM; 30% vs. 13%, p = 0.053). No significant difference in the maximal LVWT was observed. However, the presence of a helical pattern showed a significant association with non sustained ventricular tachycardia (NSVT; 22% vs. 7%; p = 0.029) and was associated to a higher risk of sudden cardiac death (SCD) calculated with the European society of cardiology (ESC) calculator (p = 0.006). Notably, patients with a more extense spiral had a higher incidence of heart failure (75% vs. 34%, p = 0.012) and all-cause death (21 vs. 3%, p = 0.049). A helical pattern is frequent in HCM and can be readily assessed on CMR standard cine sequences. In conclusion, a helical pattern carries negative clinical implications and is associated to a higher estimated risk of SCD.