How are the predictors of sudden death modified after septal myectomy surgery?

Background: Hypertrophic cardiomyopathy is a condition associated with an increased risk of sudden death compared to the general population. Extended septal myectomy surgery has been suggested to impact the reduction of sudden death events according to various publications. The aim of this study was to assess changes in the prevalence of sudden death predictors in a population of patients undergoing extended septal myectomy surgery. Methods: Ninety-four consecutive patients underwent extended septal myectomy surgery due to symptomatic hypertrophic cardiomyopathy. Risk factors for sudden death, as defined by the American Heart Association and the European Society of Cardiology, were evaluated before and three months after surgery. Results: The mean age of the population was 57 +/- 13 years. A significant reduction was observed in the maximum septal thickness from 21.3 to 14 mm (p<0.001), along with a decrease in the anteroposterior diameter of the left atrium from 51 to 47 mm (p=0.021). Resting intraventricular gradients decreased from 49.2 to 6.4 mmHg (p<0.001), and Valsalva-induced gradients decreased from 93.9 to 8.7 mmHg (p<0.001). Non-sustained ventricular tachycardia decreased from 6% to 2% (p<0.001), and atrial fibrillation decreased from 30% to 15% (p<0.001). Ischemic behavior during exercise stress echo decreased from 6% to 0%, and the European Society of Cardiology sudden death risk score reduced from 3.32 to 1.44 (p<0.001). Conclusions: In this cohort of hypertrophic cardiomyopathy patients, extended septal myectomy surgery was associated with a reduction in the number and magnitude of sudden death predictors, potentially explaining the reduced mortality reported in the literature.