Papillary muscle free strain- promosing parameter to predict sudden cardiac death in hypertrophic cardiomyopathy?

Hypertrophic Cardiomyopathy (HCM) generally have a good prognosis.In the long follow-up study over 5 decades annual overall HCM-related mortality was 1.3%/y (0.7% first decade to 1.8% in second and third decades).The sudden cardiac death (SCD) mortality rate was also low (0.1%/y first decade to 0.44% in second and third decades) 1 .SCD is the most feared HCM complication and the only effective treatment for this is Implantable Cardioverter Defibrillator (ICD) that is responsible for >10-fold decrease in HCM related mortality 2 .In 2014,the European Society of Cardiology (ESC) come out with risk score comprising 7 variables but this risk score have low sensitivity 3,4 .This led to the search for additional risk factors such as percentage of late gadolinium enhancement (LGE) in the left ventricle, presence of apical aneurysm and left ventricle ejection fraction <50% .The American Society of Cardiology/American Heart Association (ACC/AHA) incorporate this for their guidelines in 2020 5 .Eventhough this guidelines have high sensitivity, it have low ability to identify low risk patients which can lead to inappropriate ICD implantation 4 .The ongoing challenge is to identify the small yet significant group of patients who are at risk of sudden cardiac death, heart failure, and death resulting from heart failure.Neither the 2014 nor the 2020 SCD risk calculators/predictors, nor even the latest 2022 ESC guidelines, have incorporated the relatively new echocardiography technique of speckle-tracking strain measurements.This technique is non-doppler oriented, angle independent and have been shown to be highly reproducible with