Usefulness of exercise stress echocardiography for predicting cardiovascular events and atrial fibrillation in hypertrophic cardiomyopathy.

Background: In hypertrophic cardiomyopathy (HCM), the determinants of exercise tolerance and the usefulness of exercise stress echocardiography (ESE) for predicting hard endpoints have not been fully investigated. We aimed to assess the key parameters of ESE for exercise tolerance and the factors predictive of cardiovascular events and new-onset atrial fibrillation (AF) in patients with HCM.

Methods: Seventy-four consecutive patients with HCM who underwent ESE and with an ejection fraction ≥50 % were enrolled. The primary endpoint was a composite of cardiovascular death, heart failure hospitalization, ventricular fibrillation or tachycardia, and ventricular assist device implantation. The secondary endpoint was new-onset AF.

Results: The primary endpoint occurred in 13 patients. The left and right ventricular functions during exercise were responsible for decreased exercise tolerance. Peak exercise e' and tricuspid annular plane systolic excursion (TAPSE) significantly predicted increased primary outcome risk (hazard ratio 1.35, 95 % confidence interval 1.10-1.76, p = 0.003; hazard ratio 1.19, 95 % confidence interval 1.07-1.32, p = 0.002, respectively), and the results were consistent even after adjustment by maximum workload. These ESE parameters improved the prognostic model containing estimated glomerular filtration rate (eGFR) and left atrial (LA) volume index. In AF-naive patients (n = 58), LA volume, peak exercise LA reservoir strain, and left ventricular outflow tract (LVOT) pressure gradient predicted new-onset AF.

Conclusions: In patients with HCM, ESE parameters related to left and right ventricular function were responsible for low exercise tolerance. Furthermore, e' and TAPSE at peak workload could be useful for predicting cardiovascular events in addition to eGFR and LA volume index. LVOT pressure gradient and LA function during exercise predicted new-onset AF.