Left-ventricular outflow tract acceleration time is associated with symptoms in patients with obstructive hypertrophic cardiomyopathy

Aims: Not all obstructive hypertrophic cardiomyopathy (HCM) patients are symptomatic. The relation between obstructive HCM and symptoms is not well understood. The hypothesis of this study is that left-ventricular outflow tract (LVOT) acceleration time (AT) is associated with symptoms. Methods: We included 187 patients (61% men, mean age 55 ± 14 years) with obstructive HCM, defined as a maximal wall thickness ≥ 15 mm and a resting or provoked LVOT peak gradient ≥ 30 mmHg. Peak velocity (PV), left-ventricular (LV) ejection time (ET), and AT (the time between LVOT flow onset and the moment of PV) were measured on continuous-wave (CW) Doppler tracings. Logistic and Cox proportional hazard regression analyses were used to evaluate the relation between symptoms [New York Heart Association (NYHA) class ≥ II] and echocardiographic measurements, including AT. Reproducibility was assessed using the intraclass correlation coefficient (ICC). Results: Symptomatic patients were more often female and had higher mean AT values. Logistic regression demonstrated a significant association between AT and symptomatic status (odds ratio 1.31 per 10 ms, p < 0.01) after adjustment for sex, negative inotropes, PV, LVOT diameter, and diastolic dysfunction. AT was independently associated with symptoms and septal reduction during follow-up (hazard ratio 1.09 per 10 ms, p < 0.05). The ICC was 0.98 with a mean difference of 0.28 ± 8.4 ms. Conclusion: In obstructive HCM patients, increased AT is significantly related to symptoms after adjustment for sex, negative inotropes, PV, LVOT diameter, and diastolic dysfunction, and is associated with the symptomatic status during follow-up. AT represents an easily measured echocardiographic variable with excellent inter-reader reproducibility.