Exercise capacity in hypertrophic cardiomyopathy depends on left ventricular diastolic function

Area of Science:

• Cardiology
• Echocardiography
• Cardiovascular Physiology

Background:

• Left ventricular (LV) diastolic dysfunction is implicated in reduced exercise capacity in hypertrophic cardiomyopathy (HC).
• Accurate prediction of exercise capacity is crucial for managing HC patients.

Purpose of the Study:

• To evaluate the predictive capability of echocardiographic diastolic function indexes for exercise capacity in HC patients.
• To identify specific echocardiographic parameters that correlate with exercise tolerance in HC.

Main Methods:

• Fifty-two drug-naïve HC patients underwent M-mode and Doppler echocardiography to assess diastolic function.
• Measurements included left atrial fractional shortening and pulmonary venous flow velocities.
• Exercise capacity was quantified using maximum oxygen consumption (VO2 max) via cardiopulmonary exercise testing.

Main Results:

• Maximum oxygen consumption significantly correlated with left atrial fractional shortening and pulmonary venous diastolic velocity.
• Stepwise regression identified left atrial fractional shortening and pulmonary venous systolic filling fraction as independent predictors of VO2 max.
• Doppler-derived transmitral flow indexes did not correlate with exercise capacity.

Conclusions:

• Passive left ventricular diastolic function, assessed by left atrial M-mode and pulmonary venous Doppler, is a primary determinant of exercise capacity in HC.
• These echocardiographic parameters offer valuable insights into exercise limitation in hypertrophic cardiomyopathy.