Relationship between echocardiographic parameters and exercise test duration in patients after myocardial infarction

The interdependence between echocardiographic parameters of left ventricle function, severity of heart failure (HF) and exercise test duration has not been thoroughly examined.

We compared echocardiographic data in patients after myocardial infarction divided according to NYHA class to mild (class I and II, group 1 = 24 subjects) and advanced HF group (III and IV, group 2 = 36) and assessed their correlation with exercise duration (ED) in a symptom-limited treadmill test. Then we tried to determine independent predictors of ED.

The group with advanced HF had lower left ventricle ejection fraction, shorter duration and deceleration times of both mitral inflow waves (Et and At, Edt and Adt) and higher E/A ratio (1.4 +/- 1.1 vs. 0.9 +/- 0.4; p < 0.05) with more frequent restriction and pseudonormalization pattern (56% vs. 12%). Also early wave propagation (21 +/- 7 vs. 29 +/- 11 cm/s; p < 0.001) and all tissue Doppler velocities were lower, but ratio of early wave peak velocity to early diastolic velocity of mitral annulus was higher (E/E' 10.5 +/- 5 vs. 6.1 +/- 1.3 for velocity ratio; p < 0.001) in subjects with more severe clinical symptoms. Significant negative correlation with ED was observed for difference between duration of pulmonary vein atrial reversal flow and atrial wave of mitral inflow (DeltaAt; r = -0.54) and for E/E' ratio (r = -0.48), the highest positive correlation for left ventricular ejection fraction and duration of mitral inflow atrial phase (EF; r = 0.48, At; r = 0.46). In multivariate stepwise regression analysis two independent predictors of ED were identified: age and DeltaAt (Art-At).

Diastolic parameters showing the strongest correlation with ED (DeltaAt and E/E') are connected with restrictive left ventricle physiology. The only independent predictors of exercise duration in patients after myocardial infarction were: age and DeltaAt.