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

Abstract

Background: The interdependence between echocardiographic parameters of left ventricle function, severity of heart failure (HF) and exercise test duration has not been thoroughly examined.
Methods: 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.
Results: 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 (∆At; 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 ∆At (Art–At).
Conclusions: Diastolic parameters showing the strongest correlation with ED (∆At 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 ∆At.