Detection of ischemical dyssynchrony in patients with normal duration of QRS at rest and during exercise echocardiography (Dyssynchrony in coronary artery disease patients during exercise)

Aim. Ischemic segments cannot develop a sufficient amount of strength during systole, so theoretically they begin to contract later in comparison with non-ischemic zones. There is a lack of information about methods that can detect dyssynchrony during exercise in patients with QRS not longer 100 ms. The aim of the study was to compare different methods of detection regarding left ventricular moving dyssynchrony in patients with significant coronary stenosis artery lesions: pulsed-wave of PW-TDI, strain (S) and strain rate (SR). Methods. The study included 133 subjects: 106 consecutive patients who were scheduled for coronary angiography with previous stress-echocardiography and 27 healthy persons. All the patients underwent a supine bicycle exercise test. Results. Seventy-six patients had stenoses and 30 subjects had no significant lesions by coronary angiography. There was a detectable difference between time parameters of left ventricle contraction for the two groups and controls before and during exercise using all Doppler methods. Subgroups of patients without previous myocardial infarction and without hypertrophy of left ventricle had the same results. Maximal difference was observed using strain method. There was a moderate correlation between time parameters and the existence of significant lesions of coronary arteries. Conclusion. Patients without prolongations of QRS with significant lesions of coronary arteries have detectable left ventricular dyssynchrony before and during exercise.