Right Ventricle Myocardium Contractility as Parameter of Cardiac Resynchronization Efficacy

Aim. To evaluate the significance of the right ventricle (RV) myocardium contractility in assessment of cardiac resynchronization therapy (CRT). Material and methods. Totally, 80 patients included, with dilation cardiomyopathy (49 males, 31 females), mean age 54±10,5 y.o.), heart failure (HF) of III functional class (FC) by NYHA, ejection fraction (EF) of the left ventricle (LV) was 30,1±3,8%, 6-minute walking distance — 290,5±64,3 m, end-diastolic volume (EDV) — 220,7±50,9 mL. Stable sinus rhythm was found in 45 patients, and chronic medication resistant atrial fibrillation — in35. In patients, the disorders of intraventricular conduction were found as the His left bundle branch block with QRS width from 146 ms to 240 ms (183±32 ms). Implanting of the resynchronization device was done by standard method for biventricular electrocardiostimulation. Permanent atrial fibrillation patients, as 2nd step, underwent complete atrioventricular block formation. In all patients, by radionuclide equal tomoventriculography, the contractility was studied, of the left and right ventricle myocardium, before CRT and 12 moths post-procedure. Results. Control study was conducted in 1 year; positive clinical dynamics was noticed: FC of HF decreased from III to II. Clinical responders were 69 patients (86,25%), did not respond 11 (13,75%). As the criteria of the “respond” on CRT we used increased 15% and more EF during 12 months. Among the responders, there was positive clinical dynamics: EF of LV increased from 30,1±3,8% to 42,8±4,8% (p≤0,001), LV EDV decreased from 220,7±50,9 to 197,9±47,8 mL (p≤0,005), in nonresponders EF LV remained almost unchanged: from 30,1±3,8% to 33,8±3,8% (p≤0,001), and EDV of LV increased: 220,7±50,9 to 227,8±27,8 mL (p≤0,001). All participants were retrospectively selected into 2 groups: responders and nonresponders on CRT. Radionuclide tomoventriculography was used for the changes for 12 months ofLV and RV contractility investigation. Maximum filling rate and the mean filling velocity during 1/3 of diastole were significantly worse in the 2nd group patients, by 30% and 60%, respectively. Other parameters in the groups did not differ significantly. Conclusion. Hence, the data points on the relation of RV contractility improvement by CRT with positive cardiac resynchronization, together with the improvement of theLV contractility. Resynchronization in severe chronic HF patients, with saved contractility of the right chambers, is more effective, and higher scintigraphical values of maximum filling rate and the mean filling velocity during 1/3 of diastole might be prognosis criteria of positive response on CRT.