Background/aim: Cardiac resynchronization therapy (CRT) improves ventricular dyssynchrony and is associated with an improvement in symptoms, quality of life and prognosis in patients with severe heart failure and intraventricular conduction delay. Different pacing modalities produce variable activation patterns and may be a cause of different haemodynamic changes. The aim of our study was to investigate acute haemodynamic changes with different CRT configurations during optimization procedure.
Methods: This study included 30 patients with severe left ventricular systolic dysfunction and left bundle branch block with wide QRS (EF 24.33 +/- 3.7%, QRS 159 +/- 17.3 ms, New York Heart Association III/IV 25/5) with implanted CRT device. The whole group of patients had severe mitral regurgitation in order to measure dP/dt. After implantation and before discharge all the patients underwent optimization procedure guided by Doppler echocardiography. Left and right ventricular pre-ejection intervals (LVPEI and RVPEI), interventricular mechanical delay (IVD) and the maximal rate of ventricular pressure rise during early systole (max dP/dt) were measured during left and biventricular pacing with three different atrioventricular (AV) delays.
Results: After CRT device optimization, optimal AV delay and CRT mode were defined. Left ventricular pre-ejection intervals changed from 170.5 +/- 24.6 to 145.9 +/- 9.5 (p < 0.001), RVPEI from 102.4 +/- 15.9 to 119.8 +/- 10.9 (p < 0.001), IVD from 68.1 +/- 18.3 to 26.5 +/- 8.2 (p < 0.001) and dP/dt from 524.2 +/- 67 to 678.2 +/- 88.5 (p < 0.01).
Conclusion: In patients receiving CRT echocardiographic assessment of the acute haemodynamic response to CRT is a useful tool in optimization procedure. The variability of Doppler parameters with different CRT modalities emphasizes the necessity of individualized approach in optimization procedure.