tailieunhanh - Ebook Cardiac resynchronization therapy: Part 2

(BQ) Part 2 book "Cardiac resynchronization therapy" presents the following contents: Optimization of the interventricular (V-V) interval during cardiac resynchronization therapy, complications of cardiac resynchronization therapy, asynchrony in coronary artery disease, cardiac resynchronization therapy in right bundle branch block,. | 12 Optimization of the interventricular V-V interval during cardiac resynchronization therapy S Serge Barold Arzu Ilercil Stéphane Garrigue and Bengt Herweg Programmability of the interventricular interval Pathophysiologic basis for programming the V-V interval Clinical studies of V-V interval programming General considerations Effect of V-V timing on the ECG of biventricular pacemakers Automatic device-based optimization of the V-V delay PROGRAMMABILITY OF THE INTERVENTRICULAR INTERVAL The methods for atrioventricular AV optimization in patients receiving cardiac resynchronization therapy CRT are almost universally used for programming the optimal interventricular V-V Conventional M-mode echocardiography for the measurement of left ventricular LV dyssynchrony using septal-to-posterior wall motion delay may be unreliable and poorly Determination of the extent of residual LV dyssynchrony after V-V programming requires more sophisticated echocardiographic techniques such as tissue Doppler techniques peak velocity time difference delayed longitudinal contraction score etc. three-dimensional 3D echocardiography and automatic endocardial border Contemporary biventricular devices permit programming of the V-V interval usually in steps from 80 ms LV first to -80 ms right ventricle RV first to optimize LV hemodynamics. This design was the result of cogent pathophysiologic considerations that simultaneous activation of the two ventricles for CRT was PATHOPHYSIOLOGIC BASIS FOR PROGRAMMING THE V-V INTERVAL Perego et al13 advanced arguments that the best mechanical efficiency in CRT is not necessarily achieved by simultaneous pacing of the two ventricles hence the importance of programmability of the V-V interval Figure 1. In normal hearts activation of the two ventricles does not occur simultaneously . epicardial RV depolarization starts a few milliseconds earlier than LV 15 2. In CRT epicardial LV