Effect of Pacing Chamber and Atrioventricular Delay on Acute Systolic Function of Paced Patients With Congestive Heart Failure

Abstract

Background-Previous studies of pacing therapy for dilated congestive heart failure (CHF) have not established the relative importance of pacing site, AV delay, and patient heterogeneity on outcome. These variables were compared by a novel technique that evaluated immediate changes in hemodynamic function during brief periods of atrial-synchronous ventricular pacing. Methods and Results-Twenty-seven CHF patients with severe left ventricular (LV) systolic dysfunction and LV conduction disorder were implanted with endocardial pacing leads in the right atrium and right ventricle (RV) and an epicardial lead on the LV and instrumented with micromanometer catheters in the LV, aorta, and RV. Patients in normal sinus rhythm were stimulated in the RV, LV, or both ventricles simultaneously (BV) at preselected AV delays in a repeating 5-paced/15-nonpaced beat sequence. Maximum LV pressure derivative (LVϩdP/dt) and aortic pulse pressure (PP) changed immediately at pacing onset, increasing at a patient-specific optimal AV delay in 20 patients with wide surface QRS (180Ϯ22 ms) and decreasing at short AV delays in 5 patients with narrower QRS (128Ϯ12 ms) (PϽ0.0001). Overall, BV and LV pacing increased LVϩdP/dt and PP more than RV pacing (PϽ0.01), whereas LV pacing increased LVϩdP/dt more than BV pacing (PϽ0.01). Conclusions-In this population, CHF patients with sufficiently wide surface QRS benefit from atrial-synchronous ventricular pacing, LV stimulation is required for maximum acute benefit, and the maximum benefit at any site occurs with a patient-specific AV delay. (Circulation. 1999;99:2993-3001.)

Short-Term Effects of Right-Left Heart Sequential Cardiac Resynchronization in Patients With Heart Failure, Chronic Atrial Fibrillation, and Atrioventricular Nodal Block

“…Myocardial relaxation is influenced by chamber load and homogeneity of activation. [15][16][17][18] In previous work, we did not find an improvement in ventricular relaxation with resynchronization therapy, 4 and Auricchio et al 5 found that CRT had only a modest effect on relaxation. This may, however, reflect the more complex influence of Figure 3.…”

“…Such studies have been performed in patients with sinus rhythm and with an existing intraventricular conduction defect. 4,5,9 The mechanisms by which LV-only pacing works remain somewhat controversial. 10 Fusion with electrical activity from the AV node is a possibility [11][12][13] ; however, experimental data have suggested that electrical synchrony is not a prerequisite for mechanical synchrony.…”

“…This was somewhat at odds with data showing that LV-only pacing (maximal LV preactivation) yields results similar to those with BiV. 4,5 Indeed, Perego et al 3 found improved systolic function with sequential compared with simultaneous pacing only with LV preactivation. Our results support such asymmetry, favoring LV preactivation for sequential CRT.…”

Optimal site selection and image fusion guidance technology to facilitate cardiac resynchronization therapy

“…However, at present 30% of patients fail to respond clinically through improved quality of life, exercise capacity and New York Heart Association (NYHA) functional classification of HF and up to 50% show no beneficial changes in cardiac function [3]. Suboptimal LV lead position is a common culprit when evaluating poor outcomes after CRT [4–7]. Equally, several groups have reported enhanced response rates when targeting tissue which displays evidence of favorable viability [8–11] or advantageous mechanical [12–18] or electrical [19–23] properties.…”

Aortic recoarctation as the source of arterial embolism 32 years after synthetic patch angioplasty

“…1 2 Following encouraging results from acute haemodynamic studies, [3][4][5][6] several groups initiated pilot studies of permanent biventricular pacing. 7 8 Results from those open, non-randomised trials were encouraging, revealing a significant improvement in New York Heart Association (NYHA) functional classification, exercise tolerance, and quality of life in those patients.…”