Improved left ventricular mechanics from acute VDD pacing in patients with dilated cardiomyopathy and ventricular conduction delay.

BACKGROUND Ventricular pacing can improve hemodynamics in heart failure patients, but direct effects on left ventricular (LV) function from varying pacing site and atrioventricular (AV) delay remain unknown. We hypothesized that the magnitude and location of basal intraventricular conduction delay critically influences pacing responses and that single-site pacing in the delay-activated region yields similar or better responses to biventricular pacing. METHODS AND RESULTS Aortic and LV pressures were measured in 18 heart failure patients (mean+/-SD: LV ejection fraction, 19+/-7%; LV end-diastolic pressure, 25+/-8 mm Hg; QRS duration, 157+/-36 ms). Data under normal sinus rhythm were compared with ventricular pacing (VDD) at varying sites and AV delays (randomized order). Right ventricular (RV) apical or midseptal pacing had negligible contractile/systolic effects. However, LV free-wall pacing raised dP/dtmax by 23.7+/-19.0% and pulse-pressure by 18.0+/-18.4% (P<0.01). Biventricular pacing yielded less change (+12.8+/-9.3% in dP/dtmax, P<0.05 versus LV). Pressure-volume analysis performed in 11 patients consistently revealed minimal changes with RV pacing but increased stroke work and lower end-systolic volumes with LV pacing. Optimal AV intervals averaged 125+/-49 ms, and within this range, AV delay had less influence on LV function than pacing site. Basal QRS duration positively correlated with %DeltadP/dtmax (P<0.005), but pacing efficacy was not associated with QRS narrowing. Conduction delay pattern generally predicted pacing sites with most effect. CONCLUSIONS VDD pacing acutely enhances contractile function in heart failure patients with intraventricular conduction delay. Single-site pacing at the site of greatest delay achieves similar or greater benefits to biventricular pacing in such patients. These data clarify pacing-effect mechanisms and should help in candidate identification for future studies.

[1]  J. Daubert,et al.  Four Chamber Pacing in Dilated Cardiomyopathy , 1994, Pacing and clinical electrophysiology : PACE.

[2]  B Buis,et al.  Continuous measurement of left ventricular volume in animals and humans by conductance catheter. , 1984, Circulation.

[3]  D. Kass.  Clinical evaluation of left heart function by conductance catheter technique. , 1992, European heart journal.

[4]  M. Rosenqvist,et al.  Results of atrioventricular synchronous pacing with optimized delay in patients with severe congestive heart failure. , 1995, The American journal of cardiology.

[5]  J. Morris-Thurgood,et al.  Septal Short Atrioventricular Delay Pacing: Additional Hemodynamic Improvements in Heart Failure , 1994, Pacing and clinical electrophysiology : PACE.

[6]  L. Mestroni,et al.  Beta-adrenergic neuroeffector abnormalities in the failing human heart are produced by local rather than systemic mechanisms. , 1992, The Journal of clinical investigation.

[7]  K. Boheler,et al.  Altered sarcoplasmic reticulum Ca2(+)-ATPase gene expression in the human ventricle during end-stage heart failure. , 1990, The Journal of clinical investigation.

[8]  M. Rousseau,et al.  Effects of asynchrony on myocardial relaxation at rest and during exercise in conscious dogs. , 1988, The American journal of physiology.

[9]  H. Drexler,et al.  Relation between myocardial function and expression of sarcoplasmic reticulum Ca(2+)-ATPase in failing and nonfailing human myocardium. , 1994, Circulation research.

[10]  E L Yellin,et al.  Left ventricular filling dynamics and diastolic function. , 1990, Progress in cardiovascular diseases.

[11]  P. Fletcher,et al.  VDD Pacing at Short Atrioventricular Intervals Does Not Improve Cardiac Output in Patients with Dilated Heart Failure , 1994, Pacing and clinical electrophysiology : PACE.

[12]  J. Blanc,et al.  Evaluation of different ventricular pacing sites in patients with severe heart failure: results of an acute hemodynamic study. , 1997, Circulation.

[13]  A. Tajik,et al.  Mechanism of hemodynamic improvement by dual-chamber pacing for severe left ventricular dysfunction: an acute Doppler and catheterization hemodynamic study. , 1995, Journal of the American College of Cardiology.

[14]  H. Suga,et al.  Logistic time constant of isovolumic relaxation pressure-time curve in the canine left ventricle. Better alternative to exponential time constant. , 1995, Circulation.

[15]  M. Gold,et al.  Acute hemodynamic effects of atrio-biventricular pacing in humans. , 1995, The Annals of thoracic surgery.

[16]  M. Fisher,et al.  Dual-chamber pacing with a short atrioventricular delay in congestive heart failure: a randomized study. , 1995, Journal of the American College of Cardiology.

[17]  J R Jansen,et al.  Computation of aortic flow from pressure in humans using a nonlinear, three-element model. , 1993, Journal of applied physiology.

[18]  D. Gibson,et al.  Effects of dual-chamber pacing with short atrioventricular delay in dilated cardiomyopathy , 1992, The Lancet.

[19]  D. Kass,et al.  Mechanism of acute mechanical benefit from VDD pacing in hypertrophied heart: similarity of responses in hypertrophic cardiomyopathy and hypertensive heart disease. , 1998, Circulation.

[20]  D. Gibson,et al.  What is the role of pacing in dilated cardiomyopathy? , 1996, European heart journal.

[21]  H. Kataoka.  Hemodynamic Effect of Physiological Dual Chamber Pacing in a Patient with End‐Stage Dilated Cardiomyopathy: A Case Report , 1991, Pacing and clinical electrophysiology : PACE.

[22]  K. Sagawa,et al.  Influence of pacing site on canine left ventricular contraction. , 1986, The American journal of physiology.

[23]  R. O'rourke,et al.  Effect of alteration of left ventricular activation sequence on the left ventricular end-systolic pressure-volume relation in closed-chest dogs. , 1985, Circulation research.

[24]  Y Ishida,et al.  Effects of timing of atrial systole on LV filling and mitral valve closure: computer and dog studies. , 1985, The American journal of physiology.

[25]  C. Ng,et al.  Usefulness of physiologic dual-chamber pacing in drug-resistant idiopathic dilated cardiomyopathy. , 1990, The American journal of cardiology.