Comparison of acute changes in left ventricular volume, systolic and diastolic functions, and intraventricular synchronicity after biventricular and right ventricular pacing for heart failure.
ABSTRACT Biventricular pacing (BiV) therapy has recently been shown to improve systolic function and cause reverse remodeling in patients with advanced heart failure with electromechanical delay. In these patients, the benefit of right ventricular (RV)-based pacing was controversial. We compared the acute changes in systolic and diastolic function, left ventricular (LV) volume, and intraventricular synchronicity in BiV pacing, RV pacing, and without pacing (No) by means of echocardiography and tissue Doppler imaging (TDI).
TDI was performed in 33 patients with heart failure after undergoing pacemaker implantation, when the device was randomized to BiV, RV, and no pacing modes.
Systolic function was only improved during BiV pacing, but not during RV pacing. This included ejection fraction (No vs RV vs BiV = 24% +/- 12% vs 25% +/- 10% vs 30% +/- 14%, P =.02 vs No), +dp/dt (P =.01), myocardial performance index (P =.01), and isovolumic contraction time (P =.03). Mitral regurgitation was only reduced during BiV pacing (P =.02). LV early diastolic function was depressed in both RV and BiV pacing, as detected by transmitral flow (97 +/- 34 vs 80 +/- 34 vs 82 +/- 32 cm/s, both P < or =.005) and TDI (mean myocardial early diastolic velocity of 6 basal segments, 3.3 +/- 1.7 vs 2.6 +/- 1.0 vs 2.6 +/- 1.0 cm/s, both P =.01). The LV end-diastolic (187 +/- 86 vs 177 +/- 84 vs 166 +/- 79, P =.003) and end-systolic (146 +/- 77 vs 138 +/- 79 vs 122 +/- 69, P =.003) volumes were only decreased during BiV pacing. For systolic synchronicity, a significant delay in peak systolic contraction in the lateral over the septal wall (171 +/- 37 vs 217 +/- 46 ms, P =.004) was revealed by TDI when there was no pacing. This was abolished by BiV pacing, in which septal contraction was delayed (195 +/- 38 vs 201 +/- 53 ms, P = not significant). However, RV pacing restored the lateral wall delay, and systolic asynchrony reappeared (190 +/- 40 vs 227 +/- 56 ms, P =.01). Diastolic asynchrony between the septal and lateral walls was not evident in these patients and was not affected by either pacing mode.
Only BiV pacing, but not RV pacing, improves systolic function, and reduces mitral regurgitation and LV volumes in patients with heart failure and electromechanical delay. This is attributed to the improvement of systolic synchronicity. Diastolic synchronicity was unaffected, whereas early diastolic function could be jeopardized, by either pacing mode.
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ABSTRACT: Physiologic pacing is an evolving term used to describe different concepts and technologic developments in implantable devices (including pacemakers and defibrillators) over the past several decades. Currently much of the discussion about optimal physiologic pacing involves fairly recently appreciated deleterious effects of traditional right ventricular pacing. Technologic solutions to the goal of avoiding unnecessary ventricular pacing appear to be available and successful. Although much work is being done to find more physiologic ways to pace the ventricles when necessary, the solutions for this goal are less clear.Current Cardiology Reports 10/2007; 9(5):351-7.
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ABSTRACT: BACKGROUND: A meta-analysis of randomized controlled trials (RCTs) was conducted to compare the effects of right ventricular nonapical (RVNA) and right ventricular apical (RVA) pacing on cardiac function. METHODS: A systematic literature search was performed using MEDLINE, EMBASE, and the Cochrane Library to identify RCTs comparing RVNA pacing with RVA pacing with follow-up ≥2 months. Twenty RCTs involving 1,114 patients were included. RESULTS: Compared with RVA pacing, RVNA (mainly right ventricular septum [RVS]) pacing exhibited not only excellent pacing threshold and R-wave amplitude but also higher impedance. RVNA pacing showed a significant increase in left ventricular ejection fraction (LVEF) at the end of follow-up (weighted mean difference = 3.58, 95% confidence interval = 1.80-5.35), and the effects were observed in the following subgroups: 6-month follow-up, ≤12-month follow-up, >12-month follow-up, baseline LVEF ≤45%, and baseline LVEF >45%. RVS and RVA pacing significantly differed in improving LVEF (weighted mean difference = 4.82, 95% confidence interval = 2.78-6.87). In addition, RVNA pacing resulted in a narrower QRS duration, a smaller left ventricular end-systolic volume, and a lower New York Heart Association functional class. CONCLUSIONS: This meta-analysis found that RVNA (mainly RVS) pacing exhibited satisfactory long-term lead performance compared with RVA pacing and demonstrated beneficial effects in improving LVEF after the 6-month follow-up. Furthermore, it proved superior to RVA pacing in terms of interventricular synchrony and cardiac function.Pacing and Clinical Electrophysiology 02/2013; · 1.75 Impact Factor
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ABSTRACT: QRS width and echocardiography-derived indices are limited predictors of response to resynchronization therapy. We applied digital palpography, using vibration resonance imaging, to investigate the effects of right ventricular pacing and left ventricular ejection fraction (LVEF) on mechanical and electrical dyssynchrony. Forty-nine subjects were examined: 24 normal controls, 18 subjects with right ventricular apical pacing (12 with reduced LVEF), and seven subjects with reduced LVEF and narrow QRS. Digital measurement of QRS width was performed. Electric dyssynchrony index (EDI) was measured as the time interval between peak R-waves of the same QRS complex of simultaneously recorded standard limb electrocardiograms, L1 and L2. A matrix of 6 × 6 vibration recording transducers was applied to chest. The interval between the onset of Q-wave and the peak of amplitude vibration for each transducer was measured, and a three-dimensional map for the whole matrix of transducers was generated. Median values (QE1) were measured. Mechanical vibration systolic dyssynchrony index (VSDI) for each subject was determined as the standard deviation of the difference between the median value and each transducer interval. EDI was larger in subjects with right ventricular pacing. Mechanical dyssynchrony indices were larger with pacing and reduced LVEF. EDI correlated with QRS width (r(2) = 0.7), with VSDI (r(2) = 0.42), and with QE1 (r(2) = 0.74). QRS width correlated with QE1 (r(2) = 0.75). Digital chest palpography can determine dyssynchrony indices that are larger in subjects with right ventricular pacing and reduced LVEF and correlate with parameters of electrical dyssynchrony.Pacing and Clinical Electrophysiology 03/2011; 34(7):875-83. · 1.75 Impact Factor