Comparison of acute changes in left ventricular volume, systolic and diastolic functions, and intraventricular synchronicity after biventricular and right ventricular pacing for heart failure

Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, 00, Hong Kong
American heart journal (Impact Factor: 4.46). 05/2003; 145(5):E18. DOI: 10.1016/S0002-8703(03)00071-1
Source: PubMed


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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    International Journal of Cardiology 07/2014; 176(1). DOI:10.1016/j.ijcard.2014.06.037 · 4.04 Impact Factor
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    ABSTRACT: Heart failure is a major epidemic. Many people with heart failure struggle with refractory symptoms despite optimal medical therapy. Those with severe left ventricular dysfunction and ventricular conduction delay are at significant risk from either dying suddenly or dying from progression of their heart failure. Cardiac resynchronization therapy (CRT) improves hemodynamics and symptoms of heart failure and has recently been shown to improve survival. One problem facing the use of CRT is that 30% of patients fail to respond. The dominant theory is that QRS duration (electrical dyssynchrony) does not accurately reflect mechanical dyssynchrony. Echocardiographic tools have recently been developed that enable clinicians to assess the degree of mechanical dyssynchrony in patients being considered for CRT. These tools are able to predict with a significant amount of accuracy whether a patient will respond to CRT. This allows for a more refined approach to evaluating patients for CRT and optimizing the treatment of congestive heart failure.
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