Novel method of biventricular pacemaker optimization by radial artery tonometer. A case report.

Echocardiographic guided pacemaker optimization leads to significant improvement in cardiac function among nonresponders to cardiac resynchronization treatment (CRT). Simpler, noninvasive determination of cardiac function during biventricular pacemaker programming may simplify this procedure. In this report we describe a 73 year old male patient who presented with recent onset NYHA class III symptoms 7 months post-CRT for ischemic cardiomyopathy. During pacemaker optimization using A-pacing at 60 bpm, optimal atrioventricular (AV) delay was found to be 290 ms by both pulsed wave (PW) echo Doppler as well as by the simultaneously measured radial artery pulse waveform analysis by tonometry. No discernable atrial mechanical activity was visible despite presence of sinus rhythm up to an AV delay of 190 ms. Further improvement in cardiac function and decrease in mechanical dyssynchrony was shown with VV optimization by tissue Doppler imaging (TDI). Our report emphasizes the need for individualized biventricular pacemaker optimization post-CRT and that concomitant assessment via radial artery pulse waveform analysis by tonometry along with PW and TDI may provide additional information during pacemaker programming to assist in pacemaker optimization.

Echocardiography in cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a new treatment modality for eligible patients with congestive heart failure (CHF). The premise of CRT is that it decreases inter and intra ventricular inhomogeneity during systolic contraction thereby improving efficiency of cardiac pump function. Presence of cardiac dyssynchrony appears to be a prerequisite for a response to CRT. Traditionally this inhomogeneity in contraction has been determined by electrocardiographic QRS widening. More recently several echocardiographic methods of assessment of dyssynchrony have become available. These methods utilize conventional M-mode and pulsed wave (PW) Doppler as well tissue Doppler imaging (TDI) METHODS: These echocardiographic parameters have been shown to be more important predictors of response to CRT than conventional QRS widening. This article will discuss echocardiographic methods of assessment of dyssynchrony and their role in predicting response to CRT. In addition role of echocardiography in post CRT pacemaker programming will also be discussed.

Predictors of reduction in mitral regurgitation in patients undergoing cardiac resynchronisation treatment.

BACKGROUND: CRT causes reduction in MR due to left ventricular (LV) remodelling, but determinants of clinically meaningful MR reduction acutely after CRT have not been evaluated. OBJECTIVES: We evaluated echocardiographic predictors of significant reduction in functional mitral regurgitation (MR) by cardiac resynchronisation treatment (CRT). METHODS: 35 patients with >or= moderate to severe MR underwent CRT for presence of electrical and/or mechanical dyssynchrony. Significant reduction in MR post-CRT was defined as reduction to less than moderate MR (MR jet area/left atrial area <25%, group 1) on follow-up echocardiogram at 1.7 (SD 2.8) months post-CRT. RESULTS: Significant MR reduction of 62% (28%) from baseline MR occurred in 18 patients vs 22% (16%) in the remaining patients (group 2), p<0.01). Follow-up left ventricular ejection fraction (LVEF) was 0.43 (0.09) in group 1 patients vs 0.29% (0.1%) in group 2 patients (p<0.001). On multivariate analysis, time to peak strain in the mid inferior segment was the only significant predictor of MR reduction post-CRT (p = 0.008, OR = 1.023 (CI 1.006 to 1.041). The sensitivity and specificity of the combined variable of time to peak strain of >400 ms in the mid inferior segment and peak negative strain of >or=9% and 8% in the basal and mid posterior segments, respectively, to predict follow-up MR was 88% and 93% respectively and positive and negative predictive value was 94% and 87%. CONCLUSION: In patients with cardiomyopathy and significant MR, the presence of delayed longitudinal strain in the mid inferior LV segment along with preserved negative systolic strain in the basal and mid posterior segments predicts substantial reduction in MR post-CRT.