Left ventricular lead electrical delay predicts response to cardiac resynchronization therapy
ABSTRACT Intracardiac electrograms can be used to guide left ventricular (LV) lead placement during implantation of cardiac resynchronization therapy (CRT) devices. Although attempts often are made to ensure that the LV lead is positioned at a site of maximal electrical delay, information on whether this is useful in predicting the acute hemodynamic response and long-term clinical outcome to CRT is limited.
The purpose of this study was to assess the ability of intracardiac (electrogram) measurements made during LV lead placement in patients undergoing CRT for predicting acute hemodynamic response and long-term clinical outcome to CRT.
Seventy-one subjects with standard indications for CRT underwent electrogram measurements and echocardiograms performed in the acute phase of this study. The LV lead electrical delay was measured intraoperatively from the onset of the surface ECG QRS complex to the onset of the sensed electrogram on the LV lead, as a percentage of the baseline QRS interval. Echocardiographic assessment of the hemodynamic response to CRT was measured as an intra-individual percentage change in dP/dt over baseline (DeltadP/dt, derived from the mitral regurgitation Doppler profile) with CRT on and off. dP/dt was measurable in 48 subjects, and acute responders to CRT were defined as those with DeltadP/dt >or=25%. Long-term response was measured as a combined endpoint of hospitalization for heart failure and/or all cause mortality at 12 months. Time to the primary endpoint was estimated by the Kaplan-Meier method, with comparisons made using the log rank test.
LV lead electrical delay correlated weakly with DeltadP/dt of the combined group (n = 48, r = 0.311, P = .029) but was strongly correlated with DeltadP/dt in the nonischemic subgroup (n = 20, r = 0.48, P = .027). LV lead electrical delay (%) was significantly longer in acute responders (69.6 +/- 23.9 vs 31.95 +/- 11.57, P = .002) among patients with nonischemic cardiomyopathy. A reduced LV lead electrical delay (<50% of the QRS duration) was associated with worse clinical outcome within the entire cohort (hazard ratio: 2.7, 95% confidence interval: 1.17-6.68, P = .032) as well as when stratified into ischemic and nonischemic subgroups.
Measuring LV lead electrical delay is useful during CRT device implantation because it may help predict hemodynamic response and long-term clinical outcome.
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ABSTRACT: The objective of the present study was to evaluate the usefulness of a left ventricle (LV) quadripolar lead in improving the hemodynamic response to cardiac resynchronization therapy (CRT). We included 27 consecutive patients implanted with a CRT device with an LV quadripolar lead. Hemodynamic parameters were evaluated at 3-month follow-up by using impedance cardiography. We assessed the highest cardiac output and the highest stroke volume (SV) obtained after atrioventricular and interventricular optimization with pacing from each of the four electrodes of the LV lead. Each patient was evaluated according to three different pacing configurations: unipolar-simulated, bipolar, and quadripolar. Biventricular pacing improved hemodynamics in comparison to the nonpaced measurements: cardiac index (CI): 2.69 L/min/m(2) versus 2.17 L/min/m(2) (P = 0.001). The hemodynamic response was highest in the quadripolar in comparison to unipolar-simulated and bipolar configurations, with an increase of 29%, 23%, and 27%, respectively, in relation to the reference CI and with an increase of 22%, 11%, and 18%, respectively, in relation to the reference indexed SV (P < 0.05, for the comparison between unipolar-simulated and quadripolar configurations). Twelve patients (44%) showed the best hemodynamic response by pacing from any of the two distal electrodes and 15 patients (56%) by pacing from the two proximal electrodes. Finally, CRT responder rates were higher in quadripolar versus bipolar and unipolar-simulated configurations: 90%, 85%, and 75%, respectively. The quadripolar LV lead was associated with a better hemodynamic response and higher CRT responder rates when compared with unipolar-simulated and bipolar LV leads. ©2014 Wiley Periodicals, Inc.Pacing and Clinical Electrophysiology 12/2014; 38(3). DOI:10.1111/pace.12545 · 1.25 Impact Factor
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ABSTRACT: This study compares, from a prospective, observational, non-randomized registry, the post-implant hospitalization rates and associated healthcare resource utilization of cardiac resynchronization therapy-defibrillator (CRT-D) patients with quadripolar (QUAD) vs. bipolar (BIP) left ventricular (LV) leads.Europace 11/2014; 17(1). DOI:10.1093/europace/euu290 · 3.05 Impact Factor
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ABSTRACT: Small single-center comparative studies suggest improved outcomes in cardiac resynchronization therapy (CRT) patients implanted with a quadripolar left ventricular (LV) lead in comparison with non-quadripolar (bipolar) leads. This study represents the first large multicenter prospective registry comparing implant and 6-month postoperative lead performance following CRT-defibrillator (CRT-D) implantation with quadripolar vs. bipolar leads. During a 39-month period, 418 consecutive patients having CRT-D implantation attempts with either a quadripolar (n = 230) or bipolar LV lead (n = 188) were enrolled in the registry. The primary outcome of the study was LV lead failure defined as any abnormality, excluding infection, resulting in surgical lead revision or CRT termination. Additionally, operative and follow-up data were analyzed for significant difference between groups. Baseline characteristics of both groups were similar. In 72.9 % of quadripolar leads versus 65.0 % of bipolar leads, the LV lead successfully engaged the predefined ideal target side branch (p = 0.47). Implant duration and fluoroscopy times were significantly shorter when a quadripolar lead was used (p = 0.007 and p = 0.001, respectively). The primary end point occurred in six patients (2.7 %) in the quadripolar group and in 14 patients (8.0 %) in the bipolar group (p = 0.02). Clinically significant phrenic nerve stimulation (PNS) occurred in 4.6 vs. 14.2 % of quadripolar vs. bipolar patients, respectively (p = 0.002); all PNS were resolved noninvasively through programming in the quadripolar group vs. 84 % in bipolar group (p = 0.75). The use of a bipolar lead was associated with a higher risk of surgical LV lead revision (6.3 vs. 2.3 %; p = 0.057) and a higher incidence of dislodgment (5.7 vs. 2.7 %; p = 0.16). This multicenter study demonstrates that the use of a quadripolar LV lead results in significantly lower rates of lead-related problems and reduced procedural and fluoroscopic times for biventricular system implantation. This has important implications for LV pacing lead choice.Journal of Interventional Cardiac Electrophysiology 12/2014; 42(1). DOI:10.1007/s10840-014-9956-1 · 1.55 Impact Factor