Isolated left ventricular pacing results in worse long-term clinical outcome when compared with biventricular pacing: a single-centre randomized study.

AIMS: The objective of this study was to compare long-term clinical effects of biventricular pacing with isolated left ventricular pacing. METHODS AND RESULTS: Forty consecutive patients with idiopathic dilated cardiomyopathy and indication for cardiac resynchronization therapy were randomized to biventricular or isolated left ventricular pacing. Clinical and echocardiographic parameters were studied regularly prior to implantation and during 1 year of follow-up. Patients with atrial fibrillation were excluded from the study. A retrospective cross-sectional outcome analysis was performed 4 years after the beginning of the study. Biventricular pacing was associated with more pronounced clinical and echocardiographic benefit compared with left ventricular pacing. Biventricular pacing was associated with significantly more distinct reverse remodelling. Left ventricular ejection fraction improved by 12.5 per cent-points (95% CI 7.3-17.7) compared with 5.1 per cent-points (95% CI 1.1-9.2) (P = 0.01) and left ventricular end-diastolic diameter decreased by 8.69 mm (95% CI 5.2-12.2) compared with 5.1 mm (95% CI 1.5-8.7) (P = 0.05) in the biventricular and left-ventricular pacing group, respectively. Semi-quantitative summarization of response points revealed a greater benefit in the biventricular vs. left ventricular pacing group [mean sum of response points 3.25 (95% CI 2.62-3.88) vs. 2.35 (95% CI 1.74-2.96), respectively, P = 0.06]. After 3 years of follow-up, there was no cardiovascular death in the biventricular pacing group compared with three cardiovascular deaths in the left ventricular pacing group. CONCLUSION: In patients with idiopathic dilated cardiomyopathy, biventricular pacing is associated with significantly more pronounced benefit in clinical outcomes and reverse remodelling. A retrospective analysis after 3 years of follow-up suggests that isolated left ventricular pacing may be associated with a higher mortality rate compared with biventricular pacing.

Assessment of left ventricular function in non-dilated and dilated hearts: comparison of contrast-enhanced 2-dimensional echocardiography with multi-detector row CT angiography.

OBJECTIVE: Multidetector-row CT (MDCT) and contrast-enhanced echocardiography (CEE) are being increasingly used for assessment of left ventricular (LV) function. Excellent spatial and contrast resolution of MDCT allows this evaluation along with coronary angiography. CEE improves the accuracy of 2D echocardiography. Data on side-by-side comparison of both techniques for assessment of LV size and function in subjects with a non-dilated or dilated left ventricle are limited. METHODS AND RESULTS: Our study population included 64 patients. Group I included 31 patients with an implanted pacemaker who had a non-dilated left ventricle with preserved systolic function. Group II comprised 33 patients with dilated cardiomyopathy and severe systolic LV dysfunction. LV end-diastolic and end-systolic volumes (LVEDV, LVESV) and ejection fraction (LVEF) were assessed using both CEE and short-axis MDCT. The results obtained by both techniques were compared by linear regression and Bland-Altman analysis. Additionally, intra- and interobserver reproducibility was assessed. Both CEE and MDCT measurements highly correlated (r = 0.61-0.94). However, CEE significantly underestimated LVEDV and LVESV, and this bias was higher with enlarged LV volumes. LVEF was overestimated by CEE in both groups with a higher bias in the group with preserved systolic function. Both intra- and interobserver reproducibility was significantly better for MDCT, the worst reproducibility was observed for CEE in group I. CONCLUSION: Despite a high correlation between MDCT and CEE measurements, CEE provides consistently lower volumes and higher LVEF. This suggests that both methods are not completely interchangeable. Reproducibility of CEE is inferior to reproducibility of MDCT, especially in non-dilated left ventricles with preserved function.