Key result
Right ventricular pacing reduced left ventricular outflow tract gradient by 35% in blinded randomized controlled trials, with a non-significant trend toward improved NYHA class.
Why the study?
Right ventricular pacing for left ventricular outflow tract gradient reduction in hypertrophic obstructive cardiomyopathy remains controversial.
Does right ventricular pacing reduce left ventricular outflow tract gradient in adults with hypertrophic obstructive cardiomyopathy?
Meta-Analysis (n=1,135)
Does right ventricular pacing reduce left ventricular outflow tract gradient in adults with hypertrophic obstructive cardiomyopathy?
Right ventricular pacing effectively reduces LVOT gradient in HOCM, but the massive symptomatic benefits reported in observational studies are largely driven by bias, highlighting the need for more blinded RCTs.
Answers are grounded in this paper and cite their sources.
Confirms modest LVOT gradient reduction with right ventricular pacing in HOCM via blinded RCTs; challenges observational overestimation of symptomatic benefits.
AIMS: Right ventricular pacing for left ventricular outflow tract gradient reduction in hypertrophic obstructive cardiomyopathy remains controversial. We undertook a meta-analysis for echocardiographic and functional outcomes. METHODS AND RESULTS: Thirty-four studies comprising 1135 patients met eligibility criteria. In the four blinded randomized controlled trials (RCTs), pacing reduced gradient by 35% [95% confidence interval (CI) 23.2-46.9, P < 0.0001], but there was only a trend towards improved New York Heart Association (NYHA) class [odds ratio (OR) 1.82, CI 0.96-3.44; P = 0.066]. The unblinded observational studies reported a 54.3% (CI 44.1-64.6, P < 0.0001) reduction in gradient, which was a 18.6% greater reduction than the RCTs (P = 0.0351 for difference between study designs). Observational studies reported an effect on unblinded NYHA class at an OR of 8.39 (CI 4.39-16.04, P < 0.0001), 450% larger than the OR in RCTs (P = 0.0042 for difference between study designs). Across all studies, the gradient progressively decreased at longer follow durations, by 5.2% per month (CI 2.5-7.9, P = 0.0001). CONCLUSION: Right ventricular pacing reduces gradient in blinded RCTs. There is a non-significant trend to reduction in NYHA class. The bias in assessment of NYHA class in observational studies appears to be more than twice as large as any genuine treatment effect.
No takes yet. Share an insight, caveat, or question.
Arnold et al. (2019) conducted a meta-analysis in Hypertrophic obstructive cardiomyopathy (n=1,135). Right ventricular pacing vs. No pacing was evaluated on Change in left ventricular outflow tract gradient (ΔLVOTg) (35% reduction, 95% CI 23.2-46.9, p=<0.0001). Right ventricular pacing reduced left ventricular outflow tract gradient by 35% in blinded randomized controlled trials, with a non-significant trend toward improved NYHA class.
Synapse has enriched 10 related papers. Consider them for comparative context: