October 25, 2007Journal of Cardiovascular Electrophysiology
Effects of Simultaneous and Optimized Sequential Cardiac Resynchronization Therapy on Myocardial Oxidative Metabolism and Efficiency
Key result
CRT increases stroke volume and work metabolic index versus AAI pacing, without added sequential benefit.
- n=8
Why the study?
The effects of sequential cardiac resynchronization therapy on myocardial oxidative metabolism and efficiency had not been previously assessed.
Does sequential CRT improve myocardial oxidative metabolism and efficiency compared to simultaneous CRT or AAI pacing in patients with NYHA class III heart failure?
Comparison
AAI pacing vs simultaneous CRT vs sequential CRT
Design
Cross-sectional study with repeated measures
Follow-up
1 hour per pacing mode
Authors
Discussion
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Implication
Preliminary CRT efficiency data should not alter practice; leaves open larger randomized confirmation in heart failure.
Structured PICO
Does sequential CRT improve myocardial oxidative metabolism and efficiency compared to simultaneous CRT or AAI pacing in patients with NYHA class III heart failure?
P
Population
8 patients with NYHA class III heart failure evaluated approximately 196 days post-CRT implant.
I
Intervention
Sequential cardiac resynchronization therapy (CRT) for 1 hour
C
Comparator
AAI pacing and simultaneous CRT (each for 1 hour)
O
Outcome
Myocardial oxidative metabolism (MVO2) and myocardial efficiency (work metabolic index)surrogate
In a small cohort of heart failure patients, CRT improved myocardial efficiency and stroke volume without increasing oxidative metabolism, though sequential CRT offered no significant advantage over simultaneous CRT.
Limitations
- Small selected population
- small selected population
Cite This Study
Christenson et al. (2007) studied NYHA class III heart failure (n=8). Simultaneous and sequential cardiac resynchronization therapy (CRT) vs. AAI pacing was evaluated on Myocardial oxidative metabolism (MVO2), stroke volume index (SVI), and work metabolic index (WMI). CRT significantly increased stroke volume index (P<0.001) and work metabolic index (P=0.002) compared to AAI pacing, with no significant additional benefit from sequential over simultaneous CRT.