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Relationship between atrioventricular delay, QT interval and cardiac function in patients with implanted DDD
T Ishikawa1, T Sugano, S Sumita
1Second Department of Internal Medicine, Yokohama City University Urafune Hospital, Yokohama, Japan.
Summary
Optimizing atrioventricular (AV) delay in DDD pacemaker patients can improve cardiac function. The study found that the optimal AV delay, which maximizes cardiac output, can be accurately predicted by measuring the QT interval.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Atrioventricular (AV) delay optimization can influence cardiac function in patients with pacemakers.
- The QT interval's relationship with cardiac output and AV delay requires further investigation.
Purpose of the Study:
- To investigate the relationship between AV delay, QT interval, and cardiac output in patients with DDD pacemakers.
- To determine if QT interval can predict optimal AV delay for cardiac function.
Main Methods:
- Studied 12 patients with complete or high-degree AV block and DDD pacemakers.
- Measured cardiac output (CO) and QT interval at various AV delays, keeping pacing rate constant.
- Analyzed the correlation between AV delay, CO, and QT interval.
Main Results:
- Optimizing AV delay significantly increased cardiac output (P<0.002) and prolonged the QT interval.
- A significant positive correlation (r=0.85, P<0.001) was found between optimal AV delay for CO and predicted optimal AV delay from QT interval.
- Optimal AV delay for maximal CO was 161+/-33 ms, and predicted optimal AV delay from maximal QT interval was 167+/-29 ms.
Conclusions:
- The QT interval is a reliable predictor of optimal atrioventricular delay for maximizing cardiac output in DDD pacemaker patients.
- This finding may allow for non-invasive optimization of pacemaker settings.