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Clinical Trial
. 2004 Dec 17:2:30.
doi: 10.1186/1476-7120-2-30.

Echocardiographic AV-interval optimization in patients with reduced left ventricular function

C Melzer  1 , A C Borges, F Knebel, W S Richter, W Combs, G Baumann, H Theres
Affiliations
Clinical Trial

Echocardiographic AV-interval optimization in patients with reduced left ventricular function

C Melzer et al. Cardiovasc Ultrasound. .

Abstract

Background: Ritter's method is a tool used to optimize AV delay in DDD pacemaker patients with normal left ventricular function only. The goal of our study was to evaluate Ritter's method in AV delay-interval optimization in patients with reduced left ventricular function.

Methods: Patients with implanted DDD pacemakers and AVB III degrees were assigned to one of two groups according to ejection fraction (EF): Group 1 (EF > 35%) and Group 2 (EF < 35%). AV delay optimization was performed by means of radionuclide ventriculography (RNV) and application of Ritter's method.

Results: For each of the patients examined, we succeeded in defining an optimal AV interval by means of both RNV and Ritter's method. The optimal AV delay determined by RNV correlated well with the delay found by Ritter's method, especially among those patients with reduced EF. The intra-class correlation coefficient was 0.8965 in Group 1 and 0.9228 in Group 2. The optimal AV interval in Group 1 was 190 +/- 28.5 ms, and 180 +/- 35 ms in Group 2.

Conclusion: Ritter's method is also effective for optimization of AV intervals among patients with reduced left ventricular function (EF < 35%). The results obtained by RNV correlate well with those from Ritter's method. Individual programming of the AV interval is fundamentally essential in all cases.

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Figures

Figure 1
Figure 1
Ritter's method: The first step is determination of "a" for a nonphysiologically short AV interval (e.g. 125 ms), followed be determination of "b" for a nonphysiologically long AV interval (e.g. 250 ms).
Figure 2
Figure 2
The correlation of the results of the RNV and Ritter methods, with respect to the optimal AV interval for Group 1.
Figure 4
Figure 4
The maximum difference in left ventricular EF, determined by RNV and as a function of the programmed AV interval, for each of the patients examined.
Figure 3
Figure 3
The correlation of the results of the RNV and Ritter methods, with respect to the optimal AV interval for Group 2.
See this image and copyright information in PMC

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