Assessment of the optimal atrio-ventricular delay in DDD paced patients by impedance plethysmography

Abstract

The beneficial haemodynamic effects of sequential atrioventricular (AV) pacing have been clearly established and are dependent on the AV delay and pacing rate. However, the optimal AV delay is difficult to determine in each particular patient. We used a modified impedance plethysmographic method to assess variations in stroke volume for different AV delay and pacing rate settings. Impedance measurements showed a good correlation with CO2 rebreathing stroke volume measurements in VVI patients. Impedance variations were then used to set the optimal AV delay at different pacing rates in DDD patients. The inverse relationship between the optimal AV delay and the pacing rate has been accurately identified in most of the patients but is not predictable. In all cases, the cardiac output was higher in DDD mode at the optimal AV delay than in VVI mode. In some patients with a damaged myocardium, the stroke volume appeared to be highly sensitive to multiple AV delay settings. Impedance plethysmography can permit such repetitive non-invasive quick measurements, increasing the accuracy of optimal AV delay determination and is well suited for routine examination of patients with cardiac dual chamber pacemakers.

Immediate and chronic effects of AV-delay optimization in patients with cardiac resynchronization therapy

“…Currently several methods are being used for optimization of AV-delay at various institutions including optimization according to the Ritter formula [28,29], use of bioimpedance [30], radionuclide ventriculography [31] or finger plethysmography [32], use of automated suggestion based on historical databases which take into account intrinsic AV-delay, QRS width and electrode positioning (ExpertEase, Guidant). Due to a lack of chronic data on the benefit of AV-delay optimization some centers simply program the device with a short AV-interval between 100 and 130 ms, although a recent study demonstrated a benefit of echocardiographically guided optimization of AV-delay [33].…”

Optimization of Atrioventricular Delay and Follow-up in a Patient With Congestive Heart Failure With an Implanted DDD Pacemaker

“…The optimal AV delay is usually estimated by Doppler echocardiography, 16 radionuclide angiography 17 or plethysmographic impedance. 18 Our new method is easy and not time-consuming and so AV delay optimization can be easily repeated, making it a useful method for the follow-up of patients with congestive heart failure and a DDD-PM.…”

Determination of the Optimal Atrioventricular Interval in Sick Sinus Syndrome During DDD Pacing

“…Optimal AV interval in DDD pacing has been determined by many investigators with echocardiography, 7,10–12,16,17 peak endocardial acceleration, 18,19 and impedance cardiography 20,21 . In most of these studies, however, optimal AV interval was determined in patients with AV block.…”

“…Optimal AV interval in DDD pacing has been determined by many investigators with echocardiography, 7,10-12,16,17 peak endocardial acceleration, 18,19 and impedance cardiography. 20,21 In most of these studies, however, optimal AV interval was determined in patients with AV block. Ishikawa et al demonstrated that optimal AV interval could be predicted easily by a simple formula with pulsed Doppler echocardiography: slightly prolonged AV interval minus the interval between end of the A wave and the complete closure of mitral valve at the AV interval setting.…”