Key result
Doppler-guided AV delay optimization is linked to an increase in stroke volume to ~63 ml.
Observational (n=32)
Open-label
No
May enhance stroke volume via echo-optimized AV delay in DDD-paced cardiomyopathy; leaves open outcome benefits in prospective trials.
Ten DDD paced patients, suffering from dilated cardiomyopathy in the NYHA functional classes III or IV were studied by means of Doppler echocardiography at different programmed values of atrioventricular (AV) delay (200, 150, 120, 100, and 80 msec). The following variables were evaluated: LV diameter, ejection fraction, mitral and aortic flow velocity integrals, and stroke volume. During VDD pacing, a resting AV delay associated with the best diastolic filling and systolic function was identified and programmed individually. Shortening of the AV delay to about 100 msec was associated with a gradual and progressive improvement. Further decrease caused an impairment of systolic function. The patients were clinically and hemodynamically reevaluated after 2 months of follow-up. A reduction of NYHA class and an improvement of LV function were consistently found. The reported data suggest that programming of an optimal AV delay may improve myocardial function in DDD paced patients with congestive heart failure. This result may be the consequence of an optimization of left ventricular filling and a better use of the Frank-Starling law.
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Guardigli et al. (1994) conducted an observational in Complete AV block or heart failure requiring dual-chamber pacing or cardiac resynchronization therapy (n=32). AV delay optimization using combined transmitral flow (TMF) and pulmonary venous (PV) flow vs. Shorter (AVD_OPT - 50 ms) or longer (AVD_OPT + 50 ms) AV delays was evaluated on Stroke volume (ml) at optimal AV delay vs shorter/longer AV delays (p=0.001). AV delay optimization using combined transmitral and pulmonary venous flow was feasible in 84% of patients and increased stroke volume to 63 ml vs 57 ml at shorter and 56 ml at longer delays (P=0.001).
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