Related Experiment Videos
The importance of different atrioventricular delay for left ventricular filling in sequential pacing: clinical
M G Modena1, R Rossi, A Carcagnì
1Department of Internal Medicine, Institute of Cardiology, Modena, Italy.
Insights
Optimizing atrioventricular (AV) delay in DDD pacemakers can normalize ventricular filling and improve cardiac function in patients with abnormal relaxation patterns. This study highlights the clinical benefits of personalized AV delay programming.
Area of Science:
- Cardiology
- Biomedical Engineering
- Clinical Electrophysiology
Background:
- Patients with DDD pacemakers for AV block often have impaired ventricular filling patterns.
- Ventricular hypertrophy and abnormal relaxation can affect diastolic function in paced individuals.
- Optimizing atrioventricular (AV) delay is crucial for hemodynamic efficiency in pacemaker patients.
Purpose of the Study:
- To assess the impact of different AV delays on ventricular filling in patients with DDD pacemakers.
- To evaluate the clinical consequences of AV delay optimization on cardiac functional capacity.
- To determine if modifying AV delay can normalize abnormal ventricular filling patterns.
Main Methods:
- 30 patients with DDD pacemakers and AV block were studied, divided into groups based on ventricular filling patterns.
- Echocardiography and Doppler assessments were used to evaluate ventricular hypertrophy and relaxation.
- AV delay was systematically modified (200, 150, 100, 75 ms), and exercise tests measured functional capacity (VO2 Max).
Main Results:
- Patients with abnormal relaxation (Group I) showed improved filling patterns when AV delay was reduced to 100 ms.
- Optimization of AV delay in Group I led to improved Weber class and increased VO2 Max after 6 months.
- Patients with normal filling patterns (Group II) did not show significant changes with AV delay modification.
Conclusions:
- Modification of AV delay can normalize ventricular filling in DDD pacemaker patients with normal ejection fraction but abnormal relaxation.
- Personalized AV delay programming can enhance cardiac functional capacity and exercise tolerance.
- This strategy offers a non-invasive method to improve outcomes in select pacemaker populations.
Abstract:
We assessed the influence and clinical consequences of different AV delay on ventricular filling in 30 patients (mean age 60 +/- 5 years) who had DDD pacemakers for AV block. All 30 patients presented a normal ejection fraction, but in 18 cases (Group I), an echo-Doppler examination revealed ventricular hypertrophy (mean end-diastolic wall thickness of 1.4 +/- 0.16 cm, LV mass index 155 +/- 17 g/m2), and an abnormal relaxation pattern (isovolumetric relaxation time = 124.72 +/- 11.82; early to late peak velocity = 0.6 +/- 0.03; deceleration time = 296.83 +/- 34.02 ms). Group II included the remaining 12 patients who had a normal filling pattern. In all 30 patients, the pattern was reassessed following modification of the AV delay (200, 150, 100, and 75 ms). Patients at baseline (AV delay of 200 ms) also underwent an exercise test with determination of respiratory gas exchange. In Group I, 13 (72.5%) patients were classified as Weber class B (VO2 Max 16.8 +/- 1.7 mL/min per kg); and 5 (27.5%) were Class A (VO2 Max 22.5 +/- 1.4 mL/min per kg). In Group II, all 12 patients were classified as Weber Class A. In Group II, changes in AV delay caused no consistent variations in filling pattern, and therefore AV delay was not modified. In Group I patients, since reduction to 100 ms resulted in normalization of the filling pattern, the AV delay was programmed to 100 ms. A graded exercise test repeated after 6 months' follow-up showed an improved Weber class in 13 patients (from B to A) and greater VO2 Max in the remaining five already in Class A. We concluded that, in sequential paced patients with normal ejection fraction but abnormal relaxation pattern, modification in AV delay can induce normalization of filling and improvement in cardiac functional capacity.