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Can right-sided atrioventricular sequential pacing provide benefit for selected patients with severe congestive heart
Insights
Right-sided atrioventricular sequential pacing improved cardiac output in 46% of patients with advanced cardiomyopathy. Optimal results were seen with specific atrioventricular delays, suggesting personalized pacing strategies for severe left ventricular dysfunction.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Heart Failure Management
Background:
- Advanced cardiomyopathy significantly impairs left ventricular function and cardiac output.
- Atrioventricular (AV) pacing is a therapeutic option, but optimal pacing strategies require investigation.
- Right-sided pacing approaches need evaluation for efficacy in diverse cardiomyopathy etiologies.
Purpose of the Study:
- To assess the efficacy of right-sided atrioventricular (AV) sequential pacing in patients with advanced cardiomyopathy.
- To determine the impact of different AV intervals on cardiac output and hemodynamic parameters.
- To identify patient subgroups who benefit from AV sequential pacing.
Main Methods:
- Twenty-six patients with advanced cardiomyopathy underwent temporary transvenous pacing with electrodes in the right atrium and ventricle.
- Hemodynamic parameters including cardiac output, pressures, and vascular resistance were measured.
- Pacing was performed in VVI and DDD modes with varying AV intervals (40-250 msec).
Main Results:
- Overall cardiac output did not increase significantly (p=0.51).
- VVI pacing decreased stroke volume (p<0.01).
- Twelve patients (46%) were responders, showing >1 L/min cardiac output increase with DDD pacing at 150-175 msec AV delay. This also decreased systemic vascular resistance.
Conclusions:
- Right-sided AV sequential pacing can improve cardiac output and left ventricular function in a subset of patients with advanced cardiomyopathy.
- Optimal AV delay is crucial for maximizing benefits, with 150 msec showing significant improvements.
- Individual testing is recommended to identify responders for personalized pacing therapy.
Abstract:
This study reports on the methods and results of applying right-sided atrioventricular (AV) pacing in 26 patients with advanced cardiomyopathy. Ten of these patients had ischemic cardiomyopathy. Of the 16 patients with nonischemic cardiomyopathy, 10 were idiopathic and 6 were due to secondary causes. The patients had a mean age of 56 +/- 12 years and a left ventricular ejection fraction of 26 +/- 11%. Two transvenous stimulation electrodes were temporarily placed in the high right atrium and right ventricle, respectively. A Swan Ganz catheter was positioned into the pulmonary artery to determine cardiac output by the thermodilution method and to measure the pressure in the pulmonary artery and right atrium. In addition, aortic pressure was measured through a catheter sheath via the right femoral artery. Systemic and pulmonary vascular resistance were calculated. Stimulation was performed in VVI and DDD pacing modes using different AV intervals (40, 80, 125, 150, 175, 200, and 250 msec). No increase of cardiac output was observed for the overall study cohort (p = 0.51). At VVI pacing, stroke volume significantly decreased from 66 +/- 20 mL to 53 +/- 13 mL (p < 0.01). We distinguished between responders who developed an increase of cardiac output of > 1 L/min (n = 12, 46%) and nonresponders (n = 14, 54%). Etiology of either ischemic or nonischemic cardiomyopathy for responders, as well as conduction disturbances (first-degree AV block, LBBB, RBBB), were equally distributed among both groups. Using an AV delay of 150 and 175 msec, responders to DDD pacing derived a significant increase in cardiac output. An AV delay of 150 msec produced both a significant increase of stroke volume and decrease of systemic vascular resistance. In 46% of patients with dilated cardiomyopathy of either ischemic or nonischemic origin, right-sided AV-sequential pacing brought about an improvement of left ventricular function in terms of enhanced cardiac output. We suggest individual testing in all patients with severe left ventricular dysfunction to find responders.