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A time-related study by Doppler and M-mode echocardiography of hemodynamics, heart size, and AV valvular function
Insights
Rate-responsive ventricular pacing (RRP) in elderly patients led to decreased stroke volume and left ventricular dimensions. This pacing strategy also increased the incidence of mitral and tricuspid insufficiency.
Area of Science:
- Cardiology
- Biomedical Engineering
- Geriatric Medicine
Background:
- Elderly patients with pacemakers may benefit from rate-responsive pacing (RRP) to increase cardiac output.
- Understanding the impact of RRP on cardiac function and valvular integrity is crucial for this population.
Purpose of the Study:
- To evaluate the effects of RRP on cardiac dimensions and function in elderly patients.
- To assess the incidence of mitral and tricuspid insufficiency (MI and TI) with RRP.
Main Methods:
- Noninvasive Doppler and M-mode echocardiography were used to measure stroke volume (SV), left atrial (LA) size, left ventricular end-diastolic (EDD) and end-systolic dimensions (ESD), and fractional shortening (FS).
- Mitral and tricuspid insufficiency were assessed before and at 1, 3, and 6 months after initiating RRP in 13 elderly patients (mean age, 75 years).
Main Results:
- Stroke volume at rest significantly decreased after 3 and 6 months of RRP (p < 0.05 and p < 0.01, respectively).
- Left ventricular end-diastolic dimension and fractional shortening were significantly reduced after 6 months of RRP (p < 0.002 and p < 0.02, respectively).
- The incidence of mitral and/or tricuspid insufficiency increased, with 69% of patients developing these conditions within 6 months.
Conclusions:
- Rate-responsive ventricular pacing in elderly patients is associated with a decline in stroke volume and ventricular dimensions.
- RRP may contribute to an increased prevalence of mitral and tricuspid insufficiency in this patient group.
Abstract:
Noninvasive Doppler and M-mode echocardiography were used to: measure stroke volume (SV), left atrial (LA) size, left ventricular end-diastolic (EDD), end-systolic dimensions (ESD), left ventricular fractional shortening (FS), and for determination of mitral and tricuspid insufficiency (MI and TI) before starting and after 1, 3, and 6 months of rate-responsive ventricular pacing (RRP). The study group consisted of 13 patients (mean age, 75 years) who could be expected to benefit from an increase in cardiac output mediated by an increment of heart rate during exercise. In VVI + activity mode (RRP), the pacemaker was programmed to a basic heart rate of 60 and a maximum heart rate of 125 bpm. The SV at rest was 71 +/- 5 before RRP, and fell to 57 +/- 4 after 3 months (p less than 0.05) and to 53 +/- 4 ml/beat after 6 months of RRP (p less than .01). The LA size and ESD were unchanged during follow-up. The EDD decreased from 6.2 +/- 0.3 to 5.4 +/- 0.2 (p less than 0.002) during the first 6 months of RRP. The FS was reduced from 33 +/- 4 to 27 +/- 3% (p less than 0.02) during the first 6 months of RRP. Four of 6 patients treated previously with a VVI pacemaker (mean duration, 9 years) had MI + TI, and 3 of the 7 patients not paced previously had MI before RRP. In the last group, 1 new patient developed MI, 1 new patient developed MI + TI, and 2 patients who had MI also developed TI within 6 months of pacing. Thus, of 13 patients, 9 (69%) had either MI or MI + TI.