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Relationship between diastolic mitral regurgitation and PQ intervals or cardiac function in patients implanted with
T Ishikawa1, K Kimura, T Nihei
1Second Department of Internal Medicine, Yokohama City University, Japan.
Abstract:
Diastolic mitral regurgitation (MR) is known to be induced by prolonging atrioventricular (AV) delay in patients implanted with a DDD pacemaker. We studied the relationship between diastolic MR and PQ intervals on cardiac function in 50 patients (71.3 +/- 11.3 years old: mean +/- SD), who had been implanted with DDD pacemakers. In 19 patients, prior to pacemaker implantation, pulmonary capillary wedge pressure (PCWP) was measured using a Swan-Ganz catheter during AV sequential pacing with an AV delay of 0.165 seconds. Transmitral blood flow was measured with pulsed Doppler echocardiography, while prolonging AV delay stepwise by 0.025 seconds from 0.065 seconds for about 5 minutes each. In nine patients, AV delay could not be prolonged enough due to occurrence of intrinsic AV conduction. In the other 41 patients, diastolic MR was induced by prolonging AV delay. The critical PQ intervals that induced diastolic MR ranged from 0.14 to 0.26 (0.23 +/- 0.03) seconds. Four of five patients whose critical PQ intervals were 0.20 seconds or shorter had heart failure, while 36 patients whose critical PQ intervals were greater than 0.20 seconds were free from signs and symptoms of heart failure. Their PCWPs were 2-27 (7.5 +/- 5.1) mmHg. There was a significant negative correlation between the critical PQ intervals for the appearance of diastolic MR and PCWP during AV sequential pacing, which was performed prior to pacemaker implantation (r = -0.85, P less than 0.001). It is suggested that the appearance of diastolic MR is determined mainly by PQ intervals and cardiac function.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Prolonging atrioventricular (AV) delay in DDD pacemaker patients can induce diastolic mitral regurgitation (MR). Critical PQ intervals and cardiac function significantly influence the occurrence of this condition.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- Diastolic mitral regurgitation (MR) is a known complication of DDD pacemaker implantation.
- Atrioventricular (AV) delay is a critical parameter in pacemaker function.
Purpose of the Study:
- To investigate the relationship between diastolic MR, PQ intervals, and cardiac function in DDD pacemaker patients.
- To identify critical PQ intervals that induce diastolic MR.
Main Methods:
- Studied 50 patients with DDD pacemakers.
- Measured pulmonary capillary wedge pressure (PCWP) and transmitral blood flow using Doppler echocardiography.
- Systematically prolonged AV delay to determine critical PQ intervals for MR induction.
Main Results:
- Diastolic MR was induced in 41 patients by prolonging AV delay.
- Critical PQ intervals ranged from 0.14 to 0.26 seconds (mean 0.23 ± 0.03).
- A significant negative correlation (r = -0.85, P < 0.001) was found between critical PQ intervals and PCWP.
Conclusions:
- Diastolic MR appearance is primarily determined by PQ intervals and cardiac function.
- Pacemaker programming requires careful consideration of AV delay to prevent MR.