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Left atrial size and wall motion in patients with permanent ventricular and atrial pacing
J Kubica1, L Stolarczyk, E Krzyminska
1III Department of Internal Medicine, Medical Academy of Gdańsk, Poland.
Insights
Permanent ventricular pacing with ventriculoatrial conduction (VAC) significantly increases left atrial size and reduces wall motion, raising risks for atrial arrhythmias and embolic events compared to other pacing methods.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Permanent ventricular pacing is linked to higher rates of atrial arrhythmias and embolic complications.
- Ventriculoatrial conduction (VAC) is hypothesized to cause hemodynamic disturbances leading to these complications.
- Understanding the impact of pacing modes on atrial mechanics is crucial for patient outcomes.
Purpose of the Study:
- To compare left atrial size and wall motion in patients undergoing different permanent pacemaker implantation modes.
- To investigate the specific effects of ventriculoatrial conduction on atrial dimensions and function.
- To evaluate atrial changes in patients with VVI pacing versus those with atrial or atrioventricular sequential pacing.
Main Methods:
- Echocardiography (two-dimensional/M-mode) was used to assess left atrial size and wall motion.
- Three patient groups were studied: VVI pacing with VAC, primary AAI pacing, and AAI/DDD pacing after VVI failure.
- Measurements included mean diastolic and systolic atrial diameters and atrial wall motion percentage.
Main Results:
- Patients with VVI pacing and VAC (Group 1) exhibited significantly larger mean diastolic and systolic atrial diameters (P < 0.005).
- Atrial wall motion was significantly reduced in the VVI pacing with VAC group (P < 0.005), measuring 7.4% of diastolic diameter.
- Patients with pacemakers preserving atrioventricular synchrony (Groups 2 and 3) showed similar, smaller atrial dimensions and greater wall motion (approx. 22% of diastolic diameter).
Conclusions:
- Ventriculoatrial conduction significantly enlarges the left atrium and impairs atrial wall motion.
- These changes associated with VAC predispose patients to atrial arrhythmias and embolic complications.
- Preserving atrioventricular synchrony through appropriate pacing modes mitigates adverse atrial remodeling.
Abstract:
It is well known that during permanent ventricular pacing atrial arrhythmias and embolic complications occur much more frequently in comparison to permanent atrial or sequential pacing. Hemodynamic disturbances caused by ventriculoatrial conduction (VAC) are thought to be responsible for those complications. The aim of this study was to compare the left atrial size and its wall motion in three groups of patients with sick sinus syndrome. Group 1: 58 patients with VVI pacing and VAC observed (22 males, 36 females, aged 31-86, mean 62.3). Group 2: 43 patients with primary AAI pacing (13 males, 30 females, aged 27-74, mean 57.8). Group 3: 13 patients with AAI or DDD replacing the primary VVI mode due to pacemaker syndrome and/or heart failure, all with VAC present during VVI pacing (7 males, 6 females, aged 26-80, mean 59.8). Two-dimensional/M-mode echocardiography was performed in all these patients. In group 1 mean diastolic as well as mean systolic atrial diameters were significantly greater (P less than 0.005) and wall motion significantly smaller (P less than 0.005) in comparison to the other groups. Left atrial wall motion amounted to only 7.4% of the mean diastolic diameter in this group. Mean left atrial diastolic and systolic diameters and wall motion in patients with pacemakers preserving atrioventricular synchrony (group 2 and group 3) were almost identical and wall motion amounted to about 22% of the diastolic diameter in both these groups. We conclude that ventriculoatrial conduction leads to significant enlargement of left atrium and to the atrial wall-motion decrease. This predisposes to arrhythmias and embolic complications.(ABSTRACT TRUNCATED AT 250 WORDS)