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c-AMP and ANP levels in VVI and DDD pacing with different AV delays during daily activity and exercise
G Theodorakis1, D Kremastinos, M M Livanis
1Cardiac Department, Athens General Hospital, Greece.
Insights
Dual-chamber pacing (DDD) with a 150 ms atrioventricular delay (AVD) increased atrial natriuretic peptide (ANP) release during exercise. DDD pacing with a 100 ms AVD showed lower adrenergic activity and ANP release compared to VVI pacing.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- Complete heart block necessitates pacemaker implantation.
- Pacemaker modes like VVI and DDD offer different pacing strategies.
- Atrioventricular delay (AVD) optimization is crucial for cardiac function.
Purpose of the Study:
- To compare the effects of VVI and DDD pacing modes with varying atrioventricular delays (AVDs) on neurohormonal responses during rest and exercise.
- To investigate the impact of different AVDs on plasma atrial natriuretic peptide (ANP) and cyclic AMP (c-AMP) levels.
- To assess adrenergic activity under different pacing conditions.
Main Methods:
- Nine patients with complete heart block paced in DDD mode were studied.
- Measurements included plasma ANP and c-AMP at rest and peak exercise.
- Pacing conditions: VVI and DDD with 100 ms and 150 ms AVDs at rest and during exercise.
Main Results:
- Resting ANP levels were higher with VVI pacing compared to DDD pacing at 150 ms AVD.
- Exercise increased ANP release significantly only with DDD pacing at 150 ms AVD.
- Exercise c-AMP levels were higher with DDD pacing at 150 ms AVD and VVI pacing compared to rest.
- DDD pacing with 100 ms AVD showed potentially lower adrenergic activity and ANP release during exercise.
Conclusions:
- DDD pacing with a longer AVD (150 ms) may enhance ANP release during exercise compared to VVI pacing.
- Shorter AVDs in DDD pacing might be associated with reduced adrenergic stimulation during exercise.
- Pacemaker mode and AVD selection can influence neurohormonal responses in patients with complete heart block.
Abstract:
Nine patients (three males) mean age 68 +/- 8 years, having complete heart block, and paced in the DDD mode were examined in VVI and DDD pacing with 100 and 150 ms atrioventricular delays (AVD) during rest and exercise. Plasma atrial natriuretic peptide (ANP) and cyclic AMP (c-AMP) were measured at rest and at peak exercise test. ANP plasma levels at rest were significantly higher in VVI pacing compared to 150 AVD (P less than 0.03). On exercise, ANP release was statistically increased only in DDD with 150 ms AVD, while in VVI it remained in high levels at exercise but no significant change was found (p:ns). c-AMP during rest was unchanged in any pacing mode or AVD, but on exercise DDD pacing with short AVD (100 ms) released lower c-AMP plasma levels, than at rest (p:ns). DDD pacing with long AVD (150 ms) during exercise produced statistically higher c-AMP plasma levels (P less than 0.05) than at rest. Also in VVI pacing the c-AMP plasma levels were statistically higher than at rest (P less than 0.02). Adrenergic activity seems to be lower during exercise in DDD pacing with shorter AVD (100 ms) than in DDD with 150 ms AVD or VVI pacing. No difference was found in c-AMP plasma levels at rest. ANP release was also found to be lower at exercise in DDD pacing with short AVD (100 ms) than in DDD with 150 ms AVD. ANP plasma levels at rest were statistically higher in VVI pacing.