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Intrapatient comparison between chronic VVIR and DDD pacing in patients affected by high degree AV block without
C Menozzi1, M Brignole, P V Moracchini
1Division of Cardiology, S.M. Nuova Hospital, Reggio Emilia, Italy.
Insights
Dual-chamber (DDD) pacing significantly improves symptoms and cardiac output in high-degree atrioventricular block patients compared to single-chamber ventricular pacing (VVIR). Most patients preferred DDD pacing, highlighting its clinical benefits.
Area of Science:
- Cardiology
- Biomedical Engineering
- Clinical Electrophysiology
Background:
- High-degree atrioventricular (AV) block can impair cardiac function.
- The clinical superiority of dual-chamber pacing (DDD) over single-chamber ventricular pacing (VVIR) in these patients remains debated.
- Optimal pacing mode selection is crucial for patient well-being and cardiovascular health.
Purpose of the Study:
- To compare the clinical efficacy of DDD pacing versus VVIR pacing in patients with high-degree AV block.
- To evaluate the impact of pacing mode on patient-reported symptoms and key cardiovascular parameters.
- To determine patient preference between DDD and VVIR pacing modes.
Main Methods:
- An intrapatient, randomized, double-blind, cross-over study was conducted in 14 high-degree AV block patients.
- Patients were paced using a dual-chamber pacemaker programmed to either DDD or VVIR mode for 6-week periods.
- Symptoms were quantified using a semiquantitative score, and cardiovascular parameters (cardiac output, body weight, atrial natriuretic peptide) were measured.
Main Results:
- Patients reported significantly fewer symptoms with DDD pacing (4.6 +/- 2.7) compared to VVIR pacing (10.4 +/- 6.7).
- Eight out of 14 patients preferred DDD pacing, with five crossing over early due to intolerable symptoms on VVIR.
- DDD pacing resulted in improved cardiac output (5.7 +/- 1.6 L/min vs. 4.7 +/- 1.4 L/min) and reduced atrial natriuretic peptide levels.
Conclusions:
- DDD pacing offers significant clinical advantages over VVIR pacing in patients with high-degree AV block.
- Improved symptom scores and enhanced cardiac output underscore the benefits of maintaining atrioventricular synchrony.
- DDD pacing is the preferred mode for managing high-degree AV block, enhancing patient quality of life.
Abstract:
In patients affected by high degree AV block without preexisting congestive heart failure there is no definite demonstration that DDD pacing gives real clinical advantages in respect to VVIR pacing. We performed an intrapatient, long-term study between the two pacing modes in 14 high degree AV block patients, using the Medtronic Synergyst 7027 dual chamber pacemaker, who could be programmed alternatively in DDD or VVIR mode. After a 4-week run-in period following the pacemaker implant, patients completed a randomized, double-blind, cross-over study to compare the effect of 6-week period VVIR and DDD pacing on symptoms and cardiovascular parameters. A semiquantitative score scale was used to quantify the symptoms of general well-being, palpitations, dizziness, pulsating sensation in the neck or abdomen, shortness of breath at rest and during effort, chest pain, and NYHA classification. The sum of symptom scores was 10.4 +/- 6.7 in VVIR period and 4.6 +/- 2.7 in DDD period (P less than 0.001); five patients (36%) crossed over early from VVIR to DDD because of intolerable symptoms; overall, eight patients preferred the DDD mode and no one preferred the VVIR. Cardiac output at rest (echo-Doppler method) was 4.7 +/- 1.4 versus 5.7 +/- 1.6 liter/min (P less than 0.01), body weight was 65.9 +/- 6.6 versus 64.9 +/- 6.1 kg (P less than 0.02), atrial natriuretic peptide was 236 +/- 112 versus 198 +/- 110 pg/mL (P less than 0.01), respectively, during VVIR and DDD modes. Effort tolerance was similar with the two modes of pacing (68 +/- 15 vs 70 +/- 18 watts/min).(ABSTRACT TRUNCATED AT 250 WORDS)