Pacing for hypertrophic cardiomyopathy Title of Trial
Pacing in Cardiomyopathy (PIC) Study
Date and Citation of Primary Publication(s) or References
Kappenberger L, Linde C, Daubert C, et al for the PIC study group. Pacing in hypertrophic cardiomyopathy. Eur Heart J 1997; 18: 1249-56.
Purpose of the Trial
Evaluate the effects of pacing therapy in patients with hypertrophic cardiomyopathy.
Study Category
Pacing
Patient Population
Inclusion Criteria
Hypertrophic cardiomyopathy with a resting or provocable gradient > 30 mm Hg and NYHA Class II or III functional limitation despite maximal drug therapy. Acute pacing trial to evaluate effects of pacing.
Exclusion Criteria
NYHA class IV, drug refractory systemic hypertension, documented coronary artery disease, ejection fraction < 0.50, chronic atrial fibrillation, age < 18 years old, or pacing required for a standard bradycardia indication (except drug induced bradycardia)
Study Design
Randomized double blind crossover trial. Pacemakers were programmed to either active DDD pacing mode with a short AV delay (30 ms) or to the AAI pacing mode at a rate of 30 bpm. Patients were in each pacing mode for 12 weeks.
Primary Endpoints
NYHA class, quality of life
Secondary Endpoints
Exercise tolerance
Baseline Characteristics
Patient number: 83 patients
Mean Age: 53 years
Gender: 40% female
Other characteristics:
In 77% of patients pacing was associated with a > 30% reduction in peak gradient.
Time to Follow-up
Two 12-week periods
Results
The DDD pacing mode with a short AV delay was associated with a reduction in left ventricular outflow tract gradient (59 ± 36 mm Hg to 30 ± 25 mmHg; p < 0.001). As shown in Table 1, NYHA class improved from baseline regardless of whether the patient was programmed to the AAI or DDD with short AV delay pacing modes. A significant placebo effect was noted with 29% of patients improving with the pacemaker in the AAI pacing mode. As shown in Table 2, the DDD with short AV delay pacing mode was associated with significant improvement in symptoms compared to the AAI pacing mode. However, no difference in exercise duration was noted between the two pacing modes. In a post-hoc analysis, DDD pacing with a short AV delay increased exercise tolerance by 21% in patients with reduced exercise tolerance at baseline (< 10 minutes on a standard Bruce protocol).
Table 1: Effects of pacing mode on NYHA class
| NYHA class | Baseline | AAI | DDD with short AV delay |
| I | 0 | 4 | 29 |
| II | 28 | 37 | 36 |
| III | 42 | 28 | 5 |
| IV | 0 | 1 | 0 |
Table 2: Symptoms and Exercise duration
| | AAI | DDD with short AV delay | P |
| NYHA functional class | 2.4 | 1.7 | 0.0001 |
Dyspnea grade
(0 to 4) | 2.4 | 1.4 | 0.0001 |
Angina grade
(0 to 4) | 1 | 0.4 | 0.005 |
| Exercise duration for all patients (min) | 12.2 | 12.4 | NS |
| Exercise duration for patients with duration > 10 minutes at baseline (min) | 14.2 | 14.2 | NS |
| Exercise duration for patients with duration < 10 minutes at baseline (min) | 8.1 | 9.8 | 0.008 |
Sponsor
Medtronic, Swiss National Foundation for Scientific Research, and the Swedish Heart and Lung Foundation Trial Status: Completed
