Quality of life and clinical outcomes in elderly patients treated with ventricular pacing as compared with dual-chamber pacing. - PASE(QOL)

Description:

Single vs. dual chamber pacing and quality of life in elderly patients

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 407
NYHA Class: 70% of the population was NYHA class I or II.
Mean Follow Up: 550 days
Mean Patient Age: 76
Female: 40
Mean Ejection Fraction: The ejection fraction was known in the case of 254 patients (62 percent) and was normal in 56 percent of these patients.

Patient Populations:

65 years of age or older
Sinus rhythm
Requiring a permanent pacemaker for the prevention or treatment of bradycardia
Written informed consent

Exclusions:

Inability to participate in the quality-of-life assessments
Clinically overt congestive heart failure at the time of implantation
Atrial fibrillation without any documented sinus mechanism for more than six months
Serious noncardiac illness
Inadequate atrial-capture or sensing thresholds.

Primary Endpoints:

Health related quality of life, as measured by the SF-36 survey instrument.

Secondary Endpoints:

Secondary: Death from all causes
First nonfatal stroke or death
First hospitalization for heart failure
Development of atrial fibrillation
Development of pacemaker syndrome

Drug/Procedures Used:

Intermedics dual-chamber rate-adaptive pacemakers (models 294-03, 293-03, 294-03R, and 294-05), programmed to either DDDR or VVIR modes.

Principal Findings:

A total of 203 patients were randomized to dual-chamber pacing; the remaining 204 patients were assigned to ventricular pacing. The indications for the implantation of a permanent pacemaker included atrioventricular block in 201 patients (49 percent, of whom 119 patients, or 59 percent, had third-degree block), sinus-node dysfunction in 175 patients (43 percent), and other diagnoses in 31 (8 percent). Ventriculoatrial (retrograde) conduction at the time of implantation was present in 29 percent.

Follow-up visits and health-status assessments took place 3, 9, and 18 months after enrollment and at the end of the study. Assessment of health status before randomization was performed at the local clinical site, before the pacemaker mode was assigned. Subsequent assessments were made by telephone from the coordinating center.

During the course of the trial, pacemaker syndrome severe enough to warrant reprogramming from ventricular to dual-chamber pacing was diagnosed in 53 patients assigned to ventricular pacing (26 percent), in 45 percent of whom sinus-node dysfunction was the reason for implantation. Crossover from ventricular to dual-chamber pacing occurred early: 44 percent of the 53 crossovers occurred within one month after implantation, and 77 percent within six months. After crossover, the patients had improvement in SF-36 scores, including scores for physical function (+22, P = 0.03) and emotional role (+27, P = 0.01).

In the overall group, there was significant improvement in health-related quality of life between base line (before implantation) and three months after implantation, as measured by several SF-36 subscales (social function, P<0.001; physical role, P<0.001; emotional role, P<0.001; mental health, P<0.001; energy, P<0.001).

There were no significant differences in scores between the ventricular-pacing group and the dual-chamber-pacing group in any of the SF-36 subscales at 3 months or 18 months. After nine months of follow-up, there was a significant difference favoring dual-chamber pacing only in scores for the mental health subscale (P = 0.03)

Longitudinal analyses, detected a borderline improvement in scores on the emotional-role subscale in patients assigned to dual-chamber pacing (P= 0.04).

There were no significant differences in cardiovascular functional status between groups, as assessed by the Specific Activity Scale, at either the three-month or the nine-month assessment. However, there was a significant difference favoring dual- chamber pacing at the 18-month visit ( Table 4), and longitudinal analysis demonstrated a significant difference favoring dual-chamber pacing (P = 0.045).

There were no significant differences between the ventricular-pacing group and the dual-chamber-pacing group in the rates of death from all causes, stroke or death, stroke or death or hospitalization for heart failure, and the development of atrial fibrillation.

Among the patients who received pacemakers because of sinus-node dysfunction, there were significant differences favoring dual-chamber pacing at three months in scores on the physical-role subscale (P = 0.02), social-function subscale (P = 0.03), and emotional-role subscale (P = 0.002) of SF-36.

Among the patients with atrioventricular block at implantation, there were no significant differences between groups in any of the SF-36 subscales, in longitudinal analyses of the Specific Activity Scale, or in any of the prespecified clinical endpoints.

Interpretation:

The design of the study did not permit maintenance of an accurate registry to compare the screened and enrolled populations. However, the demographic and clinical characteristics of the participants were very similar to those of recipients of dual-chamber pacemakers in the Medicare data base. In this study, pacemaker placement led to dramatic improvements in health-related quality of life. This uncontrolled observation is consistent with the reported low rate of recurrence of symptoms after pacemaker implantation. However, when patients with ventricular pacing were compared with patients with dual-chamber pacing, there were no convincing differences in general health-related quality of life. Analysis of two prespecified subgroups - patients with sinus-node dysfunction and those with atrioventricular block at implantation - did reveal a favorable response to dual-chamber pacing in patients with sinus-node dysfunction. Nonetheless, these differences are considerably smaller than were previously thought.

References:

N Engl J Med 1998; 338:1097-104. Final results.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, EP Basic Science, Acute Heart Failure

Keywords: Atrioventricular Block, Stroke, Follow-Up Studies, Cardiac Pacing, Artificial, Quality of Life, Heart Failure, Pacemaker, Artificial, Bradycardia, Informed Consent, Medicare, Mental Health


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