Pacemaker Mode Selection:

Abstract

The evidence base for pacing, specifically with regards to outcome-based randomized trials, is only beginning to emerge. At present, the guidelines for pacing in sinus node dysfunction (SND), atrioventricular block (AVB), and vasovagal syncope are largely based on observational, not randomized studies. The findings from observational studies that physiological pacing was associated with reduced mortality, fewer strokes, less heart failure, and less AF when compared with ventricular pacing, were not uniformly supported by the early randomized trials of a relatively small sample size. Thus, it has become increasingly clear that large scale randomized trials are necessary to measure reliably the benefit, if any, of progressively more expensive and complex pacemakers. To provide reliable answers to these important questions, three large multicenter randomized trials in Canada, the United Kingdom, and the United States have been designed and conducted. The present review analyzed the results of completed randomized trials on pacemaker mode selection. To date, > 6,000 patients requiring permanent pacing to prevent bradycardia have been randomized; among these, dual chamber pacing did not prevent stroke or improve survival when compared with ventricular pacing. However, dual chamber pacing led to a moderate reduction of incident and chronic AF, reduced symptoms of heart failure in patients with SND, prevented pacemaker syndrome, and modestly improved quality-of-life. Further, a 5-10% reduction in mortality by atrial-based pacing cannot be excluded based on the results of the analyzed trials. The availability of data from ongoing randomized trials and their meta analysis should complete the totality of evidence during the next several years.

Ambulatory Holter monitoring in asymptomatic patients with DDD pacemakers – do we need ACC/AHA Guidelines revision?

“…According to ACC/AHA [ 1 ] guidelines 24-hour ECG Holter monitoring (HM) in asymptomatic patients in the early period after pacemaker (PM) implantation is not recommended (class IIb). Holter monitoring is an alternative method for telemonitoring of patients with PMs.…”

“…Modern PMs and endocardial leads compared to the first ones are really perfect devices, with low frequency of dysfunctions [ 2 – 7 ]. On the other hand, since the first implantation of a permanent pacing system in 1958, progressive technology development has led to extremely complex dual chamber devices, with many therapeutic and diagnostic algorithms [ 1 – 5 ].…”