Association of Prolonged QRS Duration With Death in a Clinical Trial of Pacemaker Therapy for Sinus Node Dysfunction

Abstract

for the Mode Selection Trial (MOST) InvestigatorsBackground-Prolonged QRS duration (QRSd) is an important prognostic indicator for death and heart failure hospitalization in patients with systolic heart failure. The relationship of baseline QRSd to death and heart failure hospitalization in patients with sinus node dysfunction who require pacemaker therapy is unknown. Methods and Results-Baseline QRSd from 12-lead ECGs before pacemaker implantation were analyzed in the Mode Selection Trial (MOST), a 6-year, 2010-patient randomized trial of dual-chamber versus ventricular pacing in sinus node dysfunction. Baseline QRSd was Ն120 ms in 23.4% of patients and was associated with older age, lower ejection fraction, cardiomyopathy, and prior heart failure. Adjusted Cox models demonstrated baseline QRSd Ն120 ms was a strong independent predictor of death (hazard ratio [

Abnormal Conduction Increases Risk of Adverse Outcomes From Right Ventricular Pacing

“…Across the spectrum from narrow to markedly prolonged, QRS duration has been shown to be an independent marker of mortality in patients with and without congestive heart failure (1,3,6). Recent studies have also observed that, when combined with severe left ventricular dysfunction, right ventricular pacing worsens clinical outcome (4,7), particularly when it occurs frequently (8).…”

“…There is a growing body of evidence that the dyssynchrony induced by right ventricular pacing has an adverse effect on outcome in patients undergoing implantation of either a permanent pacemaker or an implantable cardioverterdefibrillator (ICD) (1,2). The DAVID (Dual Chamber and VVI Implantable Defibrillator) trial found an increased risk of the combined end point of death and hospitalization for new or worsening congestive heart failure (CHF) in ICD patients paced DDDR-70 versus VVI-40.…”

Relationship between QRS duration and prognosis in non-ST-segment elevation acute coronary syndrome

“…Prolonged QRSd has been found to be a predictor of CvD in patients with heart failure [1,2], hypertension [10], sick sinus syndrome [11] and ST-segment elevation AMI [3,4]. Recently, Desai et al have reported that general people with QRSd N 130 ms experience nearly twice the risk of CvD compared to those with QRSd b 110 ms [12].…”

Creating a cardiac pacemaker by gene therapy

“…Lastly, another important aspect related to pacemaking is the site from which the impulse is being delivered to the heart. Identification of the best location for the implant is paramount not only for maximizing the obligatory benefit of a backup pacing system, but also for avoiding the risks and outright detrimental effects of single chamber pacing (as single chamber pacemaking can induce significant ventricular dyssynchrony that can adversely affect quality of life and left ventricular systolic function as well as negatively impact on morbidity and mortality) [82,84]. Such a location would have to be identified for the placement of the implant, to allow it access to the native conduction system.…”