MOST: Implications for Device Selection in Elderly Patients
Background: The purpose of this study was to describe the incidence and predictors of sudden cardiac death (SCD) and heart failure (HF) death, and coexisting indications for ICDs and CRT, in patients with sinus node disease (SND) treated with pacemakers.
Methods and Results: Baseline variables were used to predict SCD and HF death among 1,135 patients in the Mode Selection Trial, a 6-year trial of pacing mode in SND. There were 73 deaths among 177 patients with EF ≤35% (41.2%), 46/156 (29.5%) with EF 36-49%, and 147/802(18.3%) with EF ≥50%. SCD accounted for 21.9%, 23.9%, and 14.3% of deaths with EF ≤35%, 36-49%, and ≥50%. HF deaths accounted for 23.3%, 19.6%, and 3.4% of deaths with EF ≤ 35%, 36-49%, and ≥ 50%. EF ≤ 35% predicted SCD (hazard ratio [HR] 3.68, 95% confidence interval [CI] 1.72-7.89, P = 0.002) and HF death (HR 10.17, 95% CI 3.35, 30.82, P=0.001). Four-year SCD rate with EF ≤35% was 15.5% (3.9% annually).
Nearly one-fifth of patients qualified for ICDs (EF ≤35%) and half of these had QRS ≥120ms. However, >40% died within 33 months (4-year noncardiac death rate ∼22%).
Conclusions: Reduced EF predicts SCD and HF death in SND treated with pacemakers. SCD rates among patients with EF ≤ 35% are similar to control arms of primary prevention ICD trials, but mortality rates are significantly higher. Whether ICDs or CRT to provide bradycardia support would prolong life in elderly patients with EF ≤35% and SND merits prospective investigation.
Approximately 240,000 patients in the United States receive bradycardia pacemakers yearly, and this number increased by nearly 25% between 1997 and 2001. This increase in the United States is also reflected worldwide, with implantation rates that have increased consistently over the past two decades primarily due to increased usage in sinus node disease (SND), the most common reason for pacemaker implantation in industrialized nations. Approximately 90% of pacemaker recipients are >60 years old, and 30% or more are >80 years old in many nations. These patients have been excluded, underrepresented, or not systematically evaluated in randomized clinical trials of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy (CRT) due to advanced age and/or an indication for permanent pacing. The purpose of this study was to investigate the incidence and baseline predictors of sudden cardiac death (SCD) and heart failure (HF) death in the largest randomized trial of pacing in SND (the mode selection trial, MOST), and to provide an estimate of the proportion of typical pacemaker patients who might meet indications for ICDs and CRT.
Abstract and Introduction
Abstract
Background: The purpose of this study was to describe the incidence and predictors of sudden cardiac death (SCD) and heart failure (HF) death, and coexisting indications for ICDs and CRT, in patients with sinus node disease (SND) treated with pacemakers.
Methods and Results: Baseline variables were used to predict SCD and HF death among 1,135 patients in the Mode Selection Trial, a 6-year trial of pacing mode in SND. There were 73 deaths among 177 patients with EF ≤35% (41.2%), 46/156 (29.5%) with EF 36-49%, and 147/802(18.3%) with EF ≥50%. SCD accounted for 21.9%, 23.9%, and 14.3% of deaths with EF ≤35%, 36-49%, and ≥50%. HF deaths accounted for 23.3%, 19.6%, and 3.4% of deaths with EF ≤ 35%, 36-49%, and ≥ 50%. EF ≤ 35% predicted SCD (hazard ratio [HR] 3.68, 95% confidence interval [CI] 1.72-7.89, P = 0.002) and HF death (HR 10.17, 95% CI 3.35, 30.82, P=0.001). Four-year SCD rate with EF ≤35% was 15.5% (3.9% annually).
Nearly one-fifth of patients qualified for ICDs (EF ≤35%) and half of these had QRS ≥120ms. However, >40% died within 33 months (4-year noncardiac death rate ∼22%).
Conclusions: Reduced EF predicts SCD and HF death in SND treated with pacemakers. SCD rates among patients with EF ≤ 35% are similar to control arms of primary prevention ICD trials, but mortality rates are significantly higher. Whether ICDs or CRT to provide bradycardia support would prolong life in elderly patients with EF ≤35% and SND merits prospective investigation.
Introduction
Approximately 240,000 patients in the United States receive bradycardia pacemakers yearly, and this number increased by nearly 25% between 1997 and 2001. This increase in the United States is also reflected worldwide, with implantation rates that have increased consistently over the past two decades primarily due to increased usage in sinus node disease (SND), the most common reason for pacemaker implantation in industrialized nations. Approximately 90% of pacemaker recipients are >60 years old, and 30% or more are >80 years old in many nations. These patients have been excluded, underrepresented, or not systematically evaluated in randomized clinical trials of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy (CRT) due to advanced age and/or an indication for permanent pacing. The purpose of this study was to investigate the incidence and baseline predictors of sudden cardiac death (SCD) and heart failure (HF) death in the largest randomized trial of pacing in SND (the mode selection trial, MOST), and to provide an estimate of the proportion of typical pacemaker patients who might meet indications for ICDs and CRT.
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