Pacemakers and defibrillators for congestive heart failure

Abstract

Although medical therapy is the primary therapy for patients with heart failure, the use of pacemakers to improve cardiac hemodynamics is under investigation. Despite promising initial results, controlled studies have not verified the benefit of application of VDD or DDD pacing to a nonselected population of severely symptomatic congestive heart failure (CHF) patients to simply shorten their atrioventricular (AV) delay. There is increasing interest in pacing the left side of the heart or simultaneously pacing the right and left ventricles. Early studies suggest that these techniques may produce favorable hemodynamic effects in patients with CHF. Controlled, randomized studies are now underway. Further, it has been shown that sudden cardiac death accounts for 50% of deaths in patients with CHF. The value of an implantable cardioverter defibrillator (ICD) in secondary prevention of sudden cardiac death is well established. The use of ICD for primary prevention of sudden cardiac death in patients with CHF is being actively evaluated. Several large multicenter trials are underway, some combined with biventricular pacing, and should provide useful data in the coming years.

Physical Therapy Implications in Managing Patients with Pacemakers and Defibrillators

“…Although CRT has been a potential therapeutic modality for the past 6 to 8 years, it is only now receiving greater clinical use. [17][18][19][20][21][22] Although the improvements in these important indices of survival in CHF are noteworthy, investigation of the specific effects of CRT on mortality are needed. [17][18][19][20][21][22] Furthermore, several important predictors of mortality have also been improved with CRT including left ventricular size, norepinephrine levels, heart rate and heart rate variability, peak oxygen consumption, New York Heart Association classification, and 6-minute walk test distance ambulated.…”

“…[17][18][19][20][21][22] Furthermore, several important predictors of mortality have also been improved with CRT including left ventricular size, norepinephrine levels, heart rate and heart rate variability, peak oxygen consumption, New York Heart Association classification, and 6-minute walk test distance ambulated. [17][18][19][20][21][22] The beneficial effects of CRT in persons with CHF are likely due to the combined effects of the first 5 factors listed in Table 3. Nonetheless, the improvements in many of the manifestations of CHF shown in Table 3 are likely to improve the functional abilities and quality of life of individuals with CHF.…”

“…Nonetheless, the improvements in many of the manifestations of CHF shown in Table 3 are likely to improve the functional abilities and quality of life of individuals with CHF. [17][18][19][20][21][22] Despite the potential beneficial effects of CRT on the manifestations of CHF there are several potential adverse effects of CRT in persons with CHF, including infection, bleeding disorders, pacemaker dysfunction, and possibly increased arrhythmias (Table 4). The improvements in atrioventricular conduction; ventricular filling, activation and contraction; and improved ventricular wall motion likely produce the remaining beneficial effects listed in Table 3.…”

Biventricular Implantable Cardioverter Defibrillator and Inappropriate Shocks

“…Biventricular pacemakers have been advocated in drug‐refractory symptomatic heart failure 2 . These two devices are required in similar groups of patients because patients with advanced heart failure also are at increased risk for sudden death 3 …”