Cardiac Resynchronization Therapy improves functional capacity and quality of life in patients with persistent class III and IV heart failure despite optimal medical therapy, and there is also evidence that Cardiac Resynchronization Therapy may reverse structural remodeling in selected patients. Although individual trials of Cardiac Resynchronization Therapy were underpowered to assess survival, a meta-analysis of outcomes from four randomized trials involving more than 800 patients found that Cardiac Resynchronization Therapy reduces mortality from heart failure. (more…)

Neurocardiogenic Vasovagal syncope is more common in younger patients but also should be considered in elderly patients with unexplained syncope. Although the triggering mechanisms are complex and may differ among young and elderly patients, the efferent responses generally can be categorized as cardioinhibitory (pauses of = 3 seconds or heart rate <40 beats per minute for more than 10 seconds), vasodepressor (systolic blood pressure falls by 50 mm Hg or more without symptoms or 30 to 50 mm Hg with symptoms of syncope or presyncope, and the heart rate does not decrease by more than 10%), (more…)

Pacemaker therapy is indicated in patients with symptomatic bradycardia (syncope, presyncope, dyspnea, and exercise intolerance) correlated to sinus node dysfunction (pauses, persistent bradycardia, or chronotropic incompetence). In elderly patients, sinus node dysfunction is often associated with atrial tachyarrhythmias, including AF. Because of the frequent association of sinus node dysfunction with AF, VVI and VVIR pacing were once considered the preferred pacing modes. Recent studies suggest that atrial-based pacing in patients with sinus node dysfunction is beneficial for preventing progression of AF. (more…)

Several clinical tools are available for identification of patients at risk of cardiac arrhythmias or its consequences that may benefit from interventions to reduce morbidity and risk of sudden death. These include noninvasive tests, such as a standard (more…)

Carotid sinus hypersensitivity ( more than 3-second pause or a decrease in systolic blood pressure = 50 mm Hg during carotid sinus massage) predominantly affects elderly patients, although the prevalence in the general population has not been precisely defined. In elderly patients with recurrent syncope, carotid sinus hypersensitivity has been reported in up to 35% of cases. Permanent pacing in patients with carotid sinus syndrome (carotid sinus hypersensitivity associated with syncope) is indicated. Observational and randomized studies have shown that recurrent symptoms are significantly reduced after permanent pacemaker implantation in patients with carotid sinus syndrome. (more…)

Aging is associated with progressive fibrosis of the sinoatrial node and AV conduction system, resulting in bradycardia, which may be further exacerbated by disease and medications, resulting in symptoms requiring permanent pacemaker implantation. More than 80% of pacemaker recipients in the United States are older than 65 years, and the median age is 75 years. As the population ages, it is anticipated that the number of older persons requiring permanent cardiac pacemakers, as well as the associated costs, will continue to rise. (more…)

Atrial Fibrillation affects approximately 2.3 million people in the United States and is the most common rhythm disorder among U.S. patients hospitalized with a primary diagnosis of an cardiac arrhythmia. The median age of Atrial Fibrillation patients is 75 years; 84% are older than 65 years. Pooled data from studies of chronic Atrial Fibrillation in North America, Britain, and Iceland suggest a prevalence of 0.5% to 1% in the general population. (more…)

Supraventricular Tachyarrhythmia

The principles of drug and non-drug management of supraventricular tachyarrhythmia (SVT) are similar to those outlined for stroke Atrial Fibrillation. However, for most supraventricular tachyarrhythmia, the arrhythmogenic substrate is isolated and well defined. AV nodal reentrant tachycardia (localized to the region of AVN) and atrioventricular reentrant tachycardia (with use of an accessory pathway) are the two most common types of supraventricular tachyarrhythmia. Atrial tachycardia can be reentrant or non-reentrant in mechanism, can be right or left atrial in origin, and can occur more frequently in the elderly population than in younger patients. (more…)

Results from several recently completed trials have important implications for the primary prevention of Sudden Cardiac Death Prevention (Table below). In patients with coronary artery disease, prior myocardial infarction, and ejection fraction of 30% or less, a survival benefit was found with prophylactic implantation of a cardioverter defibrillator compared with medical therapy (MADIT-II). In the MADIT-II trial, benefits in patients with preexisting left bundle branch block were more pronounced. In the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), an ICD was associated with improved survival compared with amiodarone or medical therapy in patients with class II or III heart failure symptoms and an ejection fraction of 35% or less, and the benefit was evident in patients with or without ischemia (48%). (more…)

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The same genetic and cell approaches used for treatment of bradyarrhythmia can potentially be modified for tachyarrhythmias treatment. Arrhythmogenesis typically results from increased automaticity, triggered activity, or reentry. Different genetic approaches can, therefore, be designed based on the individual mechanism. (more…)