Destination therapy with left ventricular assist devices: for whom and when?

Historically, cardiac transplantation is the only definitive therapy for mortality reduction, symptom reduction, and improved quality of life in advanced heart failure. Because of improvement in cardiovascular care there is now a growing number of patients such as the elderly and those with abundant comorbidity who are not eligible for cardiac transplant. Durable mechanical circulatory support is the new reality in the treatment of advanced heart failure in this population subset. The left ventricular assist device (LVAD) has evolved from humble origins as a short-term extracorporeal and pulsatile device into a durable intracorporeal continuous flow device capable of providing permanent support in the form of destination therapy (DT) LVAD. Data gathered from original landmark clinical trials including Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH), and the Heart Mate II Trial, and the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) provide insight into the type of patient and the timing in which to consider DT LVAD therapy. There are a number individual patient warning signs and symptoms that predate clinical decline; thus, identifying individuals who might benefit from a DT LVAD strategy. The adverse event burden that accompanies DT LVAD therapy cannot be ignored when considering LVAD as an adjunct to ongoing medical therapy. Trends in patient selection regarding mechanical circulatory support continue to evolve along with the technology. As more clinical outcome data are gathered we will continue to refine our patient selection criteria and timing of implant.

Exercise testing in asymptomatic gene carriers exposes a latent electrical substrate of arrhythmogenic right ventricular cardiomyopathy.

OBJECTIVES: The aim of this study was to determine if exercise testing could expose a latent electrical substrate of arrhythmogenic right ventricular cardiomyopathy (ARVC) in asymptomatic gene carriers. BACKGROUND: Management of asymptomatic ARVC gene carriers is challenging because of variable penetrance of disease and the recognition that sudden cardiac death may be the first clinical manifestation. METHODS: Exercise-induced abnormalities during exercise treadmill testing (ETT) were initially compared in 60 subjects: 30 asymptomatic ARVC gene carriers and 30 healthy controls. In phase 2 of the study, ETT results of 25 patients with ARVC with histories of sustained ventricular arrhythmia or cardiac arrest were evaluated to determine if ETT abnormalities in asymptomatic gene carriers were common to patients with a malignant electrical form of the disease. RESULTS: Depolarization abnormalities during ETT were found to develop more frequently in asymptomatic gene carriers compared with healthy controls: epsilon waves appeared in 4 of 28 (14%) compared with 0 of 30 (0%) (p = 0.048), premature ventricular contractions in 17 of 30 (57%) compared with 3 of 30 (10%) (p = 0.0003), and new QRS terminal activation duration ≥ 55 ms in 7 of 22 (32%) compared with 2 of 29 (7%) (p = 0.03). Superior axis premature ventricular contractions occurred only in gene carriers. In the second phase of the study, the frequency of these abnormalities was found to be high in patients with symptomatic ARVC: new epsilon waves appeared in 3 of 18 (17%), superior axis premature ventricular contractions in 21 of 25 (84%), and new terminal activation duration ≥ 55 ms in 8 of 12 (67%). CONCLUSIONS: Exercise testing exposes a latent electrical substrate in asymptomatic ARVC gene carriers that is shared by patients with ARVC with histories of ventricular arrhythmia. ETT may be useful in guiding treatment decisions, exercise prescription, and prioritizing medical surveillance in asymptomatic ARVC gene carriers.