Protection from outpatient sudden cardiac death following ICD removal using a wearable cardioverter defibrillator.

BACKGROUND: An implantable cardioverter defibrillator (ICD) is effective in preventing sudden cardiac death (SCD). Once an ICD is removed and reimplantation is not feasible, a wearable cardioverter defibrillator (WCD) may be an alternative option. We determined the effectiveness of WCD for SCD prevention in patients who were discharged after ICD removal. METHODS: A retrospective study was conducted on all WCD (LifeVest, ZOLL, Pittsburgh, PA, USA) patients who underwent ICD removal due to cardiac device infections (CDIs) at two referral centers between January 1, 2005 and December 31, 2009. Clinical characteristics, device information, and WCD data were analyzed. Sudden cardiac arrest was defined as all sustained ventricular tachycardia (VT) and ventricular fibrillation occurring within a single 24-hour period. RESULTS: Ninety-seven patients (mean age 62.8 ± 13.3, male 80.4%) were included in the study. The median duration of antibiotic use was 14.7 days (interquartile range [IQR] 10-30). The median daily WCD use was 20 hours/day and the median length of use was 21 days (IQR 5-47). A total of three patients were shocked by WCD. Two patients had four episodes of sustained VT, successfully terminated by the WCD. A third patient experienced two inappropriate treatments due to oversensitivity of the signal artifact. Three patients experienced sudden death outside the hospital while not wearing the device. Five patients died while hospitalized. CONCLUSION: WCD can prevent SCD, until ICD reimplantation is feasible in patients who underwent device removals for CDI. However, patient compliance is essential for the effective use of this device.

Clinical utility of intravascular ultrasound in the assessment of coronary allograft vasculopathy: a review.

Coronary artery vasculopathy (CAV) is one of the major factors that limit the long-term survival of heart transplant recipients. It is difficult to diagnose CAV, especially in the early stages. Traditional coronary angiography has been used for the diagnosis of CAV, but this method has limitations. Current literature suggests that intravascular ultrasound (IVUS) is a safe imaging technique that is beneficial for the early diagnosis of CAV; in comparison, IVUS with virtual histology (IVUS-VH) is an even more promising diagnostic utility. Despite its advantages, IVUS is currently not routinely utilized as the primary diagnostic modality for CAV in heart transplant recipients. In this review, we evaluate and summarize the clinical utility of IVUS in the early diagnosis of CAV, including its utility for assessing vessel remodeling, plaque composition, and prognostic value; morphometric analysis; and guiding therapy. After reviewing the relevant published literature, it is our recommendation that the use of IVUS be considered in all post-transplant CAV screening.

Arrhythmias and heart failure.

Atrial fibrillation and ventricular tachyarrhythmias are frequently seen in patients with heart failure, and complicate the management of such patients. Both types of arrhythmia lead to increased morbidity and mortality, and often prove to be challenging issues to manage. The many randomized studies that have been performed in patients with these conditions and concomitant heart failure have helped in designing optimal treatment strategies.

Renal dysfunction in heart failure patients: what is the evidence?

Congestive heart failure (CHF) is an increasingly common medical condition and the fastest growing cardiovascular diagnosis in North America. Over one-third of patients with heart failure also have renal insufficiency. It has been shown that renal insufficiency confers worsened outcomes to patients with heart failure. However, a majority of the larger and therapy-defining heart failure medication and device trials exclude patients with advanced renal dysfunction. These studies also infrequently perform subgroup analyses based on the degree of renal dysfunction. The lack of information on heart failure patients who have renal insufficiency likely contributes to their being prescribed mortality and morbidity reducing medications and receiving diagnostic and therapeutic procedures at lower rates than heart failure patients with normal renal function. Inclusion of patients with renal insufficiency in heart failure studies and published guidelines for medication, device, and interventional therapies would likely improve patient outcomes.