Isoproterenol as an adjunct for treatment of idiopathic ventricular fibrillation storm in a pregnant woman.

Idiopathic ventricular fibrillation is a rare entity seen in a very small subset of patients presenting to the emergency department. Management of ventricular arrhythmias in pregnant women is similar to that in nonpregnant women, but special consideration is given to avoid adverse fetal effects when selecting antiarrhythmic agents. Electrical defibrillation is the intervention of choice in both pregnant and nonpregnant patients with ventricular fibrillation of all etiologies. This was not associated with any significant adverse effects for mother or fetus. Although lidocaine and sotalol are Food and Drug Administration category B antiarrhythmics used in pregnancy, Food and Drug Administration category C antiarrhythmics such as ß-blockers and category D drugs such as amiodarone can be used as pharmacologic adjuncts to facilitate termination of recurrent ventricular fibrillation where other agents have failed. Isoproterenol has been used to terminate recurrent ventricular fibrillation in patients with Brugada syndrome and torsades de pointes resistant to magnesium therapy. This case report describes a previously healthy 32-year-old pregnant woman with recurrent idiopathic ventricular fibrillation that failed to respond to standard therapy including electrical defibrillation, intravenous lidocaine, metoprolol, and amiodarone but eventually terminated with isoproterenol infusion.

Expressive aphasia in a patient with recent dual-chamber cardioverter-defibrillator implantation: a preventable complication.

Transvenous pacemaker and/or defibrillator lead placement into the left heart chambers is rarely done. Approximately a third of such cases reported in the literature presented with signs of thromboembolism, mostly neurological deficits. We describe a patient who presented with a cerebrovascular accident three months after inadvertent and unrecognized lead placement into the left atrium and ventricle through a sinus venosus atrial septal defect. Implant techniques to avoid this complication are discussed.

Catheter ablation of atrial fibrillation in the elderly.

PURPOSE OF REVIEW: Atrial fibrillation is increasingly prevalent among older adults and is a major contributor to morbidity in this population due to associated strokes, heart failure, and quality of life impairment. Catheter ablation for atrial fibrillation is demonstrated to be superior to antiarrhythmic therapy for the control of symptomatic and medically refractory atrial fibrillation, but its safety and efficacy in the elderly are not well understood. Clinical trials to guide the optimal management strategy in this population are lacking. RECENT FINDINGS: Several nonrandomized clinical studies have recently addressed the issue of catheter ablation in the elderly and show favorable rates of success. Unfortunately, these studies are limited by the relatively small numbers of patients examined and often by their single-center and retrospective nature. SUMMARY: Before the results of these studies can be extrapolated, data from larger cohorts of elderly patients followed prospectively are desperately needed.

Time-dependent risk of Fidelis lead failure.

The Medtronic Sprint Fidelis leads (models 6930, 6931, 6948, 6949) are 6.6-F bipolar high-voltage implantable cardioverter-defibrillator electrodes that were first introduced in September 2004. In October 2007, Fidelis leads were removed from the market. We sought to determine the time-dependent hazard of the Fidelis failure rate to date. A retrospective chart review was conducted in all patients who underwent implantation of a Sprint Fidelis lead (426 leads) at our center. We primarily implanted models 6931 and 6949. With 1,056 years of combined follow-up (average 2.3 +/- 1), 38 of 426 (8.92%) Sprint Fidelis leads failed (3.6%/year). The hazard of fracture increased exponentially over time by a power of 2.13 (95% confidence interval [CI] 1.98 to 2.27, p <0.001) and the 3-year survival was 90.8% (95% CI 87.4 to 94.3). If a Fidelis lead was functioning normally at 1 year, the chance it would survive another year was 97.4% (95% CI 95.7 to 99.1); if functioning at 2 years, the chance of surviving another year was 94.7% (95% CI 91.8 to 97.7); and if functioning at 3 years, the chance of surviving 1 more year was 86.7% (95% CI 78.8 to 95.5). Other commonly used implantable cardioverter-defibrillator leads showed no evidence of increased failure rates. In conclusion, to date, the hazard of Fidelis lead fracture is increasing exponentially with time and, based on our data, occurring at a higher rate than the latest manufacturer's performance update. Further accumulative data are needed because it remains unknown if the fracture rate will level off or continue to increase.

Catheter ablation of atrial fibrillation in the elderly: where do we stand?

Catheter ablation has emerged as an important therapy for the management of drug refractory symptomatic paroxysmal and persistent atrial fibrillation (AF). Although the elderly account for the majority of patients with AF, limited data exists regarding the use of catheter ablation for elderly patients with AF. As AF ablation has become more widespread, ablation techniques have improved and the complication rate has decreased. As a result, referrals of elderly patients for catheter ablation of AF are on the rise. Two retrospective analyses have recently demonstrated that catheter ablation of AF in the elderly can safely be performed and results are comparable to a younger population with up to 80% or more of patients maintaining sinus rhythm at 12 months follow-up. We compared the results of 15 consecutive patients > or = 70 years old with symptomatic paroxysmal atrial fibrillation who underwent catheter ablation of AF at our institution to 45 randomly sampled younger patients. The primary endpoint of our study, presence of sinus rhythm in the absence of symptoms at 12 months follow-up, was present in 60% of elderly patients and 80% of younger patients (p = 0.17). There was no statistically significant difference in complication rate between the younger and elderly patients. In this article we present the results of our study and review the published literature to date regarding the clinical efficacy and safety of catheter ablation for AF in elderly patients with paroxysmal and persistent atrial fibrillation.

Recurrent ventricular arrhythmia storms in the age of implantable cardioverter defibrillator therapy: a comprehensive review.

Rapidly recurrent ventricular arrhythmia is not an infrequent clinical entity in the era of implantable cardioverter defibrillator therapy. Clinical presentation can vary dramatically, from multiple defibrillator shocks with hemodynamic instability, to asymptomatic delivery of anti-tachycardia pacing. Although some investigators have reported disparate prognostic implications with electrical storm, in larger trials of both primary and secondary defibrillator populations, electrical storm appears to be a harbinger of cardiac death with a notably high mortality early post event. While acute cessation of electrical storm is generally achievable with medical therapy, it is critical to recognize that the causes for subsequent mortality are often not arrhythmic in nature. Thus, the challenge for cardiovascular practitioners is to maximize substrate based therapy and modification to not only prevent further episodes of electrical storm and possibly curtail the considerable risk of subsequent cardiac mortality.

Evolving clinical application of cardiac MRI.

Over the past decade, cardiac magnetic resonance imaging (MRI) has emerged as a new technology representing the next major advance in noninvasive cardiac imaging. It provides unique and accurate data representative of cardiac structure, function, and perfusion at both the gross anatomical and myocardial levels. Cardiac MRI proves to be highly accurate and reproducible in many challenging areas in clinical cardiology, including diagnosis of constrictive pericarditis, differentiation of ischemic from dilated cardiomyopathy, confirmation of the diagnosis of myocarditis, and definition and quantification of myocardial viability. As compelling studies support its clinical utility, the evolution of cardiac MRI is gaining speed. In many cases, such as the diagnosis of anomalous origin of the coronary arteries, it is the gold standard diagnostic technique.

The efficacy of aliskiren, a direct renin inhibitor, in the treatment of hypertension.

Aliskiren is a potent, highly specific renin inhibitor with better oral bioavailability than earlier renin inhibitors and a long plasma half-life that makes it suitable for once-daily dosing. The efficacy and safety of aliskiren in treating hypertension has been studied in clinical trials both as monotherapy, comparing it with existing antihypertensive therapies, and in combination with other antihypertensive agents, including the diuretic hydrochlorothiazide, the angiotensin-converting enzyme inhibitor ramipril, and the calcium channel blocker amlodipine. From the extensive database acquired to date, it is clear that aliskiren is an effective antihypertensive agent, with once-daily administration resulting in dose-dependent systolic and diastolic blood pressure reductions. Combinations with existing antihypertensives are producing promising additional blood pressure-lowering effects.

Implantable cardioverter-defibrillators for secondary prevention: is it worth it in the elderly?

Aging is associated with structural alterations in the heart that predispose the elderly to life-threatening ventricular arrhythmias. The majority of sudden cardiac deaths occur in people aged 65 and older. As the proportion of elderly in our population continues to grow, a greater number of elderly patients with malignant ventricular arrhythmias will require appropriate medical management. Clinical outcome trials have demonstrated that implantable cardioverter-defibrillators (ICDs) improve overall survival compared with pharmacologic therapy when used for the secondary prevention of cardiac arrest. Despite proven efficacy, physicians may be reluctant to implant a defibrillator in an older patient. This review summarizes the data pertaining to the use of defibrillators for secondary prevention in the elderly. ICD use for secondary prevention reduces all-cause mortality and appears to be economically advantageous in an older patient population. Currently, there is no convincing data to suggest that ICD therapy should be withheld from a patient based on age alone.