Transient Second-Degree Atrioventricular Block: A Rare Finding in Sickle Cell Crisis.

Sickle cell disease (SCD) affects approximately 100,000 Americans, and it occurs in one out of every 365 African American births. Cardiac complications are a common feature of SCD and are an essential cause of the morbidity and mortality associated with SCD. However, there is insufficient literature on SCD and atrioventricular (AV) blocks.

A Unique Interplay of Multiple Predisposing Factors Culminating in a Catastrophic QT Prolongation.

Implantable cardioverter-defibrillators (ICDs) are used in patients without a reversible cause for long QT syndrome (LQTS) and secondary prevention in patients with LQTS-associated sudden cardiac arrest. We present a female patient with multiple reversible factors for QT prolongation, including the use of antidepressants, antidiarrheals, antiemetics, and antihistamines; chronic malabsorption from bariatric surgery; probable Gitelman syndrome and urinary losses of electrolytes, causing QT prolongation which leads to polymorphic ventricular tachycardia and a successfully resuscitated cardiac arrest. Our patient also had history suggestive of probable congenital LQTS with multiple childhood syncopal episodes and a history of seizures in first-degree relatives, further justifying the placement of an ICD.

Ventricular geometry-regularized QRSd predicts cardiac resynchronization therapy response: machine learning from crosstalk between electrocardiography and echocardiography.

Up to one-third of patients selected by current guidelines do not respond to cardiac resynchronization therapy (CRT), the aim of this study was to find out novel analytical approaches to improve pre-implantation CRT response prediction. Among 31 pre-implantation features of clinical, laboratory, electrocardiography (ECG), and echocardiography variables in a consecutive cohort of patients receiving a first-time CRT device (CRT-pacemaker or CRT-defibrillator), we developed a machine learning (ML) model with three classification algorithms (support vector machines (SVM), K nearest neighbors, and random subspaces) with the best features combination to predict CRT response. Three categorical variables, left bundle branch block (LBBB), nonischemic cardiomyopathy, and female gender, were independently associated with CRT responses.

Lyme carditis: Early occurrence and prolonged recovery.

Lyme carditis is an uncommon manifestation of early disseminated Lyme disease. This case illustrates a 66-year-old male with complaints of fatigue, myalgias, and fever after a tick bite 3days earlier. A large erythema migrans was found on the chest wall.

The kidney in heart failure: friend or foe?

Heart failure constitutes a significant source of morbidity and mortality in the United States and its incidence and prevalence continue to grow, increasing its burden on the health care system. Renal dysfunction in patients with heart failure is common and has been associated with adverse clinical outcomes. This complex interaction is characterized by a pathophysiological disequilibrium between the heart and the kidney, in which cardiac malfunction promotes renal impairment, which in turn feeds back for further deterioration of cardiovascular function.

The cardiorenal syndrome in heart failure: an evolving paradigm.

Heart failure constitutes a significant source of morbidity and mortality in the United States, and its incidence and prevalence continue to grow, increasing its burden on the healthcare system. Renal dysfunction in patients with heart failure is common and has been associated with adverse clinical outcomes. This interaction, termed the cardiorenal syndrome, is a complex phenomenon characterized by a pathophysiologic disequilibrium between the heart and the kidney, in which malfunction of 1 organ consequently promotes the impairment of the other.

Left versus right atrial difference in dominant frequency, K(+) channel transcripts, and fibrosis in patients developing atrial fibrillation after cardiac surgery.

Background: The development of atrial fibrillation (AF) after cardiac surgery is associated with adverse outcomes; however, the mechanism(s) that trigger and maintain AF in these patients are unknown.

Objective: The purpose of this study was to test our hypothesis that postoperative AF is maintained by high-frequency sources in the left atrium (LA) resulting from ion channel and structural features that differ from the right atrium (RA).

Methods: Forty-four patients with no previous history of AF who underwent cardiac surgery consented to LA and RA biopsies.

Malignant neurally-mediated syncope: pathophysiology and treatment.

Neurally-mediated syncope is the most common cause of transient loss of consciousness. In this report, we describe an index case of a 43-year-old man with multiple episodes of neurally-mediated syncope. He underwent tilt-table testing, resulting in asystole for 15 seconds with generalized convulsions.

Myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart.

Myocardial stunning refers to contractile dysfunction that persists after an ischemic episode and restoration of coronary blood flow. In this article, 2 cases of myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart are presented. The incidence of this condition is unknown.

Atrial fibrillation in heart failure: prognostic significance and management.

AF in Heart Failure. Atrial fibrillation and congestive heart failure are commonly occurring cardiac disorders that often exist concomitantly. The prognostic significance of the presence or absence of atrial fibrillation, as an independent risk factor, in patients with heart failure remains controversial.

Complications of biventricular pacing.

Purpose Of Review: Cardiac resynchronization therapy, a biventricular pacemaker-based therapy for heart failure, is increasingly being used based on a variety of clinical studies. However, the complications and risks related to different aspects of this novel therapy are not well documented. This review summarizes the data derived from major clinical trials about the complications related to implantation, hardware, and programming of biventricular devices.

A review of clinical trials assessing the efficacy and safety of newer antiarrhythmic drugs in atrial fibrillation.

Clinical trials assessing the efficacy of anti- arrhythmic drugs for terminating atrial fibrillation have demonstrated that rate control drugs have little to no added efficacy compared to placebo; however, spontaneous conversion of recent-onset atrial fibrillation is common. Antiarrhythmic drugs such as oral dofetilide, oral bolus-flecainide and propafenone and intravenous ibutilide all have a role in terminating atrial fibrillation. Active comparator trials have demonstrated that amiodarone is more efficacious in maintaining sinus rhythm than propafenone and sotalol.

Old and new antiarrhythmic drugs for converting and maintaining sinus rhythm in atrial fibrillation: comparative efficacy and results of trials.

In managing atrial fibrillation (AF), the main therapeutic strategies include rate control, termination of the arrhythmia, and the prevention of recurrences and thromboembolic events. Safety and efficacy considerations are important in optimizing the choice of an antiarrhythmic drug for the treatment of AF. Recently approved antiarrhythmics, such as dofetilide, and promising investigational drugs, such as azimilide and dronedarone, may change the treatment landscape for AF.

Atrial fibrillation in patients with heart failure.

Atrial fibrillation and heart failure are very common cardiac disorders, and both are associated with symptoms, significant morbidity, and mortality. Studies have attempted to determine the prognostic significance of atrial fibrillation in patients with heart failure. Whether atrial fibrillation is an independent risk factor of mortality remains controversial.

Entrainment of ventricular tachycardia with a permanent biventricular pacemaker.

Biventricular pacing has been introduced as a treatment for congestive heart failure. These devices presently pace and sense from two disparate ventricular sites. Antitachycardia pacing (ATP) is used for termination of sustained monomorphic ventricular tachycardia (VT) and has been incorporated with simultaneous dual site ventricular pacing for treatment of VT.

Maintaining stability of sinus rhythm in atrial fibrillation: antiarrhythmic drugs versus ablation.

In managing atrial fibrillation, the main therapeutic strategies include rate control, termination of the arrhythmia, and pr vention of recurrences and thromboembolic events. Rate control with digoxin, b-blockers, verapamil, and diltiazem may be preferred in drug refractory and sedentary patients with markedly dilated left atrium and atrial fibrillation of long duration. Drugs useful in the maintenance of sinus rhythm include quinidine, procainamide, disopyramide, sotalol, amiodarone, dofetilide, flecainide, and propafenone.