QT Dispersion and Drug-Induced Torsade de Pointes.

Background Amiodarone causes less drug-induced torsade de pointes (TdP) compared to other class III antiarrhythmics. Two theories proposed for this finding include that amiodarone has less repolarization heterogeneity, and/or decreases early after depolarization (EADs). Corrected QT (QTc) dispersion as measured on a surface electrocardiogram (ECG) represents spatial heterogeneity of ventricular repolarization.

Utility of a Leadless Pacemaker as a Backup to Left Ventricle-only Pacing in a Patient with Prior Device-related Severe Tricuspid Regurgitation.

The contribution of endocardial cardiac device leads to severe tricuspid regurgitation (TR) has become increasingly recognized. Current strategies for treating cardiac device lead-related TR have limitations. We present a case of a pacemaker-dependent patient with severe TR as a complication of multiple cardiac device leads who underwent laser lead extraction, which was followed by implantation of a dual-chamber pacemaker with a coronary sinus lead for left ventricular pacing and a leadless transcatheter pacemaker for backup right ventricular (RV) pacing.

Comparison of Predictors of Heart Failure With Preserved Versus Reduced Ejection Fraction in a Multiracial Cohort of Preclinical Left Ventricular Diastolic Dysfunction.

Preclinical diastolic dysfunction (PDD) is a well-known but poorly understood risk factor for heart failure. We aimed to investigate risk factors contributing to progression of PDD to heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). Patients with echocardiogram from 2003 to 2008 with left ventricular ejection fraction ≥50%, grade I diastolic dysfunction, and free of clinical heart failure were included.

Ventricular septal rupture complicating acute myocardial infarction in the modern era with mechanical circulatory support: a single center observational study.

Ventricular septal rupture (VSR) is a rare but devastating complication after acute myocardial infarction (AMI). While the incidence has decreased, the mortality rate from VSR has remained extremely high. The use of mechanical circulatory support with intra-aortic balloon pump (IABP) and extracorporal membrane oxygenation (ECMO) may be useful in providing hemodynamic stability and time for myocardial scarring.

Mechanical valve obstruction: Review of diagnostic and treatment strategies.

Prosthetic valve obstruction (PVO) is a rare but feared complication of mechanical valve replacement. Diagnostic evaluation should focus on differentiating prosthetic valve thrombosis (PVT) from pannus formation, as their treatment options differ. History of sub-optimal anti-coagulation and post-op time course to development of PVO are useful clinical characteristics in differentiating thrombus from pannus formation.

Patent foramen ovale: Unanswered questions.

The foramen ovale is a remnant of the fetal circulation that remains patent in 20-25% of the adult population. Although long overlooked as a potential pathway that could produce pathologic conditions, the presence of a patent foramen ovale (PFO) has been associated with a higher than expected frequency in a variety of clinical syndromes including cryptogenic stroke, migraines, sleep apnea, platypnea-orthodeoxia, deep sea diving associated decompression illness, and high altitude pulmonary edema. A unifying hypothesis is that a chemical or particulate matter from the venous circulation crosses the PFO conduit between the right and left atria to produce a variety of clinical syndromes.