Toxicologic Myocardial Sensitization

Drug-induced polymorphic ventricular tachycardia (torsades de pointes) may lead to syncope or sudden cardiac death. One mechanism by which drugs and toxins may predispose to the development of this malignant dysrhythmia is through their ability to produce myocardial sensitization. The concept of myocardial sensitization actually represents a series of events involving altered cellular repolarization produced by blockade of myocardial potassium channels. Altered potassium ion flow raises the likelihood that an ectopic beat will occur via an early afterdepolarization and simultaneously alters the myocardial tissue to make it favorable for reentrant dysrhythmias, such as torsades de pointes, to propagate. Alternatively, calcium overload of the myocyte produces ectopy by causing delayed afterdepolarizations, which if the substrate for reentry is present, will result in ventricular tachycardia. This paper discusses the mechanisms underlying the production of both the altered myocardial substrate and the afterdepolarizations.     

Risk stratification in surgically repaired tetralogy of Fallot

Tetralogy of Fallot is the most common form of congenital heart disease in implantable cardioverter–defibrillator (ICD) recipients. Indeed, sudden death of presumed arrhythmic etiology is the most frequent mode of demise in patients with surgically repaired tetralogy of Fallot, often in early-to-mid adulthood. Nevertheless, the overall annual incidence of sudden death is actually low. Therein lies the major challenge of risk stratification. This review highlights some of the complexities involved in risk stratifying patients with tetralogy of Fallot, underscoring the importance of avoiding oversimplification by means of a rigid algorithm that dictates therapy. To complement sound clinical judgment, a quantitative probabilistic approach is presented, which considers the body of literature from primary prevention ICD trials, risk factors identified by observational studies, the value of programmed ventricular stimulation and insights gleaned from studying ICD recipients with tetralogy of Fallot.     

Lemierre's syndrome

Lemierre's syndrome is a rare disease, mostly affecting young adults in good health, which can lead to significant morbidity and mortality. We report one case with favourable outcome and clinical features stereotypics: angina, septic thrombosis of the internal jugular vein, pulmonary septic metastasis, Fusobacterium necrophorum on blood cultures. Antibiotic therapy targeting anaerobes has been rapidly initiated and maintained 4-6 weeks. The anticoagulation has been maintained 4 weeks.