The Muscle-Bound Heart.

Hypertrophic cardiomyopathy (HCM) is a familial cardiac disease manifested in a wide phenotype and diverse genotype and, thus, presenting unpredictable risks mainly on young adults. Extensive studies are being conducted to categorize patients and link phenotype with genotype for a better management and control of the disease with all its complications. Because the full mechanisms behind HCM are still not revealed, therapeutics are not definitive.

Arrhythmogenic Right Ventricular Cardiomyopathy Caused by a Novel Frameshift Mutation.

Arrhythmogenic right ventricular cardiomyopathy is a rare cardiomyopathy that might be asymptomatic or symptomatic, causing palpations or syncope, and might lead to sudden cardiac death. It is recommended that physical exertion be reduced. It is also recommended that those with syncope and ventricular tachycardia/ventricular fibrillation have an implantable cardioverter-defibrillator placed.

Incessant Long R-P Tachycardia.

A 13-year-old boy had a positive P wave in V1 with a negative P wave in lead I, aVL, and aVR, as well as a positive P wave in the inferior leads, which correlated with a left atrial appendage (LAA) atrial tachycardia (AT) focus. P-wave morphologies can provide clues regarding an AT's origin, and this P-wave negative in lead I favored LAA AT. Careful mapping along the atria and coronary sinus to determine the earliest site of activation for the surface P wave is a reliable method for precisely localizing the AT origin as a target for catheter ablation.

Utility of the exercise electrocardiogram testing in sudden cardiac death risk stratification.

Background: Sudden cardiac death (SCD) remains a major public health problem. Current established criteria identifying those at risk of sudden arrhythmic death, and likely to benefit from implantable cardioverter defibrillators (ICDs), are neither sensitive nor specific. Exercise electrocardiogram (ECG) testing was traditionally used for information concerning patients' symptoms, exercise capacity, cardiovascular function, myocardial ischemia detection, and hemodynamic responses during activity in patients with hypertrophic cardiomyopathy.