The electrocardiogram (ECG) is a valuable tool for assessing the cardiac conduction system. The measurements routinely obtained with ECG include heart rate, PR interval, QRS duration and the QT ...

In myocardial excitation, the delay between the excitation of the atria and ventricles is determined by the sum of atrial and atrioventricular nodal conduction. This delay, measured in milliseconds, ...

A first-degree atrioventricular node block occurs when conduction through the AV node is slowed, thereby delaying the time it takes for the action potential to travel from the sinoatrial node through ...

A 68-year-old male with morbid obesity and no past medical history comes to the office complaining of fatigue and shortness of breath. He does not feel dizzy and has never passed out. He takes no ...

A common electrocardiogram finding that has largely been considered insignificant may actually signal an increased risk of atrial fibrillation, the future need for a permanent pacemaker and an ...

The diagnosis is normal sinus rhythm, atrial bigeminy, first-degree atrioventricular (AV) block (prolonged AV conduction), and right bundle branch block (RBBB). The rhythm is slightly irregular, with ...

QRS interval widening appears to be highly specific for the diagnosis of hyperkalemia in patients with end-stage kidney disease. ECG changes, in general, have poor sensitivities for hyperkalemia in ...

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center. College athletes who have recently recovered from COVID-19 infection show cardiac abnormalities on ...

This cohort study assessed ECG parameters in transgender men and women before and after use of gender-affirming hormone therapies. Testosterone use in transgender men was associated with shorter ...

The U.S. Federal Aviation Administration (FAA) broadened a standard for normal heart function in pilots because medical evidence showed no symptoms or additional health risk up to the raised threshold ...