The initial part of the ECG shows a regular rhythm at a rate of 140 beats/min, with an abrupt slowing to rates ranging from 50 to 68 beats/min. All of the QRS complexes are identical, with a normal ...

At quick glance, this looks like an electrical alternans. But careful examination, especially of V4, shows that every other beat has a shorter PR interval and a slurred upstroke (delta wave), ...

2. Short PR interval and delta waves consistent with Wolff-Parkinson-White (WPW) syndrome Explanation: Wolff-Parkinson-White syndrome occurs when a person is born with an "accessory pathway" that can ...

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, ...