Cardiac-resynchronization therapy (CRT) reduces morbidity and mortality in chronic systolic heart failure with a wide QRS complex. Mechanical dyssynchrony also occurs in patients with a narrow QRS ...

The mechanism of the benefits achieved with the therapy has been attributed to resynchronization of the dyssynchronous segments resulting from bundle branch block, especially left bundle branch block ...

The rhythm is irregular, but the long intervals are the same (↔) and the short intervals (┌┐) are the same. One premature QRS complex (↑) is observed. Therefore, the rhythm is regularly irregular. The ...

The QRS complex consists of the Q wave, the R wave and the S wave. The QRS complex comes after the P wave when the SA nodal action potential travels through the AV node to the ventricles to cause ...

Narrow-complex tachyarrhythmias are rapid heart rhythms originating in the upper heart chambers, characterized by a QRS duration of less than 120 milliseconds on an EKG. These arrhythmias can be ...

A specialist tells how to interpret subtle changes on the ECG, including those caused by two life-threatening syndromes you might otherwise miss. Reading ECGs is like learning to appreciate art—it is ...