What do delta waves signify on an ECG?

Delta waves on an ECG are characteristic of Wolff-Parkinson-White (WPW) syndrome, which is a condition caused by an accessory pathway (bundle of Kent) that allows for a faster conduction system in the heart. This results in early ventricular depolarization, which appears as a slurring of the upstroke of the QRS complex, referred to as delta waves.

In WPW syndrome, the presence of these delta waves is crucial in making the diagnosis, as they indicate the abnormal electrical conduction due to the accessory pathway. This condition can lead to episodes of tachycardia, and the recognition of delta waves on an ECG is essential for proper management and treatment.

In contrast, myocardial ischemia, left ventricular hypertrophy, and a normal variant would not produce delta waves; these conditions typically present with different ECG features. Myocardial ischemia might show ST segment changes or T wave abnormalities, left ventricular hypertrophy can present with increased voltage criteria, and normal variants typically do not include delta waves or the specific patterns seen in WPW.