What is a Delta wave on an ECG?

As a medical professional with expertise in cardiology, I can explain that a Delta wave on an ECG (electrocardiogram) is a specific type of waveform that can indicate the presence of a pre-excitation syndrome, most commonly Wolff-Parkinson-White (WPW) syndrome. This condition is characterized by an abnormal electrical pathway in the heart that can lead to a variety of heart rhythm disturbances. Here's a step-by-step breakdown of the Delta wave: 1. Identification: The Delta wave is identified by its slurred, slow upstroke from the baseline, which is best seen in the initial part of the QRS complex. 2. Significance: The presence of a Delta wave suggests that there is an accessory pathway conducting electricity ahead of the normal conduction system, causing a portion of the heart muscle to be activated early. 3. Implications: This early activation can lead to a rapid heart rate (tachycardia) and, in severe cases, a life-threatening condition called sudden cardiac death. 4. Diagnosis: The diagnosis of WPW syndrome is made by observing the characteristic Delta wave on an ECG, along with symptoms such as palpitations, dizziness, or fainting. 5. Treatment: Treatment options for WPW syndrome include medication to control heart rate and rhythm, and in some cases, a procedure called catheter ablation to eliminate the accessory pathway.

WPW is commonly diagnosed on the basis of the electrocardiogram in an asymptomatic individual. In this case, it is manifested as a delta wave, which is a slurred upstroke in the QRS complex that is associated with a short PR interval.