Ventricular Tachycardia ECG Characteristics

One of the key differences between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) on an electrocardiogram (ECG) is the absence of P waves in both conditions, along with a heart rate exceeding 100 beats per minute. In normal ECG readings, P waves are present and represent atrial depolarization. However, in tachycardic conditions, this pattern changes significantly.

ECG Features of Supraventricular Tachycardia

In cases of supraventricular tachycardia, the ECG typically shows visible T waves and normal QRS complexes. These QRS waves are narrow in shape, with durations ranging from 0.06 to 0.10 seconds, and generally do not exceed 0.12 seconds. This narrow QRS complex indicates that the electrical impulse is following the heart's normal conduction pathway, despite the elevated heart rate.

ECG Indicators of Ventricular Tachycardia

Key Diagnostic Criteria

On the other hand, ventricular tachycardia presents with a more distinct ECG pattern characterized by the absence of T waves and a QRS duration longer than 0.12 seconds. This widened QRS complex suggests that the abnormal electrical activity originates from the ventricles rather than the atria or sinus node.

Clinical Implications

Ventricular tachycardia is often associated with structural heart disease and poses a higher clinical risk compared to supraventricular tachycardia. It may lead to hemodynamic instability and, in severe cases, progress to ventricular fibrillation—a life-threatening arrhythmia. Therefore, prompt identification and management of VT are crucial in clinical settings.