Where do PVCs typically fall in relation to the previous heartbeat?

Premature ventricular contractions (PVCs) are characterized by an early occurrence of a heartbeat originating from the ventricles. When analyzing the typical ECG waveform, the relationship of PVCs to the previous heartbeat is crucial for understanding their nature.

PVCs typically occur after the T wave of the preceding heartbeat. In a normal cardiac cycle, the T wave represents the repolarization of the ventricles, indicating the end of the previous ventricular contraction. When a PVC occurs, it interrupts this normal cycle and presents as a QRS complex that is wider and differently shaped compared to the normal QRS complex that follows the atrial depolarization (represented by the P wave).

Understanding this timing is important for interpreting arrhythmias and managing patients' cardiac health, as it helps in determining the frequency and potential significance of the PVCs in relation to the overall cardiac rhythm. Recognizing that PVCs arise following the T wave allows healthcare providers to better assess the impact on the cardiac cycle and any associated symptoms the patient may experience.