Note the premature ventricular contraction (PVC) that triggers the AVNRT in this ECG. If a premature atrial contraction (PAC) or premature ventricular contraction (PVC) occurs at the right time ...
This would even include sinus tachycardia with a right or left bundle branch block, atrial fibrillation/flutter with a right or left bundle branch block or AVNRT with a right or left bundle branch ...