Demonstration of Ventricular Parasystole on a Standard 12-Lead Electrocardiogram
James A Reiffel
During a clinical trial assessing the efficacy of ranolazine for the suppression of atrial fibrillation, a patient was encountered who, aside from paroxysmal atrial fibrillation, had premature ventricular complexes (PVC) on his electrocardiogram (ECG). A close examination of the ECG rhythm strip revealed that these PVC’s had: 1) a regular interectopic interval or multiple thereof (approximately 1720 ms), 2) fusion complexes with the underlying sinus rhythm QRS complexes, and 3) variable coupling intervals. This constellation of findings defines a parasystolic focus, making this rhythm sinus rhythm with ventricular parasystole. A dose of ranolazine 1000 mg po bid satisfactorily reduced the patient’s atrial fibrillation and also suppressed virtually all of the ventricular ectopy.
