Significance of a negative sinus P wave in lead V 2 of the clinical electrocardiogram.

BACKGROUND: A negative sinus P wave in lead V2 (NPV2 ) of the electrocardiogram (ECG) is rare when leads are positioned correctly. This study was undertaken to clarify the significance of an unusually high incidence of this anomaly found in ECGs at my institution.

METHODS: One thousand four hundred thirty-five ECGs were randomly selected to determine the incidence and gender frequency in tracings showing positive (PPV2 ), and biphasic (BPV2 ) P waves in V2 , as well as NPV2 . To those cases with NPV2 , 84 cases with that anomaly from earlier archived ECGs were added to give a larger group for analysis. Medical records were reviewed for clinical details and other archived ECGs.

RESULTS: PPV2 , BPV2 , and NPV2 were found in 1,216 (84.5%), 150 (10.5%), and 69 cases (4.8%), respectively. Cases with NPV2 were more likely to be female (46 of 69 or 67.7%) than were those with either PPV2 (500 of 1,216 or 41.1%; p < .001), or BPV2 (71 of 150 or 47.3%; p < .01). NPV2 was commonly associated with ECG findings of left atrial abnormality (LAA), septal myocardial infarction, or a ventricular repolarization abnormality, but when multiple ECGs were available in these cases, such abnormalities were usually absent when there was either PPV2 or BPV2 .

CONCLUSIONS: With correct precordial lead placement, NPV2 is rare and BPV2 is also uncommon, and their presence should alert one to the probability of high placement of V1 and V2 , which can produce ECGs that mimic LAA, septal infarction, and ventricular repolarization abnormality.