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

Background: A negative sinus P wave in lead V (NPV ) 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 (PPV ), and biphasic (BPV ) P waves in V , as well as NPV .

Some observations on and controversies about coronary arterial spasm.

The pathogenesis, clinical features, diagnosis, and treatment of spasm of epicardial coronary arteries are reviewed briefly, especially with regard to some issues that remain controversial. For diagnosis, emphasis is placed on the need for objective observations during an attack, even if that requires an attempt at pharmacologic provocation during coronary arteriography, or during echocardiography when prior arteriography has demonstrated the absence of severe coronary stenosis.

The fragmented QRS: does it really indicate a ventricular abnormality?

Objective: Notching of R and S waves in the QRS complex can result from myocardial infarction. As defined in recent studies, the 'fragmented QRS' (fQRS) showed high sensitivity and specificity for the presence of myocardial scar as imaged by myocardial perfusion scanning in participants studied for ischemic heart disease. The present study attempted to determine the significance of the fQRS in electrocardiograms of patients who had myocardial imaging for a variety of reasons by a variety of methods.

Left septal fascicular block: myth or reality?

Anatomic studies have shown that the left bundle branch divides into three fascicles in most humans. Changes in the 12 lead ECG (electrocardiogram) due to conduction abnormalities of the left anterior fascicle and left posterior fascicle are now part of the standard repertoire of electrocardiographic interpretation. There are no standard criteria for detecting conduction defects involving the third left fascicle, the septal or median fascicle, and the very existence of such defects is still a matter of controversy.