Significance of electrocardiographic isolated abnormal terminal P-wave force (left atrial abnormality). An echocardiographic and clinical correlation.

An abnormal terminal negative deflection in precordial lead V1 (PTFV1) is occasionally present as an isolated electrocardiographic finding. To determine the significance of this, 41 patients with PTFV1 greater than or equal to 0.04 mms were recalled for a repeated electrocardiogram as well as an echocardiographic examination. Patients were classified as cardiovascular normal (n = 15) or abnormal (n = 26). Left atrial enlargement was the most common echocardiographic abnormality found, but represented less than a third of the total. P-wave prolongation (greater than 110 ms) was present in 30 of the 41 patients and 21 of the 26 abnormal patients. This persisted into the second study, while the PTFV1 fell significantly in both the normal and abnormal groups. Among the P-wave abnormalities found, combinations were used to identify patients most likely to have cardiovascular disease. The most discriminating was an initial abnormal PTFV1 in combination with P-wave prolongation (sensitivity, 82%; specificity, 40%; positive predictive value, 70%; and negative predictive value, 55%). Maximal specificity (93%) and positive predictive value (88%) were achieved when P-wave prolongation and PTFV1 greater than or equal to 0.06 mms were present in both studies, although the sensitivity for this criterion was only 27%. The isolated P-wave abnormality described may be helpful in suggesting the presence of underlying cardiovascular disease and indicate the need for further evaluation.