RIGHT PRECORDIAL Q-WAVES DUE TO ANTERIOR FASCICULAR BLOCK - CLINICAL AND VECTORCARDIOGRAPHIC STUDY

The ECG and clinical data of 1008 patients with anterior fascicular block (AFB) were analysed. The patients were divided into two groups: group 1, those showing no q waves in precordial leads V2 V3; and group 2, 139 patients (13.78%), showing qrS pattern in V2, V3 leads with small, narrow and not-slurred q waves. In the first group, 35 patients had no clinically manifest cardiac disease and 19 patients had congenital heart disease. There were patients in this group in all decades of life. No patient in group 2 was in the first three decades of life and all had some form of acquired heart disease. Vectorcardiograms (VCG) of 35 control patients with normal electrocardiograms (ECG), 32 patients with AFB without q waves, and 30 patients with AFB and q waves were analysed and compared. The 10 and 20 msec vectors in patients with AFB, as compared to normal patients, showed a more inferior (P<0.005) and posterior (P<0.001) orientation. The posterio orientation of these vectors was more marked when q waves were associated with AFB (P<0.001). This orientation represents the VCG equivalent of the q waves seen in the ECG. There is evidence from our data, therefore, that AFB, by modifying the septal activation, causes a posterior shift of the first vector, thus facilitating the appearance of q waves if there is also a loss of septal electrical forces, as is seen with septal fibrosis or peripheral septal block. © 1978 Research in Electrocardiology, Inc.