The Electrical Axis of the Heart in Nigerian Patients with Chronic Obstructive Lung Disease in Benin City

Background: Of the electrocardiographic changes in chronic obstructive lung disease (COLD) patients, a shift of the P wave axis greater than 90° which is highly characteristic, is said to be due to hyperinflation and does not occur in interstitial lung disease. Objective : To describe the electrocardiographic changes in chronic obstructive lung disease patients. Methods: The electrical axis of the various waves of the ECG using the hexiaxial reference system in 92 Nigerian patients with COLD were examined, 39 of whom had associated cor pulmonale,. P wave axis greater than 90° was present in 2(19.1%) of 17 patients with COLD alone and 15(41.7%) out of 36 with development of cor pulmonale (p<0.001). The mean P wave axis was 64.7 ± 10.6° in those without cor pulmonale while it was significantly shifted to the right (83.9°) in those with cor pulmonale. The mean QRS axis was 53.50 ± 21.2° and 89.0 ±12.4° in those without and with cor pulmonale respectively (p=0.7716). The QRS axis was normal in all but one of those without cor pulmonale while there was a right axis deviation in 51.7% of those with it. ST and T wave changes were mainly present in those with associated cor pulmonale. Conclusion: The study shows that a shift of the electrical axis of the heart occurs in COLD patients mainly with the development of right ventricular hypertrophy (cor pulmonale), rather than the hyperinflation.