EFFECT OF BLOOD-GAS DERANGEMENT ON QTC DISPERSION IN SEVERE CHRONIC OBSTRUCTIVE PULMONARY-DISEASE - EVIDENCE OF AN ELECTROPATHY

Cardiac arrhythmias are common in patients with respiratory failure fr om chronic obstructive pulmonary disease (COPD). Several factors may b e potentially arrhythmogenic in these patients, including hypoxemia an d hypercapnia, acid-base disturbances, cor pulmonale and the use of di gitalis, methylxanthines, and sympathomimetic drugs. The aim of this s tudy was to examine the effect of hypoxemia and hypercapnia on QTc dis persion (QTcD) in COPD patients, and to evaluate the effect of a parti al correction of one of these pro-arrhythmic factors, the hypoxemia, o n Qtc dispersion, as QTcD has been proposed as a marker of heterogeneo us repolarization and, hence of ventricular electrical instability. We showed that in 15 hypoxemic/hypercapnic COPD patients, compared to 20 controls, the QTcD was significantly higher (49.7+/-10.6 vs. 22.9+/-9 .8 ms; P=0.0001); furthermore, after only 24 h of oxygen therapy, and hence after a partial correction of hypoxemia, there was a significant reduction in QTcD in COPD patients (49.7+/-10.6 vs. 36.3+/-10.1 ms; P =0.018). The data of the present study suggest that the increase in QT cD may be an early marker of a blood gas mediated electropathy in COPD patients. Copyright (C) 1997 Elsevier Science Ireland Ltd.