Exercise-induced desaturation and electrocardiogram changes in people with severe lung disease: An exploratory investigation of 25 serial cases

BackgroundArterial desaturation is a commonly accepted clinical basis for discontinuing physical activity in people with chronic obstructive pulmonary disease.ObjectiveThe purpose of this exploratory study was to examine the electrocardiograms of people with severe chronic obstructive pulmonary disease recovering from exercise-induced arterial desaturation.SubjectsSubjects (n = 25) walked for 6 minutes while oxygen saturation was monitored.MethodsWhen the Spo2 decreased below 90%, subjects were asked to sit and rest while the electrocardiograms were recorded. For all patients, Spo2 decreased 11.6% on average below baseline during walking. Four patients developed dysrhythmias during desaturation, with a mean lowest Spo2 of 85%. The Spo2 in six other patients continued to decrease below 80% despite rest, yet these patients did not develop new dysrhythmias.ConclusionsOur findings suggest that a decrease in Spo2 during exercise does not necessarily correlate with cardiac rhythm.