Electrocardiographic Changes in Coronary Care Unit Patients During Defecation

Abstract

Fifty-one consecutive patients admitted to a coronary care unit were mon itored for ECG changes while having a total of 63 bowel movements (BM's). Twenty-three patients had proven myocardial infarction while 28 had no acute cardiac disease. ECG changes in patients using either commode or bedpan facilities were compared during defecation. Patients using the commode were found to have a greater increase in heart rate and other nonspecific ECG abnormalities compared to those using the bedpan.

Electrocardiographic changes and occasional deaths have been reported during defecation ¹ and instrumentation ^2,3 of the rectum.⁴ The sudden increase in intrathoracic pressure while straining is thought to initiate the cardiovascular changes that lead to these events. The alterations in cardiovas cular dynamics which follow a "strain" are similar to those occurring during a Valsalva maneuver. ⁵ The published studies in this area present observations of subjects performing the Valsalva maneuver under controlled conditions, or in individuals without heart disease.⁶ With this in mind, patients with known or suspected acute myocardial infarction admitted to a coronary care unit were studied for electrocardiographic and heart rate changes during defecation. In addition an effort was made to compare changes occurring while using the bedpan to those observed while sitting on a commode.