Suspected acute myocardial infarction: intravenous beta-blockade outside the coronary care unit: a pilot study

ABSTRACT

Shortage of Coronary Care Unit (CCU) beds prompted a study (I) to determine the number of patients with a suspected acute myocardial infarction (SAMI) who could not be placed in the CCU, but qualified for intravanous (IV) B-Blocker therapy, and (II) to assess the safety of such therapy in a general medical ward. During a six-month period, 34 patients with chest pain and E.C.G. changes of SAMI could not be placed in the CCU. Criteria for exclusion from B-Blocker therapy were the presence of >= 1 of the following (1) age > 70 years, (2) Systolic B.P. < 100 mmHg, (3) Heart rate < 60 /min., (4) Cardiac failure, (5) Heart block, (6) Poor peripheral circulation, (7) Asthma or chronic bronchitis, and (8) Prior therapy with B-Blocker or calcium antagonists. 15 (44 percent) patients were excluded from therapy based on the above criteria. 19 (56 percent) received 5-10 mg atenolol IV within 3-10 hours of onset of chest pain and atenolol 100 mg daily was started immediately and continued indefinitely. 12 of these patients had an anterior wall, and 3 an inferior wall infarction. 3 developed congestive cardiac failure and none required anti-arrhythmic therapy. There were 2 deaths - 1 from ventricular asystole, and the other from cardiogenic shock 8 and 12 hours respectively after IV atenolol. While this small-scale study highlights the need for more CCU beds for optimum care, our results suggest that selected patients with SAMI managed in the general medical wards can still safely obtain the benefits of IV B-Blockade. (AU)