"Ischemic" Heart Disease in Fire Fighters with Normal Coronary Arteries

Abstract

Near maximal stress testing conducted on a group (N = 90) of randomly selected Los Angeles City [California, USA] fire fighters (age 40-59 yr) revealed that 10% had ischemic ECG changes. These ischemic ECG responses were confirmed during a 2nd test conducted 2-4 wk after the initial test. Coronary heart disease (CHD) risk factor analysis revealed that generally the men were not at high risk for CHD. Six of the 9 men elected to undergo cardiac catheterization and angiography. One patient had severe triple vessel disease and subsequently underwent aorto-coronary bypass surgery. Another has 50% obstruction in the circumflex branch of the left coronary while the other 4 men had no visible signs of coronary obstruction. The men with normal coronaries, however, did show signs of abnormal cardiac function during atrial pacing. One man had cardiac enlargement, hypokinesis, ischemic ECG and abnormal lactate metabolism. Another had abnormal lactate metabolism and ischemic ECG. A 3rd man had moderate cardiac enlargement with anterior wall hypokinesis. The 4th had ischemic ECG changes with angina but otherwise normal cardiac function. All 4 of these men had pressures within normal limits. Some fire fighters have ischemic heart disease with patent coronary arteries. This disease may be due to job related factors (i.e., Co and other noxious fumes, catecholamines, etc.) which reduce myocardial O2 supply or greatly increase myocardial O2 demands.