الفهرس 
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Abstract
This prospective comparative observational study, to compare the incidence of myocardial injury in patients with hypovolemic shock versus septic shock, after approval of Ethical committee of critical care department on forty patients in general ICU divided into two groups of twenty patients each equal.
The primary function of the coronary circulation is to meet the metabolic demand of the heart. Coronary blood flow increases from the baseline or resting level to the maximum depending on myocardial oxygen requirements. An adequate increase of coronary blood flow is required to meet myocardial oxygen consumption, during exercise, the coronary blood flow increases up to 4–6 times.
In conditions such as left ventricular hypertrophy (LVH), myocardial ischemia, and diabetes mellitus (DM) the normal increase in coronary flow can be blunted. The maximal increase in coronary flow above resting levels is defined as coronary flow reserve (CRF). Myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle. MI may cause heart failure, an irregular heartbeat, cardiogenic shock, or cardiac arrest. A number of tests are useful to help with diagnosis, including electrocardiograms (ECGs), blood tests include troponin and creatine kinase MB.
In hemodynamic, patients with septic shock presented by lower value of mean arterial blood pressure (more hypotension) than hypovolemic shock, so patients with septic were more frequently hypotensive and in need of mechanical ventilation and inotropic support. ECG failed to identify all patients with elevated levels of cTnI, a low sensitivity of ECG in diagnosing the occurrence of acute myocardial injury has been reported in the critically ills.
The main finding in this study is the relationship between the duration of hypotension and cTnI levels: the longer the hypotensive episode was, the higher was the cTnI elevation. Arterial pressure is one of the most important determinants of myocardial blood flow. When systolic pressure falls below 80 mmHg, followed by maldistribution of coronary blood flow and the potential for myocardial ischemia and infarction may occur, as in previous study.
Cardiac troponin level was observed higher level in septic than in hypovolemic patients, due to toxins that adversely affected the vasoactive response of blood vessels and myocardial activity. This is inconsistent with previous study; hypovolemic patients have a higher levels of troponin I than patients in septic shock, and patients with a higher level of cardiac enzymes, and the longer episode of hypotension, have a higher incidence of myocardial infarction and have a higher mortality rate.