The consequences of decreased coronary blood flow are influenced by the quantum of reduction in blood flow and the duration of the reduced blood flow. Decreased coronary blood flow results in oxygen deprivation to the heart muscles and when this disruption is slight the consequence is impairment in the relaxation of the heart muscle and weakened contraction, as experienced in the case of angina pectoris. This decreased blood flow may be transient, which is reversible through the use of nitroglycerin tablets. However, when the ischemia due to reduced coronary blood flow is prolonged it may lead to decreased myocardial contraction or dyskinesis that is not easily reversible and prolongs for many hours. The consequence of chronic reduction in coronary blood flow is the failure of the myocardium to contract normally termed hibernation, which may or may not result in necrosis of the myocardium. Severe blockage of the coronary blood flow results in myocardial infarction. In all these consequences due to impaired coronary blood flow substantial dyskinesis occurs, causing the rest of the myocardium to take up this extra load. This results in hypertrophy of the unaffected portions of the ventricle (Fuster et al, 2004).
Cardiac catheterization is an invasive procedure that is conducted to evaluate blood flow to the myocardium of the heart and assess the effectiveness of the pumping of the heart. In cardiac catheterization a medical professional introduces a thin plastic tube called the catheter into an artery or vein of the arms or leg. From this site it is progressively advanced into the chambers of the heart or the coronary arteries for the required evaluation (American Heart Association, 2009).
Even though there has been continual improvement in the techniques employed in noninvasive testing of hemodynamics to provide greater accuracy, cardiac catheterization has