Presentation 3

Ischemic Heart Disease(IHD)  is a condition in which there is an inadequate supply of blood and oxygen to a portion of the myocardium  it typically occurs when there is an imbalance between myocardial oxygen supply and demand.  The most common cause of myocardial ischemia is atherosclerotic disease of coronary artery  sufficient to cause a regional reduction in myocardial blood flow and  inadequate perfusion of the myocardium supplied by the involved coronary artery.  By far the leading cause of morbidity & mortality in industrialized countries  Clinicopathological syndromes of IHD are : Angina pectories  Characterized by paroxysmal pericordial chest pain caused by transient myocardial ischemia  There are three overlapping patterns

1

1. Stable angina  The commonest form  Caused by reduction of coronary perfusion mainly by fixed coronary atherosclerotic lesion  Relieved by rest & precipitated by physical & emotional exertion or any other cause that ↑ cardiac work load 2. Prinzemental (variant) angina  Relatively uncommon  It occurs at rest  Caused by coronary artery spasm  Generally respond to vasodilators( nitroglycerines, Ca+2 channel blockers ) 3. Unstable angina  Occurs at rest & progressively become sever ,lasts longer period  Induced by disruption of atherosclerotic plaque with superimposed thrombosis  Often is a harbinger of onset of MI 2

 Myocardial infarction ( MI )  Ischemic death of myocardial tissue associated with impaired blood flow sufficient to produce lethal cell injury  Obstructed blood flow can be caused by  Thrombosis, ulceration, and hemorrhage in an atherosclerotic plaque  Prolonged vasospasm  Based on morphology there are two types 1. Transmural MI necrosis involve full thickness of ventricular wall 2. Subendocardial ( intramural) MI necrosis involve inner half of ventricular wall Valvular heart disease  Dysfunction of the heart valves result from  Congenital defects  Ischemic damage  Degenerative changes  Inflammation  Rheumatic endocarditis is the most common cause

3

 In rheumatic endocarditis inflammatory changes cause  Scar tissue to form on the valve leaflets  Subsequent deformation of the valve structure  Two types of mechanical disruptions may occur in valvular disease  Narrowing of the valve opening( stenosis)  Failure of the valve to close completely(regurgitation) Myocardial heart disease  Cardiomyopathies  Describe heart disease resulting from 10 abnormalities in the myocardium  The causes in in many cases are unknown  Based on clinical, functional & pathological patterns it is classified in to three 3. Dilated cardiomyopathy  Most common type ( 90% )  Characterized by progressive cardiac hypertrophy, dilatation, & contractile ( systolic ) dysfunction  Myocaditis, alcohol, genetic defect are causes in minority of cases(<5%)

4

 In most cases the cause is unknown( idiopathic)  Morphology  The heart weighs 2-3x normal wt with dilatation chambers  Hypertrophied cardiac myocyte & interstitial fibrosis 1. Hypertrophic cardiomyopathy  Characterized by massive hypertrophy of left ventricle without cardiac chamber dilatation  Familial disease( can be inherited genetically)  Morphology  Disproportionate thickening of ventricular septum  Extensive myocyte hypertrophy  Interstitial fibrosis 2. Restrictive cardiomyopathy  Least common form  Characterized by abnormal rigidity of heart mainly due to gross endocardial thickening without dilatation

5

Congenital heart disease  Describe abnormalities of heart or great vessels that present since birth  Most arise from fault in embryogenesis during gestational weeks 3-8  Conventionally divided in to three 2.Cyanotic congenital heart disease  Produce cyanosis with right to left shunt  Include the following  Tetralogy of fallot  Transposition of great arteries  Trancus arteriosus 3.Acyanotic congenital heart disease  Left to right shift with no cyanosis  Include the following  Ventricular septal defect  Atrial septal defect  Patent ductus arteriosis

6

1. Obstructive congenital anomalies  Outflow obstruction with no shunt at all  May occur at the level of heart valves or within great vessels  Include  Aortic stenosis  Pulmonary stenosis  Coarctation of aorta  Tetralogy of Fallot  is the most common cyanotic congenital heart defect,  representing about 10% of all congenital heart defects  Anatomically, there are four structural defects:  VSD,  pulmonary stenosis,  overriding aorta and  right ventricular hypertrophy. 7

8