Common Cardiovascular Anomalies and Diseases Heart Attack: This is a vascular disease of the heart characterized by inadequate blood supply to heart muscle leading to their damage and ultimate death. Heart Block: This is a nervous disease of the heart in which the ventricles contract independent of the SA node. In this condition the heart usually beats at a slower rate most of the time.

Myocardial Infarction (MI): This is a vascular disease of the heart characterized by necrotic myocardial changes following inadequate or interrupted blood flow to the myocardium. It is most commonly caused by coronary insufficiency resulting from atherosclerosis of the coronary arteries. Myocardial infarction could be slowly progressive or acute (sudden) in nature. The necrotic myocardial tissue is usually replaced by fibrous tissue scar.

Angina Pectoris: This is severe constricting pain or feeling of tightness in the chest. It is usually caused by arterial constriction due to: 1.Stress 2.Strenuous exercise after a heavy meal 3.Sudden exposure to a cold environment Angina pain is normally relieved by a few minutes of rest after it occurred It is also relieved by the administration of a vasodilator e.g. Sublingual Nitroglycerin which relaxes the coronary arteries. Angina pain is often less severe than the pain of myocardial infarction which is also not relieved by rest.

Cardiac Functions and Ions Low Potassium and Calcium in blood depresses the heart while Excess of calcium could lead to sustained cardiac muscle contraction resulting in death (Death by lethal injection)

SOME CARDIAC PARAMETERS Heart rate (HR): Female /min Male – 64-72/min Average – 75/min Fetal heart rate = Abnormal Heart rate Tachycardia = over 100/min Bradycardia = below 60/min Stroke Volume (SV) – 70ml (Same for right and left ventricles) Cardiac output – HR x SV =70 x 75 = 5252ml = approximately 5 litres. Systemic BP120/80 mmHg Pulmonary BP25/8 mmHg

End-Diastolic-Volume120ml. End-Systolic-Volume50ml Therefore, Stroke volume = EDV-ESV= =70ml Venous return is increased by: 1.Slow heart rate 2.Exercise Venous return increases EDV

Afterload = Back pressure exerted by Arterial Blood. It is the pressure the ventricles must overcome before they could eject blood. It is equal to the diastolic pressure (80 or 8 mmHg) and impedes the ability of the ventricles to release blood. High afterload leads to high ESV but reduced SV