Ischemic Heart Disease - Presentation and Diagnosis MCQs

Ans. is `b' i.e., Nicotine and carbon monoxide and tar Mechanisms for smoking-induced Coronary heart disease Carbon monoxide induces atherogenesis. Nicotine stimulation of adrenergic drive raising both BP and myocardial oxygen demand. Lipid metabolism with fall in protective high-density lipoproteins. Note : Tar is associated with carcinogenesis (not atherosclerosis). But amongst the given options option b is the best answer as it consists of both nicotine and CO.

ECG changes start to manifest usually when serum K > 6 mEq/L The earliest ECG finding in a patient with hyperkalemia is tall, tented T waves It is followed by other changes like P wave flattening, PR prolongation, QRS widening, appearance of sine wave pattern Hypokalemia is characterised by ECG changes like T wave flattening/inversion, ST segment depression, appearance of 'u' wave and prolonged QU interval. Reference: Harrison's Principles of Internal Medicine 21 st edition Page 1911

Right coronary artery supplies the right ventricle, the posterior third of the interventricular septum, the inferior wall of the left ventricle and a portion of the posterior wall of the left ventricle. (leads II, III, aVF corresponds to inferior wall) Occasionally the posterior interventricular septum may be supplied by a branch of the of the left circumflex artery, called left dominant circulation. The left anterior descending and left circumflex coronary arteries arise at the left main coronary artery bifurcation and supply the anterior left ventricle, the bulk of the interventricular septum (anterior two thirds), the apex, and the lateral and posterior left ventricular walls. Reference: Harrison's Principles of Internal Medicine 21 st edition Page no: 2035

The frequency of involvement of coronaries in MI is left anterior descending artery > right coronary artery > left circumflex artery Left anterior descending artery is also referred to as 'widow's artery'. Reference: Harrison's Principles of Internal Medicine 21 st edition Page no: 2044

Nitrates are often effective in patients with syndrome X, which is currently termed 'microvascular angina'. Cardiac syndrome X consists of angina-like chest pain during exertion, characteristic ECG changes during exercise testing, normal coronary arteries on cardiac catheterisation and no inducible coronary artery spasm during catheterisation. It should not be confused with the metabolic syndrome X, which comprises central obesity, glucose intolerance, dyslipidemia, and high blood pressure. Reference: Harrison's Principles of Internal Medicine 21 st edition Page no: 2031, 2034

Right ventricular myocardial infarction (RVMI) usually occurs in association with an inferior-wall left ventricular infarction, as revealed by the ECG. In ECG, along with ST elevation in leads II, III, aVF which suggests an inferior wall MI, a patient with RVMI may also have ST elevation in V1 and in right sided chest leads V3R-V6R. The typical clinical findings in RVMI include bradycardia (due to AV node involvement), hypotension, raised JVP with positive Kussmaul sign (inspiratory rise of JVP). Hypotension is typically treated with IV fluids (0.9% saline) There is usually a right coronary occlusion. Characteristic clinical features include a low cardiac output syndrome with jugular venous distension but no pulmonary vascular congestion. Reference: Harrison's Principles of Internal Medicine 21 st edition Page no: 2062

Neurogenic shock is associated with bradycardia and hypotension. It is a type of distributive shock.

The history of acute loss of vision affecting one eye suggests an acute vascular occlusion, especially given the associated vascular risks. The others cause a more chronic visual loss. Reference: Harrison's Principles of Internal Medicine, 21 st ed, Ch: 32, Pg: 222