Medicine Hack

Definition: It is an abnormal communication between an artery and a vein (or veins). It may be 1) a congenital malformation, 2) acquired by the trauma of a penetrating wound, 3) iatrogenic in which AVFs are created surgically in the arms or legs of patients undergoing renal dialysis. All arteriovenous communications have a structural and a physiological effect. Structural effect: The veins become dilated, tortuous and thick walled (arterialised). Physiological effect: There is high-pressure from the arterial system and an enhanced venous return/venous pressure. This results in an increase in pulse rate and cardiac output. The pulse pressure is high if there is a large and persistent shunt. Left ventricular enlargement and later cardiac failure may occur. A congenital fistula in the young may cause overgrowth of a limb. In the leg, indolent ulcers may result from relative ischaemia below the short circuit. Clinical features: Clinically, a pulsatile swelling or dilated to

Women Men Measure Reference Range Abnormal Reference Range Abnormal Mildly Moderately Severely Mildly Moderately Severely Linear method Endocardial fraction shortening, % 27-45 22-26 17-21 ≤16 25-43 20-24 15-19 ≤14 Midwall fractional shortening, % 15-23 13-14 11-21 ≤10 14-22 12-13 10-11 ≤10 2D method Ejection fraction, % ≥ 55 45-54 30-44 < 30 ≥ 55 45-54 30-44 < 30

CEA is an oncofetal antigen, a glycoprotein that is usually produced only during fetal life and is not present in the healthy adult blood. It is associated with certain malignancies, particularly epithelial tumors. It is a very non-specific tumour marker. Normal values: Non-smokers: 0–3 ng/mL [μg/L] Smokers: 0-5 ng/mL [μg/L] Elevated levels in:   1) Adenocarcinoma of colon cancer (72%) (right side of colon>left side),  2) Pancreatic cancer (91%),  3) Lung cancer (76%),  4) Stomach cancer (61%),  5) Breast cancer,  6) Cancer of ovary,  7) Cholangiocarcinoma,  8) Gall bladder cancer. Other non-neoplastic conditions include:  1) Cigarette smokers,  2) Benign liver disease (acute 50% and chronic 90%),  3) Benign GI disease (peptic ulcer, pancreatitis, colitis,cholecystitis). Elevations >20 ng/mL are generally associated with malignancy and metastasis. Screening:   The test is not sensitive or specific enough to be useful in cancer screening

Right Axis Deviation I. Spurious: left-right arm electrode reversal (look for negative P wave and negative QRS complex in lead I) II. Normal variant III. Dextrocardia IV. Right ventricular overload A. Acute (e.g., pulmonary embolus or severe asthmatic attack) B. Chronic 1. Chronic obstructive pulmonary disease 2. Any cause of right ventricular hypertrophy (e.g., pulmonic stenosis or primary pulmonary hypertension) V. Lateral wall myocardial infarction

Low-Voltage QRS Complexes 1. Artifactual or spurious (especially unrecognized standardization of the ECG at half the usual gain, i.e., 5 mm/mV). Always check this first! 2. Adrenal insufficiency (Addison's disease) 3. Anasarca (generalized edema) 4. Cardiac infiltration or replacement (e.g., amyloid, tumor) 5. Cardiac transplantation, especially with acute or chronic rejection 6. Cardiomyopathies 7. Chronic obstructive pulmonary disease 8. Constrictive pericarditis 9. Hypothyroidism/myxedema (usually with sinus bradycardia) 10. Left

APBs result from ectopic stimuli i.e. these beats arise from somewhere in either the left or right atrium but not in the SA node. After an atrial depolarization, the stimulus that spread normally through the His-Purkinje system into the ventricles gives a normal QRS complex. APBs have the following major features:   1. The atrial depolarization is premature, occurring before the next normal P wave is due. 2. The QRS complex of the APB is often preceded by a visible P wave that usually has a slightly different shape and/or different PR interval from the P wave seen with normal sinus beats. The PR interval of the APB may be either longer or shorter than the PR interval of the normal beats. In some cases, the P wave may be buried in the T wave of the preceding beat. 3. After the APB, a slight pause generally occurs before the normal sinus beat resumes. This usually slight delay is due to “resetting” of the SA node pacemaker by the premature atrial stimulus. This slight delay contras