Cardiology — Flashcards

Flashcard 171: What is the main mechanism of simvastatin?

Answer: Inhibition of HMG-CoA reductase

Extra: Statins (like simvastatin) competitively inhibit HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis. This leads to an upregulation of LDL receptors on the surface of hepatocytes, increasing the clearance of LDL from the plasma.

Flashcard 172: How do you measure the QT interval on ECG?

Answer: • Time between start of the Q wave and the end of the T wave

Flashcard 173: Name the common thiazide-like diuretics used in the management of hypertension.

Answer: Indapamide, Chlorthalidone, Metolazone

Extra: Thiazide-like diuretics (e.g., Chlorthalidone, Indapamide) have a longer half-life and are more potent than true thiazides (e.g., Hydrochlorothiazide, Bendroflumethiazide). They lack the benzothiadiazine core but share the same mechanism of inhibiting the Na+/Cl- symporter in the distal convoluted tubule.

Flashcard 174: if an Angina patient is on monotherapy and cannot tolerate the addition of a calcium channel blocker or a beta-blocker then consider?

Answer: • Long-acting Nitrate (Isosorbide Mononitrate • Ivabradine • Nicorandil • Ranolazine

Flashcard 175: What antibiotic would interact with statins?

Answer: • Clarithromycin (macrolide)

Flashcard 176: What murmur is heard in Atrial Septal Defect?

Answer: Midsystolic ejection murmur (over pulmonary area) and a wide, fixed split S2.

Extra: The ejection systolic murmur in ASD is due to increased blood flow across the pulmonary valve (functional pulmonary stenosis), NOT flow across the atrial septum itself. The fixed split S2 occurs because the pressurized left-to-right shunt maintains high flow to the right heart regardless of the respiratory cycle.

Flashcard 177: What is Trifascicular Block?

Answer: • RBBB • Left - Axis Deviation • + 1st-Degree Heart Block

Flashcard 178: What is atrial myxoma?

Answer: • Benign tumour commonly occuring in the left atrium

Flashcard 179: What cardiac medication has a risk of causing thrombophlebitis?

Answer: Amiodarone

Extra: Amiodarone is a potent skin and vein irritant (phlebitis) due to its iodine content and high/low pH. When administered intravenously, it should preferably be delivered through a central line or a large peripheral vein to minimize the risk of thrombophlebitis.

Flashcard 180: When is secondary statin prevention indicated?

Answer: • When they've had an event already, and need to prevent a second event from happening again