The central ray for a lateral toe (2nd digit) is:

DRUG THERAPY OF ARRHYTHMIAS   Class 0 — HCN Channel Blocker: Ivabradine Mechanism of Action Blocks HCN (“funny”) channels in SA node→ ↓ Na⁺ If current→ ↓ slope of phase 4 depolarization→ ↓ HR & ↓ SA node automaticity Pharmacokinetics Oral Metabolized by CYP3A4 → drug interactions Excreted in feces & urine Uses Chronic HF (HR ≥ 70 bpm) Stable angina (HR ≥ 70 bpm) Sinus tachycardia Adverse Effects: Bradycardia   Class I — Na⁺ Channel Blockers Class IA: Quinidine, Procainamide, Disopyramide Mechanism Moderate Na⁺ blockade→ ↓ depolarization rate→ ↑ AP duration & ↑ ERP→ Prolong QT Effects ↓ Automaticity ↓ Conduction ↑ Refractory period → ↓ reentry Uses SVT (AF, A-fib) VT/V-fib WPW (procainamide) Adverse Effects ⚠️ Torsades de pointes (QT prolongation) Disopyramide → anticholinergic (CI in myasthenia gravis) Quinidine → cinchonism, hemolysis (G6PD) Procainamide → lupus, bone marrow suppression Negative inotropy → CI in HF   Class IB: Lidocaine, Mexiletine Mechanism: Weak Na⁺ blockade → ↓ AP duration Effects ↓ Automaticity ↓ Conduction & ↓ ERP Uses Ventricular arrhythmias (post-MI) Digitalis-induced arrhythmia Adverse Effects CNS toxicity (tremor, seizures) Lidocaine → neurotoxicity (high dose) Mexiletine → hepatotoxicity Negative inotropy   Class IC: Flecainide, Propafenone Mechanism: Strong Na⁺ blockade → markedly ↓ depolarization → no change in AP duration Effects ↓ Automaticity ↓ Conduction → ↓ reentry ↑ QT interval Uses SVT (AF, A-fib) Resistant VT WPW Adverse Effects ⚠️ High pro-arrhythmic risk (boxed warning) Flecainide → ventricular arrhythmias Negative inotropy → CI in HF Propafenone → bronchospasm (β-blocking effect)   Class II — Autonomic Modulators Class IIa — β-Blockers: Metoprolol, Atenolol, Propranolol, Esmolol, Carvedilol Mechanism: Block β1 → ↓ cAMP → ↓ phase 4 slope Effects ↓ HR (↓ SA node) ↓ AV conduction ↓ QT Uses SVT (especially stress-induced) Premature beats Atrial & ventricular arrhythmias Long QT syndrome   Class IIb — β-Agonist: Isoproterenol Mechanism β1 → ↑ HR, conduction β2 → vasodilation Uses Bradycardia AV block (temporary) Torsades (bradycardia-dependent) Adverse Effects Tachyarrhythmias Hypotension   Class IIc — M2 Antagonist: Atropine Mechanism: Blocks M2 receptors → ↑ SA automaticity → ↑ AV conduction Uses Bradycardia AV block Adverse Effects Anticholinergic: Dry mouth Blurred vision Urinary retention Tachycardia   Class IId — M2 Activator: Digoxin Mechanism ↑ Vagal tone → ↓ HR & AV conduction Inhibits Na⁺/K⁺ ATPase → ↑ Ca²⁺ → ↑ contractility Uses AF (rate control when others not suitable) HFrEF (limited use now) Key Contraindications Hypokalemia Hypercalcemia AV block, bradycardia WPW with AF Adverse Effects Narrow therapeutic index GI, visual disturbances ⚠️ Arrhythmias   Class IIe — Adenosine A1 Agonist: Adenosine Mechanism: ↑ K⁺ efflux, ↓ Ca²⁺ influx → hyperpolarization Effects ↓ SA node activity ↓ AV conduction Uses PSVT (first-line emergency) Adverse Effects Flushing, chest discomfort (~1 min) Bronchospasm (CI in asthma) Interactions ↓ effect: caffeine, theophylline   Question: A 67-year-old man with chronic heart failure (ejection fraction 35%) presents for follow-up. He reports persistent elevated heart rate (~78–85 bpm) despite being on optimal guideline-directed medical therapy. Blood pressure is 118/72 mmHg. The provider considers adding a medication that selectively reduces SA node firing without affecting myocardial contractility. Which of the following is the most appropriate drug for this patient?

What is the degree of rotation for an AP oblique with medial rotation of the foot?

The central ray angle and direction for a lateral knee is:

When the ASIS to tabletop measurement is greater than 24cm, the central ray for an AP projection of the knee is:

DRUG THERAPY OF HEART FAILURE (HF)   1) RAAS Inhibitors   A. ACE Inhibitors (ACEIs): Enalapril, Lisinopril, Captopril Effects: ↓ mortality (proven survival benefit) ↓ preload & afterload ↓ remodeling Use: First-line in HFrEF (if no fluid overload → ACEI alone; if overload → + diuretic) AEs: Cough (↑ bradykinin) Angioedema Hyperkalemia Renal impairment   B. ARBs: Valsartan, Losartan Use: ACEI intolerance (cough/angioedema) Alternative RAAS blockade AEs: Hyperkalemia Hypotension Renal dysfunction(No cough—no bradykinin effect)   C. ARNI (Angiotensin Receptor–Neprilysin Inhibitor): Sacubitril/Valsartan (Entresto) Mechanism Sacubitril → inhibits neprilysin → ↑ natriuretic peptides ↑ ANP/BNP → natriuresis, vasodilation, ↓ remodeling Valsartan → blocks AT1 receptor → prevents Ang II effects Important Concept Neprilysin breakdowns: Natriuretic peptides (beneficial) Ang II + bradykinin (problem if not blocked) Therefore MUST combine with ARB AEs: Hypotension Hyperkalemia Renal failure Angioedema (esp. if combined with ACEI) Contraindication: ACEI use within 36 hours → risk of severe angioedema   D. Aldosterone Antagonists (ARAs): Spironolactone (± Eplerenone) Effects: ↓ Na⁺ retention, ↑ K⁺ retention ↓ fibrosis & remodeling ↓ mortality in severe HFrEF AEs: Hyperkalemia Gynecomastia (spironolactone)   2) Diuretics Mechanism ↓ Na⁺/H₂O → ↓ plasma volume ↓ preload → ↓ pulmonary edema, peripheral edema ↓ congestion symptoms   A. Thiazides Mild–moderate HF Works only if renal function adequate   B. Loop Diuretics: Furosemide Uses: Acute pulmonary edema Severe CHF Renal impairment cases   C. Potassium-Sparing: Spironolactone Also in RAAS class Used in combination therapy Mortality benefit in severe HF   3) Direct Vasodilators Mechanism ↓ preload (venodilation) ↓ afterload (arteriolar dilation)   A. Nitrates (Venodilation → ↓ preload) Nitroglycerin (IV in acute HF) Isosorbide dinitrate   B. Hydralazine (Arteriolar dilation → ↓ afterload) Useful in: Acute HF with hypertension Pulmonary edema   C. Combination Therapy: Hydralazine + Isosorbide Dinitrate (BiDil) ↓ preload + afterload ↓ remodeling ↓ mortality in African American patients Used when: ACEI/ARB not tolerated or insufficient   D. Nitroprusside (IV) Balanced venous + arterial dilation Used in hypertensive emergencies with HF   4) β-Blockers (Disease-Modifying Therapy) Rationale Chronic sympathetic activation causes: Tachycardia Remodeling Increased O₂ demand RAAS activation β-blockers reverse these effects Effects: ↓ mortality ↓ remodeling ↓ HR → ↓ myocardial oxygen demand ↓ renin → ↓ RAAS activation Drugs: β1-selective: Metoprolol, Bisoprolol Mixed α1/β: Carvedilol Clinical Use: Stable mild–moderate HFrEF Always start LOW and go SLOW Contraindication: Acute decompensated HF Use with other cardiac depressants (e.g., non-DHP CCBs)   5) Positive Inotropic Drugs (Acute or Refractory HF) A. β1-Agonist: Dobutamine ↑ cAMP → ↑ Ca²⁺ → ↑ contractility IV only Uses: Acute decompensated HF Cardiogenic shock AEs: Tachycardia Angina   B. PDE-3 Inhibitor: Milrinone ↑ cAMP (cardiac + vascular) Effects: ↑ contractility Vasodilation → ↓ preload & afterload Uses: Acute HF Post–heart transplant support Refractory cardiogenic shock AEs: Hypotension Arrhythmias N/V   C. Digoxin (Na⁺/K⁺ ATPase inhibitor) ↑ intracellular Ca²⁺ → ↑ contractility Also ↑ vagal tone → ↓ HR Use: Refractory systolic HF (rare now) Limitations: Narrow therapeutic window Not first-line   6) Ivabradine (HCN Channel Blocker) Blocks SA node “funny current” (If) Effect: ↓ HR without affecting contractility Uses: Chronic HFrEF with HR ≥ 70 bpm Stable angina AEs: Bradycardia   7) Cardiac Myosin Inhibitors: Aficamten Mechanism: ↓ actin-myosin interaction → ↓ contractility Use: Hypertrophic cardiomyopathy (NOT standard HF therapy)   Question: A 67-year-old man with HFrEF (EF 30%) has been taking lisinopril for several months. His cardiologist plans to switch him to sacubitril/valsartan to further reduce mortality and hospitalizations. He took his last dose of lisinopril this morning and is eager to start the new medication today. Which of the following is the most appropriate next step?

To test for possible fictitious recording of sales, the most appropriate direction of testing would be from

DRUG THERAPY OF HYPERLIPIDEMIA   1. Inhibition of Cholesterol Synthesis HMG-CoA Reductase Inhibitors (Statins) Atorvastatin, Rosuvastatin, Simvastatin, Pravastatin, Lovastatin   Mechanism Inhibit HMG-CoA reductase → ↓ hepatic cholesterol synthesis ↑ LDL receptors → ↑ LDL uptake from blood ↓ LDL, ↓ VLDL, mild ↑ HDL Lipid effects ↓↓↓ LDL (20–60%) ↓ TG (10–30%) ↑ HDL (5–10%) Pleiotropic (non-lipid) benefits ↓ inflammation & ROS ↓ endothelial dysfunction ↓ platelet aggregation Stabilize atherosclerotic plaques Pharmacokinetics (high yield) Oral CYP3A4 metabolism: atorvastatin, simvastatin, lovastatin → many drug interactions Pravastatin/rosuvastatin → minimal CYP metabolism → safer interactions Biliary excretion (mostly) Dose adjustment in renal disease (except atorvastatin preferred in severe CKD) Uses All dyslipidemias (first-line) ASCVD prevention (CAD, stroke prevention) Combination therapy with ezetimibe or PCSK9 inhibitors Adverse effects Myopathy → myositis → rhabdomyolysis (↑ CK) Worse with: fibrates (esp. gemfibrozil), niacin, colchicine Hepatotoxicity (↑ LFTs) ↑ Risk of type 2 DM Contraindicated in active liver disease Avoid in pregnancy & breastfeeding   2. ↑ Lipoprotein Lipase (LPL) Activation — Fibrates Fenofibrate (preferred), Gemfibrozil   Mechanism Activate PPAR-α → ↑ LPL activity ↑ TG breakdown → ↓ VLDL Lipid effects ↓↓↓ TG (35–50%) ↓ LDL (5–15%) ↑ HDL (5–20%) Uses Severe hypertriglyceridemia (pancreatitis prevention) Mixed dyslipidemia with high TG Adverse effects GI upset Myopathy (↑ with statins, especially gemfibrozil) Gallstones (↑ biliary cholesterol) Hepatotoxicity Possible ↑ CV risk (gemfibrozil concern) Key interaction Gemfibrozil ↑ statin toxicity (CYP inhibition) Pregnancy Avoid unless severe TG (>1000 risk pancreatitis)   3. Inhibition of Cholesterol Absorption Ezetimibe   Mechanism Blocks NPC1L1 transporter in intestinal brush border ↓ cholesterol absorption → ↓ hepatic cholesterol → ↑ LDL receptors Lipid effects ↓ LDL (~15–20%) Mild ↓ TG Slight ↑ HDL Uses Add-on to statins (very common) Statin intolerance Adverse effects Diarrhea Mild ↑ LFTs Myalgia (rare, ↑ with statins) Contraindications Active liver disease Pregnancy (limited data)   4. PCSK9 Inhibitors (MOST POWERFUL LDL-Lowering Drugs) Alirocumab, Evolocumab   Mechanism Inhibit PCSK9 → prevent LDL receptor degradation ↑ LDL receptors → massive LDL clearance Lipid effects ↓↓↓↓↓ LDL (40–70%) ↓ TG ↑ HDL Uses Familial hypercholesterolemia ASCVD patients needing additional LDL lowering Statin-resistant hyperlipidemia Adverse effects Injection site reactions URTI, nasopharyngitis Rare hypersensitivity Route Subcutaneous every 2–4 weeks   5. Omega-3 Fatty Acids Icosapent ethyl (EPA-only) Omega-3 acid ethyl esters (EPA + DHA)   Mechanism ↓ hepatic VLDL synthesis ↑ fatty acid oxidation ↑ LPL activity Anti-inflammatory effects Lipid effects ↓↓↓ TG (25–45%) ↑ HDL Minimal LDL effect (EPA-only preferred) Uses Severe hypertriglyceridemia ASCVD risk reduction (especially EPA-only formulation) Adverse effects Fishy taste (compliance issue) GI upset ↑ bleeding time at high doses (platelet inhibition)   Question: A 58-year-old man with a history of coronary artery disease is started on a medication that inhibits HMG-CoA reductase. Three weeks later, he reports muscle pain and weakness. Laboratory testing shows: Creatine kinase (CK): 12,300 U/L (normal: 30–200 U/L) AST/ALT: mildly elevated The patient is also taking gemfibrozil for hypertriglyceridemia. Which of the following best explains this patient’s condition?

DRUG THERAPY OF ARRHYTHMIAS   Class III — K⁺ Channel Blockers Class IIIa — Non-selective K⁺ Blockers: Dofetilide, Ibutilide, Sotalol, Dronedarone Mechanism: Block K⁺ efflux → ↑ AP duration & ↑ ERP → Prolong QT Uses: AF, VT, VF, WPW Adverse Effects ⚠️ Torsades de pointes Dronedarone: CI in HF ↑ mortality in permanent AF   Amiodarone (Special) “Antiarrhythmic shotgun” Class I, II, III, IV actions Pharmacokinetics Very long half-life (25–60 days) CYP3A4 interactions Uses Life-threatening arrhythmias only Major Adverse Effects (HIGH-YIELD) Pulmonary fibrosis Hepatotoxicity Hypo-/hyperthyroidism Corneal deposits Blue-gray skin discoloration Neurotoxicity   Class IV — Ca²⁺ Channel Blockers: Verapamil, Diltiazem Mechanism: Block L-type Ca²⁺ channels Effects ↓ SA node automaticity ↓ AV conduction Uses SVT AF   Miscellaneous: Magnesium Sulfate (MgSO₄) Mechanism: ↓ Ca²⁺ influx/release Uses Torsades de pointes (first-line) VT/VF (esp. hypomagnesemia) Adverse Effects Hypotension Respiratory depression ↓ reflexes   Question: A 72-year-old woman is brought to the emergency department after a syncopal episode. ECG shows polymorphic ventricular tachycardia consistent with torsades de pointes. She has a prolonged QT interval on baseline ECG. Which of the following is the first-line treatment?

To test for possible understatement of sales, the most appropriate direction of testing would be from