What is the correct position of the patient’s arm for an AP projection of the scapula?

DRUG THERAPY OF CORONARY ARTERY DISEASE   β-Blockers (BBs) Examples Selective β1 (cardioselective): Metoprolol, Atenolol Non-selective β1 + β2: Propranolol Mixed β1, β2 + α1: Carvedilol Mechanism / Rationale β-blockers improve myocardial oxygen balance by: ↓ Myocardial O₂ demand ↓ Contractility ↓ Heart rate (↓ SA node automaticity) ↓ AV node conduction → ↓ HR ↑ Myocardial O₂ supply Prolong diastole → ↑ coronary perfusion time Uses Stable angina (prophylaxis + treatment) Acute coronary syndrome (ACS) if no contraindications: Avoid in shock, severe bradycardia, heart block, decompensated HF Often combined with nitrates → prevents reflex tachycardia Contraindications / Important cautions Prinzmetal (vasospastic) angina Non-selective β-blockers are contraindicated: Block β2 vasodilation → unopposed α1 vasoconstriction → coronary vasospasm → may precipitate MI Cocaine-associated chest pain Non-selective β-blockers worsen vasospasm: Cocaine ↑ catecholamines → unopposed α activity → severe vasoconstriction   Organic Nitrates Examples Nitroglycerin (GTN) Isosorbide dinitrate Isosorbide mononitrate Mechanism / Rationale ↓ Myocardial O₂ demand Venodilation → ↓ preload Arterial dilation → ↓ afterload ↑ Myocardial O₂ supply Coronary vasodilation → ↑ blood flow Redistributes blood to ischemic regions Antiplatelet effect (transdermal NG) ↓ platelet aggregation via inhibition of GPIIb/IIIa binding Uses Acute angina relief: Sublingual nitroglycerin → relief in 2–5 min May repeat every 5 min up to 3 doses Chronic stable angina prophylaxis (long-acting forms) ACS with persistent chest pain Acute HTN emergencies, acute decompensated HF (IV nitroglycerin)   Calcium Channel Blockers (CCBs) Mechanism / Rationale ↓ Myocardial O₂ demand ↓ preload and afterload (vasodilation) ↓ contractility (especially non-dihydropyridines) ↓ heart rate (↓ SA node) ↓ AV node conduction ↑ Myocardial O₂ supply Coronary vasodilation → improved perfusion Clinical Uses Stable angina (alternative or adjunct to β-blockers) Prinzmetal (vasospastic) angina (very important indication) Long-acting formulations preferred Short-acting nifedipine should be avoided alone (risk of reflex tachycardia) Combination therapy With β-blockers → prevents reflex tachycardia With nitrates → non-dihydropyridines help blunt tachycardia   Ranolazin Mechanism / Rationale Acts specifically on ischemic myocardium: Inhibits late Na⁺ current during repolarization→ ↓ intracellular Na⁺→ ↓ Ca²⁺ overload (via Na⁺/Ca²⁺ exchanger)→ ↓ intracellular Ca²⁺ Net effects: Improves myocardial metabolism ↓ contractility → ↓ O₂ demand Antiarrhythmic effects (Class Id): ↓ automaticity ↓ early afterdepolarizations (EADs) Key advantage: does NOT significantly affect HR or BP Pharmacokinetics Oral administration Metabolized via CYP3A → significant drug interactions Renal excretion Uses Chronic stable angina (especially when HR/BP limit other drugs) Adjunct in refractory angina Some use in ventricular arrhythmias (off-label) Adverse Effects Common: Nausea Dizziness Headache Constipation Serious: QT interval prolongation → risk of torsades de pointes Contraindication Avoid with other QT-prolonging drugs   Question: A 54-year-old man presents with episodic chest pain that occurs at rest, often in the early morning. ECG during pain shows transient ST-segment elevation. He is diagnosed with Prinzmetal (vasospastic) angina. Which of the following medications is contraindicated because it may worsen his condition?

The central ray for an AP internal rotation of the shoulder is directed:

The central ray for a PA projection of the second digit is directed to the:

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?