Jawaharlal Nehru Technological University Hyderabad Pharm. D II Year PHARMACOTHERAPEUTICS-I Previous Question Paper (February - 2023 - R08)

Cardiac arrhythmia is managed by controlling the heart rate, rhythm, and preventing thromboembolic complications. The Vaughan Williams classification categorizes antiarrhythmic drugs based on their mechanism of action: Class I (sodium channel blockers like lidocaine and flecainide), Class II (beta-blockers like metoprolol), Class III (potassium channel blockers like amiodarone and sotalol), and Class IV (calcium channel blockers like verapamil and diltiazem). Pharmacotherapy involves selecting agents based on the type of arrhythmia (e.g., atrial fibrillation vs. ventricular tachycardia), underlying structural heart disease, and patient-specific factors. In acute settings, electrical cardioversion or intravenous antiarrhythmics are used, while chronic management focuses on rate control and rhythm maintenance, often supplemented by anticoagulation therapy to prevent stroke.

The treatment options for Congestive Cardiac Failure (CCF) aim to reduce symptoms, improve quality of life, and decrease mortality. Key therapeutic classes include:

• RAAS Inhibitors: ACE inhibitors (e.g., enalapril) or ARBs (e.g., losartan) to reduce preload and afterload.
• Beta-blockers: (e.g., carvedilol, bisoprolol) to improve long-term survival by reducing sympathetic drive.
• Diuretics: Loop diuretics (e.g., furosemide) for symptomatic relief of fluid overload and edema.
• Aldosterone Antagonists: (e.g., spironolactone) to prevent cardiac remodeling.
• Inotropic Agents: Digoxin, primarily used for symptom control in patients with atrial fibrillation or persistent symptoms despite standard therapy.
• Vasodilators: Hydralazine and isosorbide dinitrate, particularly for patients intolerant to ACE inhibitors or ARBs.
• SGLT2 Inhibitors: (e.g., dapagliflozin) now recommended for reducing cardiovascular death and hospitalization in heart failure.

The management of Acute Myocardial Infarction (AMI) focuses on rapid reperfusion and stabilization. The treatment algorithm follows these essential steps:

• Initial Stabilization: Administer oxygen, aspirin (162-325 mg), sublingual nitroglycerin for chest pain, and morphine if pain persists.
• Reperfusion Therapy: For STEMI, primary Percutaneous Coronary Intervention (PCI) is the gold standard if available within 90 minutes. If PCI is unavailable, fibrinolytic therapy (e.g., alteplase, tenecteplase) should be administered within 30 minutes of arrival.
• Adjunctive Pharmacotherapy: Initiate dual antiplatelet therapy (DAPT) with P2Y12 inhibitors (clopidogrel, ticagrelor), anticoagulation (heparin or enoxaparin), beta-blockers to reduce myocardial oxygen demand, and high-intensity statins.
• Secondary Prevention: Long-term management includes ACE inhibitors or ARBs, continued DAPT, statins, and lifestyle modifications.

The electrophysiology of arrhythmias arises from disturbances in impulse formation or conduction:

• Abnormal Impulse Formation: This includes enhanced automaticity (increased firing rate of pacemaker cells), triggered activity (afterdepolarizations occurring during or after repolarization), or the emergence of latent pacemakers.
• Abnormal Impulse Conduction: This is primarily caused by re-entry, where an impulse travels through a circuitous pathway due to unidirectional block and slow conduction, typically facilitated by myocardial ischemia or scarring.
• Membrane Potential Dynamics: Arrhythmias often involve alterations in ion channel kinetics, specifically the flux of Na+, K+, and Ca2+ ions, which modify the phase 0 depolarization or phase 3 repolarization of the cardiac action potential, leading to conduction delays or blocks.