S3 is the “third heart sound,” an extra low-frequency sound heard during cardiac auscultation. It occurs in early diastole, shortly after the second heart sound (S2). S3 is a clinical exam finding used in cardiology to assess hemodynamics and ventricular filling. It is commonly discussed in the context of heart failure, volume overload, and cardiomyopathy.
S2 is the **second heart sound** heard on cardiac auscultation. It reflects **closure of the semilunar valves** (aortic and pulmonic valves) at the end of systole. S2 is a **bedside physical exam finding** in cardiovascular physiology and clinical diagnosis. It is commonly used when assessing **murmurs, valvular heart disease, congenital heart disease, and pulmonary hypertension**.
S1 is the first heart sound heard during cardiac auscultation. It is a normal physical-exam finding that marks the start of ventricular systole. S1 is generated mainly by closure of the atrioventricular (AV) valves (mitral and tricuspid). Clinicians use S1 when timing murmurs and assessing valve and conduction physiology.
Heart Sounds are the audible vibrations produced by cardiac mechanical events during the cardiac cycle. They are a core topic in cardiovascular physiology and bedside diagnosis (physical examination). Clinicians use Heart Sounds during auscultation to screen for valve disease, heart failure, and hemodynamic changes. They are commonly assessed with a stethoscope and interpreted alongside vital signs, electrocardiogram (ECG), and echocardiography.
Cardiac Murmur is an extra heart sound caused by turbulent blood flow in or near the heart. It is a clinical finding identified on cardiac auscultation during the physical exam. It commonly relates to cardiac anatomy and physiology, especially heart valves and intracardiac shunts. It is used in general medicine, emergency care, cardiology, pediatrics, and preoperative assessment.
Atropine is an antimuscarinic (anticholinergic) medication that blocks acetylcholine at muscarinic receptors. In cardiology, it is primarily used as an acute therapy for certain types of symptomatic bradycardia. It acts on the cardiac conduction system—especially the sinoatrial (SA) node and atrioventricular (AV) node—to increase heart rate and AV nodal conduction. It is most commonly used in emergency and peri-procedural settings (e.g., Advanced Cardiovascular Life Support scenarios and monitored clinical environments).
Lidocaine is a medication that blocks sodium channels in nerves and cardiac cells. It is used as a local anesthetic and as an antiarrhythmic drug in selected settings. In cardiology, it is most associated with treatment of certain ventricular arrhythmias and with procedural anesthesia. It is commonly encountered in emergency care, electrophysiology contexts, and bedside procedures.
Amiodarone is an antiarrhythmic medication used to treat abnormal heart rhythms. It is part of pharmacologic therapy in cardiology rather than an anatomy or diagnostic test. It is commonly used for atrial and ventricular tachyarrhythmias in acute care and long-term rhythm control. It is notable for broad electrophysiologic effects and a long duration of action.
Digoxin is a cardiac glycoside medication used in cardiology. It affects heart muscle contraction and the cardiac conduction system. It is most commonly used in atrial fibrillation (AF) rate control and selected heart failure cases. It requires careful dosing and monitoring because its therapeutic window is narrow.
Aspirin is an oral medication in the salicylate class with analgesic, antipyretic, anti-inflammatory, and antiplatelet effects. In cardiology, it is primarily used as an antiplatelet therapy to reduce thrombus (clot) formation in arterial disease. It is commonly encountered in acute coronary syndrome (ACS), after percutaneous coronary intervention (PCI) with stenting, and in chronic coronary artery disease (CAD). It is also discussed in risk–benefit decisions around primary and secondary prevention of atherosclerotic cardiovascular disease (ASCVD).