Introduction to Cardiac Anatomy, Physiology, and EKG Analysis

Comprehensive vocabulary flashcards covering cardiovascular anatomy, hemodynamic measurements, EKG rhythms, and clinical cardiac interventions.

Cardiac Output (CO)

The volume of blood pumped per minute, determined by the equation $ext{Stroke Volume} imes ext{Heart Rate}$; the normal range is $4-8\,L/min$.

Atrial Kick

The additional flow of blood into the ventricles caused by atrial contraction; it can be lost in conditions such as atrial fibrillation.

Afterload

The force that opposes ventricular ejection, often increased by systemic hypertension or vasoconstriction.

Systemic Vascular Resistance (SVR)

The overall resistance of the systemic circulation that the left side of the heart must work against to supply the body with blood.

S1 (First Heart Sound)

The sound created by the closure of the mitral and tricuspid valves at the beginning of systole; it is loudest at the mitral area or apex.

S2 (Second Heart Sound)

The sound produced by the closure of the aortic and pulmonic valves at the beginning of diastole; it is loudest at the aortic area.

S3 (Third Heart Sound)

A sound associated with ventricular over-dilation and heart failure, best heard at the apex with the patient on their left side.

Ejection Fraction (EF)

The percentage of blood ejected from the ventricle with each heart beat; a normal range is $60-75\%$, and it decreases in heart failure.

Automaticity

The unique property of myocardial pacemaker cells to spontaneously initiate an electrical impulse without external stimulation.

Depolarization

The electrical process where positively charged ions like sodium rapidly move inside the cell, causing the heart muscle to contract.

PR Interval

The EKG measurement representing the impulse traveling from the SA node to the AV node; the normal duration is $0.12-0.20\,s$.

QRS Complex

The EKG representation of ventricular depolarization; the normal duration is $0.06-0.10\,s$.

QT Interval

The time frame representing ventricular depolarization and repolarization; the normal duration is approximately $0.34-0.44\,s$.

Isoelectric Line

A flat line on an EKG representing the absence of electrical activity, used as a baseline to detect ST segment elevation or depression.

Widowmaker

A clinical term for a blockage in the Left Anterior Descending (LAD) artery, which can lead to massive myocardial infarction or cardiogenic shock.

Atropine

The first-line medication for symptomatic bradycardia, administered in doses of $0.5\,mg$ IV every $3-5\,min$ up to a total of $3\,mg$.

Adenosine

A miscellaneous antiarrhythmic used to treat SVT by stopping the electrical impulse and causing a brief period of asystole to chemically cardiovert the heart.

Third Degree (Complete) Heart Block

A serious condition where atria and ventricles function independently due to a total block in conduction, requiring immediate pacing.

Torsades de Pointes

A form of ventricular tachycardia characterized by a 'twisting' pattern on the EKG, often associated with a prolonged QT interval and treated with IV magnesium.

Synchronized Cardioversion

A delivery of electricity timed to the R wave of the QRS complex to treat unstable tachycardias like atrial fibrillation or SVT.

Fixed Mode Pacing

A pacemaker setting where the device fires continuously at a preset rate regardless of the patient's own heart rhythm.

Demand Mode Pacing

A pacemaker setting where the device only fires if the patient's intrinsic heart rate falls below a specific programmed level.

Internal Cardioverter Defibrillator (ICD)

A permanent implanted device designed to deliver an internal defibrillatory shock if it detects life-threatening rhythms like V-fib.

H's and T's

A mnemonic for the reversible causes of Pulseless Electrical Activity (PEA), including Hypoxia, Hypovolemia, Toxins, and Tamponade.