Cardiac Perfusion, Central and Tissue Perfusion, Cardiac Output, Stroke Volume, Preload and Afterload, Contractility, Ejection Fraction, Electrical Conduction System, SA AV and Ventricular Pacemakers, ECG Interpretation, PR QRS QT Intervals, ST Segment Ch

Cardiac Perfusion, Central and Tissue Perfusion, Cardiac Output, Stroke Volume, Preload and Afterload, Contractility, Ejection Fraction, Electrical Conduction System, SA AV and Ventricular Pacemakers, ECG Interpretation, PR QRS QT Intervals, ST Segment Changes, Sinus Bradycardia, Sinus Tachycardia, Atrial Dysrhythmias, Supraventricular Tachycardia (SVT), Atrial Fibrillation, Atrial Flutter, Premature Ventricular Contractions (PVCs), Ventricular Tachycardia, Ventricular Fibrillation, Torsades de Pointes, Electrolyte Imbalances, Defibrillation and Cardioversion, Advanced Dysrhythmia Management Exam Questions Verified and Complete with A+ Graded Rationales Latest Updated 2026 What is perfusion? The flow of blood through arteries and capillaries delivering nutrients and oxygen to cells What is Central Perfusion? the amount of blood pumped by the heart each minute What is systole? the phase of the cardiac cycle when the ventricles contract What is the average ejection fraction? 50%-70% What is diastole? the phase of the cardiac cycle when ventricles fill with blood How to calculate cardiac output? heart rate x stroke volume What makes up stroke volume? preload, afterload, contractility What is preload? end of diastolic volume in the heart What are 2 factors that influence preload? Stretch capacity of myocardial fibers & amount of blood returned to the heart from the systemic circulation What is afterload? amount of resistance the heart pumps against within the vasculature the heart pumps against What factors reduce cardiac output? (4) 1. Inefficient mechanisms within the heart 2. Disease of heart muscle tissue 3. Congenital defects 4. Increased SVR from vasoconstriction What are consequences of impaired central perfusion? (3) 1. Reduction of central perfusion shock 2. Significant blood loss 3. Vasodilation throughout the body What is tissue perfusion? the volume of blood that flows through target tissues What causes impaired tissue perfusion? (3) 1. Mechanism within the organ itself 2. Excessive edema 3. Increase pressure associated with constriction or collapse of arterioles What are consequences of impaired tissue perfusion? Decrease blood flow through capillaries into the interstitial spaces allowing delivery of oxygen, fluid, and nutrients to cells What is the inherent rate of the SA node? 60-100 bpm What is the inherent rate of the AV node? 40-60 bpm What is the inherent rate of the ventricles (Bundle of HIS)? 20-40 bpm What is automaticity? the ability of cardiac cells to generate an electrical impulse spontaneously and repetitively Where does the impulse normally come from? SA node What conditions cause other cardiac cells to produce electrical impulses independently and create dysrhythmias? (5) 1. Myocardial ischemia (decreased blood flow) 2. Electrolyte imbalance 3. Hypoxia 4. Drug toxicity 5. Infarction (cell death) What is conductivity? the ability to send an electrical stimulus from cell membrane to cell membrane When do disturbances in conduction occur? Conduction is too rapid or too slow, when the pathway is totally blocked, or when the electrical impulses travels an abnormal pathway What is contractility? the ability of arterial and ventricular muscle cells to shorten their fiber length in response to electrical stimulation, causing sufficient pressure to push blood forward What is isoelectric line? no current flow in the heart after complete depolarization or complete repolarization What is the most common lead system? Lead II What does the P wave represent? atrial depolarization What does the QRS wave represent? ventricular depolarization