Cardiac Arrhythmias Flashcards
Master cardiac rhythm recognition with this essential arrhythmia flashcard deck designed for nursing students, cardiac nurses, and NCLEX candidates. Understanding ECG patterns and knowing how to respond to arrhythmias is a critical competency in medical-surgical, telemetry, ICU, and emergency nursing practice. This deck covers normal sinus rhythm, common atrial and ventricular arrhythmias, heart blocks, and life-threatening rhythms — including their ECG characteristics, causes, symptoms, and nursing interventions. Based on American Heart Association (AHA) guidelines and standard critical care nursing references.
All Cards in This Deck
Question
What are the characteristics of Normal Sinus Rhythm (NSR)?
Answer
Rate: 60–100 bpm. Regular rhythm. P wave before every QRS. PR interval: 0.12–0.20 sec. QRS: < 0.12 sec. This is the baseline against which all arrhythmias are compared.
Question
What is Sinus Tachycardia?
Answer
NSR with heart rate > 100 bpm. Normal P waves, regular rhythm. Causes: fever, pain, anxiety, dehydration, anemia, hyperthyroidism. Treat the underlying cause.
Question
What is Sinus Bradycardia?
Answer
NSR with heart rate < 60 bpm. Normal P waves, regular rhythm. Causes: athletes (normal), hypothyroidism, increased ICP, digoxin toxicity, beta-blockers. Treat if symptomatic (Atropine).
Question
What is Sinus Arrhythmia?
Answer
Irregular rhythm caused by changes in breathing — heart rate increases with inspiration and decreases with expiration. Normal in children and young adults.
Question
What are Premature Atrial Contractions (PACs)?
Answer
Early, abnormal P waves that interrupt the normal rhythm. Usually benign. Causes: caffeine, stress, alcohol, electrolyte imbalance. No treatment usually needed.
Question
What is Atrial Fibrillation (A-Fib)?
Answer
Chaotic, disorganized atrial activity with no distinct P waves — replaced by irregular fibrillatory waves. Irregularly irregular ventricular rhythm. Rate: 350–600 atrial impulses/min. Major risk: thrombus formation and stroke. Treatment: rate control, anticoagulation.
Question
What is Atrial Flutter?
Answer
Regular, rapid atrial activity at 250–350 bpm producing classic sawtooth (flutter) waves. Usually 2:1, 3:1, or 4:1 conduction to ventricles. Treatment: cardioversion, rate control, anticoagulation.
Question
What is Supraventricular Tachycardia (SVT)?
Answer
Rapid heart rate 150–250 bpm originating above the ventricles. Narrow QRS, regular rhythm. Causes: stress, caffeine, WPW syndrome. Treatment: Valsalva maneuver, adenosine, cardioversion.
Question
What is a First-Degree AV Block?
Answer
PR interval > 0.20 seconds (> 5 small squares). Every P wave is followed by a QRS. No dropped beats. Usually benign — monitor only. Causes: vagal tone, digoxin, inferior MI.
Question
What is a Second-Degree AV Block Type I (Wenckebach/Mobitz I)?
Answer
Progressive lengthening of the PR interval until a QRS is dropped. Then the cycle repeats. Usually benign but monitor. Causes: inferior MI, increased vagal tone, digoxin toxicity.
Question
What is a Second-Degree AV Block Type II (Mobitz II)?
Answer
Constant PR interval with sudden, unexpected dropped QRS beats (no progressive lengthening). More serious than Mobitz I. Risk of progressing to complete heart block. May require pacemaker.
Question
What is a Third-Degree (Complete) AV Block?
Answer
Complete dissociation between P waves and QRS complexes — atria and ventricles beat independently. Life-threatening. Requires immediate transcutaneous pacing and likely permanent pacemaker.
Question
What are Premature Ventricular Contractions (PVCs)?
Answer
Early, wide, bizarre-looking QRS complexes > 0.12 seconds with no preceding P wave. Causes: hypoxia, hypokalemia, caffeine, MI. Occasional PVCs are benign; frequent/multifocal PVCs require treatment.
Question
What is Ventricular Tachycardia (V-Tach)?
Answer
3 or more PVCs in a row at a rate > 100 bpm. Wide, bizarre QRS complexes. May be pulseless. With pulse: Amiodarone, cardioversion. Pulseless V-Tach: DEFIBRILLATE immediately + CPR.
Question
What is Ventricular Fibrillation (V-Fib)?
Answer
Chaotic, disorganized ventricular activity — no identifiable P waves, QRS, or T waves. No cardiac output. IMMEDIATELY DEFIBRILLATE + CPR. This is a cardiac arrest rhythm.
Question
What is Torsades de Pointes?
Answer
A form of polymorphic V-Tach with QRS complexes that appear to "twist" around the baseline. Associated with prolonged QT interval. Treatment: IV Magnesium sulfate, remove offending drugs.
Question
What is Asystole?
Answer
Complete absence of electrical activity — a flat line on ECG. No cardiac output. CPR + Epinephrine. Note: Confirm in 2 leads — never shock asystole (defibrillation will not help).
Question
What is Pulseless Electrical Activity (PEA)?
Answer
Organized electrical activity on ECG but no pulse (no mechanical cardiac output). CPR + Epinephrine + treat reversible causes (5 H's and 5 T's).
Question
What are the 5 H's and 5 T's of cardiac arrest?
Answer
H's: Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, Hypothermia. T's: Tension pneumothorax, Tamponade, Toxins, Thrombosis (pulmonary), Thrombosis (coronary/MI).
Question
What is a Left Bundle Branch Block (LBBB)?
Answer
Wide QRS > 0.12 seconds with a broad, notched R wave in lateral leads (I, aVL, V5, V6). The left ventricle is activated late. May indicate cardiac disease or MI.
Question
What is the difference between cardioversion and defibrillation?
Answer
Cardioversion: Synchronized shock delivered during QRS complex. Used for unstable arrhythmias WITH a pulse (A-Fib, SVT, V-Tach with pulse). Defibrillation: Unsynchronized shock. Used for pulseless V-Tach and V-Fib.
Question
What is the drug of choice for symptomatic bradycardia?
Answer
Atropine 0.5 mg IV (first-line). If atropine fails: transcutaneous pacing or dopamine/epinephrine infusion.
Question
What is adenosine used for and how is it given?
Answer
Used to terminate SVT. Given as a rapid IV push (over 1–2 seconds) followed immediately by a 20 mL NS flush, in the largest vein available (antecubital). Causes brief asystole — warn the patient.
Question
What nursing assessments are done before giving digoxin?
Answer
Check apical pulse for 1 full minute — hold if < 60 bpm. Check digoxin level (therapeutic 0.5–2 ng/mL). Monitor for toxicity: nausea, bradycardia, visual changes (yellow-green halos).
Question
What is QT prolongation and why is it dangerous?
Answer
QT interval > 440ms (men) or > 460ms (women). Indicates slow ventricular repolarization. Dangerous because it predisposes to Torsades de Pointes and sudden cardiac death. Many drugs prolong QT (antipsychotics, antibiotics, antiemetics).