NSG210 Exam 2 - Arrhythmias Chapter Summary (Hinkle Ch. 22)
Source: Hinkle & Cheever, Brunner & Suddarth’s 15th ed., Ch. 22 “Management of Patients With Arrhythmias and Conduction Problems”, plus the Sep 30 lecture deck. Condensed from the full study guide nsg210-2026-09-30-arrhythmias and the chapter outline nsg210-hinkle-ch22-arrhythmias-outline. Dysrhythmias were the largest single topic on Exam 2. Companion page: nsg210-exam-2-valves-summary.
The Core Idea
- Rhythms are named by where the impulse starts: sinus (SA node), atrial, junctional (AV node), or ventricular.
- A narrow QRS (under 0.12) means the impulse came from above the ventricles. A wide, bizarre QRS (0.12 or more) means ventricular origin.
- Treat the patient, not the monitor. The same rhythm can be stable in one patient and unstable in another. Signs of instability: hypotension, altered mental status, chest pain, signs of shock or acute heart failure.
- Fast rates shorten diastole, which reduces filling time and coronary perfusion and drops cardiac output.
Normal Values and Reading a Strip
| Item | Normal | Means |
|---|---|---|
| Small box | 0.04 sec | Large box is 0.20 sec |
| P wave | Before every QRS | Atrial depolarization |
| PR interval | 0.12-0.20 sec | SA node firing, atrial depolarization, AV node conduction |
| QRS | Under 0.12 sec | Ventricular depolarization |
| QT | 0.32-0.40 sec (use QTc) | Ventricular depolarization plus repolarization; long QT leads to torsades |
| ST segment | Isoelectric | Elevation or depression may mean ischemia |
- Rate, regular rhythm: 1,500 divided by the small boxes between two R waves (25 boxes is 60; 15 boxes is 100).
- Rate, irregular rhythm: count R-R intervals in a 6-second strip and multiply by 10.
- Electrode prep: soap and water, not alcohol. Poor contact causes artifact.
Rhythms at a Glance
| Rhythm | Rate | Strip clues | Treatment |
|---|---|---|---|
| Sinus bradycardia | Under 60 | Normal P before each QRS | Treat only if symptomatic: stop vagal stimulation, hold the drug (beta-blocker, CCB, digoxin); atropine 1 mg IV (ACLS 2025), then pacing, dopamine or epinephrine |
| Sinus tachycardia | Over 100, usually under 120 | Normal P (may hide in T); gradual onset | Find and fix the cause: fever, pain, bleeding, hypovolemia, anxiety, hypoxia |
| Sinus arrhythmia | 60-100 | Speeds up on inspiration | None |
| PAC | Underlying | Early, odd-shaped P | Remove triggers (caffeine, alcohol, nicotine, low K) |
| Atrial fibrillation | Atrial 300-600; ventricular 120-200 untreated | No P waves, wavy f waves, irregularly irregular | Rate control, anticoagulation, rhythm control (see below) |
| Atrial flutter | Atrial 250-400 | Saw-tooth F waves, often 2:1 to 4:1 | Like AF; cardioversion often works |
| Junctional rhythm | 40-60 | P absent, inverted, or after QRS; PR under 0.12 | Treat like bradycardia if symptomatic; check for digoxin toxicity |
| SVT / AVNRT | 150-250 | Narrow, very regular, abrupt start and stop, P hard to see | Vagal maneuvers, then adenosine; verapamil, beta-blocker; synchronized cardioversion if unstable; ablation long-term |
| PVC | Underlying | Early wide bizarre QRS, no P | Look for causes: hypokalemia, hypoxia, ischemia, caffeine, digoxin toxicity |
| Ventricular tachycardia | 100-200 | 3 or more PVCs in a row, wide QRS | With pulse, stable: amiodarone, procainamide, lidocaine. With pulse, unstable: synchronized cardioversion. Pulseless: defibrillate, CPR |
| Torsades de pointes | Fast | Polymorphic VT, twisting; prolonged QT before onset | IV magnesium, correct K and Mg; stop QT-prolonging drugs |
| Ventricular fibrillation | Over 300, chaotic | No QRS, no pulse | CPR plus immediate defibrillation; epinephrine, amiodarone |
| Asystole | None | Flat line, confirm in two leads | CPR, epinephrine; do NOT shock; treat Hs and Ts |
Tachycardia sorting rule: sinus tach is gradual with a cause; SVT is abrupt, narrow and very regular; wide and fast is VT until proven otherwise.
AV Heart Blocks
| Block | PR interval | Dropped beats | Danger |
|---|---|---|---|
| First-degree | Over 0.20, constant | None | Usually benign; watch for progression |
| Second-degree type I (Wenckebach) | Gets longer each beat | One P dropped, then the cycle repeats | Usually benign |
| Second-degree type II | Constant | P waves dropped without warning | Can progress to complete block; prepare to pace |
| Third-degree (complete) | No relationship | P and QRS march independently, more P than QRS | Serious; pacing |
- Memory aid: “longer, longer, drop” is Wenckebach. Constant then drop is type II. Nothing connects is third-degree.
- Atropine is the first drug for symptomatic block, but it does NOT work for type II or third-degree block. Those go to transcutaneous pacing, then a permanent pacemaker.
- Common causes: digoxin, beta-blockers, CCBs, ischemia or MI, increased vagal tone.
Atrial Fibrillation in Detail
- The most common sustained arrhythmia. The atria quiver, so the atrial kick (25-30% of cardiac output) is lost.
- Biggest danger: blood pools in the left atrial appendage and forms clots, which can cause a stroke.
- Assess for a pulse deficit (apical rate minus radial rate). Count the apical pulse for a full minute.
- Stroke risk score is CHA2DS2-VASc: CHF 1, HTN 1, Age 75+ 2, Diabetes 1, prior Stroke or TIA 2, Vascular disease 1, Age 65-74 1, Sex female 1. Score 2+ in men or 3+ in women means anticoagulate (warfarin, apixaban, rivaroxaban, dabigatran). A mechanical valve always means warfarin.
- Warfarin INR goal for AF: 2.0-3.0. Bridge with heparin or LMWH until therapeutic.
- Rate control: beta-blocker or diltiazem/verapamil, target resting HR under 80.
- Rhythm control: AF lasting 48 hours or longer needs anticoagulation first or a TEE to rule out a clot before cardioversion. Continue anticoagulation at least 4 weeks after.
- WPW with AF (wide, very fast, irregular): avoid digoxin, diltiazem and verapamil.
Cardioversion vs Defibrillation
| Synchronized cardioversion | Defibrillation | |
|---|---|---|
| Use | Tachycardia WITH a pulse (unstable SVT, AF, flutter, VT with pulse) | NO pulse: VF, pulseless VT |
| Sync button | On (shock timed to the QRS, avoiding the T wave) | Off |
| Prep | Sedation, NPO, hold digoxin 48 hours, anticoagulate if AF over 48 hours | None; start CPR until the pads are on |
| Energy | 50-360 J | Biphasic 120-200 J |
- Memory aid: synchronized for a pulse, unsynchronized for no pulse.
- Safety: call “clear” for self, others and oxygen. Never use ultrasound gel. Keep pads off medication patches. Resume CPR immediately after a shock.
- Asystole and PEA are never shocked.
Key Medications
| Drug | Use | Nursing |
|---|---|---|
| Adenosine | SVT | Rapid IV push, 20 mL saline flush, raise the arm, use a port close to the heart; warn of brief flushing, chest pressure, a short pause (transient asystole) |
| Atropine | Symptomatic bradycardia | ACLS 2025: 1 mg IV every 3-5 min, max 3 mg (Hinkle text says 0.5 mg; check what your instructor uses) |
| Amiodarone | VT, VF, AF | Pulmonary toxicity (baseline PFTs), corneal deposits, photosensitivity, raises digoxin levels; monitor QT, hypotension |
| Beta-blockers (metoprolol) | Rate control | Check apical pulse and BP before dose; bronchospasm; masks hypoglycemia; do not stop abruptly |
| Diltiazem, verapamil | Rate control, SVT | Hypotension, bradycardia, constipation; avoid in WPW |
| Digoxin | AF rate control | Hold if apical pulse under 60; toxicity: nausea, vision changes (yellow halos), arrhythmias; low K raises toxicity |
| Lidocaine | Ventricular arrhythmias | Confusion, tremors, especially in older adults |
| Magnesium | Torsades | Correct K and Mg too |
| Epinephrine | Cardiac arrest | 1 mg IV every 3-5 min |
| Anticoagulants | AF stroke prevention | Bleeding precautions; warfarin uses INR; vitamin K is the reversal agent |
QT-prolonging drugs to know: haloperidol, ciprofloxacin, erythromycin, methadone, lithium, ondansetron. Low K, Ca or Mg also prolongs QT.
Pacemakers and ICDs
- Capture: a pacer spike followed right away by a P wave or a wide QRS.
- Loss of capture: spike with no complex after it.
- Undersensing: spikes fire even though the patient has their own beats.
- Oversensing: no spikes when the patient needs pacing.
- Transcutaneous pacing is painful: sedate and give analgesia if the patient is alert.
- Most common early complication of a permanent pacemaker: lead dislodgment. Limit arm movement on the insertion side and do not raise the arm above the shoulder for about 2 weeks.
- Other complications: infection, hematoma, pneumothorax. Hiccups may mean phrenic nerve stimulation or perforation.
- Teaching: check pulse daily; keep a cell phone 6 inches away on the opposite side; avoid MRI and strong magnets; walk through airport detectors and ask for a hand search instead of the wand; carry an ID card.
- ICD: the patient keeps a log of shocks and what came before. A shock will not harm someone touching the patient. Call 911 if they feel unwell after a shock or get more than one shock. Anxiety and depression are common; refer to support groups.
Nursing Priorities
- First move with any new rhythm: assess the patient (pulse, BP, LOC, symptoms), then look at the strip.
- Signs of low cardiac output: dizziness, syncope, hypotension, chest pain, cool pale skin, falling urine output, narrowing pulse pressure.
- Correct contributing causes: hypoxia, potassium and magnesium levels, acid-base balance, caffeine, missed doses.
- Reduce anxiety: stay with the patient and stay calm. Lower sympathetic drive means fewer arrhythmias.
- Teach: take the pulse before rate-altering drugs, steady drug levels, anticoagulant bleeding precautions, and CPR for the family.
Likely Exam Angles
- Pulseless patient: defibrillate VF or pulseless VT; give CPR and epinephrine for asystole or PEA (no shock).
- Unstable patient with a pulse and fast rhythm: synchronized cardioversion.
- Stable narrow regular tachycardia: vagal maneuvers first, then adenosine.
- Symptomatic bradycardia: atropine first; if it fails, or the block is type II or third-degree, pace.
- AF patient: priority is stroke prevention (anticoagulation) and rate control; anticoagulate or TEE before cardioversion if over 48 hours.
- PVCs in a post-op or pneumonia patient: check potassium, magnesium and oxygenation.
- Sinus tach after surgery: think bleeding, pain, fever, hypovolemia. Do not just slow the rate.
- Prolonged QT on a new drug: hold and report; the risk is torsades.
- Digoxin: hold for apical pulse under 60, check potassium, watch for vision changes.
- Strip calculation: 1,500 divided by small boxes, or 6-second count times 10.