CEN

Dysrhythmia recognition and management are fundamental emergency nursing competencies. Systematic ECG interpretation includes assessing rate, rhythm, P waves, PR interval, QRS duration, and ST-T wave changes.

Sinus bradycardia features a rate below 60 bpm with normal P waves and intervals. Symptomatic bradycardia causing hypotension, altered mental status, or chest pain requires treatment. Atropine 1 mg IV is the first-line agent, repeated every 3-5 minutes to a maximum of 3 mg. Transcutaneous pacing provides temporary support. Dopamine or epinephrine infusions may be necessary.

Sinus tachycardia features a rate above 100 bpm with normal morphology. Treatment focuses on identifying and addressing underlying causes such as pain, fever, hypovolemia, or anxiety.

Atrial fibrillation shows irregularly irregular rhythm without distinct P waves. Rapid ventricular response may cause hemodynamic instability. Rate control agents include beta-blockers, calcium channel blockers, and digoxin. Unstable patients require synchronized cardioversion. Anticoagulation decisions consider stroke risk using CHA2DS2-VASc scoring.

Atrial flutter demonstrates a sawtooth pattern with atrial rates of 250-350 bpm and variable ventricular response. Management parallels atrial fibrillation with rate control, rhythm control, and anticoagulation considerations.

Supraventricular tachycardia (SVT) presents as a narrow-complex tachycardia with regular rhythm and rates of 150-250 bpm. Vagal maneuvers may terminate the rhythm. Adenosine 6 mg rapid IV push, followed by 12 mg if needed, is the pharmacologic treatment of choice. Unstable SVT requires synchronized cardioversion.

Ventricular tachycardia shows wide QRS complexes (greater than 0.12 seconds) at rates exceeding 100 bpm. Sustained VT lasting over 30 seconds or causing hemodynamic compromise requires immediate intervention. Pulseless VT is treated as ventricular fibrillation with defibrillation. Stable monomorphic VT may respond to amiodarone or procainamide. Unstable VT with pulses requires synchronized cardioversion.

Ventricular fibrillation produces chaotic electrical activity without organized ventricular contraction. Immediate defibrillation is essential. CPR should continue between shocks. Epinephrine and amiodarone are administered per ACLS protocols.

Asystole shows no electrical activity. CPR is continued while addressing reversible causes. Epinephrine is administered every 3-5 minutes. Atropine is no longer recommended for asystole.

Pulseless electrical activity (PEA) displays organized electrical activity without detectable pulses. Treatment focuses on identifying and correcting underlying causes using the H's and T's framework: hypovolemia, hypoxia, hydrogen ion excess, hypo/hyperkalemia, hypothermia, tension pneumothorax, tamponade, toxins, and thrombosis.

First-degree AV block shows prolonged PR interval greater than 0.20 seconds with all P waves conducted. This is generally benign and requires no treatment.

Second-degree AV block Type I (Wenckebach) demonstrates progressive PR prolongation until a beat is dropped. It is often transient and may not require intervention unless symptomatic.

Second-degree AV block Type II shows consistent PR intervals with intermittent non-conducted P waves. This rhythm carries a higher risk of progression to complete heart block and often requires pacing.

Third-degree AV block (complete heart block) shows complete dissociation between atrial and ventricular activity. The ventricular escape rhythm may be junctional or ventricular. Transcutaneous pacing is typically required, with transvenous pacing for definitive management.

Dysrhythmias At A Gl Ance

Rhythm	KeyECGFeatures	PriorityTreatment
Sinusbradycardia	Rate<60bpm normalPwavesand ,	Ifsymptomatic:atropine transcutaneouspacing dopamineor , ,
	intervals	epinephrineinfusion
Atrialfibrillation	Irregularlyirregular nodistinctP ,	Ratecontrol;synchronizedcardioversionifunstable;anticoagulation
	waves	perCHA2DS2-VASc
Atrialflutter	Sawtooth pattern atrial rate 250–350 ,	Rate/rhythmcontrol anticoagulation ,
	bpm
SVT	Narrow regular 150–250 bpm , ,	Vagalmaneuvers;adenosine6mgthen12mg;cardioversionif
		unstable
Ventricular	WideQRS(>012s) rate>100bpm . ,	Pulseless:defibrillate;stable:amiodaroneorprocainamide;unstable
tachycardia		withpulse:synchronizedcardioversion
Ventricular	Chaoticactivity noorganized ,	Immediatedefibrillation CPR epinephrine amiodarone , , ,
fibrillation	contraction
Asystole/PEA	Noelectricalactivity/organized	CPR epinephrine every 3–5 min treat H's and T's , ,
	activitywithoutapulse
First-degree AV	PR>020s allPwavesconducted . ,	Usuallynone
block
Second -degree	ProgressivePRlengtheninguntila	Oftennoneunlesssymptomatic
TypeI	droppedbeat
Second -degree	ConstantPRwithintermittentdropped	Oftenrequirespacing
TypeII	beats
Third -degree AV	CompleteAVdissociation	Transcutaneous thentransvenouspacing ,
block