Peaked T waves are the earliest sign of hyperkalemia, progressing to QRS widening and sine-wave patterns.

Pulseless VT is a shockable rhythm. Immediate defibrillation is the priority, followed by CPR and epinephrine administration.

Atrial fibrillation is characterized by an irregularly irregular rhythm with no distinct P waves.

For biphasic defibrillators, the initial dose is 120-200J. For monophasic defibrillators, use 360J.

Atropine is the first-line treatment for symptomatic bradycardia (1 mg IV every 3-5 min, max 3 mg). If ineffective, pacing or dopamine/epinephrine infusion may be required.

Amiodarone is the preferred antiarrhythmic for stable monomorphic VT, given as 150 mg IV over 10 minutes.

The first step in ECG analysis is assessing the rate and rhythm to determine if it's bradycardia, tachycardia, or an arrest rhythm (VF/pVT, asystole, PEA). More detailed interpretation follows after this initial assessment.

VF and pulseless VT are the only two rhythms that require immediate defibrillation. PEA and asystole require CPR and epinephrine but are not shockable.

VT presents with a wide QRS (>0.12s), while SVT has a narrow QRS unless aberrant conduction is present.