How do I distinguish metabolic from toxic causes of wide-complex PEA?

Distinguishing metabolic causes (e.g., hyperkalemia) from drug-induced, clinically significant concentration causes (such as sodium channel blocker toxicity) in wide‐complex PEA relies on context, history, ECG nuances, and laboratory data. In metabolic disturbances like hyperkalemia, you often see a history of renal dysfunction or acidosis with associated ECG findings (peaked T waves progressing to widening) and lab confirmation, whereas in sodium channel blocker toxicity you may have a history suggestive of overdose, markedly prolonged QRS duration sometimes with a rightward axis, and a pattern that improves with sodium bicarbonate administration ^1^2.