Hyperkalemia ECG presentation and acute treatment sequence?

• A. Tachycardia with short PR; give epinephrine
• B. Normal ECG
• C. Flat T waves and U waves
• D. Peaked T waves progressing to widened QRS and possible sine wave; treat with calcium chloride/gluconate, insulin with glucose, albuterol, and potassium shift; address underlying cause; prepare for dialysis

Answer: (D)

Hyperkalemia elevates the risk of dangerous cardiac rhythms, and the ECG changes reflect that increasing irritability of the heart as potassium climbs. The classic progression starts with tall, peaked T waves as repolarization accelerates. As potassium rises further, the PR interval lengthens and the QRS complex widens, and in severe cases the rhythm can degenerate into a sine-wave pattern with a high risk of lethal arrhythmias. The emergency treatment sequence is designed to stabilize the heart first and then reduce the potassium level.

Begin by protecting the myocardium with IV calcium (calcium chloride or calcium gluconate). This does not lower potassium, but it raises the threshold potential and reduces excitability, buying time to correct the derangement. After the heart is stabilized, move to shifting potassium intracellularly: administer insulin with glucose to drive K+ into cells, and give a beta-2 agonist such as albuterol to promote intracellular shifting. If acidosis is present, bicarbonate can help with shifting potassium as well. Finally, remove potassium from the body or limit further gain, using strategies such as diuretics, potassium-binding resins, or dialysis in patients with kidney failure or when hyperkalemia is refractory or life-threatening. Throughout, address the underlying cause (renal failure, tumor lysis, medication effects, tissue breakdown) and prepare for definitive measures like dialysis when indicated.

Other patterns don’t fit the scenario: a normal ECG wouldn’t reflect this acute, dangerous elevation, and patterns like flat T waves with U waves point to hypokalemia, not hyperkalemia. The described sequence aligns with the urgent priorities for acute hyperkalemia management.