Hyperkalaemic complete heart block. A report of 2 unique cases and a review of the literature.

Two White male patients with temporary complete heart block (CHB) secondary to hyperkalaemia are presented. One, a 40-year-old man, developed CHB with ensuing shock within the first 24 hours of repeat aortic valve replacement for a paraprosthetic leak caused by previous endocarditis. This patient experienced iatrogenic hyperkalaemia. The second was an 81-year-old man who had chronic renal failure and presented with Stokes-Adams attacks. This patient was initially thought to have degenerative CHB and nearly underwent inadvertent permanent pacemaker insertion. Both patients were initially treated with emergency temporary cardiac pacing with subsequent successful management. Temporary CHB secondary to hyperkalaemia, from whatever cause, has very rarely been documented in the literature. A review of this potentially lethal complication is undertaken and the significance of unifascicular and bifascicular conduction block as a consequence of hyperkalaemia is discussed.