Abstract 15474: New Onset Left Bundle Branch Block Secondary to Severe Hyperkalemia

Abstract

Case presentation: A 79-year-old female with history of renal failure on hemodialysis (HD) presented with generalized weakness. Her last HD was 3 days ago. On examination, she was vitally stable. Blood tests demonstrated a potassium (K+) of 8.3 mmol/L, confirmed on repeat testing. ECG revealed wide QRS, tall T waves and a new left bundle branch block (Figure 1). She was immediately treated with calcium chloride, insulin, dextrose and polystyrene sulfonate. The patient was admitted to the ICU and underwent emergent HD. Repeat K+ post HD reversed to 4.0 mmol/L and ECG reflected normal sinus rhythm with resolution of ST-T wave changes (Figure 2). Discussion: Hyperkalemia can lead to cardiac arrhythmias and sudden death. The ECG changes are dependent on severity of hyperkalemia. It can vary from narrow based, peaked T waves to ventricular fibrillation. Hyperkalemia can also lead to interventricular conduction delays, which, with severity, can take the form of right or left bundle branch block (LLLB). The conduction delay from hyperkalemia usually lasts only in initial or terminal portions as opposed to throughout the QRS complex as seen in bundle branch block disease. Association of LLLB with hyperkalemia is an uncommon but important occurrence and has only scarcely been reported in literature. Its prevalence remains unknown. With the growing use of renin-angiotensin aldosterone system inhibitors, more patients are prone to experience life threatening electrolyte disturbances. A thorough knowledge of the ECG manifestations related to hyperkalemia is crucial to ensure emergent treatment. This may result in improved outcomes in such patients with cardiovascular and renal diseases.