Electrical Instability in the Setting of Hypokalemia: From Ventricular Bigeminy to Ventricular Tachycardia – A Case Report

Introduction: Electrolyte imbalances, particularly hypokalemia, and hyponatremia, are critical contributors to cardiac electrical instability, predisposing patients to life-threatening arrhythmias such as ventricular bigeminy and ventricular tachycardia (VT). These disturbances impair myocardial repolarization, enhance ectopic activity, and are exacerbated in elderly populations due to age-related metabolic vulnerabilities and polypharmacy. Case Report: A 67-year-old hypertensive female presented with palpitations, generalized weakness, and syncope. Initial evaluation revealed severe hypokalemia (K⁺ 1.6 mmol/L), hyponatremia (Na⁺ 126 mmol/L), and ventricular bigeminy on electrocardiogram (ECG), progressing to pulseless VT. She was managed with intravenous potassium repletion, antiarrhythmics, and defibrillation. Despite transient seizure and hemodynamic instability, multidisciplinary care stabilized her condition, with residual premature ventricular contractions (PVCs) post-resuscitation. Discussion: Hypokalemia-induced sodium-potassium ATPase dysfunction prolonged repolarization, triggering PVCs and re-entrant VT. Concurrent hyponatremia exacerbated myocardial excitability. The patient’s age, diuretic use, and Sick Sinus Syndrome synergistically increased arrhythmia risk. Delayed recognition of nonspecific geriatric symptoms and conservative potassium correction highlighted challenges in elderly care. Multidisciplinary collaboration and aggressive electrolyte normalization were pivotal in preventing fatal outcomes. Conclusion: This case underscores the lethal potential of hypokalemia in elderly patients, emphasizing the need for prompt electrolyte correction, continuous cardiac monitoring, and age-specific protocols. Long-term strategies, including dietary modification and potassium-sparing antihypertensives, are essential to mitigate recurrence. Early recognition of subtle symptoms and proactive multidisciplinary management are critical in high-risk populations.