Severe Hypokalemia and Life-Threatening Ventricular Arrhythmias: A Case of Normotensive Primary Aldosteronism

Primary aldosteronism (PA), the most common cause of secondary hypertension, is characterized by autonomous adrenal aldosterone overproduction independent of the renin-angiotensin system, resulting in sodium retention, potassium wasting, and cardiovascular sequelae that exceed the risk attributable to blood pressure elevation alone. Although hypertension is the predominant clinical manifestation, PA may also present without hypertension or hypokalemia, making atypical presentations a significant diagnostic challenge. Aldosterone-mediated myocardial fibrosis combined with hypokalemia-driven electrophysiologic instability can precipitate life-threatening ventricular arrhythmias that may constitute the dominant clinical presentation in the absence of classic features. We present a case of normotensive PA in which diagnostic delay resulted in recurrent ventricular arrhythmias and sudden cardiac arrest before identification of the underlying etiology, underscoring the importance of aldosterone-to-renin ratio (ARR) screening in patients with unexplained treatment-resistant hypokalemia and arrhythmia regardless of blood pressure status. Early recognition and targeted treatment of PA in atypical presentations are essential to mitigate irreversible cardiovascular morbidity.