P180 EXTREMELY WIDE QRS TACHYCARDIA IN SEVERE HYPERKALEMIA: THE IMPORTANCE OF MONITORING MRA THERAPY

Abstract

Abstract Although uncommon in the general population, hyperkalemia can affect up to 50% of patients with heart failure who are receiving MRA and/or are affected by CKD . Since potassium is the most abundant intracellular cation, hyperkaliemia causes a profound change in action potential, which manifests as expected electrocardiographic changes (lower voltage P wave, AV block, wide QRS, high voltage T wave) and arrhythmias. Clinic case. A 77–year–old woman was admitted to ED for dyspnea. She had a medical history of stage 3 CKD and a HFrEF with a recent admission in medical department for worsening congestion, from which was dimitted with a supratherapeutic dose of MRA (canrenone 300 mg/die). Physical examination at the admission excluded signs of central or peripheral congestion . An EKG was performed and revealed an heart rate of 95 beats per minute and extremely wide QRS (280 ms). Contextually, a blood gas analysis showed high potassium level (K 9 mmol/l) and metabolic acidosis. Due to the inability to demonstrate the presence of P wave and a regular A–V conduction, a differential diagnosis between a VT and a SVT with a wide QRS was required. The presence of a fusion beat, a negative concordance of QRS in the precordials derivation, and an extreme right axis deviation led to a diagnosis of slow VT. Cuncurrently with the onset of hyperkalemia therapy, an ECV with sinus rhythm restoration was done. The following EKGs showed expected electrical changes based on the measured potassium level. After ECV with K 8 mmol/l: QRS remained wide (180ms) with an heart rate of 65 beats per minute in the presence of possible junctional rhythm or sino–ventricular rhythm, which is sometimes described in hyperkalemia as an expression of atrial inectability with the exception of the conduction fibers. After 1 hour with K 6.3 mmol/l: QRS of normal duration with an HR of 60 bpm and a sinus rhythm but with low voltage P wave and concomitant AV block of I grade that was gradually restored with the normalization of potassium levels after canrenone suspension. Because the numerous side effects of hyperkaliemia careful monitoring of MRA therapy and potassium level plays a critical role in the prevention and diagnosis of arrhythmias and EKG changes in patients with HFrEF.