BACKGROUND: Hypokalemia is a potentially reversible cause of ventricular tachyarrhythmias (VTAs) such as polymorphic ventricular tachycardia/ventricular fibrillation (PMVT/VF) and sustained monomorphic ventricular tachycardia (SMVT). Despite its established role in arrhythmogenesis, the clinical implications of hypokalemia in patients with distinct VTA subtypes remain poorly understood.

OBJECTIVE: The aims of this study were to study the clinical characteristics, management, and outcome of patients with hypokalemia-associated VTAs and to investigate the prognosis of distinct VTA subtypes after correction of hypokalemia with or without additional VT-targeted therapies (VTTTs), such as catheter ablation or antiarrhythmic drugs.

METHODS: Consecutive patients admitted with hypokalemia-associated VTAs were analyzed after hypokalemia correction. Patients were categorized by VTA subtype and followed for VT recurrence, 24-month VT-free survival, and all-cause mortality. Those with other reversible causes of VTAs were excluded.

RESULTS: Sixty-five patients (mean age 69 ± 12 years; 20% (n = 13) women; mean left ventricular ejection fraction 32% ± 13%; 54% (n = 35) with New York Heart Association class III/IV; 8% (n = 5) with a left ventricular assist device) were studied; 68% (n = 44) presented with SMVT. Patients with SMVT were younger (65 ± 11 years vs 77 ± 10 years; P < .001) and had more advanced left ventricular dilation (left ventricular end-diastolic diameter 64 ± 12 mm vs 57 ± 12 mm; P = .03). Over a median follow-up of 18 months, 24-month VT-free survival was 28%. Patients with SMVT had higher VT recurrence (50% vs 10%; P = .002) and lower 24-month VT-free survival (16% vs 52%; P = .005) than did those with PMVT/VF. Among patients with SMVT, those receiving VTTTs (36%, (n = 16/44)) showed improved 24-month VT-free survival compared with hypokalemia correction alone (31% vs 7%; P = .02).

CONCLUSION: Hypokalemia-associated VTAs are associated with advanced heart failure and linked to poor outcomes, especially in patients with SMVT. Although potassium correction may be sufficient for patients with hypokalemia-associated PMVT/VF, those with SMVT require additional VTTTs to improve outcomes.