Management and outcome of different types of ventricular tachycardia associated with hypokalemia

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.