Bidirectional ventricular tachycardia due to coronary allograft vasculopathy a unique presentation

Bidirectional ventricular tachycardia due to digoxin-diuretic interaction in post-cardiac surgery patient: a case report

Bidirectional ventricular tachycardia (BVT) is a rare form of malignant ventricular arrhythmia characterized by beat-to-beat alternation in the QRS axis. BVT is a hallmark of digitalis toxicity, but digoxin-induced BVT secondary to digoxin-diuretic interaction in cardiac surgery patients is not widely reported. We present the case of a 62-year-old woman undergoing mitral valve replacement with tricuspid annuloplasty who developed postoperative congestive heart failure and vasoplegic syndrome requiring norepinephrine, vasopressin, and loop diuretics. During postoperative care, she presented atrial fibrillation with rapid ventricular response, achieving rate control with digoxin, but later displayed hemodynamically stable BVT associated with digitalis toxicity. The case highlights the importance of physicians monitoring digoxin toxicity when prescribing digoxin to patients with a diuretic regimen, particularly loop diuretics. During digoxin-induced-BVT, supportive treatment, including discontinuing digitalis coupled with potassium and magnesium supplements, can be considered as long as digoxin-specific antibodies are unavailable, and the patient is hemodynamically stable.

Bidirectional Ventricular Tachycardia: Challenges and Solutions

Bidirectional ventricular tachycardia (BiVT) is a rare form of ventricular tachycardia that manifests on surface electrocardiogram by dual QRS morphologies alternating on a beat-to-beat basis. It was first reported in the 1920s as a complication of digoxin, and since then, it has been reported in other conditions including fulminant myocarditis, sarcoidosis, catecholaminergic polymorphic ventricular tachycardia, and Andersen-Tawil syndrome. The mechanism for BiVT is not as well known as other forms of ventricular tachycardia but appears to include typical mechanisms including triggered activity from afterdepolarizations, abnormal automaticity, or reentry. This review will go beyond the definition, surface electrocardiogram, mechanisms, causes, and treatment of BiVT as per our current understanding.

Arrhythmias in the Heart Transplant Patient

Orthotopic heart transplantation (OHT) is currently the most effective long-term therapy for patients with end-stage cardiac disease, even as left ventricular devices show markedly improved outcomes. As surgical techniques and immunosuppressive regimens have been refined, short-term mortality caused by sepsis has decreased, while morbidity caused by repeated rejection episodes and vasculopathy has increased, and is often manifested by arrhythmias. These chronic transplant complications require early and aggressive multidisciplinary treatment. Understanding the relationship between arrhythmias and these complications in the acute and chronic stages following OHT is critical in improving patient prognosis, as arrhythmias may be the earliest or sole presentation. Finally, decentralised/ denervated hearts represent a unique opportunity to investigate the underlying mechanisms of arrhythmias.