These two cases demonstrate that although the incidence of malignant arrhythmias such as BVT in ICI-associated myocarditis is low, the risk of sudden death remains extremely high.
Key Findings
Results
A 45-year-old male with advanced intrahepatic cholangiocarcinoma developed PD-1 inhibitor-associated myocarditis complicated with bidirectional ventricular tachycardia after 11 cycles of camrelizumab.
Patient experienced sudden chest tightness after the 11th cycle of camrelizumab
Test results showed significantly elevated myocardial injury markers
Cardiac magnetic resonance imaging findings were consistent with acute myocarditis
Following immunotherapy discontinuation, treatment with steroid therapy, antiarrhythmic drugs, and electrical cardioversion led to marked improvements and favorable outcomes
Results
A 34-year-old female with type B1 thymoma developed PD-1 inhibitor-associated myocarditis complicated with BVT after only one second-line cycle of sintilimab, resulting in death.
Patient experienced sudden chest tightness, shortness of breath, and fatigue after receiving one second-line cycle of sintilimab
Significantly elevated myocardial injury markers were observed and ECG findings indicated BVT
Supportive therapies included steroid therapy, antiarrhythmic drugs, electrical cardioversion, invasive mechanical ventilation, and extracorporeal membrane oxygenation
Despite aggressive intervention, the patient's condition deteriorated rapidly, ultimately leading to death
This case occurred after only a single cycle of ICI therapy, highlighting that severe cardiotoxicity can manifest very early in treatment
Discussion
BVT is identified as an important but previously infrequently described ECG manifestation of severe cardiotoxicity associated with immune checkpoint inhibitors.
BVT is described as a rare but dangerous form of ventricular arrhythmia
When ICI-associated myocarditis is complicated with BVT, patients face an extremely high risk of mortality
The report adds to a growing body of evidence identifying BVT as a significant ECG manifestation of ICI-associated cardiotoxicity
Of the two cases reported, one survived and one died, illustrating the variable but high-risk nature of this complication
Discussion
Steroid therapy is identified as a crucial treatment method for patients with ICI-associated myocarditis complicated with BVT.
Both cases received steroid therapy as part of their treatment regimen
In the surviving case, steroid therapy combined with antiarrhythmic drugs and electrical cardioversion led to marked improvements
Authors state: 'steroid therapy is a crucial treatment method for patients with ICI-associated myocarditis complicated with BVT'
The fatal case received steroids but still deteriorated, suggesting steroid therapy alone may be insufficient in the most critical presentations
Discussion
Dynamic monitoring of myocardial injury markers and ECG is recommended for patients with ICI-associated myocarditis.
Authors recommend dynamic (ongoing) monitoring of myocardial injury markers in patients with ICI-associated myocarditis
ECG monitoring is considered essential given the risk of BVT development
Both cases presented with significantly elevated myocardial injury markers alongside ECG evidence of BVT
Early detection through monitoring is implied as important for timely intervention given the rapid deterioration seen in the fatal case
What This Means
This research describes two patients who developed a serious and rare heart complication — bidirectional ventricular tachycardia (BVT), an abnormal and dangerous heart rhythm — as a result of cancer immunotherapy drugs that target a protein called PD-1. One patient was a 45-year-old man with bile duct cancer who had received 11 rounds of the drug camrelizumab, and the other was a 34-year-old woman with a type of thymus cancer who had received just one dose of sintilimab. Both developed inflamed heart muscle (myocarditis) along with this dangerous arrhythmia. The man recovered after stopping immunotherapy and receiving steroids, anti-arrhythmic medications, and electrical cardioversion (a shock to reset the heart rhythm). The woman, despite receiving all of these treatments plus mechanical ventilation and a heart-lung bypass machine (ECMO), did not survive.
This research suggests that while the combination of ICI-associated myocarditis and BVT is rare, it carries an extremely high risk of sudden death. Notably, one patient developed this life-threatening complication after just a single dose of immunotherapy, highlighting that severe cardiac side effects can occur at any point during treatment — even very early. The authors observed that steroid therapy appears to be a critical component of treatment for this condition, though it may not be sufficient in the most severe cases.
The practical implication of these findings is that patients receiving PD-1 inhibitor immunotherapy should be closely and continuously monitored with heart enzyme blood tests and electrocardiograms (ECGs), since early detection of myocarditis and abnormal heart rhythms may improve the chances of successful treatment. BVT should now be recognized as an important, though rare, warning sign of serious heart toxicity from immune checkpoint inhibitor drugs.
Lian X, Wang H, Wang N. (2026). Case Report: Two cases of PD-1 inhibitor-associated myocarditis with bidirectional ventricular tachycardia.. Frontiers in immunology. https://doi.org/10.3389/fimmu.2026.1832047