Case Report: Takotsubo Syndrome During Long-Term Dasatinib Therapy: A Case Report and Critical Review of Causal Attribution

Takotsubo syndrome (TTS) represents a diagnostic and therapeutic challenge in patients with cancer, in whom malignancy-related factors and anticancer therapies may coexist as potential predisposing or triggering factors. We report the case of a 68-year-old woman with chronic myeloid leukemia receiving dasatinib for two years who presented with acute heart failure. Initial echocardiography showed apical akinesia with a left ventricular ejection fraction of 38% and severely impaired global longitudinal strain (−6.3%). Coronary angiography revealed no significant obstructive coronary artery disease. Within two days, left ventricular function substantially improved, with an ejection fraction of 57% and global longitudinal strain of −14.2%. Cardiac magnetic resonance performed during this recovery phase demonstrated apical and mid-ventricular myocardial edema without late gadolinium enhancement, supporting the diagnosis of TTS. Although dasatinib-related myocardial and vascular effects provide biological plausibility for a potential contribution to TTS, a direct causal relationship could not be established. The long interval between treatment initiation and TTS onset, together with the coexistence of cancer-related predisposing factors, supports a multifactorial interpretation. Following multidisciplinary evaluation, dasatinib was continued under close cardiovascular monitoring. This case highlights that diagnostic certainty of TTS does not necessarily imply etiological certainty. In patients receiving long-term anticancer therapy, careful causal assessment is essential to distinguish a potential drug contribution from a multifactorial substrate and to avoid unnecessary discontinuation of effective cancer treatment.