Melphalan‐Induced Supraventricular Tachycardia: Incidence and Risk Factors

BACKGROUND: Cardiotoxicity of aggressive chemotherapeutic regimens includes cardiomyopathy and arrhythmias. Although cardiomyopathy is a well-recognized entity, arrhythmias are poorly studied. HYPOTHESIS: Certain chemotherapeutic regimes are associated with supraventricular arrhythmias, particularly atrial fibrillation. METHODS: We retrospectively reviewed the data on patients who received hematopoietic stem cell transplant (bone marrow transplant; BMT) from 1998 to 2005 and developed supraventricular tachycardia (SVT) during the same hospital admission. The Fisher χ2 test and the Student t test were used for comparison of categorical and continuous variables, respectively. RESULTS: During the period of 1998-2005, there were 1221 BMTs, 62 (5.1%) of which were complicated by SVT. Melphalan-based regimens demonstrated a significantly higher rate of SVT than any other chemotherapy. Out of 438 patients who received melphalan, 48 (11%) developed atrial fibrillation (n = 35) or SVT (n = 13) during the same hospital admission, and 390 did not. Patients with SVT were older, had higher baseline creatinine, larger size of the left atrium, and more cardiac comorbidities. Incidence of SVT was associated with greater length of stay (24.9 ± 8.9 d vs 19.6 ± 5.8 days, P<0.0001), even after adjustment for comorbidities. CONCLUSIONS: Supraventricular tachycardia, mostly atrial fibrillation, complicates about 5% of chemotherapeutic treatments used with BMT. Melphalan is the most arrhythmogenic agent, and is associated with SVT in 11% of patients. Development of SVT results in about a 4-day increase in the length of hospital stay.