Paclitaxel dysrhythmias

Paclitaxel causes disturbances in cardiac rhythm, but the relevance of these effects has not been fully elucidated. Originally, aU patients in trials of paclitaxel were under continuous cardiac monitoring, owing to the risk of hypersensitivity reactions, and cardiac disturbances were therefore more likely to be detected. Many trials limited eligibility to patients without a history of cardiac abnormalities and to those who were not taking medications likely to alter cardiac conduction. The incidence of cardiac dysrhythmias in the population under study not treated with paclitaxel is unknown, and it is therefore not always possible to attribute dysrhythmias to paclitaxel in these patients. The Cremophor EL vehicle does not appear to be implicated in the incidence of dysrhythmias, although hypotension associated with hypersensitivity reactions may occur (13). 

The authors of a review of the cardiac toxicity associated with paclitaxel in a number of studies concluded that the overall incidence of serious cardiac events is low (0.1%) (20). Heart block and conduction abnormalities occurred infrequently and were often asymptomatic. Sinus bradycardia was the most frequent, occurring in 30% of patients. The causal relation of paclitaxel to atrial and ventricular dysrhythmias and cardiac ischemia was not entirely clear. There did not appear to be any evidence of cumulative toxicity or augmentation of acute cardiac effects of the anthracydines. 

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