The effect of cardiac surgery on the Q-T interval. Are patients at higher risk of torsades de pointes post cardiac surgery?

Abstract

2012 at Wellington Hospital. Patients were contacted at 30 days and 1 year to determine outcomes and compliance.Results: We enrolled 293 ACS patients initially treated with clopidogrel. Of these patients, 96 were medically managed (32%), 156 underwent PCI (53%) and 41 had CABG (14%). Clopidogrel was either discontinued in hospital or prescribed for a shorter duration than 12 months at discharge in 73 (25%) patients. The remaining 220 patients had a discharge prescription of 12 months of clopidogrel therapy. Of these, 23 (10%) permanently discontinued clopidogrel prior to 12 months. This was due to major surgery (43%), discontinuation at the discretion of a medical practitioner (39%), discontinued due to bleeding (10%), anticoagulant initiation (17%) and patient misunderstanding of discharge instructions (14%). A further 12 (5%) patients had interruptions of clopidogrel in the 12 months following the index coronary angiogram due to bleeding (4), surgery (6), rash (1) and patient confusion (1).Conclusion: In patients with a planned 12 month prescription of clopidogrel following ACS, a significant number of discontinuations occur. Clopidogrel was most commonly discontinued for surgical intervention, and was not reinitiatied in the majority of these cases.

Retrosternal hematoma causing torsade de pointes after coronary artery bypass graft surgery; a case report

“…A review of all cases (available in the literature) suggested cardiac surgery and craniotomies accounting for 40% of all cases with perioprative TdP ( 11 ). Reports suggest that TdP is probably not the direct effect of CABG, but related to CABG complications ( 12 – 14 ), such as ischemia (due to graft failure) ( 12 ) or co-administartion of Q-T prolonging drugs (like amiodarone) in the perioperative period ( 13 , 15 ). It is important to remember that prolonged QTc is multifactorial and can occur by genetic and inhertited causes, as well ( 14 ).…”