Subclinical atrial tachyarrhythmias, without clinical atrial fibrillation, occurred frequently in patients with pacemakers and were associated with a significantly increased risk of ischemic stroke or systemic embolism. (Funded by St. Jude Medical; ASSERT ClinicalTrials.gov number, NCT00256152.).

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published R ESUM ELe programme de lignes directrices de la Soci et e canadienne de cardiologie (SCC) en matière de fibrillation auriculaire (FA) a et e elabor e pour aider les cliniciens à prendre en charge ces patients complexes, ainsi que pour orienter les d ecideurs politiques et les systèmes de soins de sant e sur des questions connexes. La dernière edition

We agree with Drs Govindarajan and Salgado that because dabigatran 110 mg BID is associated with a lower risk of bleeding, it might be preferred over the 150-mg BID dose in patients with atrial fibrillation who are Ͼ75 years old and in clinical situations associated with a high risk of bleeding (eg, soon after thrombolysis or in the first few days after an invasive procedure). 1,2 Although not approved in the United States, the 110-mg BID dose of dabigatran is approved for use in Canada (where at least one third of patients are receiving it), Europe, and several other countries for patients at high risk of bleeding.Dr Reiffel requests additional information about the risks of bleeding with dabigatran compared with warfarin in atrial fibrillation patients with multiple factors that might increase the level of dabigatran in the blood. These analyses from the RE-LY database are under way but involve only small numbers of patients and are expected to provide imprecise estimates of treatment effect. We agree that it would be prudent to consider the 110-mg BID dose of dabigatran in preference to the 150-mg BID dose in these patients.We agree with Dr Rosenstein et al that an antidote for dabigatran has the potential to stop bleeding if the anticoagulant effect of the drug can be reversed rapidly. Despite the lack of an antidote, the RE-LY trial demonstrated that both doses of dabigatran (110 mg BID and 150 mg BID) were associated with lower rates of total, intracranial, and life-threatening bleeding than warfarin. 2 The mechanism of reduction in intracranial bleeding with both doses of dabigatran compared with warfarin has not been established but might simply be explained by avoidance of the high risk of intracranial bleeding with warfarin. Reasons for the high risk of intracranial bleeding with warfarin require further investigation. Concomitant use of a proton pump inhibitor might mitigate the increase in risk of gastrointestinal bleeding associated with dabigatran 150 mg BID. Avoidance of concomitant antiplatelet therapy might also reduce the risk.

As compared with bridging therapy with heparin, a strategy of continued warfarin treatment at the time of pacemaker or ICD surgery markedly reduced the incidence of clinically significant device-pocket hematoma. (Funded by the Canadian Institutes of Health Research and the Ministry of Health and Long-Term Care of Ontario; BRUISE CONTROL ClinicalTrials.gov number, NCT00800137.).