Jafna L. Cox

Canadian Cardiovascular Society Atrial Fibrillation Guidelines 2010: Catheter Ablation for Atrial Fibrillation/Atrial Flutter

Catheter ablation of atrial fibrillation (AF) offers a promising treatment for the maintenance of sinus rhythm in patients for whom a rhythm control strategy is desired. While the precise mechanisms of AF are incompletely understood, there is substantial evidence that in many cases (particularly for paroxysmal AF), ectopic activity most commonly located in and around the pulmonary veins of the left atrium plays a central role in triggering and/or maintaining arrhythmic episodes. Catheter ablation involves electrically disconnecting the pulmonary veins from the rest of the left atrium to prevent AF from being triggered. Further substrate modification may be required in patients with more persistent AF. Successful ablation of AF has never been shown to alter mortality or obviate the need for oral anticoagulation; thus, the primary indication for this procedure should be improvement of symptoms caused by AF. The success rate of catheter ablation for AF is superior to the efficacy of antiarrhythmic drugs, but success is still in the range of 75%-90% after 2 procedures. Ablation is also associated with a complication rate of 2%-3%. Thus, ablation should primarily be used as a second-line therapy after failure of antiarrhythmic drugs. In contrast to AF, catheter ablation of atrial flutter has a higher success rate with a smaller incidence of complications. Thus, catheter ablation for atrial flutter may be considered a first-line alternative to antiarrhythmic drugs.

Sex Versus Gender-Related Characteristics: Which Predicts Outcome After Acute Coronary Syndrome in the Young?

BACKGROUNDnGender reflects social norms for women and men, whereas sex defines biological characteristics. Gender-related characteristics explain some differences in access to care for premature acute coronary syndrome (ACS); whether they are associated with cardiovascular outcomes is unknown.nnnOBJECTIVESnThis study estimated associations between gender and sex with recurrent ACS and major adverse cardiac events (MACE) (e.g., ACS, cardiac mortality, revascularization) over 12 months in patients with ACS.nnnMETHODSnWe studied 273 women and 636 men age 18 to 55 years from GENESIS-PRAXY (GENdEr and Sex determInantS of cardiovascular disease: from bench to beyond-Premature Acute Coronary SYndrome), a prospective observational cohort study, who were hospitalized for ACS between January 2009 and April 2013. Gender-related characteristics (e.g.,xa0social roles) were assessed using a self-administered questionnaire, and a composite measure of gender was derived. Outcomes included recurrent ACS and MACE over 12 months.nnnRESULTSnFeminine roles and personality traits were associated with higher rates of recurrent ACS and MACE compared with masculine characteristics. This difference persisted for recurrent ACS, after multivariable adjustment (hazard ratio from score 0 to 100: 4.50; 95% confidence interval: 1.05 to 19.27), and was a nonstatistically significant trend for MACE (hazard ratio: 1.54; 95% confidence interval: 0.90 to 2.66). A possible explanation is increased anxiety, the only condition that was more prevalent in patients with feminine characteristics and that rendered the association between gender and recurrent ACS nonstatistically significant (hazard ratio: 3.56; 95% confidence interval: 0.81 to 15.61). Female sex was not associated with outcomes post-ACS.nnnCONCLUSIONSnYounger adults with ACS with feminine gender are at an increased risk of recurrent ACS over 12 months, independent of female sex.

Secular trends in acute coronary syndrome hospitalization from 1994 to 2005

BACKGROUNDnAcute coronary syndrome (ACS) is one of the most frequent reasons for hospitalization worldwide. Although substantial advances have been made in the prevention and treatment of coronary artery disease, their impact on the rates of ACS hospitalization is unclear.nnnMETHODSnData from the Canadian Institute for Health Information Discharge Abstract Database were used to estimate secular trends in ACS hospitalization. A total of 1.3 million ACS hospitalizations in Canada from April 1, 1994, to March 31, 2006, were examined. Overall hospitalization rates were standardized for age and sex using 1991 Canadian census data, and hospitalization rates were also stratified by age group, sex and Canadian province to assess trends in each subgroup.nnnRESULTSnThe Canadian age- and sex-standardized ACS hospitalization rate was 508 per 100,000 persons in 1994, and 317 per 100,000 persons in 2005 - a relative reduction of 37.8% and an average annual relative reduction of 3.9% per year. Declines in ACS hospitalization rates were observed among men (annual relative reduction 3.9%, relative reduction 39.0%) and women (annual relative reduction 3.8%, relative reduction 35.8%). Declining trends were also observed among patients of different age groups and among patients hospitalized across all Canadian provinces.nnnINTERPRETATIONnOver the past decade, a substantial decline in ACS hospitalization rates occurred, which has not been previously observed. This finding is likely due to improvements in primary and secondary prevention of coronary artery disease. The present studys data should provide important insights and guidance for future health care planning in Canada.

Heart failure clinics are associated with clinical benefit in both tertiary and community care settings: Data from the Improving Cardiovascular Outcomes in Nova Scotia (ICONS) registry

BACKGROUNDnHeart failure (HF) clinics are known to improve outcomes of patients with HF. Studies have been limited to single, usually tertiary centres whose experience may not apply to the general HF population.nnnOBJECTIVESnTo determine the effectiveness of HF clinics in reducing death or all-cause rehospitalization in a real-world population.nnnMETHODSnA retrospective analysis of the Improving Cardiovascular Outcomes in Nova Scotia (ICONS) disease registry was performed. All 8731 patients with a diagnosis of HF (844 managed in HF clinics) who were discharged from the hospital between October 15, 1997, and July 1, 2000, were identified. Patients enrolled in any one of four HF clinics (two community-based and two academic-based) were compared with those who were not. The primary outcome was the one-year combined hospitalization and mortality.nnnRESULTSnPatients followed in HF clinics were younger (68 versus 75 years), more likely to be men (63% versus 48%), and had a lower ejection fraction (35% versus 44%), lower systolic blood pressure (137 mmHg verus 146 mmHg) and lower serum creatinine (121 micromol/L versus 130 micromol/L). There was no difference in the prevalence of hypertension (56%), diabetes (35%) or stroke/transient ischemic attack (16%). The one-year mortality rate was 23%, while 31% of patients were rehospitalized; the combined end point was 51%. Enrollment in an HF clinic was independently associated with reduced risk of total mortality (hazard ratio [HR] 0.69 [95% CI 0.51 to 0.90], P=0.008; number needed to treat for one year to prevent the occurrence of one event [NNT]=16), all-cause hospital readmission (HR 0.27 [95% CI 0.21 to 0.36], P<0.0001; NNT=4), and combined mortality or hospital readmission (HR 0.73 [95% CI 0.60 to 0.89], P<0.0015; NNT=5).nnnDISCUSSIONnHF clinics are associated with reductions in rehospitalization and mortality in an unselected HF population, independent of whether they are academic- or community-based. Such clinics should be made widely available to the HF population.

The Risk Stratification and Stroke Prevention Therapy Care Gap in Canadian Atrial Fibrillation Patients

BACKGROUNDnCanadian atrial fibrillation (AF) guidelines recommend that all AF patients be risk stratified with respect to stroke and bleeding, and that most should receive antithrombotic therapy.nnnMETHODSnAs part of the Canadian Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation (FREEDOM AF) chart audit, data were collected on 4670 patients ≥ 18 years old without significant valvular heart disease from the primary care practices of 474 physicians (February to September, 2011).nnnRESULTSnPhysicians did not provide an estimate of stroke and bleeding risk in 15% and 25% of patients, respectively. When risks were provided, they were on the basis of a predictive stroke and bleeding risk index in only 50% and 26% of patients, respectively. There were over- and underestimation of stroke and bleeding risk in a large proportion of patients. Antithrombotic therapy included warfarin (90%); 24% of patients had a time in the therapeutic range (TTR) < 50%, 9% between 50% and 60%, 11% between 60% and 70%, and 56% had a TTR ≥ 70%.nnnCONCLUSIONSnIn a large Canadian AF population, primary care physicians did not provide a stroke or bleeding risk in a substantial proportion of their AF patients. When estimates were provided, they were on the basis of a predictive stroke and bleeding risk index in less than half of the patients. Furthermore, there was under- and overestimation of stroke and bleeding risk in a substantial proportion of patients. As many as 1 in 3 patients receiving warfarin have their TTR < 60%. These findings suggest an opportunity to enhance knowledge translation to primary care physicians.

Should all patients be treated with an angiotensin-converting enzyme inhibitor after coronary artery bypass graft surgery? The impact of angiotensin-converting enzyme inhibitors, statins, and β-blockers after coronary artery bypass graft surgery

BACKGROUNDnWe sought to evaluate the association between angiotensin-converting enzyme (ACE) inhibitors and outcomes after coronary artery bypass graft surgery (CABG).nnnMETHODSnPostoperative outpatient utilization of ACE inhibitors, statins, and β-blockers was assessed in a cohort of 3,718 patients after CABG 65 years and older. The primary outcome was freedom from a composite of all-cause mortality or hospital readmission for cardiac events or procedures.nnnRESULTSnUse of all 3 medication classes increased significantly over the study period. Female patients and patients with a history of myocardial infarction, diabetes, and poor left ventricular function were independently associated with ACE inhibitor use on multivariate analysis (all P < .05). At a median follow-up of 3 years, postoperative therapy with an ACE inhibitor had no effect on death or rehospitalization for cardiovascular events (adjusted hazard ratio [HR] 1.12, 95% CI 0.96-1.30, P = .16). However, statins (HR 0.65, 95% CI 0.57-0.74, P < .0001) and β-blockers (HR 0.83, 95% CI 0.74-0.93, P = .001) were associated with a significantly improved event-free survival.nnnCONCLUSIONSnAmong patients after CABG 65 years or older, ACE inhibitors had no independent effect on mortality or recurrent ischemic events in the midterm after CABG, although a benefit was observed for statins and β-blockers.

Effective practical management of patients with atrial fibrillation when using new oral anticoagulants.

Abstract Practical management of stroke prevention in patients with non-valvular atrial fibrillation (AF) requires physicians to find the optimal balance between maximizing prevention of ischaemic stroke and minimizing the risk of bleeding. Vitamin K antagonists have traditionally been used for stroke prevention in patients with AF; however, they have been associated with increased risk of bleeding, particularly intracranial haemorrhage. New oral anticoagulants (OACs) have shown similar efficacy to the vitamin K antagonist warfarin but with a reduced risk of bleeding, particularly life-threatening bleeding such as intracranial haemorrhage. Decisions about which new OAC therapy to use may be influenced by patient characteristics such as age, renal function, co-medication use, and bleeding risk. This review uses a case-based approach to highlight the practical management issues to be considered by the physician when selecting a new OAC for stroke prevention in patients with non-valvular AF.