Major changes in acute ST elevation myocardial infarction (STEMI) management prompted a comprehensive rewriting of the American College of Cardiology/American Heart Association Guidelines. The Canadian Cardiovascular Society (CCS) participated in both the writing process and the external review. Subsequently, a Canadian Working Group (CWG), formed under the auspices of the CCS, developed a perspective and adaptation for Canada. Herein, accounting for specific realities of the Canadian cardiovascular health system, is a discussion of the implications for prehospital care and transport, optimal reperfusion therapy and an approach to decision making regarding reperfusion options and invasive therapy following fibrinolytic therapy. Major recent developments regarding indications for implantable cardioverter defibrillator(s) (ICDs) also prompted a review of indications for ICDs and the optimal timing of implantation given the potential for recovery of left ventricular function. At least a 40-day, preferably a 12-week, waiting period was judged to be optimal to evaluate left ventricular function post-STEMI. A recommended algorithm for the insertion of an ICD is provided. Implementation of the new STEMI guidelines has substantial implications for resources, organization and priorities of the Canadian health care system. While on the one hand, the necessary incremental funding to provide tertiary and quaternary care and to support revascularization and device implantation capability is desirable, it is equally or more important to develop enhanced prehospital care, including the capacity for early recognition, risk assessment, fibrinolytic therapy and/or triage to a tertiary care centre as part of an enlightened approach to improving cardiac care.
The 2011 Canadian Cardiovascular Society Heart Failure (HF) Guidelines Focused Update reviews the recently published clinical trials that will potentially impact on management. Also reviewed is the less studied but clinically important area of sleep apnea. Finally, patients with advanced HF represent a group of patients who pose major difficulties to clinicians. Advanced HF therefore is examined from the perspectives of HF complicated by renal failure, the role of palliative care, and the role of mechanical circulatory support (MCS). All of these topics are reviewed from a perspective of practical applications. Important new studies have demonstrated in less symptomatic HF patients that cardiac resynchronization therapy will be of benefit. As well, aldosterone receptor antagonists can be used with benefit in less symptomatic HF patients. The important role of palliative care and the need to address end-of-life issues in advanced HF are emphasized. Physicians need to be aware of the possibility of sleep apnea complicating the course of HF and the role of a sleep study for the proper assessment and management of the conditon. Patients with either acute severe or chronic advanced HF with otherwise good life expectancy should be referred to a cardiac centre capable of providing MCS. Furthermore, patients awaiting heart transplantation who deteriorate or are otherwise not likely to survive until a donor organ is found should be referred for MCS.
Comment In: Can J Cardiol. 2011 Nov-Dec;27(6):871.e721885242
The pharmacologic management of atrial fibrillation (AF), the most common sustained cardiac arrhythmia, has been traditionally dichotomized into control of ventricular rate or re-establishment and maintenance of sinus rhythm.
The purpose of this study was to evaluate the use of rate-controlling drugs and antiarrhythmic drugs (AAD) in the Canadian Registry of Atrial Fibrillation (CARAF) over a 16-year period from 1991 through 2007.
1,400 patients with new-onset paroxysmal AF who were enrolled in CARAF were included in this analysis. We assessed trends in ventricular rate-controlling medication use (digoxin, beta-blockers, and calcium channel blockers) and AAD (class IA, IC, and III antiarrhythmic agents) at baseline and follow-up visits as well as by calendar year.
AAD use increased initially from 1991 to 1994 (peak use 42.5%) before steadily declining. Sotalol use decreased (27% to 6%), whereas amiodarone use increased (1.6% to 17.9%). Rate-controlling medication use decreased from 1991 to 1995 (54.1% to 34.1%) due to declining digoxin use (62.9% to 16.3%). After 1999, there was a continued increase in rate-controlling medication use (peak use 52.5% in 2007) due to increased beta-blocker use (17% to 45.7%). Calcium channel blockers use changed little over the duration of the study.
The management of AF has undergone significant shifts since 1990, reflecting the influence of drug development, prevailing belief systems, the impact of large clinical trials, and evidence-based recommendations. Monitoring of pharmacotherapy trends will provide insight into the real-world application of evidence-based guidelines as well as allow the opportunity to identify deficiencies and improve patient care.
The goals of atrial fibrillation (AF) and atrial flutter (AFL) arrhythmia management are to alleviate patient symptoms, improve patient quality of life, and minimize the morbidity associated with AF and AFL. Arrhythmia management usually commences with drugs to slow the ventricular rate. The addition of class I or class III antiarrhythmic drugs for restoration or maintenance of sinus rhythm is largely determined by patient symptoms and preferences. For rate control, treatment of persistent or permanent AF and AFL should aim for a resting heart rate of 35%, dronedarone, sotalol, or amiodarone is recommended. In patients with left ventricular ejection fraction
Cardiac resynchronization (CRT) prolongs survival in patients with systolic heart failure and QRS prolongation. However, most trials excluded patients with permanent atrial fibrillation.
The Resynchronization for Ambulatory Heart Failure Trial (RAFT) randomized patients to an implantable cardioverter defibrillator (ICD) or ICD+CRT, stratified by the presence of permanent atrial fibrillation. Patients with permanent atrial fibrillation were randomized to CRT-ICD (n=114) or ICD (n=115). Patients receiving a CRT-ICD were similar to those receiving an ICD: age (71.6±7.3 versus 70.4±7.7 years), left ventricular ejection fraction (22.9±5.3% versus 22.3±5.1%), and QRS duration (151.0±23.6 versus 153.4±24.7 ms). There was no difference in the primary outcome of death or heart failure hospitalization between those assigned to CRT-ICD versus ICD (hazard ratio, 0.96; 95% CI, 0.65-1.41; P=0.82). Cardiovascular death was similar between treatment arms (hazard ratio, 0.97; 95% CI, 0.55-1.71; P=0.91); however, there was a trend for fewer heart failure hospitalizations with CRT-ICD (hazard ratio, 0.58; 95% CI, 0.38-1.01; P=0.052). The change in 6-minute hall walk duration between baseline and 12 months was not different between treatment arms (CRT-ICD: 19±84 m versus ICD: 16±76 m; P=0.88). Patients treated with CRT-ICD showed a trend for a greater improvement in Minnesota Living with Heart Failure score between baseline and 6 months (CRT-ICD: 41±21 to 31±21; ICD: 33±20 to 28±20; P=0.057).
Patients with permanent atrial fibrillation who are otherwise CRT candidates appear to gain minimal benefit from CRT-ICD compared with a standard ICD.
Both "physiologic" (dual-chamber or atrial only) or ventricular-pacing-only permanent pacemakers provide chronotropic competence, with unknown health-related quality of life (QOL) differences between these options. The QOL studies within the Canadian Trial of Physiologic Pacing were performed to assess whether QOL differences exist in patients randomized to these 2 pacing modes.
Two QOL protocols were performed: 1) a substudy of 269 patients with detailed QOL measures (The Medical Outcomes Study, Short-Form [SF-36], the Pacemaker Syndrome Scale, an activity scale, and a pacemaker-specific scale) at baseline and 6 months after implantation; and 2) a parent study assessment of QOL in 1721 patients with a 12-item QOL instrument package (SF-6, "ladder of life," and pacemaker syndrome scale) given 6 months after implantation only.
In the substudy, pacing was associated with an average significant (P
This study examined the predictors of early complications after defibrillator implantation.
Although implantable cardioverter-defibrillators are widely used, predictors of procedural complications and the consequences of these events have not been determined.
In a prospective, multicenter, population-based clinical outcomes registry of all newly implanted defibrillator patients at 18 centers in Ontario, Canada, we examined 45-day complications and all-cause mortality from February 2007 to May 2009. Complications were determined longitudinally and were categorized as direct implant-related or indirect events.
Among 3,340 patients (mean age 63.8 +/- 12.5 years, 78.5% men), major complications occurred in 4.1% of de novo procedures. Compared with those undergoing a single-chamber device, implantation of a cardiac resynchronization defibrillator (adjusted hazard ratio [HR]: 2.17, 95% confidence interval [CI]: 1.38 to 3.43, p
Heart failure is considered an epidemic of the modern era. In selected candidates on optimal medical therapy, cardiac resynchronization therapy (CRT) has emerged as a valuable adjunctive treatment. Despite its demonstrated salutary effects on clinical evolution, left ventricular (LV) function, and overall survival, at least 30% of patients fail to respond to CRT.
The Greater Evaluation of Resychronization Therapy for Heart Failure (GREATER-EARTH) (ClinicalTrials.gov Identifier NCT00901212) is a randomized, double-blind, multicentre study involving 11 centres across Canada and compares LV CRT with biventricular CRT in patients with severe LV dysfunction and a QRS duration>120 ms.
This article describes the rationale and design of the study and presents the baseline characteristics of all randomized patients. The primary outcome consists of the effects of CRT on submaximal exercise tolerance (treadmill test), and secondary outcomes explore mechanisms of asynchrony and effects of CRT on asynchrony and LV function.
The study was initiated in November 2003, with the last patient randomized on February 12, 2009. As expected, follow-up was in February 2010 and the results are presently being analyzed in March 2010.
Advances in resuscitation science have dramatically improved survival rates following cardiac arrest. However, about 60% of adults that regain spontaneous circulation die before leaving the hospital. Recently it has been shown that inducing hypothermia in cardiac arrest survivors immediately following their arrival in hospital can dramatically improve both overall survival and neurological outcomes. Despite the strong evidence for its efficacy and the apparent simplicity of this intervention, recent surveys show that therapeutic hypothermia is delivered inconsistently, incompletely, and often with delay.
This study will evaluate a multi-faceted knowledge translation strategy designed to increase the utilization rate of induced hypothermia in survivors of cardiac arrest across a network of 37 hospitals in Southwestern Ontario, Canada. The study is designed as a stepped wedge randomized trial lasting two years. Individual hospitals will be randomly assigned to four different wedges that will receive the active knowledge translation strategy according to a sequential rollout over a number of time periods. By the end of the study, all hospitals will have received the intervention. The primary aim is to measure the effectiveness of a multifaceted knowledge translation plan involving education, reminders, and audit-feedback for improving the use of induced hypothermia in survivors of cardiac arrest presenting to the emergency department. The primary outcome is the proportion of eligible OHCA patients that are cooled to a body temperature of 32 to 34?C within six hours of arrival in the hospital. Secondary outcomes will include process of care measures and clinical outcomes.
Inducing hypothermia in cardiac arrest survivors immediately following their arrival to hospital has been shown to dramatically improve both overall survival and neurological outcomes. However, this lifesaving treatment is frequently not applied in practice. If this trial is positive, our results will have broad implications by showing that a knowledge translation strategy shared across a collaborative network of hospitals can increase the number of patients that receive this lifesaving intervention in a timely manner.
ClinicalTrials.gov Trial Identifier: NCT00683683.
Cites: JAMA. 1999 Oct 20;282(15):1458-6510535437
Cites: N Engl J Med. 2002 Feb 21;346(8):549-5611856793
Cites: N Engl J Med. 2002 Feb 21;346(8):557-6311856794
Cites: Resuscitation. 2003 Jan;56(1):9-1312505732
Cites: Resuscitation. 1996 Nov;33(1):69-848959776
Cites: Ann Emerg Med. 1997 Aug;30(2):146-539250636