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Biomedical subjects

Christopher S Simpson

Publications and source records attributed to Christopher S Simpson.

10 recordsLinked to original sources
PubMed2006

The pacemaker and implantable cardioverter defibrillator recall issue - a Canadian perspective.

In 2005, an unprecedented number of recalls were issued on pacemakers and implantable cardioverter defibrillators. While recalls in the cardiac rhythm device industry are not new, the sheer magnitude of potentially affected patients in 2005 led to a great deal of concern, frustration, and even anger. Physicians have, in many instances, been uncertain when (or if) to recommend device replacement in an environment where the magnitude of the risk and the potential consequences of device failure have not been well defined in a timely way. Doctors and patients are now calling for reform of postmarket analysis and reporting mechanisms. The present article provides a uniquely Canadian perspective on this international issue. Potential solutions include the development of a set of realistic and common expectations, a restoration of confidence in postmarket analysis and reporting mechanisms, increased data transparency, and an increased role for patient and physician groups.

Canada↗
PubMed2006

Universal access -- but when? Treating the right patient at the right time: access to electrophysiology services in Canada.

The Canadian Cardiovascular Society Access to Care Working Group has published a series of commentaries on access to cardiovascular care in Canada. The present article reviews the evidence for timely access to electrophysiology services. Using the best available evidence along with expert consensus by the Canadian Heart Rhythm Society, the panel proposed a series of benchmarks for access to the full scope of electrophysiology services, from initial consultation through to operative procedures. The proposed benchmarks are presented herein.

Canada↗
PubMed2005

Downward delegation of implantable cardioverter defibrillator decision-making in a restricted-resource environment: the pitfalls of bedside rationing.

Implantable cardioverter defibrillators have been shown to reduce all-cause mortality in some patient populations at risk of sudden death. New Canadian guidelines recommend implantable cardioverter defibrillator therapy for these patients. However, the need for these devices exceeds the funded volumes in many Canadian jurisdictions. As a result, rationing of this resource has been necessary. While rationing at the macro (Ministry of Health) and meso (hospital) levels has achieved some level of acceptance by society, the responsibility for the decisions taken at the micro (individual) patient level actually rests with the physician at the bedside. This 'bedside rationing' creates a moral dilemma for physicians, who are torn between their traditional fiduciary role as 'patient advocate' and the competing role of 'gatekeeper'. This 'downward delegation' of rationing decision-making obscures the reality that rationing occurs, and encourages covert, opaque and inconsistent approaches. The remedy is the development of fair, legitimate procedures for making rationing decisions that include guidelines that structure and constrain those decisions. Macro- and meso-level stakeholders must also recognize and take responsibility for their part in restricting resources in a broadly inclusive and transparent process.

Canada↗
PubMed2005

Canadian Cardiovascular Society/Canadian Heart Rhythm Society position paper on implantable cardioverter defibrillator use in Canada.

The Canadian Heart Rhythm Society in conjunction with the Canadian Cardiovascular Society is committed to the promotion of evidence-based practice in Canada. Since the last Canadian guidelines on the management of sudden cardiac death were published in 2000, several well-conducted clinical trials evaluating the implantable cardioverter defibrillator have been completed and published. The Canadian Cardiovascular Society Council has granted permission to review and update guidelines for the indications for implantable cardioverter defibrillators. Furthermore, data are emerging on the potential benefits of biventricular pacing therapy (cardiac resynchronization) for heart failure; recommendations for the use of this therapy have been included in the present paper. Ethical considerations and the economic implications of these recommendations are also included. Canada's heart rhythm specialists, represented by the Canadian Heart Rhythm Society, have been joined by two heart failure specialists, a medical ethicist and an economist, to develop the present position paper. Members of the Canadian Heart Rhythm Society participated in the discussion of these recommendations in open forum meetings and by electronic communication.

Death, Sudden, Cardiac↗
PubMed2005

Rate control versus rhythm control--decision making.

The present review examines the data and presents recommendations concerning the selection of rate-control or rhythm-control strategies, as opposed to the selection of specific therapies for rate control or rhythm control. There are several trials completed and others in progress that address issues surrounding the comparison of the two strategies, primarily using pharmacological therapies. The main results and some subanalyses of these trials are briefly reviewed. Gaps in the available data are identified. On the basis of the data, there is no clear advantage of one strategy over the other, although each seems to have potential advantages in different subsets of patients. Accordingly, the main recommendations are that either approach is acceptable, and that selection of a rhythm-management strategy should be individualized. This recommendation is based on a primarily pharmacological approach because that is currently the most common form of therapy used for rhythm management and because the evidence base is composed of comparisons of drug therapies. A number of clinical factors are identified to help individualize therapy and, included in these, is patient preference. It is also recommended that treating physicians be prepared to cross over from one strategy to another or change to nonpharmacological therapies when treatment goals are not achieved or adverse effects prevail.

Atrial Fibrillation↗
PubMed2005

Similarities and differences between atrial flutter and atrial fibrillation.

Atrial flutter and atrial fibrillation have a complex relationship that has mechanistic, diagnostic, therapeutic and prognostic components. While thromboembolic risk management and pharmacological strategies share many similarities, there are important differences. Radiofrequency ablation should be considered to be an early, first-line alternative to pharmacological strategies for many patients with atrial flutter.

Atrial Fibrillation↗
PubMed2004

Atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained dysrhythmia in adults. It is ironic, then, that although mechanisms and effective treatments for most other supraventricular tachyarrhythmias have been discovered, AF remains incompletely understood and poorly treated. Nonetheless, our understanding of the pathophysiology of AF has improved in the last half-century, including some groundbreaking observations made in the last 10 years. Indeed, for some patients, the potential for cure now appears to be available. Because no unifying mechanism of AF has been proven, the aim of this review is to describe some of the common and important concepts behind current mechanistic theories of AF and how they contribute to our clinical understanding of AF.

Anti-Arrhythmia Agents↗
PubMed2004

Mandatory physician reporting of drivers with cardiac disease: ethical and practical considerations.

Many jurisdictions in Canada have enacted legislation that requires physicians to report their patients to the Ministry of Transport if they have a medical condition that may put them at increased risk to operate a motor vehicle. The Canadian Cardiovascular Society has published guidelines that are designed to assist physicians and policy-makers in their decision-making. Legislation is designed to protect society, and the guidelines are designed to fulfill that mandate. However, in the present paper, important issues that have not been addressed to date are discussed. What is the efficacy of mandatory reporting legislation? What are the harms done to patients who are restricted from driving? What are the costs of the mandatory reporting system? How can the scientific/technical assessment of risk be reconciled with the social/ethical view of risk assessment? Until these issues are addressed, important questions about the ethics, efficacy and cost of mandatory physician reporting will remain unanswered.

Accidents, Traffic↗
PubMed2003

Atrial fibrillation in the pacemaker clinic.

BACKGROUND: Electrocardiographic (ECG) recognition of the underlying rhythm in patients with ventricular pacing can be difficult. Atrial fibrillation (AF) in particular may go unreported. OBJECTIVES: To compare the underlying atrial rhythm determined in the pacemaker clinic with the 12-lead ECG interpretation of the atrial rhythm in those who were continuously paced in the ventricle. It was intended to determine whether long term anticoagulation therapy was related to whether AF was diagnosed before or after pacemaker implantation. METHODS: Pacemaker clinic patients were enrolled if they had a 100% paced ventricular rhythm. The underlying rhythm was determined using pacemaker programming manoeuvres. A 12-lead ECG was recorded on all patients within 10 min of their pacemaker assessment and interpreted by one of the several geographic full-time cardiologists at the centre. All cardiologists were blinded to the results of pacemaker assessment and to the clinical history. RESULTS: Fifty-six patients were enrolled. At the pacemaker clinic, 37 were determined to be in AF and three were in atrial flutter (AFL). Of these 40 patients with AF/AFL, 28 were correctly identified as such on the 12-lead ECG interpretation. Twelve of the 40 were interpreted only as having an 'electronic ventricular pacemaker' (EVP). Sixteen of the 40 patients (40.0%) with AF or AFL were not taking warfarin. Twenty-two of 25 patients with an AF/AFL diagnosis before pacemaker implantation were taking warfarin, compared with two of 15 patients with AF/AFL diagnosis after pacemaker implantation (P<0.0001). CONCLUSION: These results show that the underlying rhythm in patients with ventricular pacing is frequently unrecognized by routine ECG interpretation. This may be of particular importance in the AF/AFL population as a potential contributor to the underuse of warfarin, especially when AF develops after pacemaker implantation. The pacemaker clinic may be in a position to play an important role in the identification of these patients.

Ambulatory Care Facilities↗