Canadian Cardiovascular Society 2023 Guidelines on the Fitness to Drive

Cardiovascular conditions are among the most frequent causes of impairment to drive, because they might induce unpredictable mental state alterations via diverse mechanisms like myocardial ischemia, cardiac arrhythmias, and vascular dysfunction. Accordingly, health professionals are often asked to assess patients' fitness to drive (FTD). The Canadian Cardiovascular Society previously published FTD guidelines in 2003-2004; herein, we present updated FTD guidelines. Because there are no randomized trials on FTD, observational studies were used to estimate the risk of driving impairment in each situation, and recommendations made on the basis of Canadian Cardiovascular Society Risk of Harm formula. More restrictive recommendations were made for commercial drivers, who spend longer average times behind the wheel, use larger vehicles, and might transport a larger number of passengers. We provide guidance for individuals with: (1) active coronary artery disease; (2) various forms of valvular heart disease; (3) heart failure, heart transplant, and left ventricular assist device situations; (4) arrhythmia syndromes; (5) implantable devices; (6) syncope history; and (7) congenital heart disease. We suggest appropriate waiting times after cardiac interventions or acute illnesses before driving resumption. When short-term driving cessation is recommended, recommendations are on the basis of expert consensus rather than the Risk of Harm formula because risk elevation is expected to be transient. These recommendations, although not a substitute for clinical judgement or governmental regulations, provide specialists, primary care providers, and allied health professionals with a comprehensive list of a wide range of cardiac conditions, with guidance provided on the basis of the level of risk of impairment, along with recommendations about ability to drive and the suggested duration of restrictions.

Predictors of pacemaker requirement in patients receiving implantable loop recorders for unexplained syncope: A systematic review and meta-analysis

BACKGROUND

Implantable loop recorders (ILRs) are increasingly used to evaluate patients with unexplained syncope. Identification of all predictors of bradycardic syncope and consequent permanent pacemaker (PPM) insertion is of substantial clinical interest as patients in the highest risk category may benefit from upfront pacemaker insertion.

OBJECTIVE

We performed a systematic review and meta-analysis to identify risk predictors for PPM insertion in ILR recipients with unexplained syncope.

METHODS

An electronic database search (MEDLINE, Embase, Scopus, Cochrane) was performed in June 2023. Studies evaluating ILR recipients with unexplained syncope and recording risk factors for eventual PPM insertion were included. A random effects model was used to calculate the pooled odds ratio (OR) for clinical and electrocardiographic characteristics with respect to future PPM requirement.

RESULTS

Eight studies evaluating 1007 ILR recipients were included; 268 patients (26.6%) underwent PPM insertion during study follow-up. PPM recipients were older (mean age, 70.2 ± 15.4 years vs 61.6 ± 19.7 years; P < .001). PR prolongation on baseline electrocardiography was a significant predictor of PPM requirement (pooled OR, 2.91; 95% confidence interval, 1.63-5.20). The presence of distal conduction system disease, encompassing any bundle branch or fascicular block, yielded a pooled OR of 2.88 for PPM insertion (95% confidence interval, 1.53-5.41). Injurious syncope and lack of syncopal prodrome were not significant predictors of PPM insertion. Sinus node dysfunction accounted for 62% of PPM insertions, whereas atrioventricular block accounted for 26%.

CONCLUSION

Approximately one-quarter of ILR recipients for unexplained syncope require eventual PPM insertion. Advancing age, PR prolongation, and distal conduction disease are the strongest predictors for PPM requirement.

Twenty-five years of research on syncope

Over the last 25 years, the Europace journal has greatly contributed to dissemination of research and knowledge in the field of syncope. More than 400 manuscripts have been published in the journal. They undoubtedly improved our understanding of syncope. This symptom is now clearly differentiated from other forms of transient loss of consciousness. The critical role of vasodepression and/or cardioinhibition as final mechanisms of reflex syncope is emphasized. Current diagnostic approach sharply separates between cardiac and autonomic pathways. Physiologic insights have been translated, through rigorously designed clinical trials, into non-pharmacological or pharmacological interventions and interventional therapies. The following manuscript is intended to give the reader the current state of the art of knowledge of syncope by highlighting landmark contributions of the Europace journal.

Prediction of Pacemaker Requirement in Patients With Unexplained Syncope: The DROP Score

BACKGROUND

Implantable loop recorders (ILR) are increasingly utilised in the evaluation of unexplained syncope. However, they are expensive and do not protect against future syncope.

OBJECTIVES

To compare patients requiring permanent pacemaker (PPM) implantation during ILR follow-up with those without abnormalities detected on ILR in order to identify potential predictors of benefit from upfront pacing.

METHODS

We analysed 100 consecutive patients receiving ILR: Group 1 (n=50) underwent PPM insertion due to bradyarrhythmias detected on ILR; Group 2 (n=50) had no arrhythmias detected on ILR over >3 years follow-up. Baseline clinical characteristics, syncope history, electrocardiographic and echocardiographic parameters were assessed to identify predictors of ultimate requirement for pacing.

RESULTS

Group 1 (64% male, median age 70.8 years; IQR 65.5-78.8) were older than Group 2 (58% male, median 60.2 years; IQR 44.0-73.0 p=0.001) and were less likely to have related historical factors such as overheating, posture and exercise (98% vs 70% p<0.001). PR interval was also longer in Group 1 (192±51 vs 169±23 p=0.006) with greater prevalence of distal conduction system disease (30% vs 4.3% p=0.002). Significant univariate predictors for PPM insertion were distal conduction disease (p=0.007), first degree atrioventricular (AV) block (p=0.003), absence of precipitating factors (p=0.004), and age >65 years (p=0.001). Injury sustained, recurrent syncope, history of atrial fibrillation (AF) or heart failure, left atrial (LA) size and left ventricular ejection fraction (LVEF) were not predictive. These significant predictors were incorporated into the DROP score¹ (0-4). Using time-to-event analysis, no patients with a score of 0 progressed to pacing, while higher scores (3-4) strongly predicted pacing requirement (log-rank p<0.001).

CONCLUSION

The DROP score may be helpful in identifying patients likely to benefit from upfront permanent pacemaker (PPM) insertion following unexplained syncope. Larger prospective studies are required to validate this tool.

A Cost-Utility Analysis of the Syncope: Pacing or Recording In ThE Later Years Trial

Background

The Syncope: Pacing or Recording in the Later Years (SPRITELY) trial reported that a strategy of empiric permanent pacing in patients with syncope and bifascicular block reduces major adverse events more effectively than acting on the results of an implantable cardiac monitor (ICM). Our objective was to determine the cost-effectiveness of using the ICM, compared with a pacemaker (PM), in the management of older adults (age > 50 years) with bifascicular block and syncope enrolled in the SPRITELY trial.

Methods

SPRITELY was a pragmatic, open-label randomized controlled trial with a median follow-up of 33 months. The primary outcome of this analysis is the cost per additional quality-adjusted life-year (QALY). Resource utilization and utility data were collected prospectively, and outcomes at 2 years were compared between the 2 arms. A decision analytic model simulated a 3-year time horizon.

Results

The mean cost incurred by participants randomized to the PM arm was $9918, compared to $15,416 (both in Canadian dollars) for participants randomized to the ICM arm. The ICM strategy resulted in 0.167 QALYs fewer than the PM strategy. Cost and QALY outcomes are sensitive to the proportion of participants randomized to the ICM arm who subsequently required PM insertion. In 40,000 iterations of probabilistic sensitivity analysis, the PM strategy resulted in cost-savings in 99.7% of iterations, compared with the ICM strategy.

Conclusions

The PM strategy was dominant—that is, less costly and estimated to result in a greater number of QALYs. For patients with unexplained syncope, bifascicular block, and age > 50 years, a PM is more likely to be cost-effective than an ICM.

Bifascicular block in unexplained syncope is underrecognized and under-evaluated: A single-center audit of ESC guidelines adherence

Background

The presence of bifascicular block on electrocardiography suggests that otherwise-unexplained syncope may be due to complete heart block. European Society of Cardiology (ESC) recommends investigating it with electrophysiology study (EPS). PPM is indicated if high-degree atrioventricular block is inducible. Long term rhythm monitoring with implantable loop recorder (ILR) is recommended if EPS is negative. We evaluated adherence to these guidelines.

Methods

This is a single-center retrospective audit of adult patients with bifascicular block hospitalized for unexplained syncope between January 2018 and August 2019 under general medicine service. Patients with an alternative explanation for syncope were excluded. Guideline adherence was assessed by formal cardiology consult and whether EPS followed by ILR and/or PPM were offered.

Results

65 out of 580 adult patients (11.2%) admitted to general medicine service for syncope had a bifascicular block; 29 (5%) were identified to have bifascicular block and unexplained syncope. Median age was 77 ±10 years; 9 (31%) were female, and 6 (20.7%) patients had at least one prior hospital visit for syncope at our academic medical center. Cardiology was consulted on 17 (58.6%) patients. Two patients were evaluated by EPS (1 refused) followed by ILR. Overall, 3 out of 29 patients (10.3%) received guideline-directed evaluation during the hospitalization based on ESC guidelines. None of the patients received empiric PPM during the index hospitalization.

Conclusion

Among patients admitted to the general medicine service with unexplained syncope and bifascicular block, a minority (10.3%) underwent guideline-directed evaluation per ESC recommendations. Cardiology was consulted in 58.6% of cases.

Likelihood of injury due to vasovagal syncope: a systematic review and meta-analysis

AIMS

Vasovagal syncope (VVS) is the most common type of syncope and is usually considered a benign disorder. The potential for injury is worrisome but the likelihood is unknown. We aimed to determine the proportion of patients injured due to VVS.

METHODS AND RESULTS

A systematic search of studies published until August 2020 was performed in multiple medical and nursing databases. Included studies had data on the proportion of patients with injury due to VVS prior to study enrolment. Random effects methods were used. Twenty-three studies having 3593 patients met inclusion criteria. Patients were diagnosed clinically with VVS, and 82% had >2 syncopal episodes before enrolment. Tilt test was positive in 60% and 14 studies reported comorbidities (32.6% hypertensive). The weighted mean injury rate was 33.5% [95% confidence interval (CI): 27.3-40.5%]. The likelihood of injury correlated with population age (r = 0.4, P = 0.05), but not with sex, positive tilt test, or hypertension. The injury rates were 25.7% (95% CI: 19.1-32.8%) in studies with younger patients (mean age ≤50 years, n = 1803) and 43.4% (95% CI: 34.9-52.3%) in studies with older patients (P = 0.002). Nine studies reported major injuries; with a weighted mean rate of major injuries of 13.9% (95% CI: 9.5-19.8%).

CONCLUSION

Injuries due to syncope are frequent, occurring in 33% of patients with VVS. The risk of major injuries is substantial. Older patients are at higher risk. Clinicians should be aware of the risk of injuries when providing care and advice to patients with VVS.

Frequency of injuries associated with syncope in the prevention of syncope trials

AIMS

Syncope can lead to injuries. We determined the frequency, severity, and predictors of injuries due to syncope in cohorts of syncope patients.

METHODS AND RESULTS

Participants were enrolled in the POST2 (fludrocortisone) and POST4 (midodrine) vasovagal syncope (VVS) randomized trials, and POST3 enrolled patients with bifascicular block and syncope. Injury was defined as minor (bruising, abrasions), moderate (lacerations), and severe (fractures, burns, joint pain), and recorded up to 1 year after enrolment. A total of 459 patients (median 39 years) were analysed. There were 710 faints occurred in 186 patients during a 1-year follow-up. Fully 56/186 (30%) of patients were injured with syncope (12% of overall group). There were 102 injuries associated with the 710 faints (14%), of which 19% were moderate or severe injuries. Neither patient age, sex, nor the presence of prodromal symptoms associated with injury-free survival. Patients with bifascicular block were more prone to injury (relative risk 1.98, P = 0.018). Patients with ≥4 faints in the prior year had more injuries than those with fewer faints (relative risk 2.97, P < 0.0001), but this was due to more frequent syncope, and not more injuries per faint. In VVS patients, pharmacological therapy significantly reduced the likelihood of an injury due to a syncopal spell (relative risk 0.64, P = 0.015). Injury severity did not associate with age, sex, or prior-year syncope frequency.

CONCLUSION

Injuries are frequent in syncope patients, but only 4% of injuries were severe. None of age, sex, and prodromal symptoms associate with injury.

Electrophysiology studies for predicting atrioventricular block in patients with syncope: A systematic review and meta-analysis

BACKGROUND

Syncope may be caused by intermittent complete heart block in patients with bundle branch block. Electrophysiology studies (EPS) testing for infra-Hisian heart block are recommended by the European Society of Cardiology syncope guidelines on the basis of decades-old estimates of their negative predictive values (NPVs) for complete heart block.

OBJECTIVE

The aim of this study was to determine the NPV of EPS for complete heart block in patients with syncope and bundle branch block.

METHODS

We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL without language restriction from database inception to October 2019 for Medical Subject Headings terms and keywords related to "syncope," "heart block," and "programmed electrical stimulation." A random effects meta-analysis was conducted with a primary outcome of the proportion of patients with a negative EPS who later presented with complete heart block, diagnosed with surface electrocardiographic (ECG) recordings vs continuous implantable cardiac monitor (ICM).

RESULTS

Ten reports contained 12 cohorts with 639 patients who met the inclusion criteria. The mean age was 69 ± 7 years; 35% ± 10% were women; and 85% of patients had bifascicular block. Seven cohorts recorded clinical outcomes with external ECG recordings, and 5 cohorts featured ICMs. The mean prespecified His-to-ventricle interval criterion was ≥70 ms. In studies featuring surface ECG recordings, there were 7% (95% confidence interval 7%-17%) patients who developed complete heart block compared with 29% (95% confidence interval 24%-35%) in the studies featuring ICM (P = .0001).

CONCLUSION

The NPV of EPS in patients with syncope and bundle branch block is 0.71, sufficiently low to question its use.

Syncope and bifascicular block in the absence of structural heart disease

The treatment of patients with bifascicular block (BFB) and syncope in the absence of structural heart disease (SHD) is not well defined. The objective of our study is to compare pacemaker empirical implantation with the use of electrophysiological studies (EPS). This is a prospective cohort study that included 77 patients with unexplained cardiogenic syncope and BFB without structural heart disease between 1997 and 2012. Two groups: 36 patients received empirical pacemakers (Group A) and 41 underwent EPS (Group B) to guide their treatment. The incidence of syncope recurrence and atrioventricular block was lower in group A. Mortality and complication rates were similar between both groups. Multivariate analysis demonstrated a higher number of events (combined endpoint) in group B. Our study shows that treatment according to EPS does not improve the results of a treatment strategy based on empirical pacemaker.

Association of cardiac implantable electronic devices with survival in bifascicular block and prolonged PR interval on electrocardiogram

PURPOSE

Bifascicular block and prolonged PR interval on the electrocardiogram (ECG) have been associated with complete heart block and sudden cardiac death. We sought to determine if cardiac implantable electronic devices (CIED) improve survival in these patients.

METHODS

We assessed survival in relation to CIED status among 636 consecutive patients with bifascicular block and prolonged PR interval on the ECG. In survival analyses, CIED was considered as a time-varying covariate.

RESULTS

Average age was 76 ± 9 years, and 99% of the patients were men. A total of 167 (26%) underwent CIED (127 pacemaker only) implantation at baseline (n = 23) or during follow-up (n = 144). During 5.4 ± 3.8 years of follow-up, 83 (13%) patients developed complete or high-degree atrioventricular block and 375 (59%) died. Patients with a CIED had a longer survival compared to those without a CIED in the traditional, static analysis (log-rank p < 0.0001) but not when CIED was considered as a time-varying covariate (log-rank p = 0.76). In the multivariable model, patients with a CIED had a 34% lower risk of death (hazard ratio 0.66, 95% confidence interval 0.52-0.83; p = 0.001) than those without CIED in the traditional analysis but not in the time-varying covariate analysis (hazard ratio 1.05, 95% confidence interval 0.79-1.38; p = 0.76). Results did not change in the subgroup with a pacemaker only.

CONCLUSIONS

Bifascicular block and prolonged PR interval on ECG are associated with a high incidence of complete atrioventricular block and mortality. However, CIED implantation does not have a significant influence on survival when time-varying nature of CIED implantation is considered.

Therapy for Syncope

The diagnostic process in patients with syncope is not always easy and includes a detailed clinical history, physical examination and baseline electrocardiogram; according to the results of these initial approaches, some additional tests must be performed. Using this strategy, the cause of syncope is diagnosed in 60% to 80% of patients; in the remaining patients, risk stratification can be established to identify those patients at risk of having cardiac events or death at midterm follow-up. This article reviews the treatment of patients with syncope according to the different causes.

Syncope

Syncope is common representing approximately 3% of ED visits and up to 6% of hospital admissions, with a cost close to 2 billion dollars per year. Diagnostic testing is often poorly sensitive and evaluations commonly lack a standardized approach. A mindful and systematic approach can increase sensitivity and improve diagnostic accuracy. A thorough history and physical exam is paramount, as conclusions drawn from the history and exam will guide further assessment. Developing a strategy for the first and, if necessary, subsequent tests will improve the accuracy of identifying the etiology of syncope and reduce cost. Although syncope has a favorable prognosis, identification of patients with structural heart disease is critical, as these patients are at greatest risk for mortality. Several risk scoring systems have been developed to help separate high risk from low risk patients.

ECG monitoring in syncope

Electrocardiographic (ECG) monitoring is a well-established procedure in the work-up of patients with syncope or for diagnosing arrhythmias. The investigation of syncope remains, however, challenging and physicians have an increasing armamentarium of diagnostic tools available and with advances in technology the role of these tools has to be continuously evaluated. The gold standard for the diagnosis of syncope is a symptom-ECG correlation, and while many studies have investigated the use and indications of both short-term and long-term monitoring; there is still some uncertainty in their clinical utility and practical approach. The use of ECG monitoring and other diagnostic tools is often subject to a "shot-gun approach" rather than a strict guideline algorithm. A systematic approach and selection of ECG monitoring tools helps permit an effective usage of the limited health care resources available for the management of unexplained syncope. In this review we aim to focus and clarify the role of short-term (Holter and external loop recorders) and long-term (implantable loop recorders) ECG monitoring in the diagnosis and management of patients with unexplained syncope.

Overview of the contribution of recent clinical trials to advancement of syncope management

In this communication we review those trials that have contributed in recent years to improving our knowledge on the management (diagnosis and treatment) of syncope. In this regard, most recent trials focus on vasovagal syncope (VVS) and consequently these will be the focus of this manuscript. In essence, from a diagnostic perspective the ISSUE studies demonstrate the value of insertable loop recorders (ILR), while in terms of treatment, in the case of VVS current data strongly support use of non-pharmacologic treatment as a primary approach. There is no clear evidence supporting pharmacologic treatment with the possible exception of midodrine. Further, the most recent ISSUE trials suggest that in older very symptomatic patients with VVS in whom an asystole has been documented during spontaneous episode or possibly after ATP administration, implantation of a permanent pacemaker (PPM) can be effective. Which pacing or programming mode will be the more beneficial has not been completely clarified. Management of other forms of neurally-mediated syncope (e.g., carotid sinus syndrome) or other causes of syncope has not been addressed by clinical trials. In those cases, direction is provided by older evidence, the vast majority of which is based on observational reports or small non-randomized patient series.

Pacemaker therapy in syncope

The current evidence for pacemaker therapy is reviewed in 2 different syncopal conditions: reflex syncope with cardioinhibitory response and syncope in patients with bundle branch block. Although recent trials support the use of pacemaker therapy in selected patients with reflex syncope in whom an asystole is documented during spontaneous syncope or in whom an asystole is provoked with adenosine-5'-triphosphate administration, the best strategy in these patients and in those with syncope and bundle branch block is not well established. Ongoing clinical trials will answer this question.