William F. McIntyre

Subclinical Atrial Fibrillation in Older Patients.

Background: Long-term continuous electrocardiographic monitoring shows a substantial prevalence of asymptomatic, subclinical atrial fibrillation (SCAF) in patients with pacemakers and patients with cryptogenic stroke. Whether SCAF is also common in other patients without these conditions is unknown. Methods: We implanted subcutaneous electrocardiographic monitors (St. Jude CONFIRM-AF) in patients ≥65 years of age attending cardiovascular or neurology outpatient clinics if they had no history of atrial fibrillation but had any of the following: CHA2DS2-VASc score of ≥2, sleep apnea, or body mass index >30 kg/m2. Eligibility also required either left atrial enlargement (≥4.4 cm or volume ≥58 mL) or increased (≥290 pg/mL) serum NT-proBNP (N-terminal pro–B-type natriuretic peptide). Patients were monitored for SCAF lasting ≥5 minutes. Results: Two hundred fifty-six patients were followed up for 16.3±3.8 months. Baseline age was 74±6 years; mean CHA2DS2-VASc score was 4.1±1.4; left atrial diameter averaged 4.7±0.8 cm; and 48% had a prior stroke, transient ischemic attack, or systemic embolism. SCAF ≥5 minutes was detected in 90 patients (detection rate, 34.4%/y; 95% confidence interval [CI], 27.7–42.3). Baseline predictors of SCAF were increased age (hazard ratio [HR] per decade, 1.55; 95% CI, 1.11–2.15), left atrial dimension (HR per centimeter diameter, 1.43; 95% CI, 1.09–1.86), and blood pressure (HR per 10 mm Hg, 0.87; 95% CI, 0.78–0.98), but not prior stroke. The rate of occurrence of SCAF in those with a history of stroke, systemic embolism, or transient ischemic attack was 39.4%/y versus 30.3%/y without (P=0.32). The cumulative SCAF detection rate was higher (51.9%/y) in those with left atrial volume above the median value of 73.5 mL. Conclusions: SCAF is frequently detected by continuous electrocardiographic monitoring in older patients without a history of atrial fibrillation who are attending outpatient cardiology and neurology clinics. Its clinical significance is unclear. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01694394.

Coexisting early repolarization pattern and Brugada syndrome: recognition of potentially overlapping entities

The Brugada type 1 electrocardiographic (ECG) pattern and the early repolarization pattern (ERP) are 2 ECG patterns characterized by the appearance of J waves. Although Brugada type 1 ECG pattern in the context of the Brugada syndrome (BrS) is well known for predisposing to life-threatening ventricular arrhythmias, it has only recently come to light that ERP, which was previously believed to be benign, may also be a marker for arrhythmogenic potential. ERP and BrS share many remarkable cellular, ionic, and ECG similarities and behave comparably in terms of their response to heart rate, pharmacologic agents, and neuromodulation. The extent to which ERP and BrS may overlap remains unclear. Here, we present an illustrated case of a symptomatic patient whose ECG signature evolved spontaneously from ERP alone to ERP with a concomitant Brugada type 1 ECG pattern over a short number of days. This case lends further strength to the notion that these 2 ECG patterns may be more closely related than had been initially thought.

Electrocardiographic abnormalities in patients with acute pulmonary embolism complicated by cardiogenic shock

BACKGROUND Cardiogenic shock (CS) is a predictor of poor prognosis in patients with acute pulmonary embolism (APE). OBJECTIVES The aim of this study was to compare electrocardiography (ECG) parameters in patients with APE presenting with or without CS. METHODS A 12-lead ECG was recorded on admission at a paper speed of 25 mm/s and 10 mm/mV amplification. All ECGs were examined by a single cardiologist who was blinded to all other clinical data. All ECG measurements were made manually. RESULTS Electrocardiographic data from 500 patients with APE were analyzed, including 92 patients with CS. The following ECG parameters were associated with CS: S1Q3T3 sign, (odds ratio [OR]: 2.85, P<.001), qR or QR morphology of QRS in lead V1, (OR: 3.63, P<.001), right bundle branch block (RBBB) (OR: 2.46, P=.004), QRS fragmentation in lead V1 (OR: 2.94, P=.002), low QRS voltage (OR: 3.21, P<.001), negative T waves in leads V2 to V4 (OR: 1.81, P=.011), ST-segment depression in leads V4 to V6 (OR: 3.28, P<.001), ST-segment elevation in lead III (OR: 4.2, P<.001), ST-segment elevation in lead V1 (OR: 6.78, P<.01), and ST-segment elevation in lead aVR (OR: 4.35, P<.01). The multivariate analysis showed that low QRS voltage, RBBB, and ST-segment elevation in lead V1 remained statistically significant predictors of CS. CONCLUSIONS In patients with APE, low QRS voltage, RBBB, and ST-segment elevation in lead V1 were associated with CS.

Obstructive sleep apnea and atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. The clinical impact of AF results primarily from its association with stroke, heart failure, and increased overall mortality. Recently there has been increasing evidence of an important association between obstructive sleep apnea (OSA) and AF. OSA is a common breathing disorder affecting an estimated 5% of the population and is highly prevalent in patients with established cardiovascular disease. The prevalence of OSA among patients with AF is remarkable with estimates ranging from 32%–49%. The pathophysiological connection between AF and OSA remains speculative, but appears to be the result of apnea-induced hypoxia, intrathoracic pressure shifts, inflammation, heightened sympathetic activity, and autonomic instability leading to hypertension, diastolic dysfunction, left atrial enlargement, and electrical remodeling. Initial results appear promising that intervention with continuous positive airway pressure may be effective in reducing the burden of AF in this population, however, further investigations are needed. Here, we review the literature on the current epidemiologic data, pathophysiology, and therapeutics linking these two common conditions.

Electrocution-induced Brugada phenocopy

Brugada Syndrome (BrS) is a clinical-electrocardiographic entity predisposing to ventricular arrhythmia and sudden cardiac death. [1] The BrS electrocardiogram is often dynamic, and can change from a “coved” type-1 to a “saddleback” type II pattern to periods of transient normalization [1]. The BrS signature may be initially apparent or be concealed, requiring unmasking with sodium channel blockers or a febrile state. A series of loss-of-function mutations in the sodium channel SCN5a have been linked to the BrS pattern [1]. The term Brugada phenocopy was proposed by Perez-Riera et al [2]. to describe the Brugada pattern seen in patients with other diseases, such as chronic Chagasic cardiomyopathy, acute myocarditis or Duchenne muscular dystrophy [3], or secondary to other agents [4]. One study has suggested that patients in an acute situation who present with a Brugada phenocopymay be at an increased risk of sudden cardiac death [5]. Electrical injuries can result in severe cardiovascular alterations, including malignant ventricular arrhythmias and sudden cardiac death [6]. Approximately 1000 people die due to electrical injury annually in the United States [7], but the mechanism of fatality associated with electrical injuries is unknown. We report the case of a spontaneous, transient Brugada phenocopy seen in a patient after an electrocution event. A 52-year-oldman presented to the emergency department one hour after sustaining a 120-volt electrical injury while repairing the lighting

Resident Physicians Choices of Anticoagulation for Stroke Prevention in Patients With Nonvalvular Atrial Fibrillation

Atrial fibrillation (AF) is a common cardiac arrhythmia and is associated with an increased risk of ischemic stroke. The aim of this study was to identify practice patterns of Canadian resident physicians pertaining to stroke prevention in nonvalvular AF according to the Canadian Cardiovascular Society guidelines. A Web-based survey consisting of 16 multiple-choice questions was distributed to 11 academic centres. Questions involved identification of risks of stroke, bleeding, and selection of appropriate therapy in clinical scenarios that involve a patient with AF with a Congestive Heart Failure, Hypertension, Age, Diabetes, Stroke/Transient Ischemic Attack (CHADS2) score of 3 and no absolute contraindications to anticoagulation. There were 1014 total respondents, of whom 570 were internal, 247 family, 137 emergency medicine, and 60 adult cardiology residents. For a patient with a new diagnosis of AF, warfarin was chosen by 80.3%, novel oral anticoagulants (NOACs) by 60.3%, and acetylsalicylic acid (ASA) by 7.2% of residents. To a patient with a history of gastrointestinal bleed during ASA treatment, warfarin was recommended by 75.1%, NOACs by 36.1%, ASA by 12.1%, and 4% were unsure. For a patient with a history of an intracranial bleed, warfarin was recommended by 38.8%, NOACs by 23%, ASA by 24.8%, and 18.2% were unsure. For a patient taking warfarin who had a labile international normalized ratio, 89% would switch to a NOAC and 29.5% would continue warfarin. This study revealed that, across a wide sampling of disciplines and centres, resident physician choices of anticoagulation in nonvalvular AF differ significantly from contemporary Canadian Cardiovascular Society guidelines.

Atrial fibrillation occurring transiently with stress

Purpose of review Atrial fibrillation may be detected in the setting of an acute stressor, such as medical illness or surgery. It is uncertain if atrial fibrillation detected in these settings (AFOTS: atrial fibrillation occurring transiently with stress) is secondary to a reversible trigger or is simply paroxysmal atrial fibrillation. This distinction is critical for clinicians, who must decide if AFOTS can be dismissed as a reversible phenomenon, or if it signals the need for chronic therapy; in particular, anticoagulation. Recent findings Published studies report incidences of AFOTS ranging from 1 to 44% in patients with acute medical illness and 1 to 35% following noncardiac surgery. The highest estimates have been reported in critically ill patients and in those undergoing continuous monitoring. A small number of studies have reported the recurrence of atrial fibrillation after AFOTS to be 55–68% within 5 years of medical illness and 37% within 1 year after noncardiac surgery. These studies are limited by retrospective design and low-sensitivity ascertainment. Summary AFOTS commonly occurs in patients with acute medical illness or in the postoperative state, and atrial fibrillation recurs in over 50% of individuals. Prospective postdischarge studies using sensitive atrial fibrillation detection strategies are needed to define the relationship between AFOTS and clinical atrial fibrillation.

Pericardial Effusions: Do They All Require Pericardiocentesis?

Pericardial effusions are associated with multiple disorders, the causes of which are dependent on local epidemiologic and patient-specific factors. Pericardial effusions exhibit a broad spectrum of clinical presentations and may or may not be symptomatic. Echocardiographically guided pericardiocentesis should be reserved for patients with hemodynamic compromise, an intrathoracic mass effect, or an uncertain cause. Not all patients with pericardial effusions require pericardiocentesis, and an algorithmic approach to the decision to perform pericardiocentesis is recommended.

The Vioxx® legacy: Enduring lessons from the not so distant past.

Despite having been voluntarily withdrawn from the market almost 10 years ago, the non-steroidal anti-inflammatory drug (NSAID) rofecoxib (Vioxx, Merck & Co.) remains an infamous and controversial drug in the minds of the public and physicians alike. While it is no longer making its way into prescription bottles, its legacy lives on, in its enduring influences, on drug safety monitoring in the conduct of randomized controlled trials (RCTs) and on modern practices in drug marketing and development.

Association of Vasopressin Plus Catecholamine Vasopressors vs Catecholamines Alone With Atrial Fibrillation in Patients With Distributive Shock: A Systematic Review and Meta-analysis

Importance Vasopressin is an alternative to catecholamine vasopressors for patients with distributive shock—a condition due to excessive vasodilation, most frequently from severe infection. Blood pressure support with a noncatecholamine vasopressor may reduce stimulation of adrenergic receptors and decrease myocardial oxygen demand. Atrial fibrillation is common with catecholamines and is associated with adverse events, including mortality and increased length of stay (LOS). Objectives To determine whether treatment with vasopressin + catecholamine vasopressors compared with catecholamine vasopressors alone was associated with reductions in the risk of adverse events. Data Sources MEDLINE, EMBASE, and CENTRAL were searched from inception to February 2018. Experts were asked and meta-registries searched to identify ongoing trials. Study Selection Pairs of reviewers identified randomized clinical trials comparing vasopressin in combination with catecholamine vasopressors to catecholamines alone for patients with distributive shock. Data Extraction and Synthesis Two reviewers abstracted data independently. A random-effects model was used to combine data. Main Outcomes and Measures The primary outcome was atrial fibrillation. Other outcomes included mortality, requirement for renal replacement therapy (RRT), myocardial injury, ventricular arrhythmia, stroke, and LOS in the intensive care unit and hospital. Measures of association are reported as risk ratios (RRs) for clinical outcomes and mean differences for LOS. Results Twenty-three randomized clinical trials were identified (3088 patients; mean age, 61.1 years [14.2]; women, 45.3%). High-quality evidence supported a lower risk of atrial fibrillation associated with vasopressin treatment (RR, 0.77 [95% CI, 0.67 to 0.88]; risk difference [RD], −0.06 [95% CI, −0.13 to 0.01]). For mortality, the overall RR estimate was 0.89 (95% CI, 0.82 to 0.97; RD, −0.04 [95% CI, −0.07 to 0.00]); however, when limited to trials at low risk of bias, the RR estimate was 0.96 (95% CI, 0.84 to 1.11). The overall RR estimate for RRT was 0.74 (95% CI, 0.51 to 1.08; RD, −0.07 [95% CI, −0.12 to −0.01]). However, in an analysis limited to trials at low risk of bias, RR was 0.70 (95% CI, 0.53 to 0.92, P for interaction = .77). There were no significant differences in the pooled risks for other outcomes. Conclusions and Relevance In this systematic review and meta-analysis, the addition of vasopressin to catecholamine vasopressors compared with catecholamines alone was associated with a lower risk of atrial fibrillation. Findings for secondary outcomes varied.