Canadian Journal of Cardiology最新文献

Antiarrhythmic drugs (AADs) and catheter ablation (CA) are guideline-directed rhythm control treatment for atrial fibrillation (AF). AADs are rarely used in combination to treat AF. Dofetilde (class III agent) and flecainide (class Ic agent) are contraindicated in patients with renal dysfunction and coronary artery disease respectively. We describe a case of a patient who refused non-pharmacological treatment for recurrent AF after CA, but was treated successfully with dofetilide and flecainide combination. The patient's taking the combination was serendipitous initially. Both drugs were continued nonetheless, as it was the combination and not the individual drug that controlled AF in our patient.

Exercise-related sudden cardiac arrest or death (SCA/D) is defined as SCA/D during sports or exercise, or within 1 hour of exercise cessation (1). When exercise-related SCA/D occurs during competitive sport in a young athlete, it often attracts significant media attention and concern. However, most exercise-related SCA/D occurs in middle-aged recreational sports participants (2). The effectiveness and appropriateness of widespread cardiovascular screening to prevent exercise-related SCA/D is uncertain. Appropriate resuscitation measures, facilitated by emergency action planning (EAP) and timely access to automated external defibrillators (AEDs), remains the mainstay of sudden cardiac death (SCD) prevention (1).

Physical activity (PA) is established as a cornerstone of cardiovascular health, however, disparities in participation exist across sociocultural groups, which in turn impacts cardiovascular outcomes. Evidence suggests that while the positive cardiovascular effects of exercise are consistent across populations, notable differences in the magnitude of these benefits exist for racial and ethnic minorities and female sex. Females derive greater protection from PA compared to males, with reduced rates of sudden cardiac death (SCD). This review examines the complex interplay of race/ethnicity and sex on the cardiovascular benefits associated with PA and exercise, cardiovascular adaptations to exercise, and risks of SCD and "excessive" volume of exercise. Understanding these factors is crucial for developing targeted interventions to promote cardiovascular health and offset disparities.

Background: Despite advances in imaging techniques, endomyocardial biopsy remains the gold standard for confirming cardiac amyloidosis (CA) and defining the amyloid type. Electron microscopy may detect amyloid deposits with greater sensitivity than light microscopy; however, its capabilities have not been thoroughly investigated.

Methods: Patients with pathologically diagnosed CA were prospectively enrolled. Myocardial specimens were collected from the right ventricular septum, and light and electron microscopy were performed on the samples to compare their efficacy in detecting amyloid deposits.

Results: Sixty-five patients were pathologically diagnosed with CA, including 13 with light-chain amyloidosis, 51 with transthyretin amyloidosis, and one with unclassified amyloidosis. Amyloid deposits were detected through both examinations in 60 (92.3%) of the 65 patients. However, they were detected through only light microscopy in two cases (3.1%) and only electron microscopy in three cases (4.6%). Patients with amyloid deposits detected through a single method had reduced thickness of the intraventricular septal wall (9.5 vs. 15.1 mm, p=0.001), lower left ventricular (LV) mass index (94 vs. 147 g/m², p= 0.013), greater LV diastolic dimension (45 vs. 41 mm, p=0.044), lower LVEF (49% vs. 57%, p=0.004), lower mean pulmonary capillary wedge pressure (9 vs. 19 mmHg, p=0.021), and lower right atrial pressure (4 vs. 8 mmHg, p=0.043) than did those in whom they were detected using both methods.

Conclusions: Concomitant use of electron microscopy may improve the detection rate of amyloid deposits and prevent CA misdiagnosis, especially in patients with atypical features such as mild hypertrophy or eccentric hypertrophy with LV systolic dysfunction.

Clinical trials in acute care settings, particularly those involving small populations or high-mortality contexts, present unique challenges in design and analysis. This review explores novel statistical approaches and methodological considerations for such trials, with a focus on cardiovascular therapies. We discuss the concept of "small" sample sizes and their limitations and cover various analytical frameworks, including frequentist and Bayesian approaches, emphasizing their implications for result interpretation and reproducibility. We examine endpoints such as "days alive and free" (DAF*), which combines mortality and morbidity measures, the Win Ratio for hierarchical endpoints, and ordinal scales that capture detailed patient outcomes. These methods potentially increase statistical power and provide more clinically relevant measures compared to traditional binary outcomes; an extensive use of simulations is used to clarify this point. The use of longitudinal ordinal models is presented as a promising method to capture complex patient trajectories over time, offering insights into treatment effects at various disease stages. We also address the potential of adaptive platform trials for rare conditions, allowing for more efficient use of limited patient populations. This overview aims to guide researchers and clinicians in selecting optimal trial designs and analytical strategies, ultimately improving the quality, efficiency, and interpretability of evidence in acute care cardiology.

Right ventricular (RV) intramyocardial hematoma is a rare yet potentially life-threatening complication associated with percutaneous coronary intervention (PCI), cardiac surgery, and catheter ablation. Here, we present a unique case of RV intramyocardial hematoma that developed within hours following transcatheter aortic valve replacement (TAVR). The patient experienced hemodynamic instability due to compression of the right ventricular outflow tract (RVOT). The clinical presentation and echocardiographic findings initially suggested tamponade, prompting urgent surgical exploration with redo-sternotomy. Intraoperative findings enabled the refinement of the diagnosis and led to a conservative management approach, resulting in a favorable outcome.

Background: Quantifying exercise intensity accurately is crucial for understanding links between cumulative exercise and cardiovascular outcomes. Exercise burden, the integral of intensity and duration is often estimated from subjective self-reports which have uncertain accuracy.

Methods: We studied 40 endurance athletes (EA) 41 to 69 yrs. with >10 yrs. training history during a scripted outdoor 42 km cycling training session. Heart rate (HR) and power output (Watts) were continuously measured. Reports of perceived exertion (RPE) using a word (RPE_Word) and numerical Borg scale (RPE_Borg) were obtained during and 30 min. post ride and were related to cardiac (HR) and metabolic (MET·min) exercise endpoints.

Results: RPEs were highly variable, underestimating objective metrics of exercise intensity. Poor agreement was observed between either scale reported 30 minutes after exercise relative to heart rate: exercise RPE_Borg vs. mean exercise HR and %HR_peak (both r_s=.29, p=0.07), with no agreement between either scale vs. other objective endpoints. Agreement between RPE_Borg and RPE_Word was good during exercise (r_s=0.86, 95% CI 0.75 to 0.92, P=0.001), but diminished post ride (r_s=0.54, 95% CI 0.28 to 0.73, P=0.001). Different cardiac and metabolic profiles during exercise and a contrast between metabolic and cardiac burden was greater in less fit individuals as they accrued greater cardiac (14039±2649 vs. 11784±1132 HR·min, P<0.01) but lower metabolic (808±59 vs. 858±61 MET·min, P<0.05) burden vs. fitter EA.

Conclusions: Caution is advised in interpreting MET·min and HR burden estimated from self-reports. Objective measurements of exercise intensity are required for detailed assessment of the risks and benefits of long-term exercise.