Jo Jo Hai

Ischemic Stroke and Intracranial Hemorrhage With Aspirin, Dabigatran, and Warfarin Impact of Quality of Anticoagulation Control

Background and Purpose— Little is known about the impact of quality of anticoagulation control, as reflected by time in therapeutic range (TTR), on the effectiveness and safety of warfarin therapy in Chinese patients with atrial fibrillation. We investigated the risks of ischemic stroke and intracranial hemorrhage (ICH) in relation to warfarin at various TTRs in a real-world cohort of Chinese patients with atrial fibrillation receiving warfarin and compared with those on dabigatran, aspirin, and no therapy. Methods— This is an observational study. Results— Of 8754 Chinese patients with atrial fibrillation and CHA2DS2-VASc ≥1 (79.5±9.2 years; CHA2DS2-VASc, 4.1±1.5; and Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile International Normalized Ratio, Elderly (>65 years), Drugs/Alcohol Concomitantly [HAS-BLED], 2.2±0.9), 16.3% received warfarin, 41.1% aspirin, 4.5% dabigatran, and 38.1% received no therapy. The incidence of ischemic stroke was highest in patients with no therapy (10.38%/y), followed by patients on aspirin (7.95%/y). The incidence of stroke decreased progressively with increasing TTR quartiles (<17.9%, 17.9%–38.8%, 38.8%–56.2%, and >56.2%) from 7.34%/y (first quartile) to 3.10%/y (fourth quartile). Patients on dabigatran had the lowest incidence of stroke among all groups (2.24%/y). The incidence of ICH was lowest in patients on dabigatran (0.32%/y) compared with those on warfarin (0.90%/y), aspirin (0.80%/y), and no therapy (0.53%/y). ICH incidence decreased with increasing TTR from 1.37%/y (first quartile) to 0.74%/y (fourth quartile). Conclusions— In Chinese patients with atrial fibrillation, the benefits of warfarin therapy for stroke prevention and ICH risk are closely dependent on the quality of anticoagulation, as reflected by TTR. Even at the top TTR quartile, warfarin was associated with a higher stroke and ICH risk than dabigatran.

Relationship between changes in heart rate recovery after cardiac rehabilitation on cardiovascular mortality in patients with myocardial infarction.

BACKGROUND Heart rate recovery (HRR) at predischarge exercise stress test predicts all-cause mortality in patients with myocardial infarction (MI), but the relationship between improvement in HRR with exercise training and clinical outcomes remains unclear. OBJECTIVE The purpose of this study was to evaluate the effect of change in HRR after exercise training on clinical outcomes in MI patients. METHODS The study included 386 consecutive patients with recent MI who were enrolled into our cardiac rehabilitation program. All patients underwent symptom-limited treadmill testing at baseline and after exercise training, and were prospectively followed-up in the outpatient clinic. RESULTS Treadmill testing revealed significant improvement in HRR after 8 weeks of exercise training (17.5 +/- 10.0 bpm to 19.0 +/- 12.3 bpm, P = .011). After follow-up of 79 +/- 41 months, 40 (10.4%) patients died of cardiac events. Multivariate Cox regression analysis revealed that diabetes (hazard ratio [HR] 2.28, 95% confidence interval [CI] 1.01-5.19, P = .049), statin use (HR 0.36, 95% CI 0.16-0.80, P = .012), baseline resting heart rate > or =65 bpm (HR 5.37, 95% CI 1.33-21.61, P = .018), post-training HRR <12 bpm (HR 2.49, 95% CI 1.10-5.63, P = .028), left ventricular ejection fraction < or =30% (HR 4.70, 95% CI 1.34-16.46, P = .016), and exercise capacity < or =4 metabolic equivalents (HR 3.63, 95% CI 1.17-11.28, P = .026) were independent predictors of cardiac death. Patients who failed to improve HRR from <12 bpm to > or =12 bpm after exercise training had significantly higher mortality (HR 6.2, 95% CI 1.3-29.2, P = .022). CONCLUSION Exercise training improved HRR in patients with recent MI, and patients with HRR increased to > or =12 bpm had better cardiac survival.

Continuation of dabigatran therapy in "real-world" practice in Hong Kong

Background Dabigatran, an oral direct thrombin inhibitor, possesses several advantages over warfarin that can in principle simplify the management of stroke prevention in atrial fibrillation (AF). Nonetheless it remains unclear whether these advantages can translate to clinical practice and encourage long-term therapy. The objective was to describe long-term dabigatran therapy for stroke prevention in AF and to identify risk factors for discontinuation of therapy. Methods and Results We studied 467 consecutive Chinese patients (72±11 years, male: 53.8%) with a mean CHA2DS2-VASc score of 3.6 prescribed dabigatran for stroke prevention in AF from March 2010 to September 2013. Over a mean follow-up of 16 months, 101 patients (21.6%) permanently discontinued dabigatran. The mean time-to-discontinuation was 8 months. The most common reason for discontinuation was dyspepsia (30.7%), followed by other adverse events (17.8%) such as minor bleeding (8.9%), major gastrointestinal bleeding (7.9%), and intracranial hemorrhage (1%). Other reasons included dosing frequency (5.9%), fear of side effects (4.0%), lack of laboratory monitoring (1.0%), and cost (1.0%). Multivariable analysis revealed that low baseline estimated glomerular filtration rate (p = 0.02), absence of hypertension (p = 0.01), and prior use of a proton-pump inhibitor (p = 0.02) and H2-receptor blocker (p = 0.01) were independent predictors of drug discontinuation. In addition, there were altogether 9 ischemic strokes (1.5%/years), 3 intracranial hemorrhages (0.5%/year), and 24 major gastrointestinal bleedings (4.1%/year). Conclusion Dabigatran discontinuation is very common amongst Chinese AF patients. This reveals a management gap in the prevention of stroke in AF.

Stroke prevention using dabigatran in elderly Chinese patients with atrial fibrillation

BACKGROUND Little is known about the clinical benefit of a non-vitamin K antagonist oral anticoagulant compared with warfarin in elderly Chinese patients with atrial fibrillation (AF). OBJECTIVE The purpose of this study was to evaluate the clinical benefit of dabigatran in elderly (age ≥80 years) Chinese patients with nonvalvular AF with regard to the risk of ischemic stroke and intracranial hemorrhage (ICH). METHODS This was an observational study. RESULTS We studied 571 Chinese patients (mean age 84.8 ± 4.0 years; 58.1% women) with nonvalvular AF. The primary outcome was hospital admission for ischemic stroke, and the secondary outcome was admission for ICH. The mean CHA2DS2-VASc (congestive heart failure [1 point], hypertension [1 point], age 65-74 years [1 point] and age ≥75 years [2 points], diabetes mellitus [1 point], prior stroke or transient ischemic attack [2 points], vascular disease [1 point], sex category [female] [1 point]) and HAS-BLED (hypertension [1 point], abnormal renal/liver function [1 point], stroke [1 point], bleeding history [1 point] or predisposition [1 point], labile international normalized ratio [1 point], elderly [age >65 years] [1 point], drugs/alcohol concomitantly [1 point]) scores were 4.8 ± 1.6 and 2.4 ± 0.8, respectively. Of 571 patients, 129 (22.6%) were taking dabigatran 110 mg twice daily and the remaining were on warfarin. After a mean follow-up of 2.6 years (a total of 1471 patient-years), ischemic stroke occurred in 83 patients on warfarin (6.9% per year) compared with 4 patients on dabigatran (1.4% per year) (hazard ratio 0.22; 95% confidence interval 0.23-0.67). There were 8 incidences of ICH: 7 in patients on warfarin (0.59% per year) and 1 patient on dabigatran (0.35% per year). Dabigatran was associated with a substantially lower ischemic stroke risk (1.4% per year vs 5.4% per year) and similar ICH risk (0.35% per year vs 0.36% per year) as compared with warfarin with time in therapeutic range (TTR) ≥55%. CONCLUSION In elderly Chinese patients with AF, this study suggested that dabigatran achieved superior stroke risk reduction and similar risk of ICH compared with warfarin with TTR ≥55%. Dabigatran may be preferable to warfarin in elderly patients with AF for stroke prevention, particularly in those with poor TTR.

Electrophysiologic Characteristics of Ventricular Arrhythmias Arising From the Aortic Mitral Continuity - Potential Role of the Conduction System

Catheter ablation of ventricular arrhythmia (VA) at the fibrous aortic mitral continuity (AMC) has been described, yet the nature of the arrhythmogenic substrate remains unknown.

Clinical Characteristics, Management, and Outcomes of Hospitalized Heart Failure in a Chinese Population-The Hong Kong Heart Failure Registry.

BACKGROUND Epidemiological data for heart failure (HF) in the Chinese population is scarce. In this study, we described the clinical characteristics and outcomes of new-onset HF in our population. METHODS AND RESULTS We conducted a retrospective, observational study on consecutive Chinese patients hospitalized for new-onset HF between 2005 and 2012 in our center. A total of 1940 patients (mean age, 78.2 ± 11.8 years, 54.2% female) were identified. The rate of new HF hospitalization was 0.59 per 1000 population. The most prevalent comorbidities were hypertension (69.8%) and coronary artery disease (29.3%), and 52.3% had HF with preserved ejection fraction (HFpEF). The all-cause mortality was 19.5% at 1 year, 32.1% at 2 years, and 54% at 5 years. Cardiovascular mortality was 7.2% at 1 year, 11.8% at 2 years, and 20.7% at 5 years. No difference in all-cause mortality or cardiovascular mortality was observed between those with HF with reduced ejection fraction than HFpEF. CONCLUSIONS Our patients with new-onset HF shared similar clinical characteristics with the Caucasian population. The prognosis was poor with high all-cause mortality for both HFpEF and HF with reduced ejection fraction.

Distinguishing ventricular arrhythmia originating from the right coronary cusp, peripulmonic valve area, and the right ventricular outflow tract: utility of lead I.

Outflow tract ventricular arrhythmia (OTVA) can be complicated to target for ablation when originating from either the periaortic or pulmonary valve (PV) region. Both sites may present with a small R wave in lead V1. However, the utility of lead I in distinguishing these arrhythmia locations is unknown.

Benefit of Anticoagulation Therapy in Hyperthyroidism-Related Atrial Fibrillation

Existing data on the risk of ischemic stroke in hyperthyroidism‐related atrial fibrillation (AF) and the impact of long‐term anticoagulation in these patients, particularly those with self‐limiting AF, remain inconclusive.

The infrahisian conduction system and endocavitary cardiac structures: relevance for the invasive electrophysiologist.

With the increasing acceptability and use of catheterization ablation for ventricular tachycardia, detailed anatomic studies have been done to improve the safety and efficacy for energy delivery in and around critical cardiac structures [1–7]. More recently, ventricular fibrillation and certain forms of monomorphic ventricular tachycardia have required ablation in either the infrahisian conduction system or endocavitary cardiac structure, such as the papillary muscle, false tendons, and the right ventricular moderator band [8–13]. In this review, we explain the critical details of structure and structure–function relations of the infrahisian tissue and the cardiac endocavitary structures. We approach the structures as a single unit with endocavitary structures routinely having a rich network of the distal His-Purkinje system. In addition, several commonly applied cardiac mapping maneuvers, including parahisian pacing and pacemapping, rely on understanding conduction tissue anatomy and active myocardium within the cavity for correct interpretation. Throughout the text are interspersed boxes that tabulate and summarize key anatomic pieces of information for the invasive electrophysiologist.

Endocavitary structures in the outflow tract: Anatomy and electrophysiology of the Conus Papillary Muscles

Catheter ablation is an increasingly used and successful treatment choice for right ventricular outflow tract (RVOT) arrhythmias. While the role of endocavitary structures and the regional morphology of the ventricular inflow tract and the right atrium as a cause for difficulty with successful ablation are well described, similar issues within the RVOT are not well understood. It is also not commonly appreciated that one of the papillary muscles is located within the proximal RVOT. We report 3 patients in which ventricular arrhythmia was targeted and ablated in the conus papillary muscle. The anatomic features, potential role of the fascicular conduction system, and unique challenges with mapping arrhythmia arising from this structure are discussed.