Scott Ferreira

Real-World Experience with Insertable Cardiac Monitors to Find Atrial Fibrillation in Cryptogenic Stroke.

Background: The characteristics of atrial fibrillation (AF) episodes in cryptogenic stroke patients have recently been explored in carefully selected patient populations. However, the incidence of AF among a large, real-world population of patients with an insertable cardiac monitor (ICM) placed for the detection of AF following a cryptogenic stroke has not been investigated. Methods: Patients in the de-identified Medtronic DiscoveryLink™ database who received an ICM (Reveal LINQ™) for the purpose of AF detection following a cryptogenic stroke were included. AF detection rates (episodes ≥2 min) were quantified using Kaplan-Meier survival estimates at 1 and 6 months and compared to the CRYSTAL AF study at 6 months. The time to AF detection and maximum duration of AF episodes were also analyzed. Results: A total of 1,247 patients (age 65.3 ± 13.0 years) were followed for 182 (IQR 182-182) days. A total of 1,521 AF episodes were detected in 147 patients, resulting in AF detection rates of 4.6 and 12.2% at 30 and 182 days, respectively, and representing a 37% relative increase over that reported in the CRYSTAL AF trial at 6 months. The median time to AF detection was 58 (IQR 11-101) days and the median duration of the longest detected AF episode was 3.4 (IQR 0.4-11.8) h. Conclusions: The real-world incidence of AF among patients being monitored with an ICM after a cryptogenic stroke validates the findings of the CRYSTAL AF trial and suggests that continuous cardiac rhythm monitoring for periods longer than the current guideline recommendation of 30 days may be warranted in the evaluation of patients with cryptogenic stroke.

Beyond warfarin: A patient-centered approach to selecting novel oral anticoagulants for stroke prevention in atrial fibrillation

BACKGROUND Warfarin reduces stroke in patients with atrial fibrillation. However, its narrow therapeutic index and need for chronic monitoring are barriers to its optimal utilization in many patients. The recent introduction of 3 novel oral anticoagulants (NOACs), as alternatives to warfarin, may change the eligibility and management of patients with nonvalvular atrial fibrillation (NVAF) who require systemic anticoagulation. PURPOSE To summarize contemporary indications for anticoagulation in NVAF, and to help provide patient-centered clinical decision making for selecting warfarin or 1 of the NOACs (dabigatran, rivaroxaban, apixaban) based on randomized trials and mechanistic data for each drug. DATA SOURCES AND STUDY SELECTION The primary clinical outcome trials of warfarin and the NOACs, pharmacologic studies, and briefing documents from the US Food and Drug Administration were reviewed. DATA EXTRACTION AND DATA SYNTHESIS In randomized trials, NOACs were consistently noninferior to warfarin for reducing stroke or systemic embolism in patients with NVAF, with reductions in intracranial bleeding as well. However, NOACs have several important drug-drug interactions, exclusion criteria for specific patient subgroups (eg, severe renal disease), and each medication may have a different impact on other clinical outcomes such as myocardial infarction or gastrointestinal bleeding. Benefits of the new drugs are particularly pronounced when international normalized ratio levels on warfarin are labile. CONCLUSIONS Warfarin continues to play an important role in the prevention of stroke or systemic embolism in NVAF. Among selected patients, the use of NOACs provides equal or superior benefit, without the need for chronic anticoagulation monitoring or ongoing dose titration.

Long-term detection of atrial fibrillation with insertable cardiac monitors in a real-world cryptogenic stroke population

BACKGROUND The long-term incidence of atrial fibrillation (AF) in cryptogenic stroke (CS) patients has been explored in carefully controlled clinical trials but real-world data are limited. We investigated the two-year incidence of AF in real-world clinical practice among a large cohort of patients with an insertable cardiac monitor (ICM) placed for AF detection following CS. METHODS Patients in the de-identified Medtronic Discovery™ Link database who received an ICM (Reveal LINQ™) for the purpose of AF detection following CS were included and monitored for up to 2years. All detected AF episodes (≥2min) were adjudicated. We quantified the AF detection rate using Kaplan-Meier survival estimates, analyzed the median time to initial detection of AF, and simulated the ability of various intermittent monitoring strategies to detect AF. RESULTS A total of 1247 patients (65.3±13.0years, 53% male) were included and followed for 579±222days. AF episodes (n=4183) were detected in 238 patients, resulting in an AF detection rate of 21.5% at 2years. The median time to AF detection was 112 [IQR 35-293] days. Intermittent monitoring for AF detection was inferior to continuous ICM monitoring with sensitivities ranging from 2.9% (annual 24-hour Holter) to 29.9% (quarterly 7-day Holters), p<0.001. CONCLUSIONS AF episodes were detected via continuous monitoring with ICMs in approximately 1 of every 5 CS patients within 2years of follow-up. The vast majority of patients with AF would not have been detected with conventional external ambulatory monitors. ICMs should therefore be considered in the evaluation of CS patients.

Atrial Fibrillation Monitoring in Cryptogenic Stroke: the Gaps Between Evidence and Practice

Identifying occult paroxysmal atrial fibrillation as the etiology of cryptogenic stroke has been a top research priority in the past decade. This is because prompt initiation of anticoagulation has significantly decreased subsequent stroke risk. Available evidence suggests that prolonged cardiac monitoring after stroke increases the likelihood of detecting atrial fibrillation. However, further research is required to fill in the gaps in regard to the optimal period of monitoring, candidates for monitoring, etc. Here, we review the current evidence supporting the use of prolonged monitoring for cryptogenic stroke patients and discuss the directions of future research.

Successful Treatment of a Cardiac Resynchronization Therapy Nonresponder by Identifying Lead Malpositioning

This case describes some of the commonly overlooked device-related issues in patients who have reportedly failed to respond to cardiac resynchronization therapy (CRT). The case demonstrates voltage-dependent right ventricular capture instead of right atrial capture by a subtly malpositioned right atrial lead. CRT therapy failed to improve symptoms of heart failure and the diagnosis of “CRT nonresponder” was made. With a detailed fact-finding approach, the mechanism behind this nonresponse was identified, and the outcome of CRT was significantly improved with rectification of the problems.

A RARE CAUSE OF RECURRENT ORTHOSTATIC HYPOTENSION REFRACTORY TO CONVENTIONAL TREATMENT

Orthostatic hypotension is a common diagnosis encountered in medical practice. Conventional therapies, including correcting reversible causes, non-pharmacologic and pharmacologic treatments usually achieve facile symptom resolution. We herein present a case of neurogenic orthostatic hypotension (NOH

RECURRENT MYOCARDIAL INFARCTION IN THE YOUNG FROM CORONARY THROMBOSIS AS THE FIRST PRESENTATION OF LIFE-CHANGING DIAGNOSIS

Myocardial infarction (MI) in the young is rare. Non-atherosclerosis is the predominant etiology. We herein report a young patient with recurrent MI within 6 weeks, which led to a newly diagnosed Human Immunodeficiency Virus (HIV) infection. A 29-year-old man presented with heartburn symptoms and

Implantation of cardiac defibrillators for primary prevention: a pendulum too far?

More than 6 years have elapsed since the publication of data from the landmark Multicenter Automatic Def ibrillator Implantation Trial (MADIT)-II, which supported the use of implantable cardioverter defibrillators (ICDs) for the primary prevention of sudden cardiac death among patients with left ventricular dysfunction due to ischemic cardiomyopathy [1]. Now, like the bridge at Arnhem that may have been ‘a bridge too far’ [2], the pendulum that relates to current clinical practice with ICDs may have swung too far in favor of device implantation. This shift is noteworthy in part because the rapid and early acceptance of ICDs in clinical heart failure practice occurred in contradistinction to the slow adoption of pharmacological therapies, such as angiotensin-converting enzyme inhibitors and β-blockers [3–5]. The reasons for these differences were probably multiple but a contributing factor to the uptake of device therapy almost certainly included an unmeasured but real variable: the repeated experience physicians had with patients who suffered unexpected sudden cardiac death, combined with the historical lack of good predictive models for delineating arrhythmia risk. Initially, decision-making was complex; the devices were large, cumbersome and required implantation by thoracotomy. They were designed to shock only, using rudimentary rhythm-detection algorithms. By contrast, the indications for implantation were simple: patients who had survived a sudden death episode or who had hemodynamically unstable ventricular tachycardia. Subsequently, improvements in the implant procedure and algorithms [6], the publication of a series of positive clinical trials [1,7,8], the timely integration of trials’ data into clinical practice guidelines [9,10], coverage by third-party payers and other factors such as marketing by major device companies led to a remarkable growth in ICD implant volume [11]. For primary prevention, it was no longer necessary to subject a patient with left ventricular dysfunction to a complex series of screening tests with variable sensitivity and specificity (e.g., an invasive electrophysiological study or signal-averaged electrocardiogram) in order to delineate device candidacy; rather, the routinely obtained, simple measurement of ejection fraction was the key element in evaluating a given patient [101]. The pendulum moved quickly in favor of device implantation.