Knowledge Extraction of Cohort Characteristics in Research Publications.

When healthcare providers review the results of a clinical trial study to understand its applicability to their practice, they typically analyze how well the characteristics of the study cohort correspond to those of the patients they see. We have previously created a study cohort ontology to standardize this information and make it accessible for knowledge-based decision support. The extraction of this information from research publications is challenging, however, given the wide variance in reporting cohort characteristics in a tabular representation. To address this issue, we have developed an ontology-enabled knowledge extraction pipeline for automatically constructing knowledge graphs from the cohort characteristics found in PDF-formatted research papers. We evaluated our approach using a training and test set of 41 research publications and found an overall accuracy of 83.3% in correctly assembling the knowledge graphs. Our research provides a promising approach for extracting knowledge more broadly from tabular information in research publications.

Repeat ablation and hospitalization following cryoballoon ablation of atrial fibrillation at a single tertiary medical center.

Cryoablation for atrial fibrillation (AF) has rapidly become a mainstream treatment for AF. In this report, 163 patients who had undergone a cryoablation procedure at one clinical center were contacted by telephone 33.1 ± 3.3 months after the procedure. All patients had received cryoablation of the pulmonary vein ostia, although concomitant procedures were performed at the same time in over 50% of the patients, including radiofrequency and/or cryoablation of other areas of the left atrium. Freedom from a repeat ablation procedure was 87%, while freedom from recurrent hospitalization for AF was 89%, as compared to previous reports of 65%. Of the 13 patients who had a repeat ablation procedure, only one was found to have a reconnection of pulmonary veins, while 4 were found to have atrial flutter. Cryoablation for AF produces a durable result in most patients out to 3 years with better outcomes than previously reported.

Inhaler syncope.

Syncope can result from certain activities that trigger an exaggerated physiological response in susceptible individuals; examples include cough, laugh, and micturition syncope. We report a novel cause for syncope, that due to reflex bradycardia and asystole produced by the use of asthma inhalers. We discuss the possible mechanisms for this effect and briefly review other breathing-related causes of bradycardia.

High-intensity cardiac rehabilitation training of a firefighter after placement of an implantable cardioverter-defibrillator.

Firefighters who have received an implantable cardioverter-defibrillator (ICD) are asked to retire or are permanently placed on restricted duty because of concerns about their being incapacitated by an ICD shock during a fire emergency. We present the case of a 40-year-old firefighter who, after surviving sudden cardiac arrest and undergoing ICD implantation, sought to demonstrate his fitness for active duty by completing a high-intensity, occupation-specific cardiac rehabilitation training program. The report details the exercise training, ICD monitoring, and stress testing that he underwent. During the post-training treadmill stress test in firefighter turnout gear, the patient reached a functional capacity of 17 metabolic equivalents (METs), exceeding the 12-MET level required for his occupation. He had no ICD shock therapy or recurrent sustained arrhythmias during stress testing or at any time during his cardiac rehabilitation stay. By presenting this case, we hope to stimulate further discussion about firefighters who have an ICD, can meet the functional capacity requirements of their occupation, and want to return to work.

Effect of peri-infarct pacing early after myocardial infarction: results of the prevention of myocardial enlargement and dilatation post myocardial infarction study.

BACKGROUND: Left ventricular (LV) remodeling has been attributed to the segmental loss of viable myocardium due to myocardial infarction (MI), which results in redistribution of cardiac workload, with increased regional wall stress in and around the infarct zone. Because ventricular pacing has been shown to reduce regional wall stress and workload in regions near the pacing site, this trial was designed to test whether chronic pacing near the infarct attenuates LV remodeling. METHODS AND RESULTS: Eighty patients with an anterior MI, peak creatine kinase >2000 mU/mL, ejection fraction ≤35%, wall motion abnormality (WMA) in >5 of 16 segments, and QRS <120 ms, were randomized to either control (implantable cardioverter-defibrillator [ICD]) or biventricular pacing with peri-infarct LV lead placement (cardiac resynchronization therapy [CRT]-D) arms between 2 and 14 days after the MI. The primary end point-change in LV end-diastolic volume (LVEDV) from baseline to 12 months-was not significantly different between the 2 groups (CRT, 10.6±27.7 mL; ICD, 11.2±31.2 mL; 2-sample t test P>0.05). In a hypothesis-generating secondary analysis, there was a sustained reduction in the WMA score at 12 months in paced patients (CRT, -0.16±0.28; ICD, -0.01±0.24, 2-sample t test P=0.03). No differences were found in the therapy-related event rate, hospitalizations, or mortality (all P>0.05). CONCLUSIONS: Chronic pacing in the infarct region did not alter the primary end point of LV remodeling over 1 year.

Appropriateness of sling immobilization to prevent lead displacement after pacemaker/implantable cardioverter-defibrillator implantation.

After pacemaker/implantable cardioverter-defibrillator (pacemaker/ICD) implantation, patients are often required to immobilize the affected arm with a sling to minimize the risk of lead displacement. We examined whether performing a resistive range-of-motion exercise protocol after pacemaker/ICD surgery would result in lead displacement and, therefore, whether sling immobilization and activity restrictions are justified. Ten subjects who had undergone pacemaker/ICD surgery performed four individual resistive range-of-motion exercises (three sets of 10 repetitions for each: one warm-up set without weight and two sets with a 1- or 2-pound hand weight) with the affected arm prior to hospital discharge. For each subject, an electrophysiology nurse specialist used a noninvasive device programmer to evaluate surgical lead placement before and after the exercises. As an adjunct to the study, we queried clinicians at 48 US hospitals about sling immobilization and activity restrictions after pacemaker/ICD implantation at their institutions. No lead displacement occurred after the weightlifting exercises were performed. Based on these results in a small group of patients, it appears that requiring the use of a joint immobilization sling is overly restrictive, promotes fear, and hinders recovery. We encourage the development of consistent discharge instructions that will promote early mobility and a safe and rapid return to normal activities.

Do prehospital discharge pacemaker checks provide any additional clinical benefit?

We performed a retrospective analysis of 250 records of consecutive, newly implanted, pacemaker patients from a single center to determine the rate of postimplant complications and observations discovered before and during the prehospital discharge evaluation. No observations occurred in 246 of 250 patients (98.4%) (1-sided 95% confidence interval 96.4%). Of the 250 patients, 4 had observations that were discovered at the prehospital discharge check and required reprogramming to increase the sensitivity safety margin (3 atrial and 1 ventricular). We documented only 1 complication that was discovered before the predischarge evaluation through telemetry and resulted in an atrial lead revision.