A randomized controlled trial of simulation training in teaching coronary angiographic views.

INTRODUCTION: Simulation technology has an established role in teaching technical skills to cardiology fellows, but its impact on teaching trainees to interpret coronary angiographic (CA) images has not been systematically studied. The aim of this randomized controlled study was to test whether structured simulation training, in addition to traditional methods would improve CA image interpretation skills in a heterogeneous group of medical trainees. METHODS: We prospectively randomized a convenience sample of 105 subjects comprising of medical students (N = 20), residents (N = 68) and fellows (N = 17) from the University of Arizona. Subjects were randomized in a stratified fashion into a simulation training group which received simulation training in addition to didactic teaching (n = 53) and a control training group which received didactic teaching alone (n = 52). The change in pre and post-test score (delta score) was analyzed by a two-way ANOVA for education status and training arm. RESULTS: Subjects improved in their post-test scores with a mean change of 4.6 ± 4.0 points. Subjects in the simulation training arm had a higher delta score compared to control (5.4 ± 4.2 versus 3.8 ± 3.7, p = 0.04), with greatest impact for residents (6.6 ± 4.0 versus 3.5 ± 3.4) with a p = 0.02 for interaction of training arm and education status. CONCLUSIONS: Simulation training complements traditional methods to improve CA interpretation skill, with greatest impact on residents. This highlights the importance of incorporating high-fidelity simulation training early in cardiovascular fellowship curricula.

Thoracic versus nonthoracic MR imaging for patients with an MR nonconditional cardiac implantable electronic device.

BACKGROUND: Observational studies have explored the safety of magnetic resonance (MR) scanning of patients with cardiac implantable electronic devices (CIEDs) that are not Food and Drug Administration approved for MR scanning ("nonconditional"). However, concern has been raised that MR scanning that includes the thoracic region may pose a higher risk. This study examines the safety of MR scanning of thoracic versus nonthoracic regions of patients with CIEDs. METHODS: Patients underwent MR scanning utilizing an institutional protocol. CIED variables examined included sensing value, pacing capture threshold, lead impedance, and battery voltage. Regression analysis of the CIED variable differences (pre- to immediately post-MR and pre-MR to long-term follow-up) was performed to determine if CIED variable differences were dependent on region scanned (thoracic vs nonthoracic), time from CIED implant to MR scanning, or CIED type (pacemaker vs implantable cardioverter defibrillator). RESULTS: 238 patients (38% female, age 65 ± 15 years) underwent 339 MR scans, including 99 MR scans of the thoracic region. CIED variable differences to immediately post-MR or to long-term follow-up were not significantly different from zero (P > 0.05) and there was no dependence upon region scanned (thoracic vs nonthoracic), time from CIED implant to MR scan, or CIED type. One power-on reset occurred in a patient that underwent a cardiac MR and the CIED was successfully reprogrammed. There were no clinical adverse effects. CONCLUSIONS: CIED variable differences following MR scan were not dependent on the region scanned (thoracic vs nonthoracic) and there were no clinical adverse effects in this prospective cohort.

Comparison of regadenoson and nitroprusside to adenosine for measurement of fractional flow reserve: A systematic review and meta-analysis.

BACKGROUND: FFR is useful in defining the physiological significance of intermediate coronary stenosis and requires induction of maximal hyperemia and measurement of pressure proximal and distal to the stenosis. Hyperemia normally is induced by either IV or IC adenosine, a medication associated with short-term side effects. IV regadenoson and IC nitroprusside have been suggested as viable alternatives. This meta-analysis aims to identify all studies comparing use of intravenous (IV) regadenoson or intracoronary (IC) nitroprusside with IV adenosine to determine differences related to the agent utilized for assessment of fractional flow reserve (FFR). METHODS: We searched PubMed, EMBASE, Web of Science, SCOPUS, ClinicalTrials.gov and the Cochrane Library databases for studies comparing IV regadenoson or IC nitroprusside to IV adenosine for FFR assessment. The main outcome was difference in mean FFR measurement. The main secondary outcomes were composite side-effect profile and reclassification of lesions. RESULTS: Seven studies were included in the analysis, with a total of 375 patients. Compared to IV adenosine, there was no difference in the mean FFR derived from IV regadenoson (p=1.0) or IC nitroprusside (p=0.48). IV regadenoson was associated with 53% lower risk of pooled side effects compared to IV adenosine (p=0.05). IC nitroprusside was associated with 97% lower risk of pooled side effects compared to IV adenosine (p<0.001). CONCLUSIONS: IV regadenoson and IC nitroprusside produce similar pressure-derived FFR measurements compared to IV adenosine and have a favorable side effect profile. Both can be considered as alternative agents to IV adenosine for FFR measurement. Further clinical validation is warranted.

Associations of Prolonged QTc in Sickle Cell Disease.

Sudden death is a leading cause of mortality in sickle cell disease, implicating ventricular tachyarrhythmias. Prolonged QTc on an electrocardiogram (ECG), commonly seen with myocardial ischemia, is a known risk for polymorphic ventricular tachycardia (VT). We hypothesized that prolonged QTc is associated with mortality in sickle cell disease. ECG were analyzed from a cohort of 224 sickle patients (University of Illinois at Chicago, UIC) along with available laboratory, and echocardiographic findings, and from another cohort of 38 patients (University of Chicago, UC) for which cardiac MRI and free heme values were also measured. In the UIC cohort, QTc was potentially related to mortality with a hazard ratio (HR) of 1.22 per 10ms, (P = 0.015), and a HR = 3.19 (P = 0.045) for a QTc>480ms. In multivariate analyses, QTc remained significantly associated with survival after adjusting for inpatient ECG status (HR 1.26 per 10ms interval, P = 0.010) and genotype status [HR 1.21 per 10ms interval, P = 0.037). QTc trended toward association with mortality after adjusting for both LDH and hydroxyurea use (HR 1.21 per 10ms interval, P = 0.062) but was not significant after adjusting for TRV. In univariate analyses, QTc was related to markers of hemolysis including AST (P = 0.031), hemoglobin (P = 0.014), TR velocity (P = 0.036), higher in inpatients (P<0.001) and those with an SS compared to SC genotype (P<0.001) in the UIC cohort as well as to free heme in the UC cohort (P = 0.002). These findings support a relationship of prolonged QTc with hemolysis and potentially mortality in sickle cell disease.

Relationship of exercise capacity and left ventricular dimensions in patients with a normal ejection fraction. An exploratory study.

OBJECTIVES: Extreme endurance exercise is known to be associated with an enlargement of the left ventricular (LV) chamber, whereas inactivity results in inverse changes. It is unknown if these dimensional relationships exist in patients. METHODS: We analyzed the relationship of exercise capacity and LV dimension in a cohort of sequential patients with a normal ejection fraction undergoing stress echocardiography. In a total of 137 studies the following questions were addressed: (a) is there a difference in LV dimensions of patients with an excellent exercise capacity versus patients with a poor exercise capacity, (b) how is LV dimension and exercise capacity affected by LV wall thickness and (c) how do LV dimensions of patients who are unable to walk on a treadmill compare to the above groups. RESULTS: Patients with a poor exercise capacity or who are unable to physically exercise have a 34 percent smaller LV cavity size when compared to patients with an excellent exercise capacity (p<0.001). This reduction in LV chamber size is associated with concentric LV hypertrophy and a reciprocal increase in resting heart rate. In addition, cardiac output reserve is further blunted by chronotropic incompetence and a tachycardia-induced LV volume reduction. In conclusion the relationship of exercise capacity and cardiac dimensions described in extreme athletes also applies to patients. Our exploratory analysis suggests that patients who cannot sufficiently exercise have small LV cavities.

High dose intracoronary N-acetylcysteine in a porcine model of ST-elevation myocardial infarction.

We sought to evaluate the safety and efficacy of N-acetylcysteine (NAC) on ischemia and reperfusion in a pig model focusing on cardio-renal protection. High doses of NAC may provide protection from contrast induced nephropathy (CIN). NAC has also been demonstrated to reduce myocardial infarction size and improve left ventricular function after ischemia in both humans and animals studies. In this study we tested the safety and cardiorenal protective efficacy of intracoronary NAC delivered in the radiographic contrast agent in a pig model that simulates the catheter based reperfusion therapy of ST elevation myocardial infarctions. 27 pigs underwent 45 min of ischemia after surgical ligation of distal left descending coronary artery. With coronary reperfusion the animals received at total of 200 mL of the contrast agent Iopamidol with and without NAC to mimic radiographic contrast use during invasive reperfusion therapy. At 24 h the following endpoints were compared: LV function (MRI, echocardiography), myocardial injury (infarct size, area-at-risk, troponin, creatinine kinase) and CIN (creatinine, BUN and renal histology). The effects of NAC on platelet reactivity were also evaluated. Intracoronary administration of NAC administered in the contrast agent is safe. NAC reduces platelet reactivity and there was a trend towards a better cardiac function at 24 h. There was no significant difference in the size of the myocardial infarction. In this model of ischemia-reperfusion high dose NAC did not protect from CIN. High dose intracoronary NAC administered with the radiographic contrast is safe but does not provide significant cardio-renal protection.