Jason Rubenstein

Assessing the Risks Associated with MRI in Patients with a Pacemaker or Defibrillator

Background The presence of a cardiovascular implantable electronic device has long been a contraindication for the performance of magnetic resonance imaging (MRI). We established a prospective registry to determine the risks associated with MRI at a magnetic field strength of 1.5 tesla for patients who had a pacemaker or implantable cardioverter–defibrillator (ICD) that was “non–MRI‐conditional” (i.e., not approved by the Food and Drug Administration for MRI scanning). Methods Patients in the registry were referred for clinically indicated nonthoracic MRI at a field strength of 1.5 tesla. Devices were interrogated before and after MRI with the use of a standardized protocol and were appropriately reprogrammed before the scanning. The primary end points were death, generator or lead failure, induced arrhythmia, loss of capture, or electrical reset during the scanning. The secondary end points were changes in device settings. Results MRI was performed in 1000 cases in which patients had a pacemaker and in 500 cases in which patients had an ICD. No deaths, lead failures, losses of capture, or ventricular arrhythmias occurred during MRI. One ICD generator could not be interrogated after MRI and required immediate replacement; the device had not been appropriately programmed per protocol before the MRI. We observed six cases of self‐terminating atrial fibrillation or flutter and six cases of partial electrical reset. Changes in lead impedance, pacing threshold, battery voltage, and P‐wave and R‐wave amplitude exceeded prespecified thresholds in a small number of cases. Repeat MRI was not associated with an increase in adverse events. Conclusions In this study, device or lead failure did not occur in any patient with a non–MRI‐conditional pacemaker or ICD who underwent clinically indicated nonthoracic MRI at 1.5 tesla, was appropriately screened, and had the device reprogrammed in accordance with the prespecified protocol. (Funded by St. Jude Medical and others; MagnaSafe ClinicalTrials.gov number, NCT00907361.)

The use of periinfarct contrast-enhanced cardiac magnetic resonance imaging for the prediction of late postmyocardial infarction ventricular dysfunction

BACKGROUND Although ejection fraction (EF) both perimyocardial infarction (MI) and late post-MI are important prognostic factors, only implantable cardioverter-defibrillator trials of post-MI patients with depressed late EF have shown improved survival. This may relate to imprecision of early EF because of post-MI stunning. We sought to determine if peri-MI infarct size, as measured by cardiac magnetic resonance (CMR), is superior to early EF to predict late post-MI EF. METHODS Seventy-three patients with ST-elevation MI had infarct size and EF quantified using CMR early (<1 week) and late (>3 months) post-MI. RESULTS Late EF was significantly correlated with early EF (R = 0.734, P < .001), and with infarct size (R = -0.661, P < .001), and both early EF and infarct size were significant predictors of late EF. Subgroup analyses showed that low late EF (<or=35%) was better predicted by infarct size than early EF. Half of the patients with early EF <or=35% had a late EF >35%. There was no difference in early EF between the subgroup with a late EF >35% compared to the subgroup with late EF </=35% (29.7% +/- 4.6% vs 28.0% +/- 4.9%, P = .414). There was, however, a significant difference between these 2 groups in infarct size (22.6% +/- 10.8% vs 34.7% +/- 7.8%, P = .011). CONCLUSIONS Infarct size as determined by CMR immediately post-MI is a significant predictor of late EF and is superior to early EF in patients with initially depressed EF. Further studies are warranted to assess whether infarct size estimation by CMR after acute MI can better identify patients who are at risk for sudden cardiac death than early EF.

A comparison of cardiac magnetic resonance imaging peri-infarct border zone quantification strategies for the prediction of ventricular tachyarrhythmia inducibility

BACKGROUND Peri-infarct border zone (BZ) as quantified by late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (MRI) has been proposed as a risk stratification tool, and is associated with increased mortality. BZ has been measured by various methods in the literature. We assessed which BZ analysis best predicts inducible arrhythmia during electrophysiological study (EPS). METHODS LGE was performed in 47 patients with coronary artery disease referred for EPS to assess for ventricular tachycardia (VT). LGE data was analyzed for BZ quantification by 3 previously published methods. Method I (BZ-I) used pixels 2-3 standard deviations over the mean of normal tissue, expressed as % of left ventricular mass, Method II (BZ-II, as described by Yan) and Method III (BZ-III, as described by Schmidt). EPS results were classified as negative (non-inducible) or positive (monomorphic VT - MVT). RESULTS There were 47 subjects-age 61.7 years, 72% male. During EPS, 20 patients were non-inducible and 18 had induced MVT. Ejection fraction was not significantly different between non-inducible patients and those with MVT (34.1% vs. 28.5%, p = 0.13). BZ-I was significantly different (1.4% vs. 2.6%, p = 0.001), but not BZ-II (7.9% vs. 6.9%, p = 0.68) or BZ-III (2.7 g vs. 2.1 g, p = 0.88). Multivariate analysis demonstrated that only BZ-I was an independent predictor of EPS outcome after controling for infarct size (OR 1.97 per % change, 95% CI 1.04-3.73, p = 0.04). CONCLUSIONS This study demonstrates significant variability between the published methods for measuring BZ. Also, BZ-I is a stronger predictor of inducible MVT during EPS than ejection fraction and infarct size. BZ may be another LGE marker of elevated risk of arrhythmia.

A Novel Method for Sinus Node Modification and Phrenic Nerve Protection in Resistant Cases

This is a case report of inappropriate sinus tachycardia in a patient who had a previous unsuccessful endocardial ablation, which had been limited due to concerns of phrenic nerve injury. The patient required a repeat ablation that utilized a novel combined epicardial and endocardial approach for sinus node modification and simultaneous protection of the phrenic nerve via an epicardial balloon.

‘Coronary wrap’: IgG4 related disease of coronary artery presenting as a mass lesion

Our patient is a 68-year male who presented with fatigue. He had a past history of liver transplant 13 years back. As per routine evaluation with computed tomography (CT) scan extensive enhancing soft tissue masses surrounding the left anterior descending (LAD) and circumflex coronary arteries (Fig. 1 thin arrows) noted. A magnetic resonance imaging (MRI) was done to further characterize the abnormality. MRI confirmed CT findings and showed heterogeneously enhancing mass lesion with increased perfusion and underlying aneurysmal dilatation of LAD (Fig. 1 thick arrow). Incidental significant aortic valve stenosis was also noted. Differentials of this indeterminate soft tissue ranged from inflammatory disorder to neoplastic etiology like lymphoma. Cross sectional imaging helped cardiac surgeon to plan the biopsy. Open biopsy was performed which revealed IgG4 related disease.

Connecting the Dots: The Relevance of Scar in Nonischemic Cardiomyopathy*

Delayed-enhancement magnetic resonance imaging (DE-MRI) has emerged as the gold standard imaging technique for defining myocardial scar with high resolution. Gadolinium contrast washes out of the blood pool and accumulates in the extracellular space. Tissues with weak intracellular bonds and high

Pacemaker Quantified Physical Activity Predicts All-Cause Mortality.

There is growing recognition that physical inactivity in the general population is an important risk factor for cardiovascular disease and death [(1–3)][1]. To date, there are limited data as to the predictive value of physical activity in individuals with pacemakers and preserved left ventricular

Right ventricular size assessed by cardiovascular MRI may predict mortality after left ventricular assist device placement

Methods Patients were referred for cardiovascular magnetic resonance imaging prior to LVAD placement. We assessed the association of mortality to pre-LVAD right ventricular end systolic volume index (RVESVI), right ventricular end diastolic volume index (RVEDVI), left ventricular ejection fraction (LVEF) by CMR. Right ventricular stroke work index (RVSWI) was determined by preLVAD right heart catheterization.

CLINICAL OUTCOMES AFTER CARDIAC MRI SCANS OF NON-MRI-SAFE CARDIAC IMPLANTABLE ELECTRONIC DEVICES

Few studies have been published regarding the safety or feasibility of MRIs in patients with cardiac implantable electronic devices (CIEDs), and most have excluded patients requiring cardiac MRIs. This study evaluated the immediate and 6-month effects on device parameters in patients who underwent

Abnormal myocardial T1 mapping of hypertrophic cardiomyopathy in areas without delayed enhancement, as compared to NICM and controls at both 1.5 and 3T

Methods 55 patients were included in the study; 29 with clinically proven hypertrophic cardiomyopathy, 10 patients with no cardiac disease, and 16 patients with nonischemic cardiomyopathy. All underwent cardiac MRI at either 1.5 or 3T (Verio or Espree, Siemens) including contrast using Magnevist (Bayer HealthCare) or Multihance (Bracco Imaging). T1 maps were obtained before and 10 minutes after contrast infusion for calculation of l as previously described. Delayed steady-state free procession images were obtained. Post-processing was performed using CVI42 (Circle Imaging). For MOLLI calculation, T1 times were measured in the basal, mid, and apical regions of the septal myocardium avoiding areas with delayed hyperenhancement. Statistical analysis was performed using R Statistical Software (Foundation for Statistical Computing, Vienna, Austria).