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BACKGROUNDThe 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 cardioverterdefibrillator (ICD) that was "non-MRI-conditional" (i.e., not approved by the Food and Drug Administration for MRI scanning). METHODSPatients 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. RESULTSMRI 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. CONCLUSIONSIn this study, device or lead failure did not occur in any patient with a non-MRIconditional 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 data suggest that MRI is more accurate than echocardiography in assessing the severity of MR. MRI should be considered in those patients when MR severity as assessed by echocardiography is influencing important clinical decisions, such as the decision to undergo MR surgery.

Accurate quantification of regurgitant volume is a central component to the management of mitral regurgitation. Cardiac magnetic resonance imaging (CMR) accurately quantifies mitral regurgitation as the difference between left ventricular stroke volume and forward stroke volume using steady state free precession and phase contrast imaging. The CMR measurement of mitral regurgitant volume is reproducible and can quantify mitral regurgitation in patients without regard to regurgitant jet morphology, such as patients with multiple and eccentric jets. It can be used to quantify regurgitant volume in patients with multiple valve lesions and concomitant intracardiac shunts without the use of intravenous contrast. Studies have highlighted the accuracy and reproducibility of CMR in quantifying mitral regurgitation and have begun to link CMR to clinical outcomes.

Acquiring and quantifying LAA A(M) contraction velocity is feasible on TTE in a high percentage of patients and correlates with TEE. LAA A(M) was lower in AF compared with sinus rhythm, with spontaneous echo contrast compared to without spontaneous echo contrast, and in AF patients with a history of stroke or TIA. Those with LAA thrombus had the lowest LAA A(M) velocities. LAA A(M) is a novel functional parameter that may prove useful for risk stratification of AF.

Hormones and growth factors regulate endometrial cell growth.

BackgroundThe treatment of patients with aortic regurgitation (AR) or mitral regurgitation (MR) relies on the accurate assessment of the severity of the regurgitation as well as its effect on left ventricular (LV) size and function. Cardiovascular Magnetic Resonance (CMR) is an excellent tool for quantifying regurgitant volumes as well as LV size and function. The 2008 AHA/ACC management guidelines for the therapy of patients with AR or MR only describe LV size in terms of linear dimensions (i.e. end-diastolic and end-systolic dimension). LV volumes that correspond to these linear dimensions have not been published in the peer-reviewed literature. The purpose of this study is to determine the effect of regurgitant volume on LV volumes and chamber dimensions in patients with isolated AR or MR and preserved LV function.MethodsRegurgitant volume, LV volume, mass, linear dimensions, and ejection fraction, were determined in 34 consecutive patients with isolated AR and 23 consecutive patients with MR and no other known cardiac disease.ResultsThere is a strong, linear relationship between regurgitant volume and LV end-diastolic volume index (aortic regurgitation r2 = 0.8, mitral regurgitation r2 = 0.8). Bland-Altman analysis of regurgitant volume shows little interobserver variation (AR: 0.6 ± 4 ml; MR 4 ± 6 ml). The correlation is much poorer between regurgitant volume and commonly used clinical linear measures such as end-systolic dimension (mitral regurgitation r2 = 0.3, aortic regurgitation r2 = 0.5). For a given regurgitant volume, AR causes greater LV enlargement and hypertrophy than MR.ConclusionCMR is an accurate and robust technique for quantifying regurgitant volume in patients with AR or MR. Ventricular volumes show a stronger correlation with regurgitant volume than linear dimensions, suggesting LV volumes better reflect ventricular remodeling in patients with isolated mitral or aortic regurgitation. Ventricular volumes that correspond to published recommended linear dimensions are determined to guide the timing of surgical intervention.

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