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.)

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for the AVID InvestigatorsBackground-AVID (Angiography Versus Intravascular ultrasound-Directed stent placement) is a multicenter, randomized controlled trial designed to assess the effect of intravascular ultrasound (IVUS)-directed stent placement on the 12-month rate of target lesion revascularization (TLR). Methods and Results-After elective coronary stent placement and an optimal angiographic result (Ͻ10% stenosis), 800 patients were randomized to Angiography-or IVUS-directed therapy. Blinded IVUS was performed in the Angiography group without further therapy. In the IVUS group, IVUS criteria for optimal stent placement (Ͻ10% area stenosis, apposition, and absence of dissection) were applied. Final minimum stent area was 6.90Ϯ2.43 mm 2 in the Angiography group and 7.55Ϯ2.82 mm 2 in the IVUS group (Pϭ0.001). In the IVUS group, only 37% with inadequate expansion (Ͻ90%) received further therapy. The 12-month TLR rate was 12.0% in the Angiography group and 8.1% in the IVUS group (Pϭ0.08, 95% confidence level [CI], [Ϫ8.3% to 0.5%]). When vessels with a distal reference diameter Ͻ2.5 mm by core laboratory angiography measurement were excluded from analysis, the 12-month TLR rate was 10.1% in the Angiography group and 4.3% in the IVUS group (Pϭ0.01, 95% CI, [Ϫ10.6% to Ϫ1.2%]). With a prestent angiographic stenosis of Ն70%, the TLR rate was lower in the IVUS group compared with the Angiography group (3.1% versus 14.2%; Pϭ0.002; 95% CI, [Ϫ18.4% to Ϫ4.2%]). Conclusions-IVUS-directed bare-metal stent placement results in larger acute stent dimensions without an increase in complications and a significantly lower 12-month TLR rate for vessels Ն2.5 mm by angiography and for vessels with high-grade prestent stenosis. However, for the entire sample analyzed on an intention-to-treat basis, IVUS-directed bare-metal stent placement does not significantly reduce the 12-month TLR rate when compared with stent placement guided by angiography alone. In addition, IVUS evaluation of adequate stent expansion is underutilized by experienced operators. (Circ Cardiovasc Intervent. 2009;2:113-123.)