No abstract

A single intracoronary application of BMCs does not promote a sustained improvement of LVEF in STEMI patients with relatively preserved systolic function. It is conceivable that a subgroup of patients with more transmural infarcts may derive a sustained benefit from BMC therapy. However, this needs to be tested prospectively in a randomized trial.

Background-Intracoronary transfer of autologous bone marrow cells (BMCs) may enhance recovery of left ventricular (LV) function in patients after acute myocardial infarction (AMI). However, clinical studies addressing the effects of BMCs after AMI have covered only limited time frames ranging from 3 to 6 months. The critical question of whether BMC transfer can have a sustained impact on LV function remains unanswered. Methods and Results-After percutaneous coronary intervention with stent implantation (PCI) of the infarct-related artery, 60 patients were randomized 1:1 to a control group with optimal postinfarction therapy and a BMC transfer group that also received an intracoronary BMC infusion 4.8Ϯ1.3 days after PCI. Cardiac MRI was performed 3.5Ϯ1.5 days, 6Ϯ1 months, and 18Ϯ6 months after PCI. BMC transfer was not associated with adverse clinical events. In the control group, mean global LV ejection fraction increased by 0.7 and 3.1 percentage points after 6 and 18 months, respectively. LV ejection fraction in the BMC transfer group increased by 6.7 and 5.9 percentage points. The difference in LVEF improvement between groups was significant after 6 months but not after 18 months (Pϭ0.27). The speed of LV ejection fraction recovery over the course of 18 months was significantly higher in the BMC transfer group (Pϭ0.001). Conclusions-In this study, a single dose of intracoronary BMCs did not provide long-term benefit on LV systolic function after AMI compared with a randomized control group; however, the study suggests an acceleration of LV ejection fraction recovery after AMI by BMC therapy. (Circulation. 2006;113:1287-1294.)

Background-Cryoablation has emerged as an alternative to radiofrequency catheter ablation (RFCA) for the treatment of atrioventricular (AV) nodal reentrant tachycardia (AVNRT). The purpose of this prospective randomized study was to test whether cryoablation is as effective as RFCA during both short-term and long-term follow-up with a lower risk of permanent AV block. Methods and Results-A total of 509 patients underwent slow pathway cryoablation (nϭ251) or RFCA (nϭ258). The primary end point was immediate ablation failure, permanent AV block, and AVNRT recurrence during a 6-month follow-up. Secondary end points included procedural parameters, device functionality, and pain perception. Significantly more patients in the cryoablation group than the RFCA group reached the primary end point (12.6% versus 6.3%; Pϭ0.018). Whereas immediate ablation success (96.8% versus 98.4%) and occurrence of permanent AV block (0% versus 0.4%) did not differ, AVNRT recurrence was significantly more frequent in the cryoablation group (9.4% versus 4.4%; Pϭ0.029). In the cryoablation group, procedure duration was longer (138Ϯ54 versus 123Ϯ48 minutes; Pϭ0.0012) and more device problems occurred (13 versus 2 patients; Pϭ0.033). Pain perception was lower in the cryoablation group (PϽ0.001). Conclusions-Cryoablation for AVNRT is as effective as RFCA over the short term but is associated with a higher recurrence rate at the 6-month follow-up. The risk of permanent AV block does not differ significantly between cryoablation and RFCA. The potential benefits of cryoenergy relative to ablation safety and pain perception are counterbalanced by longer procedure times, more device problems, and a high recurrence rate. Clinical Trial Registration-URL: http://www.clinicaltrials.gov.