The modest effects of clinical studies using intracoronary administration of autologous bone marrow-derived mononuclear cells (BMCs) in patients with chronic postinfarction heart failure may be attributed to impaired homing of BMCs to the target area. Extracorporeal shock wave treatment has been experimentally shown to increase homing factors in the target tissue, resulting in enhanced retention of applied BMCs. To test the hypothesis that targeted cardiac shock wave pretreatment with subsequent application of BMCs improves recovery of left ventricular ejection fraction (LVEF) in patients with chronic heart failure. The CELLWAVE double-blind, randomized, placebo-controlled trial conducted among patients with chronic heart failure treated at Goethe University Frankfurt, Germany, between 2006 and 2011. Single-blind low-dose (n = 42), high-dose (n = 40), or placebo (n = 21) shock wave pretreatment targeted to the left ventricular anterior wall. Twenty-four hours later, patients receiving shock wave pretreatment were randomized to receive double-blind intracoronary infusion of BMCs or placebo, and patients receiving placebo shock wave received intracoronary infusion of BMCs. Primary end point was change in LVEF from baseline to 4 months in the pooled groups shock wave + placebo infusion vs shock wave + BMCs; secondary end points included regional left ventricular function assessed by magnetic resonance imaging and clinical events. The primary end point was significantly improved in the shock wave + BMCs group (absolute change in LVEF, 3.2% [95% CI, 2.0% to 4.4%]), compared with the shock wave + placebo infusion group (1.0% [95% CI, -0.3% to 2.2%]) (P = .02). Regional wall thickening improved significantly in the shock wave + BMCs group (3.6% [95% CI, 2.0% to 5.2%]) but not in the shock wave + placebo infusion group (0.5% [95% CI, -1.2% to 2.1%]) (P = .01). Overall occurrence of major adverse cardiac events was significantly less frequent in the shock wave + BMCs group (n = 32 events) compared with the placebo shock wave + BMCs (n = 18) and shock wave + placebo infusion (n = 61) groups (hazard ratio, 0.58 [95% CI, 0.40-0.85]; P = .02). Among patients with postinfarction chronic heart failure, shock wave-facilitated intracoronary administration of BMCs vs shock wave treatment alone resulted in a significant, albeit modest, improvement in LVEF at 4 months. Determining whether the increase in contractile function will translate into improved clinical outcomes requires confirmation in larger clinical end point trials. clinicaltrials.gov Identifier: NCT00326989.