SummaryWe conducted a systematic review of the effects of dexmedetomidine on cardiac outcomes following non-cardiac surgery. We included prospective, randomised peri-operative studies of dexmedetomidine that reported mortality, cardiac morbidity or adverse drug events. A PubMed Central and EMBASE search was conducted up to July 2007. The reference lists of identified papers were examined for further trials. Of 425 studies identified, 20 were included in the metaanalysis (840 patients). Dexmedetomidine was associated with a trend towards improved cardiac outcomes; all-cause mortality (OR 0.27, 95% CI 0.01-7.13, p = 0.44), non-fatal myocardial infarction (OR 0.26, 95% CI 0.04-1.60, p = 0.14), and myocardial ischaemia (OR 0.65, 95% CI 0.26-1.63, p = 0.36). Peri-operative hypotension (26%, OR 3.80, 95% CI 1.91-7.54, p = 0.0001) and bradycardia (17%, OR 5.45, 95% CI 2.98-9.95, p < 0.00001) were significantly increased. An anticholinergic did not reduce the incidence of bradycardia (p = 0.43). A randomised placebocontrolled trial of dexmedetomidine is warranted. Major peri-operative cardiac events (cardiac death, nonfatal myocardial infarction and non-fatal cardiac arrest) have been reported in 1.4% of unselected patients undergoing elective non-cardiac surgery [1,2] and between 2.6 and 5.8% in selected patients considered to be at risk of cardiac disease [1]. Peri-operative cardiac events are approximately evenly distributed between myocardial oxygen supply demand imbalance and plaque rupture [3,4]. In addition, these cardiac events may be precipitated by a number of potential triggers in the perioperative period, including inflammation, surgical stress, hypercoagulable states and peri-operative hypoxic episodes [1]. It has therefore been estimated that, at best, a single medical therapy could be expected to result in a relative risk reduction of 20-35% for the composite endpoint of cardiac death, non-fatal myocardial infarction and non-fatal cardiac arrest in the peri-operative period [2].There has been considerable interest in the utility of adrenergic antagonists in decreasing peri-operative cardiac events. Beta-adrenergic antagonists decrease peri-operative myocardial ischaemia, although it is controversial whether this results in an improved cardiac outcome [5,6]. In addition, beta-adrenergic antagonists significantly increase the incidence of drug-associated hypotension and bradycardia which require treatment [6]. It is unclear whether these side-effects adversely affect the cardioprotective efficacy of peri-operative beta-blockade.Unfortunately, some patients may not realise the potential cardioprotective benefits of peri-operative beta-blockade, as this may be either contra-indicated or difficult to initiate in the peri-operative period in patients with active bronchospasm, conduction disorders or decompensated cardiac failure. Alpha-2 agonists may be an alternative anti-adrenergic therapy in these patients. Alpha-2 agonists decrease central noradrenergic activity of the locus coeruleus [7] with a decrease in...