The Pharmaceutical Journal
Vol 271 No 7257 p39
12 July 2003

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The Lancet (www.thelancet.com)
European Society of Cardiology (www.escardio.org)

Clue to how beta-blockers can work in heart failure

Carvedilol (Eucardic) seems to improve ventricular function in patients with heart failure, but only for those with ischaemia or whose heart muscle fails to contract despite being viable. Indeed, a positive response to carvedilol could be used as a test of myocardial ischaemic risk obviating the need for coronary revascularisation.

Professor John Cleland, Castle Hill Hospital, Hull, and colleagues compared the effects of carvedilol with those of placebo in patients with stable chronic heart failure due to ischaemic left-ventricular systolic dysfunction. They found that the improvement in myocardial function induced by carvedilol was dependent on the volume of myocardium affected by ischaemia or hibernation. (Hibernation describes the state of heart muscle that is still viable but which fails to contract.) Little or no increase in ventricular function was recorded for patients who had no myocardial hibernation or ischaemia, whereas substantial increases were seen in patients affected by these syndromes.

The researchers suggest several ways in which carvedilol could improve function in hibernating myocardium. Slowing the heart rate might improve the efficiency of heart cells and enhance diastolic blood flow. This could redistribute blood flow to areas of contractile dysfunction, they say (Lancet 2003;362:14).

In an accompanying commentary, Dr Henry Dargie, department of cardiology, Western Infirmary, Glasgow, says the implications of the trial are potentially significant because British patients are not routinely investigated for hibernation status (ibid, p2).

The trial, which has the acronym CHRISTMAS, was published along side the COMET trial (ibid, p7), the main results of which were reported at the European Society of Cardiology heart failure meeting in Strasbourg last month (PJ, 28 June, p882).