Echocardiography a diagnostic test on the heart using soundwaves is more dangerous than had been thought, and could lead to life threatening complications.

The first major study into the procedure discovered that it can be life threatening in one in 210 cases which required special treatment or a stay in hospital. In addition, there were two cases of heart attack after the procedure had been completed. Five other cases also reported hallucinations for several hours.

These disturbing findings were based on 2,949 procedures carried out in 24 laboratories in Italy, by far the largest study into the safety of the test.

The new study, monitored by Dr Eugenio Picano et al from the Institute of Clinical Physiology in Pisa, concluded that the test had "more frequent, serious and unforeseeable side effects" than earlier studies had indicated.

The procedure involves the use of two drugs dobutamine and atropine and had been gaining acceptance for its safety and accuracy (The Lancet, 29 October 1994).

The US Food and Drug Administration (FDA) has received "a number of reports" of patients suffering skin burns after being given x-rays. Doctors seemed unaware that the dosage exceeded safety levels. Injuries, which included ulceration of the skin, were not apparent until several weeks after the x-rays.