A raised hemidiaphragm has been reported as an uncommon complication of cardiopulmonary bypass, possibly resulting from cold injury to the phrenic nerve. At Papworth Hospital myocardial protection during cardiac arrest relies in part on irrigation of the pericardial cavity with large volumes of Hartmann's solution at 40C. Retrospective review of the chest radiographs of 100 consecutive patients undergoing cardiopulmonary bypass showed that 31 had a raised left hemidiaphragm soon after operation. The only significant correlation was with aortic cross clamp time (p < 0.03). A prospective study of 36 consecutive patients undergoing cardiopulmonary bypass was then undertaken with diaphragmatic screening and chest radiography. Preoperative screening gave normal results in all patients. In the early postoperative period 16 (44%) had left diaphragmatic weakness or paralysis, two (5.5%) right sided weakness, and two (5.5%) bilateral weakness. Repeat screening of these patients showed resolution in all but four cases (80%) at six months and in all but two (90%) at one year. The greater number of left sided lesions than of right (8:1) is probably due to the fact that the cold jet of irrigating fluid is directed towards the left phrenic nerve. These findings have implications with regard to the optimum temperature of the irrigant fluid for myocardial protection during cardiopulmonary bypass.A raised hemidiaphragm complicating cardiopulmonary bypass has been previously reported.' The incidence is variable and the aetiology remains uncertain but has been attributed to cold injury of the left phrenic nerve.' 2 Gastric distension, left lower lobe atelectasis, pulmonary trauma,2 stretch trauma,6 and association with dissection of the left internal mammary artery-have also been proposed.We recently noted that a raised left hemidiaphragm on postoperative chest radiographs of patients undergoing open heart operations was relatively common in our unit. These investigations were undertaken to define the incidence, duration, and possible aetiology of this complication. Patients and methodsA retrospective review of the previous 100 consecutive patients undergoing operations with cardiopulmonary bypass during 1982 was undertaken. Their Address for reprint requests: Mr SR Large, Surgical Unit, Papworth Hospital, Papworth Everard, Cambridge CB3 8RE.Accepted 10 January 1985 mean age was 54 years (range 11-77) and 27 were women. The immediate preoperative, early postoperative (8-10 days), and late postoperative (6 months) posteroanterior chest radiographs were studied. The highest point of the left hemidiaphragm was compared with that of the right. If the point on the left was at the same horizontal level or higher than that on the right it was described as raised. An estimate of the incidence of raised left hemidiaphragm soon after operation and its subsequent resolution by six months was made.To investigate the aetiology of this complication the early postoperative incidence was compared in different groups of patients with rega...

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Six cardiac transplant recipients underwent maximal exercise testing before and after the administration of intravenous propranolol to assess the effect of beta blockade on their exercise heart rate response and exercise capacity. Before propranolol the patients were capable of a mean of 6.8 minutes of exercise and heart rate increased from a resting value of 102 +/- 25 a minute to 138 +/- 34 at peak exercise--a mean increase of 35%. All tests were terminated because of tiredness or muscle weakness. After one hour's rest, intravenous propranolol (0.2 mg/kg over 10 minutes) was administered with a reduction in resting heart rate from 109 +/- 28 a minute to 83 +/- 16. During the repeat exercise test the patients were capable of a mean of 4.5 minutes of exercise and all tests were terminated by extreme exhaustion and/or unsteadiness requiring immediate cessation of the treadmill. Heart rate increased from a resting value of 83 +/- 16 a minute to 96 +/- 18 at peak exercise. The exercise capability of the denervated heart is conspicuously reduced by beta blockade, presumably because of its reliance on circulating catecholamines.

Cambridge, the tPHL, Cambridge and the tPHL, St George's Hospital, London SUMMARY The first case of disseminated toxoplasmosis following cardiac transplantation in the UK is described, with details of Toxoplasma antibody tests made on other cardiac transplant patients. Sixteen of 40 (39%) of recipients had Toxoplasma antibody before operation. Eleven of 30 (37%) of donors had Toxoplasma antibody. The were four occasions when a negative recipient received a heart from a positive donor. Three survived the immediate postoperative period and two became infected with toxoplasmosis. The implications of this are discussed.Disseminated toxoplasmosis appears much more often when heart muscle from a dye test positive donor is given to a dye test negative recipient. Antibiotic therapy is limited by the fact that the antitoxoplasma drugs available are static in their effect, and need to be given for prolonged periods postoperatively. Disseminated toxoplasmosis has been described in immunocompromised hosts after transplantation of the heart,' liver,2 and kidney.

SUMMARY Donor sinus node function was studied in 10 patients from day 4 to day 24 after cardiac transplantation. Cycle length, atrial arrhythmias, corrected sinus node recovery time, and estimated sinoatrial conduction time were recorded daily. Five patients had at least two sets of results suggesting sinus node dysfunction (group A) while five patients had no such abnormalities (group B). The prognosis in group A was poor, with four of the five patients dying within four months ofthe operation; one unexpected death from arrhythmi'as'was recorded by'ambulatory electrocardiographic monitoring. All five patients in group B survived for at least eight months. In nine patients sinus node function varied from day to day, with corrected sinus node recovery time reaching a peak at 11 to 18 days after operation. The longest corrected sinus node recovery time was 11 160 ms. Neither the differences between the patients, nor the day to day variation, could be explained solely by the degree of rejection as assessed by biopsy or by the ischaemia time ofthe heart during procurement. Sinus node dysfunction soon after transplantation is associated with a poorer prognosis and might be the terminal event in some cases.