Experimentally, creatine phosphate (CP) added to St. Thomas' Hospital cardioplegic solution (STH) improved post-ischaemic recovery of cardiac function in the rat heart. We investigated the effect of adding CP (10.0 mmol/l) to STH. Fifty open-heart surgery patients were randomized into control (STH) and treated (STH + CP) groups (25 per group). Patients underwent (a) monitoring for peri- and postoperative arrhythmias (48-h Holter monitoring). (b) quantitative birefringence assessment of intraoperative myocardial protection in left and right ventricular biopsies sampled at start of bypass (pre-isch.), end of bypass (end-isch.) and after 10 min reperfusion (post-isch.), and (c) measurement of serum creatine kinase-MB isozyme (CK-MB) values for up to 4 days postoperatively; results were assessed with respect to (d) haemodynamics and postoperative clinical outcome. Inotropic support (adrenaline) was required in three patients (12%) from each group; no patient died. All patients required defibrillation, and the number of direct current shocks required for sinus rhythm was the same in each group. The occurrence and incidence of reperfusion-induced arrhythmias were the same in both groups. Serum CK and CK-MB values were similar throughout the sampling period in both groups of patients; one patient in the control group had raised CK-MB levels postoperatively, but perioperative infarction was not indicated by the electrocardiogram.(ABSTRACT TRUNCATED AT 250 WORDS)

Recently, the St. Thomas' Hospital cardioplegic solution No. 2 (Plegisol) has become available commercially in the UK. In a series of patients (n = 28) undergoing open heart surgery for a variety of lesions, a clinical validation was performed. Preservation of myocardial contractility was assessed biophysically by quantitative birefringence measurements of myocardial biopsy samples (full thickness apical left ventricle and right ventricle) taken (1) prior to ischaemia, (2) at the end of ischaemia and (3) 10-15 min after reperfusion during cardiopulmonary bypass. In addition, serum CK-MB values were measured in samples taken throughout the operation and for 4 days postoperatively. Postoperative ECG traces (taken every 6 h for 48 h and then daily up to 7 days) were analysed to identify the occurrence of perioperative infarction. There were no hospital deaths. Chronotropic support was required in 5 of 28 patients (18%) for transient heart block. Low cardiac output did not occur postoperatively. Birefringence measurements in biopsy samples taken at the end of the ischaemic period (immediately prior to reperfusion) indicated an apparent left ventricular deterioration in myocardial contractility in 12 of 28 patients (43%) when compared to biopsies sampled prior to the ischaemic period. However, after 10-15 min of aerobic reperfusion, measurements indicated that myocardial contractility recovered to almost pre-ischaemic levels in the majority of patients. Thus, in 22 of 28 patients (79%), left ventricular deterioration did not occur in post-ischaemic biopsy samples when compared to the pre-ischaemic biopsies. Similarly, 21 of 28 patients (75%) had no deterioration of birefringence values in right ventricular biopsies.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of double-orifice mitral valve (duplication of the mitral valve) in an 18-month-old baby is presented. The valve showed significant regurgitation and was replaced with a No.20 Lillehei-Kaster mitral prosthesis. Patient is kept on dipyridamole (Persantin) 10mg/Kg and aspirin 50mg/Kg daily to avoid postoperative thromboembolic complications. It is emphasized that valve replacement should be the treatment of choice in severe mitral regurgitation associated with double-orifice mitral valve.

Recent studies have suggested that oxygenation of crystalloid cardioplegic solutions improves myocardial preservation. To assess whether oxygenation of St. Thomas' Hospital cardioplegic solution No. 2 (Plegisol) improves its clinical efficacy, 50 patients were randomly assigned into 2 groups: (1) those receiving Plegisol and (2) those receiving O2-Plegisol (PO2 greater than 500 mmHg at 4 degrees C). Efficacy was assessed by (a) clinical and haemodynamic parameters, (b) quantitative birefringence changes in response to ATP and calcium as a measurement of myocardial preservation in left and right ventricular biopsies, (c) creatine kinase (MB isoenzyme) release for up to 4 days postoperatively, (d) electrocardiographic (ECG) monitoring for up to 7 days postoperatively. There were no differences in mean age, ejection fraction, aortic cross-clamp duration, or bypass duration between the 2 groups of patients. In the Plegisol group, 2 patients (8%) died and 4 patients (16%) required inotropic support, whereas in the O2-Plegisol group there were no deaths and only 2 patients (8%) required inotropic support. These differences, however, were not statistically significant. Birefringence assessment demonstrated an improved myocardial response to ATP and calcium (predominantly in the left ventricular epimyocardium and in the right ventricular biopsies) at the end of ischaemia and after reperfusion in patients given O2-Plegisol. Deterioration in cellular assessment of myocardial contractility (measured by a reduction in birefringence of greater than 0.4 nm) was reduced from 20% in Plegisol patients to 12.5% in O2-Plegisol patients. CK-MB values showed no difference at any sampling time between the 2 groups of patients; a mean peak CK-MB of 35 IU/l occurred 2 h postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

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