Thermal stressing of polyunsaturated fatty acid (PUFA)- rich culinary oils according to routine frying or cooking practices generates high levels of cytotoxic aldehydic products (predominantly trans-2-alkenals, trans,trans-alka-2,4-dienals, cis,trans-alka-2, 4-dienals, and n-alkanals), species arising from the fragmentation of conjugated hydroperoxydiene precursors. In this investigation we demonstrate that typical trans-2-alkenal compounds known to be produced from the thermally induced autoxidation of PUFAs are readily absorbed from the gut into the systemic circulation in vivo, metabolized (primarily via the addition of glutathione across their electrophilic carbon-carbon double bonds), and excreted in the urine as C-3 mercapturate conjugates in rats. Since such aldehydic products are damaging to human health, the results obtained from our investigations indicate that the dietary ingestion of thermally, autoxidatively stressed PUFA-rich culinary oils promotes the induction, development, and progression of cardiovascular diseases.

Objective-To investigate the role of low serum magnesium as a trigger for atrial fibrillation in patients with a substrate for the arrhythmia (assessed by signal averaged P wave duration). Design-A case-control study. Setting-A regional referral cardiac centre. Patients and interventions-105 consecutive patients undergoing elective coronary artery bypass surgery had signal averaged P wave recordings before operation. Serum electrolytes were analysed preoperatively and on days 1, 2, and 5 after surgery. Main outcome measures-Any episode of electrocardiographically recorded atrial fibrillation was taken as a study end point. Results-Of 102 patients discharged, 27 (26%) had documented episodes of atrial fibrillation at a mean of 2 7 days after surgery. A combination of P wave duration > 155 ms and serum magnesium on the first postoperative day of < 0-7 mmolll had a sensitivity of 75% and specificity of 80% for predicting atrial fibrillation. Duration of hospital stay (7-9 v 6-8 days) was longer in the atrial fibrillation group (P < 0.01). Stepwise regression showed age, serum magnesium < 07 mmoIl on the first postoperative day (both P < 0.001), angiotensin converting enzyme inhibitor withdrawal (P < 0.02), and signal averaged P wave duration (P = 0.04) to be independent predictors. Conclusions-The combination of signal averaged P wave duration and low serum magnesium on the first postoperative day identified the majority of patients with atrial fibrillation after coronary artery bypass surgery. Early identification and pharmacological treatment for selected patients may reduce the incidence of postoperative atrial fibrillation.

Aim-To assess initial experience of cardiac catheterisation in children by the transhepatic approach where conventional venous access is impossible. Patients and methods-Percutaneous transhepatic cardiac catheterisation was performed on six occasions in five children (three male) aged 4 to 36 months (mean 17 months). All children had documented femoral venous occlusion and all but one had occlusion of the superior vena cava. Ultrasound was used in five of the six procedures to help identify a large hepatic vein. A 4 F or 5 F sheath was introduced into the vein using the Seldinger technique. In the fourth patient, hepatic venous access was obtained immediately without the assistance of ultrasound. Results-Percutaneous transhepatic catheterisation was successfully performed at all six attempts. Total procedure time ranged from 120 to 200 minutes (mean 138 minutes) and screening time from 14 to 22 minutes (mean 16.8 minutes). A serious complication was encountered in only one patient who had a retroperitoneal bleed after administration of thrombolysis for loss of femoral arterial pulse. Conclusions-The percutaneous transhepatic technique can provide a safe alternative approach for cardiac catheterisation in children with multiple venous occlusion. The procedure can be performed very simply using the Seldinger technique and equipment normally used for conventional venous cannulation for cardiac catheterisation. (Heart 1999;82:694-696)

Objective-To assess the quality of echocardiographic images from neonates transmitted over Integrated Service Digital Network 2 (ISDN2) channels. Design-Echocardiographic images were viewed live in real time either by a direct video link or by transmission over the commercial network, using one, two, or three ISDN2 channels. The order of the viewing formats was random and four observers marked each view for potential for provision of complete diagnostic information and quality. Setting-Cardiology department of tertiary referral centre for paediatric cardiac services. ISDN lines were positioned in two nearby rooms. Telephone connection was through the commercial network and video connection by a direct video cable. Patients-10 neonates were studied (weight 2600 to 3900 g). In each, nine echocardiographic studies were undertaken to assess imaging (M mode and cross sectional) and Doppler (spectral and colour) quality. Results-No significant diVerences were found in diagnostic ability between the diVerent formats for M mode, colour, or spectral Doppler studies. For cross sectional imaging the diagnostic information and image quality increased with increasing numbers of ISDN channels. With six channels there was little diVerence from the directly connected images. Conclusions-In echocardiographic assessment of the newborn, one or two ISDN2 channels will transmit images of satisfactory quality in many situations but three or more channels are necessary to ensure minimum degradation of the live image. (Heart 1999;82:222-225)

Transcatheter closure of PDA can be accomplished in selected infants weighing <6 kg despite the manufacturer's recommended weight limit of 6 kg for most ductal occluders. The embolization rate is higher than previously reported in larger patients. Retrievability of the occluder and duct morphology needs careful consideration before deciding whether surgical ligation or transcatheter therapy is the better treatment option.