A contemporaneous multivariate prediction model for MACE after PCI was developed. The NWQIP tool allows calculation of the risk of MACE permitting meaningful risk adjusted comparisons of performance between hospitals and operators.
Background: We investigated the reproducibility of contrast transcranial Doppler (TCD), a safe non-invasive test for investigation of venous-to-arterial circulation shunts (v-aCS), usually patent foramen ovale, in young stroke patients. We also investigated whether microbubble contrast was reproducible and whether the addition of blood to agitated saline contrast affected the number of microbubbles produced. Methods: TCD investigation for v-aCS was repeated in 42 patients using a standardised protocol (i) by the same investigator and (ii) by a different investigator. Agitated saline was produced by mixing saline and 1 ml of air between two 10-ml syringes. The effect of adding blood and increasing the number of agitations was evaluated by microscopy examination using a haemocytometer to assess bubble numbers and sizes. Results: TCD: no difference was found in the highest microbubble count for the same investigator and between different investigators (p > 0.05). Reproducibility for the detection of v-aCS consistent with a patent foramen ovale was also good (ĸ values >0.8). Contrast: both the number of contrast mixes before injection and the presence of blood significantly increased the number of bubbles counted. On average, 18 agitations produced 1.86 (95% CI 1.62–2.13) times more bubbles than 6 agitations. Mixtures with blood produced on average 3.8 times more bubbles (3.08–4.69). The size of the bubbles was similar for all mixtures. Conclusions: Contrast TCD is reproducible and reliable for the detection of v-aCS. The addition of blood and 18 mixes rather than 6 significantly increased the number of microbubbles produced and may increase the effectiveness of microbubble contrast.
The link between increased QT dispersion and cardiac death in subjects with diabetes and arterial disease is well recognised. Corrected QT dispersion was studied in subjects with end stage renal failure on haemodialysis. Thirty one stable, chronic subjects on haemodialysis had 12-lead electrocardiograms (ECGs) taken before and after a single haemodialysis session. The QT interval was measured manually in each and the corrected QT and corrected QT dispersion calculated. Serum concentrations of potassium, calcium, and magnesium were measured at the same time as ECG acquisition. Corrected QT dispersion increased from a mean (SEM) 90.6 (5.8) to 117.7 (10.2) ms (p=0.002). Serum potassium and magnesium decreased from 5.0 (0.14) to 3.5 (0.09) mmol/l and 0.95 (0.04) to 0.89 (0.09) mmol/l respectively, while serum calcium increased from 2.56 (0.04) to 2.77 (0.04) mmol/l. Intradialytic weight fell by a mean of 2.1 kg. There was no significant correlation between the change in QTc dispersion and the changes in measured serum anions or the subjects' weight during dialysis. Corrected QT dispersion was higher in subjects on haemodialysis than previously suggested normal values, and was significantly increased by haemodialysis. This reflects increased inhomogeneous ventricular repolarisation, which may lead to an increased risk of arrhythmias and sudden death. Studies looking at QT dispersion in subjects on dialysis should standardise the timing of ECG recordings taken with respect to dialysis.C ardiovascular disease is a major cause of mortality and morbidity among subjects on haemodialysis. Cardiovascular death is responsible for up to 50% of deaths among subjects on dialysis. 1 Cardiac arrhythmias are frequent among the haemodialysis population, particularly during and immediately after a dialysis session. 2-5 These arrhythmias may be caused by the rapid changes in intracellular and extracellular electrolytes during the dialysis session, in hearts that are susceptible due to both myocardial ischaemia and intramyocardiocytic fibrosis. 6 7 A reliable way of predicting subjects at risk of ventricular arrhythmias would be an extremely useful tool for the dialysis physician.Recently, dispersion of the QT interval has emerged as an important predictor of ventricular arrhythmias. The QT dispersion is simply the difference between the shortest and longest QT interval on a standard surface 12-lead electrocardiograph. 8 This is a non-invasive measurement of myocardial repolarisation inhomogeneity and hence predisposition to re-entry arrhythmias. 9 A QT dispersion above 80 ms reflects a loss of synchronisation in the repolarisation process. 10 In clinical studies, a wide QT dispersion has been shown to be a risk factor for cardiac arrhythmia after myocardial infarction, 11 congestive cardiac failure, 12 peripheral vascular disease, 13 and drug induced arrhythmiogenicity. 14 It has also been shown that a wide QT dispersion can narrow when congestive cardiac failure is treated with enalapril 15 and after successful thrombolysis for acut...
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