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Biomedical subjects

D England

Publications and source records attributed to D England.

32 records · Page 2Linked to original sources
PubMed1982

The natural history of left ventricular hypertrophy in hypertrophic cardiomyopathy: an electrocardiographic study.

The natural history of electrocardiographic left ventricular hypertrophy was assessed in relation to clinical features, treatment with propranolol and prognosis in 100 patients with hypertrophic cardiomyopathy who were followed 5--20 years (mean 8 years). Seventy-one patients received propranolol, 120--800 mg/day (mean 240 mg). At diagnosis, the voltage measurement from SV1 + RV5 was 37 +/- 20 mm, the R wave in aVL was 12 +/- 6 mm and the mean frontal plane voltage was 15 +/- 10 mm. After 5 years, these values were increased to 43 +/- 22 mm (p less than 0.0002), 14 +/- 6 mm (p less than 0.003) and 17 +/- 10 mm (p less than 0.01), respectively. Neither a left ventricular outflow tract gradient nor propranolol treatment influenced these voltage changes. Twenty patients had an increase of more than 10 mm in SV1 + RV5, which was associated with exertional chest pain (p less than 0.006) and death (p less than 0.02). Four patients had a decrease of more than 10 mm in SV1 + RV5. Two of these received high-dose propranolol, one 720 mg/day for 12 years and another 800 mg/day for 12 years. No other patient received more than 480 mg of propranolol daily. In hypertrophic cardiomyopathy there is electrocardiographic evidence of progressive hypertrophy, which is associated with poor prognosis and is not influenced by treatment with propranolol in moderate dosage. Regression of hypertrophy is rare and may be related to long-term treatment with high-dose propranolol.

Adolescent↗
PubMed1981

Prognosis in hypertrophic cardiomyopathy: role of age and clinical, electrocardiographic and hemodynamic features.

Retrospective analysis of the clinical course of 254 patients with hypertrophic cardiomyopathy, followed up for 1 to 23 years (mean 6), disclosed that 58 had died, 32 of them suddenly. The 196 survivors were compared with the 32 patients who died suddenly and with the 38 who died suddenly or with heart failure. The combination of young age (14 years or less), syncope at diagnosis, severe dyspnea at last follow-up and a family history of hypertrophic cardiomyopathy and sudden death best predicted sudden death (false negative rate 30 percent, false positive rate 27 percent). A "malignant" family history was associated with poor prognosis, particularly in the younger patients; a family history of hypertrophic cardiomyopathy without sudden death was more frequent in the survivors (12 percent) than in the dead (5 percent). Patients who had a diagnosis in childhood were usually asymptomatic, had an unfavorable family history and a 5.9 percent annual mortality rate. In those aged 15 to 45 years at diagnosis, there was a 2.5 percent annual mortality rate and syncope was the only prognostic feature. Among those diagnosed between age 45 and 60 years, dyspnea and exertional chest pain were more common in the patients who died, and the annual mortality rate was 2.6 percent. Poor prognosis was better predicted by the history at the time of diagnosis and by changes in symptoms during follow-up than by an electrocardiographic or hemodynamic measurement.

Adolescent↗
PubMed1981

Arrhythmia in hypertrophic cardiomyopathy. I: Influence on prognosis.

In order to examine the association between arrhythmia and subsequent prognosis, 72-hour ambulatory electrocardiographic monitoring was performed in 86 unselected patients with hypertrophic cardiomyopathy. During monitoring 23 patients experienced at least one episode of supraventricular tachycardia and 24 had ventricular tachycardia (of whom 10 had more than three episodes). The patients were then followed for a mean of 2.6 years (range one to four). Seven patients died suddenly. Of these, five had exhibited multiform and paired ventricular extrasystoles and ventricular tachycardia. These arrhythmias were significantly associated with sudden death whereas supraventricular arrhythmias were not. The patients who died suddenly were older and had experienced more symptoms than the survivors, and three had a family history of hypertrophic cardiomyopathy and sudden death. This experience provides the basis for the assessment of treatment in patients with hypertrophic cardiomyopathy and serious ventricular arrhythmia.

Adolescent↗
PubMedDate not supplied

Assessment of chromatographic peak purity of drugs by multivariate analysis of diode-array and mass spectrometric data.

Numerous multivariate chemometric approaches have been developed for LC-UV data acquired using a diode-array detector (DAD), but these methods have not been widely exploited for LC-MS data. Principal component analysis (PCA) and subsequent axis rotation within the reduced factor space are assessed for LC-DAD and LC-MS data as approaches for estimating the number of components (i.e. the rank of the data) under a single chromatographic peak for compounds whose UV-spectra are very similar. Multivariate techniques for LC-DAD data are shown to suffer from inherent limitations of sensitivity for the minor components. The novel technique in LC-MS of plotting the rotated PCA data in two-dimensional factor space generates characteristic ion clusters, giving a visual criterion of peak purity. Single ion chromatograms produced subsequently confirm the profile of each coeluting component and give evidence of the degree of peak overlap. The application of this new chemometric technique to the detection of low levels of coeluting impurities by LC-MS is discussed as a novel approach for the validation of LC separations in pharmaceutical research and development.

Chromatography, Liquid↗