Biomedical subjects
T J MacConnell
Publications and source records attributed to T J MacConnell.
Is ventricular wall stress rather than left ventricular hypertrophy an important contributory factor to sudden cardiac death?
Sudden cardiac death comprises a significant proportion of cardiac mortality in Western society. Left ventricular hypertrophy has been identified by many authors as a possible risk factor for sudden cardiac death, however, left ventricular hypertrophy develops in response to external stimuli on the heart as a means of normalizing wall stress. It is possible that the fundamental abnormalities in wall stress, rather than the left ventricular hypertrophy itself, pose the increased risk of sudden death. Left ventricular hypertrophy, the consequence of raised wall stress, is easy to measure and easy to study and it is understandable why this parameter should have received more attention. Wall stress by contrast is difficult to measure, and worse, is variable throughout the ventricle so that it cannot be measured in a single quantifiable figure. As a consequence, only a limited amount of attention has been paid to wall stress as a possible trigger mechanism for cardiac arrhythmia. However, there is evidence from both basic and clinical research to suggest that raised wall stress may be a risk factor for sudden cardiac death and cardiac arrhythmia. This review discusses the evidence for and against left ventricular hypertrophy and wall stress as risk factors for sudden cardiac death, and also presents recent evidence that left ventricular hypertrophy in isolation can protect the heart against the arrhythmogenic effects of raised wall stress.
Torsades de pointes complicating treatment with terfenadine.
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Left ventricular hypertrophy.
Left ventricular hypertrophy (LVH) may be physiological or pathological. Only pathological LVH has been shown to be a risk factor for cardiovascular events. LVH may not be homogeneous. It seems to progress from muscle hypertrophy to eventual cell death and myocardial fibrosis. Potential for reversal of LVH may therefore depend on the stage at which it has been attempted. An interaction between LVH and serum potassium levels could have important therapeutic implications, particularly with regard to the use of thiazide diuretics as long-term treatment for hypertension.
Alcohol intoxication and alcoholism in acute male medical admissions.
In order to assess alcohol related morbidity in male hospital patients we studied all acute male admissions over a period of three months. 9.3% of patients were found to have detectable alcohol on admission (level greater than 4 mmol/l). A total of 28.3% of admissions were judged to be alcoholic by questionnaire (Michigan Alcohol Screening Test). These results suggest that acute intoxication in male hospital admissions is not as common as previously recorded. The prevalence of alcoholism, however, was disturbingly high and has significant implications for in-patient management.