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Biomedical subjects

J B Lawrenson

Publications and source records attributed to J B Lawrenson.

7 recordsLinked to original sources
PubMed2006

Why are some South African children with Down syndrome not being offered cardiac surgery?

About 1 in 1,000 children has Down syndrome. Extra chromosomal material results in a myriad of potential problems for the affected individual. About 40% of Down syndrome children will have cardiac abnormalities, ranging from the simple arterial duct to the complex atrioventricular septal defect. Virtually all these defects are amenable to surgical correction and extended survival is possible. In South Africa many of these children do not undergo cardiac surgery.

Cardiac Surgical Procedures↗
PubMed2006

Is cardiac surgery warranted in children with Down syndrome? A case-controlled review.

OBJECTIVES: To compare children with Down syndrome and children without Down syndrome and investigate whether there is a significant difference in the burden that is placed on the health care system between these two groups only in respect of the repair of congenital heart disease at Red Cross War Memorial Children's Hospital, Cape Town, South Africa. DESIGN: This study is a retrospective case control review. SETTING: Red Cross War Memorial Children's Hospital, Cape Town, South Africa. SUBJECTS: The sample group of 50 Down syndrome children who had received cardiac surgery between January 1998 and June 2003 was compared with a control group of 50 nonsyndromic children who had received cardiac surgery during the same period. OUTCOME MEASURES: Sex and diagnoses (cardiac and noncardiac), number of days spent in hospital and in ICU, complication rates, re-operation rates, early mortality rates, planned further cardiac surgery. Costs of these outcomes were not quantified in exact monetary terms. RESULTS: There was no significant difference between the two groups in terms of the burden that was placed on the health care system. Similar complication rates, re-operation rates and early mortality rates were recorded for both groups. The Down syndrome group appeared to benefit more from cardiac surgery than the non-Down syndrome group. CONCLUSION: Denying cardiac surgery to children with Down syndrome does not improve the efficiency of resource allocation. It is therefore not reasonable to suggest that the problem of scarce resources can be ameliorated by discriminating against children with Down syndrome.

Cardiac Surgical Procedures↗
PubMed1995

Cardiovascular collapse due to intravenous verapamil in two patients with persistent atrial tachycardia.

Intravenous verapamil was given to two haemodynamically stable patients with persistent atrial tachycardia, resulting in circulatory arrest requiring CPR in one and collapse with unrecordable blood pressure in the other. Both responded to resuscitation and tachycardia was subsequently controlled with propranolol in one and sotalol in the other. Factors contributing to the cardiovascular collapse included: (i) left ventricular dysfunction; and (ii) failure to convert the tachycardia to sinus rhythm. It was concluded that verapamil may be dangerous in supraventricular tachycardia not due to atrioventricular (AV) junctional re-entry, despite normal blood pressure and perfusion, particularly if left ventricular dysfunction were present. If the diagnosis of AV junctional re-entry is in doubt, adenosine is preferable as it is less likely to cause haemodynamic collapse and will assist in making the diagnosis.

Adult↗
PubMed1993

Normal left ventricular function does not protect against propafenone-induced incessant ventricular tachycardia.

Propafenone is a class Ic anti-arrhythmic agent with mild beta-blocking properties which has recently become available in South Africa. We have used the drug in 3 patients with sustained monomorphic ventricular tachycardia not due to ischaemic heart disease. All had normal left ventricular function; 1 had Wegener's granulomatosis and 2 had arrhythmogenic right ventricular dysplasia. In the latter 2, propafenone provoked incessant monomorphic ventricular tachycardia which persisted for more than 24 hours despite repeated efforts at termination. The morphology was similar to the patients' spontaneous ventricular tachycardia, but the rate was slower and the QRS complexes broader, consistent with propafenone's marked ability to slow intraventricular conduction. It is postulated that incessant tachycardia results from perpetuation of re-entry due to marked conduction slowing produced by the drug. Previous reports have suggested that this is most likely to occur in patients with poor left ventricular function, but our experience indicates that those with normal left ventricular function are also at risk, particularly if the substrate for re-entry is present. Propafenone, like all other powerful anti-arrhythmic agents, may provoke life-threatening arrhythmias and should be used with great caution after due consideration of the indications, even in patients with normal left ventricular function.

Adult↗
PubMed1988

Fatal infection caused by a multiply resistant type 3 pneumococcus.

The most virulent pneumococcal serotype (type 3) has not to date been associated with multiple antimicrobial resistance. We report an unusual gastrointestinal presentation of fatal septicemia caused by a multiply resistant type 3 pneumococcus in a setting of increasing prevalence of multiple resistance, including resistance to erythromycin, clindamycin, and tetracycline.

Adolescent↗
PubMedDate not supplied

The 22q11.2 deletion: from diversity to a single gene theory.

The 22q11 deletion syndromes are a group of conditions in which a characteristic spectrum of congenital cardiac defects may be associated with a wide range of noncardiological congenital anomalies. These syndromes are all linked by a deletion in the long arm of chromosome 22. Although it is a large deletion, containing many genes, recent advances have led to the belief that the etiology of the diverse abnormalities of these syndromes may be a single gene deletion. This review outlines the historical development of the various "22q deletion syndromes," including the DiGeorge, velocardiofacial, Takao, Cayler, and CATCH-22 syndromes, briefly describes the relevant cardiac embryogenesis, and then explains how a single gene deletion may encompass the full phenotypic spectrum.

Abnormalities, Multiple↗