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Biomedical subjects

M Munawar

Publications and source records attributed to M Munawar.

4 recordsLinked to original sources
PubMed1995

Atrial fibrillation after coronary artery bypass grafting is associated with sympathetic activation.

BACKGROUND: We prospectively investigated the role of sympathetic activation in the etiology of atrial fibrillation following coronary artery bypass grafting. METHODS: Continuous ambulatory monitoring was performed for 80 hours in 131 patients after coronary artery bypass grafting. Right atrial plasma norepinephrine levels were assessed preoperatively and every 4 hours for 48 hours postoperatively. RESULTS: Of the 131 patients, 50% (65) had development of atrial fibrillation and 36% (47) required treatment. Onset of atrial fibrillation was preceded by a significant increase in sinus rate and atrial ectopic activity. On multivariate logistic regression, elevated mean postoperative norepinephrine levels (5.78 +/- 2.83 versus 3.57 +/- 1.31 nmol/L; p < 0.0001), increased age (68.9 +/- 5.7 versus 63.8 +/- 8.7 years; p = 0.02), and decreased postoperative magnesium levels (0.79 +/- 0.09 versus 0.83 +/- 0.10 mmol/L; p = 0.02) were independently associated with the occurrence of atrial fibrillation. CONCLUSIONS: Elevated norepinephrine levels suggest that sympathetic activation may be important in the pathogenesis of atrial fibrillation after coronary artery bypass grafting, and this underlines the importance of beta-adrenoceptor blockade as prophylaxis.

Aged↗
PubMed1994

A mathematical model of sinus node function: validation by recording of sinus node electrograms.

We have applied a mathematical function to model sinus node recovery after atrial pacing at different cycle lengths in 13 autonomically denervated, anesthetized canines. This model provides "pure" indexes of sinoatrial conduction and of suppression of automaticity. We compared sinoatrial conduction computed from the model (SACTc) with sinoatrial conduction measured directly utilizing a catheter recording the sinus node electrogram (SACTd) to test the validity of the model. We used both the model and the sinus node electrogram to further define events after pacing. There was close agreement between SACTc and SACTd with correlation coefficients at pacing cycle lengths of 20 and 50% below resting of 0.86 (P < 0.0001) and 0.78 (P < 0.0001), respectively. We verified that the conventional sinus node recovery time is due both to suppression of automaticity and prolongation of sinoatrial conduction. Sinoatrial conduction time returned rapidly to normal over 1-3 beats, whereas automaticity recovered exponentially over 20-40 postpacing intervals. The model accurately describes postpacing phenomena and has the potential to provide a useful adjunct to the measurement of the sinus node electrogram for assessment of sinus node function in the experimental laboratory.

Animals↗
PubMed1985

Adverse reactions to a single dose of diethylcarbamazine in patients with Brugia malayi infection in Riau Province, West Indonesia.

A study on the adverse reactions, occurring after treating microfilaremic patients infected with B. malayi, revealed that all reacted to a single oral dose of DEC (5 mg/kg). The major reactions were fever, headache, anorexia, abdominal pain, muscle and joint pains, nausea and vomiting. There seemed to be no association between the time of fever onset and microfilarial density, but the number of cases observed was too small to make any firm conclusion. There was a tendency for more severe reactions to occur in patients with higher microfilaria counts. Local reactions, probably due to destruction of adult worms, were seen in 3 patients. The reactions were serious enough to necessitate the patients spending approximately 48 hours in bed.

Adolescent↗