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Biomedical subjects

C J McLaran

Publications and source records attributed to C J McLaran.

6 recordsLinked to original sources
PubMed1987

Double-blind study of intravenous propafenone for paroxysmal supraventricular reentrant tachycardia.

Propafenone was administered during electrophysiologic testing to determine its efficacy and safety for terminating and preventing reinduction of paroxysmal supraventricular reentrant tachycardia. Four men and 10 women (mean age 50 years, range 28 to 69) were studied. Five patients had Wolff-Parkinson-White syndrome with orthodromic atrioventricular (AV) reentrant tachycardia, three had a concealed accessory pathway with AV reentrant tachycardia and six had tachycardia due to reentry within the AV node. In the five patients with Wolff-Parkinson-White syndrome, propafenone terminated reentrant tachycardia in three (the tachycardia was reinducible in one) and had no effect in two. In the three patients with a concealed accessory pathway, propafenone terminated reentrant tachycardia in all three and prevented reinduction of the tachycardia in two. In the six patients with tachycardia due to reentry within the AV node, propafenone terminated and prevented reinduction of reentrant tachycardia. Propafenone had no effect on blood pressure, heart rate, PA interval, AV node refractoriness or rate of reentrant tachycardia. Propafenone significantly (p less than 0.05) prolonged the AH, HV, QRS and ventriculoatrial intervals and decreased the AV node Wenckebach rate. Of the nine patients receiving long-term oral propafenone therapy, eight had a reduction of at least 90% in reentrant tachycardia during a mean follow-up period of 14.5 months (range 11 to 22); all eight patients had had noninducible reentrant tachycardia after intravenous propafenone. One patient had increased frequency of reentrant tachycardia; this patient had had inducible reentrant tachycardia after intravenous propafenone. In conclusion, intravenously administered propafenone terminated reentrant tachycardia in 85% of patients and prevented reinduction in 71%, with no adverse hemodynamic effects.

Adult↗
PubMed1987

Out-of-hospital cardiac arrest in patients without clinically significant coronary artery disease: comparison of clinical, electrophysiological, and survival characteristics with those in similar patients who have clinically significant coronary artery disease.

Fifty nine survivors of out-of-hospital cardiac arrest unassociated with an acute myocardial infarction were referred for intracardiac electrophysiological study. Thirty patients who had no clinically significant coronary artery disease (group 1) were compared with 29 who did (group 2). Ventricular tachycardia or fibrillation was induced in significantly more patients in group 2 than in group 1 (69% vs 40%). Median duration of follow up, which was achieved in all patients, was 31 months in group 1 and 14 months in group 2. In group 1, an effective treatment was identified electrophysiologically in seven patients, and none died; an arrhythmia was induced, but no effective treatment was identified in five patients, and one patient died subsequently; an arrhythmia was not induced in 18 patients, 15 of whom were treated empirically with anti-arrhythmic drugs, and one died. In group 2, effective treatment was identified electrophysiologically in seven patients and three died (two of pump failure) during follow up. In 13 an arrhythmia was induced but no effective drug was identified, and six died or had a recurrence; in another nine patients without inducible arrhythmias, six subsequently died or had a recurrence. A Cox proportional hazards analysis identified previous myocardial infarction as the only predictor of recurrence. Patients without coronary artery disease who suffer an out-of-hospital cardiac arrest have a low inducibility rate at electrophysiological study and an excellent prognosis compared with patients who have coronary artery disease. Electrophysiological testing seemed to be of value in predicting the response to antiarrhythmic drugs, but non-inducibility of arrhythmias in patients with coronary artery disease was of no predictive value.

Adolescent↗
PubMed1986

Increased vagal tone as an isolated finding in patients undergoing electrophysiological testing for recurrent syncope: response to long term anticholinergic agents.

Features suggestive of an isolated increase in vagal tone during electrophysiological study were found in 12 patients with recurrent near syncope or syncope. Results at neurological and cardiac evaluation were otherwise normal. The increased tone or heightened sensitivity to vagal tone was manifested by abnormal atrioventricular nodal refractoriness and conduction that were reversed with atropine. The patients underwent long term treatment with an anticholinergic agent (propantheline bromide) and 75% improved. Before treatment they had experienced a median of seven episodes (range 3-28) of near syncope or syncope during 10.5 months (range 1-60). During treatment these episodes decreased to a median of one (range 0-15) during 22.5 months (range 3-67); six patients experienced no further symptoms. Three patients continued to have syncope while on treatment, and one of these required permanent cardiac pacing. No additional cause for syncope was identified in any patient. During electrophysiological assessment of patients with syncope, evidence may be obtained pointing to an increase in vagal tone. In many of these patients treatment with anticholinergic drugs seemed to improve or eliminate the symptoms.

Adolescent↗
PubMed1985

Tachycardia induced myocardial dysfunction. A reversible phenomenon?

Four patients with myocardial dysfunction related to tachycardia underwent electrophysiological studies, which showed a re-entrant supraventricular tachycardia using an accessory atrioventricular connexion. Serial assessment of left ventricular function by echocardiography before and after control of the tachycardia indicated a variable degree of reversibility. Endomyocardial biopsy in two patients detected non-specific histological changes. Because of the possible role of ischaemia in this condition effective control of prolonged tachycardia is needed to prevent deterioration of myocardial function.

Adolescent↗
PubMed1979

Severe hyperkalaemia with Moduretic.

Three patients with impaired renal function suffered complications of hyperkalaemia within 10 days of beginning therapy with hydrochlorothiazide and amiloride combination (Moduretic). The possible relationship between hyperkalaemia and this diuretic is discussed.

Aged↗