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Biomedical subjects

R W Henthorn

Publications and source records attributed to R W Henthorn.

43 records · Page 3Linked to original sources
PubMed1983

Torsade de pointes: the long-short initiating sequence and other clinical features: observations in 32 patients.

The clinical setting, precipitating factors, electrocardiographic features and response to treatment of 32 patients with torsade de pointes were reviewed. Thirty-one patients had underlying cardiac disease and 30 patients had a previous underlying cardiac arrhythmia. Antiarrhythmic medications, often in association with electrolyte abnormalities (such as hypokalemia and hypomagnesemia) were the most common precipitating factors. In 22 of 26 patients, the serum drug levels of the antiarrhythmic agents were found to be within the therapeutic range. However, before the administration of agents known to prolong the QT interval, 20 of the 32 patients had, either alone or in combination, baseline prolongation of the QT interval, hypokalemia or hypomagnesemia. All patients had QTc interval prolongation (mean 0.59 second) immediately before the development of torsade de pointes. Marked lability of T wave morphology was frequently noted. Cardiac pacing was the only consistently effective mode of therapy. A characteristic long-short ventricular cycle length as the initiating sequence was found in 41 of 44 episodes of torsade de pointes. Reported data support the high frequency of this electrocardiographic feature of torsade de pointes in which its onset could be analyzed. It is suggested that this electrocardiographic characteristic will aid in both establishing the diagnosis of torsade de pointes and distinguishing it from other polymorphic forms of ventricular tachycardia.

Adult↗
PubMed1983

Value of early postoperative epicardial programmed ventricular stimulation studies after surgery for ventricular tachyarrhythmias.

The value of early postoperative epicardial programmed ventricular stimulation studies after electrophysiologically-directed surgery for ventricular tachyarrhythmia was assessed in 34 patients who underwent epicardial stimulation within 7 to 30 days (mean 9.8) of surgery and were followed up for at least 6 months. The antiarrhythmic operation performed was an endocardial ventriculotomy (full encircling or limited), an endocardial resection, a wall resection or a combination of these procedures. All these interventions were directed by intraoperative mapping during sinus rhythm. Temporary epicardial wire electrodes left at the time of surgery rather than endocardial catheter electrodes were used to perform the pacing. The stimulation protocol included the introduction of up to three ventricular extrastimuli and incremental burst ventricular pacing performed at twice diastolic threshold (9.2 +/- 5.8 mA for the right ventricle and 6.0 +/- 3.5 mA for the left ventricle). A study was considered positive when ventricular tachycardia, defined as 10 or more consecutive ventricular beats, was induced by any pacing modality. Nineteen patients (Group I) had a negative study: after stimulation of both ventricles in 15 patients and of the left ventricle only in 4. Fifteen patients (Group II) had a positive study: after stimulation of the right ventricle in nine patients and of the left ventricle in six. The two groups were comparable with respect to preoperative clinical status, surgical procedures performed and postoperative ejection fraction. No arrhythmic events were observed in Group I during a mean follow-up period of 19.5 months (range 4 to 37), whereas seven arrhythmic events (47% incidence) occurred (p = 0.0008) in Group II during a mean follow-up period of 17.7 months (range 5 to 39).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Verapamil therapy in the treatment of supraventricular arrhythmias following open heart surgery.

Certain general conclusions suggest themselves on the basis of our extensive experience with treating arrhythmias in patients following open heart surgery, our specific results with verapamil therapy in the treatment of atrial fibrillation and atrial flutter in patients following open heart surgery, and the results of verapamil therapy administered in other groups of patients. First, verapamil can provide highly effective, rapid, and safe control of the ventricular response in the treatment of atrial fibrillation and atrial flutter in patients following open heart surgery. Usually, it should be used in concert with digitalis therapy. Second, extrapolation from the data of others suggests that verapamil has an important role to play in the treatment of most other supraventricular arrhythmias in patients following open heart surgery, particularly if temporary wire electrodes are not available.

Arrhythmias, Cardiac↗