Stephen F. Schaal
Ohio State University
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Featured researches published by Stephen F. Schaal.
Neurology | 1980
Robert W. Clark; Harisios Boudoulas; Stephen F. Schaal; Helmut S. Schmidt
Symptoms suggesting autonomic instability and increased adrenergic effect were identified in 53 patients with primary disorders of impaired wakefulness. Urine and plasma catecholamine concentrations were significantly increased in patients with sleep apnea. Excessive increases in heart rate during isoproterenol infusions suggested adrenergic hyperresponsiveness as an alternative explanation for symptoms of catecholamine excess in some individuals. Twenty-two patients demonstrated mitral valve prolapse (MVP), implicating primary neurologic disturbances as potential factors in the fatigue and lassitude often associated with MVP. The catecholamine abnormalities may explain some of the difficulties frequently encountered in using stimulants to treat sleep disorders.
Neurology | 1979
Robert W. Clark; Helmut S. Schmidt; Stephen F. Schaal; Harisios Boudoulas; David E. Schuller
Fourteen patients with an average of more than 60 episodes of upper airway obstruction during night sleep were treated with a nonsedating tricyclic antidepressant, protriptyline. Frequency and duration of recorded apneas decreased in 11 cases, and satisfactory control of sleep apnea was maintained with medical therapy alone in 8 of these 11 patients for 7 to 15 months. Potential adverse effects of protriptyline, particularly on the cardiovascular system, limit its use in this illness. These results indicate the possibility of pharmacologic reversal of sleep-induced incoordination of the upper airway.
Journal of Electrocardiology | 1979
Harisios Boudoulas; Stephen F. Schaal; Richard P. Lewis; John L. Robinson; Richard S. Goodwin
Twenty-four hour outpatient monitoring was compared with maximum multi-stage Treadmill exercise testing for the detection of dysrhythmias producing syncope or near syncope in 119 patients. All patients had cardiovascular disorders; only 21% had coronary artery disease. Patients with obvious cause of syncope and/or significant dysrhythmias by resting electrocardiograms (ECGs) were excluded. A significant dysrhythmia was found which was considered the probable cause of syncope or pre-syncope in 76 patients (64%). A non-cardiac cause was found in tachycardia, exercise testing identified only patients with complex ventricular dysrhythmias and missed 64% of these. Overall, dysrhythmias were found by ambulatory monitoring alone in 63 patients, by exercise testing alone in only three, and by both in 10. It is concluded that: 1) in the majority of patients with syncope or pre-syncope suspected to be of a cardiac origin, a dysrhythmia can be found; 2) ambulatory monitoring is far superior to exercise testing for detection of dysrhythmias; 3) exercise testing increases the yield for complex ventricular dysrhythmias.
The New England Journal of Medicine | 1979
Arnold J. Greenspon; John M. Stang; Richard P. Lewis; Stephen F. Schaal
CARDIAC conduction abnormalities and dysrhythmias often occur in the presence of cardiomyopathy and a history of excessive alcohol consumption. Using the repetitive ventricular response, we provoke...
Circulation | 1973
Toby R. Engel; Stephen F. Schaal
The effect of digitalis in patients with sinoatrial node dysfunction was studied. Atrial pacing studies were performed while His bundle electrograms were recorded in fourteen patients with sinus bradyeardia, syncope, or related symptoms. Measurements were repeated after 0.01 mg/kg ouabain, followed in some by 1 mg atropine. Ouabain produced a significant shortening of sinoatrial recovery time, but no significant change in heart rate. Atropine normalized sinoatrial recovery times in most patients. This study demonstrates that digitalis causes an increase in automaticity in the sick sinus syndrome as reflected by a shortened sinoatrial recovery time. The efficacy of contemplated therapeutic agents in sick sinus syndrome can be evaluated by rapid atrial pacing. When clinically indicated, digitalis may be used for congestive heart failure or tachyarrhythmias in the sick sinus syndrome in the absence of significant A-V conduction disease.
Ophthalmology | 1984
Richard G. Orlando; Matthew E. Dangel; Stephen F. Schaal
Eighteen patients receiving the cardiac drug amiodarone were followed prospectively for the development of amiodarone keratopathy. Seventeen of 18 patients (94%) developed characteristic epithelial keratopathy in at least one eye within three months of the initiation of therapy. The pattern of the epithelial deposits was noted to undergo progressive changes in configuration as a function of the duration of amiodarone therapy. These evolving changes are well defined and allow development of a grading system for amiodarone keratopathy. A grading system as well as a proposed mechanism for evolving pattern of the keratopathy are presented.
American Journal of Cardiology | 1979
Carl V. Leier; Gregory M. Jewell; Raymond D. Magorien; Richard A. Wepsic; Stephen F. Schaal
Left atrial electrograms were recorded simultaneously from sites located in the coronary sinus, right pulmonary artery and esophagus in order to determine and correlate the interatrial conduction times obtained from these locations. Ten patients with normal-sized atria and 16 patients with isolated left atrial enlargement were studied. A high correlation existed between the P wave duration and the interatrial conduction times obtained from the coronary sinus and pulmonary artery; good correlations were also found for the interatrial conduction times recorded from the pulmonary artery and esophagus correlated well with those recorded from the distal coronary sinus (the generally accepted standard for the indirect interatrial conduction time measurements). In addition to providing information on the mechanism of atrial arrhythmias, the electrograms obtained from the various indirect left atrial recording sites provide satisfactory quantification of interatrial conduction.
International Journal of Cardiology | 1990
Harisios Boudoulas; Stephen F. Schaal; John M. Stang; Mary E. Fontana; Albert J. Kolibash; Charles F. Wooley
Cardiac arrest has been reported in patients with mitral valve prolapse; however, clinical characteristics and survival information are limited since most of the cases reported include autopsy data. Nine patients (2 male, 7 female) with mitral valve prolapse were identified who had cardiac arrest; ventricular fibrillation was documented in 8 patients; resuscitation was unsuccessful in 2. Eight had a history of palpitations (months to 15 years duration) and ventricular arrhythmias, 3 had a history (5-15 years) of recurrent syncope, and 1 was totally asymptomatic. Cardiac catheterization-angiographic studies in 8 patients demonstrated normal coronary artery anatomy and mitral valve prolapse. All 9 patients had auscultatory and echocardiographic evidence of mitral valve prolapse. Seven survivors (6 still alive) were followed from 3 to 14 years after cardiac arrest. A subset of patients with mitral valve prolapse and cardiac arrest is described in whom past medical history is compatible with cardiac arrhythmias or syncope, and whose long-term prognosis appears better than patients with other causes of cardiac arrest.
American Journal of Cardiology | 1977
Richard P. Lewis; David Marsh; Joel A. Sherman; Wilbur F. Forester; Stephen F. Schaal
To improve both the sensitivity and specificity of the multistage treadmill test, postexercise systolic time intervals were prospectively studied in 73 patients with angina-like chest pain and normal resting ST-T segments. The decision to perform coronary angiography was made independent of the exercise test. Twenty-three patients had normal coronary arteries and 50 had more than 50 percent reduction of luminal diameter of one or more major coronary arteries. The systolic time intervals were measured before and 2,4,6,8 and 10 minutes after exercise. Of all the systolic time intervals, the 4 minute postexercise left ventricular ejection time proved most discriminating between normal subjects and those with coronary artery disease. The deviations of this interval from the normal regression with heart rate both before and after exercise were used to calculate the net delta left ventricular ejection time after exercise. A net increase of more than 31 msec represented 2 standard deviations above normal. Twenty-three (46 percent) of the patients with coronary artery disease had an abnormal net delta ejection time after exercise. Twenty-five (50 percent) had a positive electrocardiographic response with a 9 percent false positive rate. Thirteen (26 percent) had only a positive postexercise net delta ejection time so that a total of 76 percent of patients with coronary artery disease were identified. Thus, measurement of the postexercise net delta ejection time a simple and useful adjunct to multistage treadmill testing.
Annals of Internal Medicine | 1974
Toby R. Engel; Charles A. Bush; Stephen F. Schaal
Abstract A woman with chronic sinoatrial tachycardia developed ventricular dysfunction 9 years after the onset of the tachycardia. Her history suggests that the myocardial contractile alterations m...