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Biomedical subjects

S F Schaal

Publications and source records attributed to S F Schaal.

At least 55 records · Page 3Linked to original sources
PubMed1980

Biatrial electrograms during coarse atrial fibrillation and flutter-fibrillation.

Right and left atrial electrograms were recorded in 57 patients who demonstrated coarse atrial fibrillation or flutter-fibrillation on the scalar electrocardiogram. Atrial electrograms in coarse atrial fibrillation most often showed biatrial fibrillation with periodic slowing and regularity, while dissimilar interatrial or right intra-atrial rhythms were noted less frequently. Flutter-fibrillation on the scalar ECG required the presence of rapid regular tachysystole (flutter) somewhere in the atria and was usually associated with dissimilar interatrial or right intra-atrial rhythms, dissimilar atrial flutter rates, or fast or fragmented flutter. Coarse atrial fibrillation and flutter-fibrillation may be secondary to a variety of atrial electrical events.

Adult↗
PubMed1980

Use of chest wall stimulation to localize and treat pacemaker sensing failure.

A case of pacemaker malfunction in a permanently implanted demand transvenous pacemaker is presented. Complete "failure to sense," resulting in considerable hemodynamic embarrassment, was treated by chest wall stimulation using an external pacemaker and two superficial chest leads applied over the permanent pacemaker generator-lead junction. The technique of this procedure and its usefulness in the localization and temporary therapy of pacemaker sensing failure are discussed.

Cardiac Pacing, Artificial↗
PubMed1980

Triple AV nodal pathways in man?

A 41 year old woman underwent electrophysiological studies for the evaluation of paroxysmal supraventricular tachycardia. AV nodal conduction time and refractory period plots (atrial extra-stimulus technique) suggested the presence of triple AV nodal pathways.

Adult↗
PubMed1980

AV node dysfunction in the mitral valve prolapse syndrome.

The mitral valve prolapse syndrome is associated with a variety of atrial and ventricular arrhythmias. A portion of these patients manifest bradyarrhythmias, which in turn, may be the cause of lightheadedness and syncope. Thie study details the clinical and electrophysiologic characteristics of seven patients with symptomatic mitral valve prolapse and AV node dysfunction. The electrophysiology study demonstrated either a prolonged AH interval or abnormal response to atrial pacing in six of seven patients. A significant proportion of these patients had abnormalities of sinus node function and distal His-Purkinje conduction in addition to AV node dysfunction. AV node dysfunction in symptomatic patients with mitral valve prolapse may be secondary to autonomic dysfunction of diffuse conduction system disease.

Adolescent↗
PubMed1980

Adrenergic hyperactivity and cardiac abnormality in primary disorders of sleep.

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.

Adult↗
PubMed1979

Temporary atrial standstill.

Temporary atrial standstill is a relatively rare event requiring intraatrial electrogram recordings for its documentation. Previous reports have emphasized its relationship to drug intoxication, infarction, the immediate post open-heart surgery period, or the premorbid state; significant impairment of atrial excitability is usual. The occurrence of atrial standstill in the presence of intact atrial excitability suggests "electrical isolation" of the atria. The three patients we describe manifested temporary atrial standstill while maintaining atrial excitability. Diffuse conduction system disease and drug effects played a contributory role.

Adult↗
PubMed1979

Interatrial conduction (activation) times.

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.

Electrocardiography↗
PubMed1979

Electrophysiologic studies of perphenazine and protriptyline in a patient with psychotropic drug-induced ventricular fibrillation.

A 51 year old woman sustained ventricular fibrillation while receiving perphenazine and protriptyline. After successful resuscitation and clinical stabilization, cardiac electrophysiologic studies were performed before and after the administration of each of these medications. Perphenazine widened the ventricular echo zone and facilitated induction of short salvoes of ventricular tachycardia (repetitive ventricular response). Protriptyline also widened the ventricular echo zone and allowed easy induction of long runs of ventricular tachycardia. Both psychotropic agents increased the incidence of ventricular dysrhythmias in this patient. The electrophysiologic study is a useful technique in determining the interaction between psychotropic drugs and life-threatening arrhythmias; it may provide a means of identifying the patients with cardiac disease in whom administration of these agents may be fatal.

Major Depressive Disorder↗
PubMed1979

Superiority of 24-hour outpatient monitoring over multi-stage exercise testing for the evaluation of syncope.

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.

Adolescent↗
PubMed1979

Sleep apnea: treatment with protriptyline.

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.

Adult↗
PubMed1979

Malignant premature ventricular beats in ambulatory patients.

The characteristics of premature ventricular beats predisposing to ventricular tachycardia or fibrillation were assessed by 24-h ambulatory monitoring and maximal treadmill exercise testing in 339 cardiac patients with premature ventricular beats. Premature ventricular beats were divided into early (Q-premature ventricular beat less than QT), late (within the last 20% of the cardiac cycle), and midcycle. Ventricular tachycardia was recorded in 45 patients and ventricular fibrillation, in three. The frequency of ventricular tachycardia or fibrillation was 32% in patients with late, 16% in patients with early, and 7% in patients with midcycle premature ventricular beats (P less than 0.05). Patients with frequent (less than 10/min) multiformed premature ventricular beats had a frequency of ventricular tachycardia or fibrillation of 44%, while only 13% of patients with frequent uniformed premature ventricular beats had ventricular tachycardia (P less than 0.05). Ambulatory patients with ventricular tachycardia or fibrillation have frequent multiformed premature ventricular beats, and the ventricular tachycardia or fibrillation is usually triggered by late premature ventricular beats.

Adult↗
PubMed1978

Prolonged atrial conduction. A major predisposing factor for the development of atrial flutter.

Electrophysiological studies were performed during sinus rhythm on 21 patients who had demonstrated the spontaneous occurrence of sustained atrial flutter. The purpose was to determine if atrial conduction disease is a prediposing factor for the development of atrial flutter. Patients with atrial enlargement were excluded from the series. The control group consisted of 11 age-matched patients with normal electrocardiograms and electrophysiology studies. The flutter group showed prolongation of the mean right intra-atrial conduction time at 50 msec (control of 37 msec, P less than 0.05), the mean interatrial conduction time at 92 msec (control of 44 msec, P less than 0.001) and the mean P wave duration at 132 msec (control of 112 msec, P less than 0.01). The flutter group also demonstrated a higher incidence of sinus node dysfunction and ventricular conduction disease compared to the control group. These data indicate that patients who develop atrial flutter have atrial conduction disease. Atrial conduction disease appears to be 1) a major prediposing factor for the development of atrial flutter and 2) a part of the fibro-degenerative conduction disease spectrum.

Arrhythmia, Sinus↗
PubMed1977

Enhanced diagnostic power of exercise testing for myocardial ischemia by addition of postexercise left ventricular ejection time.

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.

Adult↗
PubMed1977

Dissimilar atrial rhythms. A patient with interatrial block.

A patient with type A Wolff-Parkinson-White syndrome and prolonged interatrial conduction intervals developed atrial flutter during the course of an electrophysiological study. The atrial flutter blocked along the left-to-right conduction pathways in a Wenckebach pattern. The dissimilar atrial rhythms of right atrial tachycardia and left atrial flutter evolved as the interatrial block increased to 2:1 conduction.

Aged↗