Travis Winsor

Ambulatory electrocardiographic recorder

Cardiac rhythm abnormalities are common. Although many arrhythmias are not harmful, some can cause symptoms and be a signal for potential cardiac arrest or stroke. Thus, the detection and quantification of these arrhythmias are important, especially for patients who have structural heart disease caused by an event such as a prior heart attack. Arrhythmias are frequently limited in duration and occurrence and cannot be detected during physical examination and routine electrocardiography (ECG) because these procedures permit only a few seconds of observation. To diagnose arrhythmias and to assess their relationship to patient symptoms, or to assess the effectiveness of an intervention to suppress them, longer periods of ECG recording are required while the patient is pursuing his or her normal routine. In this paper, we review the techniques and the clinical situations in which ambulatory ECG recordings are indicated.A recording device using a portable recorder, such as a small, battery powered tape recorder, carried on the person and provided with electrodes for attachment to the body of the user, the electrodes being operable to sense cardiac activity and to provide the input signals to a program module coupled with the recorder to cause the latter to be turned on and off at predetermined times so that it operates at predetermined periods for the purpose of recording samples of the users cardiac activity sensed by the electrodes. The program module operates to amplify the input signals from the electrodes and to cause these signals to modulate a carrier wave signal suitable for recording by the tape or other recorder. The program module also is operable to demodulate the carrier wave signal when it is played back from the recorder to reproduce an accurate reproduction of the input signals from the electrodes. The demodulated signal can then be coupled to an ECG recorder and reproduced graphically, resulting in a standard ECG tracing which accurately represents what would have been obtained if the ECG recorder had been attached to the user at the time the initial recording was made. The program module also provides for a microphone input so that a user can record a verbal description of symptoms, environment and the like during the time of abnormal cardiac activity.

Venous distensibility during pregnancy

Summary 1. There is a 150 per cent increase in venous distensibility during pregnancy which returns to normal at about 8 to 12 weeks post partum. 2. Patients with varicose veins have greater venous distensibility during pregnancy than those without varicose veins. 3. Evidence is presented that steroids affect smooth muscle in veins. Other smooth muscle structures may be afiected in a like manner. 4. It is believed that increased venous distensibility is another etiological factor in the development of varicose veins. 5. It seems logical to postpone varicose vein operations until venous distensibility has returned to normal at the eighth to twelfth week post partum. We are indebted to Frederick J. Moore, M.D., Professor of Public Health, for assistance in analysis of the da ta. Equipment was donated by the D epartment of Phys iology, University of Southern Californi a, and the H eart Research Foundation, Incorporated.

Oral nitroglycerin as a prophylactic antianginal drug: clinical, physiologic, and statistical evidence of efficacy based on a three-phase experimental design.

With the use of a three-phase experimental design, the efficacy of oral nitroglycerin has been evaluated in a total of 53 patients with documented angina pectoris due to coronary artery disease. The study were a double-blind, randomized, and cross-over comparison of controlled-release nitroglycerin (2.6 mg. tablets administered three times daily) and an indistinguishable placebo. Sixteen patients recorded anginal symptoms by the diary method over a 6 month trial of randomly sequenced 1 month periods of drug or placebo. In 15 patients, ST segments were monitored with a Holter dynamic electrocardiograph for periods of 10 to 12 hours under normal life style and evaluated by matching activities during periods of drug and placebo. In 22 patients, a multistage treadmill exercise test was conducted to an endpoint of anginal pain. The three phases of the investigation were run in succession; each phase was completed before the next one was begun. Oral nitroglycerin reduced the incidence and severity of anginal attacks by 47.2 and 49.4 per cent, respectively, and decreased the number of sublingual nitroglycerin tablets used by 51.1 per cent in comparison to placebo (p less than 0.001). Eleven of 16 patients (69 per cent) decreased their need for sublingual nitroglycerin by over 50 per cent. Based on a polynomial trend analysis over a period of 8 weeks, no tolerance to the therapeutic effects of the drug was found. With DCG monitoring, drug decreased the ST segment depression from 1.76 mm. on placebo to 1.12 mm, with a significant difference of 0.64 mm. (p less than 0.001). ST segment depression was decreased more than 0.5 mm. by drug in comparison to placebo in 10 of 15 patients (66 per cent). Larger depressions of the ST segment noted with placebo at heart rates greater than 80 beats per minute were prevented by administration of the drug. During treadmill exercise, drug delayed the onset of pain by 83 seconds (64 per cent) over placebo (p less than 0.001) and decreased the duration of pain by 70 seconds (49 per cent) in comparison to placebo (p less than 0.001). Drug did not affect heart rate or systolic blood pressure at rest or after exercise, as well as rate-pressure product for production of angina following exercise (p less than 0.05). There was no side effects reported caused by the drug. The data demonstrate that oral nitroglycerin, given as controlled-release tablets, was absorbed from the gastrointestinal tract in quantities sufficient to provide statistically significant clinical improvement of angina pectoris.

Cardiovascular Adaptations to Prolonged Physical Effort

Studies of the cardiovascular system were made among 26-mile marathon runners after at least five years of physical training. Studies made with the subjects at rest showed an electrocardiogram characterized by a vertical or semivertical electrocardiographic position of the heart in the chest, bradycardia, high voltage of the QRS complexes and high T and U waves. T waves which were low with respect to the height of the R waves were not encountered. Etiologically the heart was enlarged. Immediately after running 26 miles the transverse diameter of the heart was decreased considerably.

Clinical Application of Laser Doppler Flowmetry for Measurement of Cutaneous Circulation in Health and Disease

The cutaneous laser Doppler device (LDF) was employed to determine its usefulness in differentiating the circulation of the feet in normal subjects from that in patients with arteriosclerosis obliterans. It is shown that the laser Doppler frequencies correlated well with results from venous occlusion plethysmography, which measured volume rate of flow. Thus, one can determine volume rate of flow by the simple Doppler method. There was a linear relationship between these two methods of measurements. Using the LDF method, it was determined that normal individuals have toe flows that on the average are 42% of finger flows in supine resting subjects. In peripheral vascular disease of the lower extremities, the LDF measurements showed a decreased circulation in the large toes when the patients are supine and the lower extremities flat. The results between health and disease are exaggerated by elevating the feet, at which time the diseased circulation falls to extremely low values compared with those of normal subjects. A similar decrease in skin oxygen tension in the diseased lower extremities was observed when the limbs were elevated.

The segmental plethysmograph; a description of the instrument.

1 From the Nash Cardiovascular Research Foundation and the Cardiovascular Department, Hospital of the Good Samaritan, Los Angeles, California. This work was aided in part by grants from the Los Angeles County and the Ventura County Heart Associations and from the Heart Research Foundation, Los Angeles. The purpose of the present report is to describe a versatile segmental pneumoplethysmograph of high sensitivity, capable of recording accurately the pulse volume of a segment of a limb. The segmental plethysmograph is an instrument which records volume changes of a limb in cubic centimeters. The segmental plethysmograph is to be differentiated from an oscillometer, which records pulsations of a limb or digit in arbitrary terms (units). It is also to be distinguished from a digital plethysmograph, which records volume changes of an end organ such as a finger or toe (1-6). Since the latter part of the nineteenth century various attempts have been made to record or indicate the pulsations which originate in the arteries of an extremity. The early instruments consisted of airor fluid-filled distensible bags which were applied directly over the arteries so that the pulsations from a single artery were recorded (7-14). This method gave irregular and inconstant results, was without standardization, and did not record volume changes in absolute terms. In 1905 Brodie and Russell (15) recorded the volume changes of the extremity; their equipment, however, was not suitable for making records rapidly from a segment of a limb. In 1909 Pachon (16) utilized a bag, completely surrounding the part, which recorded pulsations with each cardiac pulsation; however, this instrument had no standardization and did not record volume change in absolute terms. Barr (17) in 1927 described a recording oscillometer which was without adequate standardization. Johnson (18) in 1932 described a standardized segmental plethysmograph which required photographic development of the record. A recording oscillometer was described in 1938 by Friedman et al. (19). In 1948, Barry et al. described a pneumoplethysmokymograph which automatically compensated for temperature changes, thus giving an accurate record of volume change of a segment of the extremity (20); however, the method is not suitable for studying patients rapidly. Oshlag and Duryee in 1950 described a

Intramyocardial diversion of coronary blood flow: Effects of isoproterenol-induced subendocardial ischemia

Abstract Isoproterenol was found to have produced adverse reactions in eight of our patients. All demonstrated large negative ST segment shifts. In experimental studies in rats, the J-shift of the electrocardiogram was sensitive to low doses of isoproterenol. Combined use of a nitrate and beta-blocker completely reversed the significant negative J-shift depression induced by isoproterenol. Dog studies using platinum electrodes to measure intramyocardial oxygen tension at the epicardium and endocardium documented an intracardiac diversion of blood flow between the subendocardium and subepicardium. Isoproterenol diverted blood flow away from the subendocardium, which is very vulnerable to ischemia and decreased perfusion. This isoproterenol-induced “coronary steal” is probably due to localized hypoxia at the subendocardium. Nitroglycerin and propranolol both selectively increased subendocardial blood flow with little effect at the subepicardium. The regulation of blood flow through the coronary circulation can be explained in part by an intramyocardial diversion phenomenon.

Influence of pentaerythritol tetranitrate (peritrate) on acute and chronic coronary insufficiency.

* From the Department of Medicine, University of Southern California Medical School, and the Nash Cardiovascular Foundation, Hospital of the Good Samaritan, Los Angeles. Gratitude is expressed to Dr. B. O. Raulston for the encouragement and cooperation extended during these studies, and to Dr. A. E. Nielsen for helping to gather information. The technical assistance of Grayce S. Fleming is gratefully acknowledged. Aid was received from the Moore-White Foundation and the Mary M. Griffith Fund. † Pentaerythritol tetranitrate was supplied as Peritrate tablets (designated during investigation as CH 27) by Chilcott Laboratories, Morris Plains, New Jersey. The present study has been carried out to determine whether or not pentaerythritol tetranitratet is effective in relieving the precordial pain and other symptoms accompanying acute or chronic coronary insufficiency. Chemically, pentaerythritol tetranitrate (PETN, Penthrite, Hasethrol, Peritrate or CH 27) has the following structure.

Congenital coarctation of the abdominal aorta a theoretically reversible type of cardiac disease

Abstract The record of a patient who had congenital coarctation of the abdominal aorta, associated with anomalous origin of the right subclavian artery from the aorta, is presented. The importance of the ante-mortem diagnosis of congenital coarctation of the abdominal aorta is discussed. This condition may be classified theoretically as a surgically reversible type of congenital cardiac disease.

Clinical evaluation of perhexiline maleate.

In a crossover double‐blind study of patients with well‐documented histories of angina pectoris, perhexiline maleate, 100 mg. 4 times a day orally, significantly decreased the number of anginal attacks. The exercise heart rate was slower during perhexiline treatment than that before treatment or during placebo treatment. Occasional evidence (3 of 10 patients) of electrocardiogram improvement was noted and similar evidence (4 of 8 patients) of the exercise tolerance test was encountered. No significanct adverse effects were noted.