To determine the value of exercise-induced R wave changes in diagnosing coronary disease 200 patients undergoing coronary angiography were studied with 16 lead precordial exercise mapping. R wave amplitude was calculated before and immediately after exercise as the sum of R in all 16 leads, the sum of the R ...

The high sustained +Gz acceleration of aerial combat maneuvering represents a unique cardiovascular stress. Twenty-two healthy males were subjected to exhaustive simulated aerial combat maneuvers (SACM) on a centrifuge, followed by the time course of the P, QRS, and T-wave voltage changes. Marked changes in the T-wave were noted both ...

The vectorcardiographic basis of indeterminate QRS axis has not been elucidated. Accordingly, Frank lead VCGs were obtained on ten consecutive subjects with biphasic QRS complexes in the six extremity leads. The frontal plane vector in each case showed a very narrow loop inscribed in a symmetrical fashion around the E ...

Changes in ECG during and after exercise were analyzed in 17 patients with exercise-induced asthma (EIA) and in 12 control patients (asthmatic patients without exercise-induced bronchial obstruction). The changes in ECG were compared with those in peak expiratory flow (PEF) rate and in arterial PCO2, PO2 and pH. It was ...

A low-cost micro-processor combined with a standard 3-channel electrocardiographic recorder was adapted to polar coordinate conversion of Frank orthogonal lead signals and display of the resultant polarcardiogram. The processor also functions as a computer of average transients for the ECG complexes and provides automatic recorder function at specified intervals during ...

The joint function of electrocardiographic cycle duration and of the spatial magnitude of the repolarization maximum vector, recorded with the physically corrected orthogonal lead system McFee-Parungao was used for studies of the effect of mental arithmetics in man and of emotional stimulation in unrestrained macaques. This approach allowed to distinguish ...

Firemen's reaction to alarm was investigated with a pulse rate and ECG analysis. The frame of reference was the psychophysiological alarm reaction and its relation to psychosomatic diseases. ECG and pulse rate measurements were recorded continuously from 22 first-string firemen. According to an exercise stress test, the subjects were healthy, ...

The d.c. ERG and the EOG were recorded from 6 patients with vitelliruptive macular degeneration (VMD, Alvdalssjukan). All EOGs were highly pathological. The a- and b-waves of the ERG were normal. These are pathognomonic findings in VMD, which starts as a generalized disturbance of the pigment epithelium. No signs of ...

To determine the usefulness of R-wave amplitude changes during exercise testing for the diagnosis of coronary artery disease (CAD) and to understand the discrepancies that have been described in the literature regarding their value, we studied two groups of patients by means of electrocardiographic (EKG) treadmill testing and coronary arteriography. ...

The role of exercise imaging with thallium-201 in the evaluation of patients suspected of having coronary artery disease was studied in 194 patients undergoing diagnostic coronary arteriography. Ninety-eight patients had 70 percent or more narrowing of one or more coronary vessels and 96 patients had either no or insignificant coronary ...

Temporal relationships between homologous EEG channels of the two hemispheres were studied in patients whose EEGs showed bilateral synchronous spike-and-wave activity. Group A (seven patients) had generalized corticoreticular epilepsy and no sign of a localized predominant epileptogenic area. In group B (12 patients), the bilateral spike-and-wave activity was present in ...

A comparison of current exercise electrocardiographic lead systems reveals differences in the sensitivity and specificity of S-T segment shifts diagnostic of obstructive coronary artery disease. The differences are explained in part by differences in population samples, lead systems and criteria for positivity. Multiple electrocardiographic lead recording in symptomatic patients during ...

To define the optimal lead system for exercise electrocardiography, data of the whole body surface potential distribution were analyzed in 25 normal subjects and in 25 patients with coronary artery disease at rest and during exercise. All patients had a normal electrocardiogram at rest. The sensitivity of the standard chest ...

The loss of muscular tone or muscular inhibition associated with sharp waves observed during abnormal tonic posture in a patient with infantile spasms of early onset is described. The latency between the beginning of a sharp wave and the muscular inhibition varied from 30 to 700 msec, and the duration ...

The potential advantages of digital computer processing of exercise electrocardiographic data include reduction of noise, compression of data, improved precision and application of optimal criteria. Most prior approaches to such processing required equipment that was both expensive and inconvenient. With the revolution in instrumentation brought about by the development of ...

Computer-quantitated measurements of the Q-T intervals, the Q-T/Q-Tc ratio (Q-T/corrected Q-T) and the terminal T wave (apex to end of T [aT-eT] interval) were evaluated in resting and exercise electrocardiograms of 130 normal men with a mean age of 40 years. Pseudo-orthogonal, bipolar X, Y and Z axis leads were ...

A significant error may be introduced in intervals measured from the onset of the QRS if an electrocardiographic lead that does not record the earliest deflection is used. To ascertain to what extent the commonly used leads can be relied on to show the earliest QRS onset, 100 normal subjects ...

A method to measure the capability of the human shock absorber system to attenuate input dynamic loading during the gait is presented. The experiments were carried out with two groups: healthy subjects and subjects with various pathological conditions. The results of the experiments show a considerable difference in the capability ...

The mechanism for R wave amplitude changes during exercise testing is controversial. To investigate this, we recorded vectorcardiograms (VCG) during supine rest and bicycle exercise in 13 normals and 33 patients with coronary heart disease. In all normals, and in those CHD patients with an exercise-induced decrease in R wave ...

Sixteen thousand resting electrocardiograms were performed on 14000 United Kingdom professional aircrew and air traffic control officers over a two-year period; 103 asymptomatic men with minor ST segment and T wave changes at rest were assessed by exercise electrocardiography and 19 responded abnormally. Five subjects had proven coronary artery disease, ...

Exercise electrocardiography was performed in 100 asymptomatic male volunteers with a mean age of 42.6 years. The R wave and total RS amplitude and the magnitude of physiologic S-T segment depression at the J junction were quantitated for a modified bipolar CC5 lead and a vertically oriented bipolar lead (VL) ...

This study demonstrates a new method for quantitatively analyzing individual intestinal spike bursts and establishes the distribution of spike burst spread under conditions of fasting and feeding in conscious healthy dogs. The dimensions and propagation lengths of individual jejunal spike bursts were determined by studying spike burst spread within slow-wave ...

Total body surface potential distributions were recorded from 20 normal young adults, 20-35 years old, during multistage maximal exercise testing on a bicycle ergometer. Using a system for measuring total body surface potential distributions from measurements at 24 locations, high-quality potential maps were obtained during exercise without requiring wave form ...

Limited information is available documenting body surface isopotential distributions during atrial excitation and recovery. To expand the current data base, body surface isopotential maps from 40 normal subjects were examined. Data were acquired at a gain of 10,000 and isopotential distributions constructed at 2-msec intervals from the onset of the ...

Each of three adult New Zealand rabbits, 2 male and 1 female albinos, was exposed dorsally or ventrally, to 2450-MHz plane waves for 20 min under each of several field conditions: 1) to continuous waves (CW) at 5 mW/cm2; 2) to pulsed waves (PW) of 1-microsecond width that recurred 700 ...

Serial electrocardiographs (ECG) and vectorcardiographs (VCG) have been performed on 10 patients admitted to hospital in status asthmaticus on 12 separate occasions. The VCG was more efficient than the ECG in the detection of right atrial and ventricular enlargement. Both investigations were equally reliable in recording changes in frontal plane ...

Mofidied limb electrode positions are often used in studies which require the recording of rest and exercise ECGs, whereby the arm electrodes are placed at the infraclavicular fossae and the left lef electrode on the left lower abdomen. The effect of the modified limb electrode positions on electrocardiographic waveforms was ...

The influence of the phase of ventilation on the transthoracic impedance and defibrillation success was studied in 6 mongrel dogs. Ventricular fibrillation was induced by a transvenous bipolar catheter electrode. Defibrillation was attempted after 1 min of ventricular fibrillation. The initial stored energy levels were 20 watt-sec for the 1st ...

The electrocardiogram (ECG) at rest and during orthostasis and exercise in 51 healthy men 18-19 years of age without history or symptoms of heart disease, but with T wave aberrations in the ECG (group T) were compared to the normal ECGs of 112 controls of the same age. These aberrations ...

Two hundred and seventy eight absence seizures were recorded from 60 patients by an intensive monitoring device. They were divided into two subtypes, typical and atypical absences based on their ictal discharges whether the spike-wave rhythm was at 3 cps or not. These two absence seizures did not differ so ...

Forty asymptomatic male patients at low risk for cardiovascular disease completed maximal treadmill testing. Electrocardiograms from leads CC5, CM5, V5, Yh and Z were recorded across multiple pretest, exercise and recovery conditions. ECG waveforms were subsequently digitized, averaged and processed to provide Q-, R-, S- and T-wave amplitudes, ST-segment means ...

In 12 patients with symptomatic coronary heart disease and three normal persons, comprehensive analyses of the electrocardiographic changes associated with symptom-limited upright exercise are made by computer analysis of the electrocardiogram recorded using a Frank XYZ lead system. This analysis provided a display of the 12 lead ECG, vectorcardiogram, polarcardiogram, ...

The typical Geller-Seifter conflict paradigm for predicting clinical efficacy of anxiolytics is a mult VI/CRF schedule in which response rates in the CRF (conflict) portion are depressed by response-contingent electric shock. In 1-h sessions, anxiolytics raise the depressed conflict rates. Recently it was shown that replacing the single shock level ...

A technique is described for recording the precordial electrocardiographic body surface map before and after exercise. The technique provides an extra dimension to the conventional exercise electrocardiogram because a measurement can be made of the area and severity of S-T segment changes that are projected onto the front of the ...

An analysis was made of the changes in ECG in 61 random patients during status asthmaticus. It was found that a statistically significant increase occurred in the amplitude of the P wave in the inferior leads. P. pulmonale was noticed in lead II in 26%, in lead III in 18%, ...

The properties of the oscillatory potentials (OPs) of the mudpuppy electroretinogram (ERG) were studied and compared with the properties of the b-wave of the ERG and the proximal negative response (PNR). Both transretinal and intraretinal ERGs were recorded in response to full-field as well as 200 and 500 microgram spot ...

Mason and Likar reported a modified ECG lead system that largely eliminates intraexercise artifact without reportedly altering the configuration of the recorded leads. This system allows continuous monitoring of all 12 leads during and after exercise and has become the standard by which other systems are compared. We have found, ...

To determine the sensitivity and specificity of chest roentgenography and electrocardiography in the detection of pericardial effusion, echocardiography was used as the diagnostic standard. Chest roentgenograms and electrocardiograms of 124 patients, 57 of whom had pericardial effusion, were read without knowledge of the echocardiographic interpretation. The sensitivity of roentgenographic diagnosis ...

Exercise electrocardiography was performed on 170 healthy black children 7 to 14 years of age in order to determine the normal childhood electrocardiographic response to exercise. R-wave amplitude decreased from 27 +/- 8 (SD) to 22 +/- 8 mm (P less than .01) and the S-wave amplitude increased from 6.9 ...

Vasomotor waves (VMW) were observed in nine cardiac patients during cardiopulmonary bypass. The period and amplitude of the waves were described together with their consistency and other pertinent data. Effects of several pharmacologic agents on these waves were tested. These VMW are likely to be caused by spontaneous oscillation of ...

15 healthy adults (5 women, 10 men) have been exposed to each of four experimental conditions: rebreathing of air or carbon monoxide, and the smoking of two low-nicotine (0.3 mg) or medium-nicotine (1.2 mg) cigarettes. The dose of carbon monoxide selected (80 ml) had no effect on resting heart rate ...

Calculation of partial zero-order rate constants for a sequential reaction was presented following indometacine photochemical degradation according to the equation A k1 leads to B k2 leads to C k3 leads to D. When zero-order rate constants k1 not equal to k2 not equal to k3 and absorptivity coefficients a ...

A method is described for the removal of AC interference from the electrocardiogram in monitors which do not have isolated inputs. The patient's leads are connected to an isolation amplifier which provides isolation between the input and the output and has a high common mode rejection ratio. The output from ...

The results of submaximal ECG exercise test were evaluated in six leads recorded simultaneously in two groups of patients with T-wave abnormalities in one or more of Leads I, II, and V4-6. Group I included 185 patients with documented ischemic heart disease (IHD) and Group II 28 patients in whom ...

The value of simple physiological parameters as heart rate and peak expiratory flow rate, and bicycle ergometer, together with electrocardiogram is emphasized. Exercise capacity, exercise induced bronchoconstriction and/or electrocardiographic abnormalities are the conditions most important to look for. Recording tidal volume and respiratory air low might give additional information about ...

The amount of transmitter in the electric organ of Torpedo was measured with a time resolution of 1 sec in the course of stimulation. In parallel, the modifications of the electrophysiological response were analysed by determining the conductance increase (deltaG) and the electromotive force of electroplaques. Large changes in the ...

Lead levels in small mammals were studied in 6 areas -- 3 associated with highways of different traffic densities, and 3 control sites in forested areas. Lead levels were also studied in insects from 2 traffic areas and in earthworms from different distances from 2 traffic areas. Lead levels were ...

To train cardiac consultants who interpret electrocardiogram rhythm strips from the field, we designed a series of prerecorded telemetered rhythms and discussions which can be sent into telemetry consoles. The patterns represent cardiac arrhythmias (eg, ventricular tachycardia, complete heart block, etc), as well as equipment problems (loose leads, misplaced leads, ...

Electrocardiograms were recorded hourly for five days in 16 caged Macaca fascicularis by means of a miniaturized ECG transmitter connected to two chest leads. The lowest heart rates were 135 +/- 35 (mean +/- SD, n= 31) beats/min at 5 a.m., and the highest were 192 +/- 22 (n = ...

The transthoracic impedance to direct-current defibrillation discharge of the half-sinusoidal waveform was compared using recently marketed disposable defibrillator electrode pads (SAF-D-FIB and DEFIB-PADS) with electrode paste as the interfaces between the defibrillator paddle electrode and chest wall. Twenty-four mongrel dogs with an average weight of 17.3 kilograms were used. Half ...