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Purpose: Although radiotherapy (RT) is an important component of cancer treatment, it induces adverse tissue reactions in the around of cancer tissue. Therefore, radioprotectives are needed to protect normal tissues. The aim of this study was to investigate the radioprotective effect of N-acetylcysteine (NAC) on RT-induced cardiac damage in rats for the acute term. Materials and methods: The animals were divided into four groups. The rats in control group were injected with saline for 7 d; the rats in NAC group were injected NAC at dose of 240 mg/kg d for 7 d; the rats in RT group were injected with saline for 7 d plus was irradiated 1 h after the last injection and the rats in NAC + RT group were injected with NAC for 7 d and irradiated 1 h after the last NAC dose. The electrocardiogram was recorded and evaluated PR interval, QRS duration, QT interval, T wave alterations and heart rate. Serum interleukin-4, interleukin-6, tumor necrosis factor-alpha, interleukin 1 beta, galectin-3 levels and creatine kinase and creatine kinase isoenzyme-MB activities were determined in all groups. Also, tissue malondialdehyde (MDA) and nitric oxide levels, superoxide dismutase, catalase and glutathione peroxidase activities were determined. In addition, histological changes of heart were evaluated. All measurements were performed 24 h after RT. Results: In the RT group, findings supporting cardiac injury were observed in the electrocardiogram. Also, cytokine levels and oxidative stress were significantly increased. Pretreatment of rats with NAC ameliorated cardiac injury induced by RT. Conclusions: Our findings suggested that NAC may be a potential radioprotector which is capable of preventing cardiac damage.

Background: Recently, more consideration is being given to the beneficial effects of lighting on the maintenance and promotion of the health and well-being of office occupants in built environments. A new lighting technology using Rayleigh scattering has made it possible to simulate a blue sky. However, to date, no studies have examined the possible beneficial effects of such artificial skylights. The aims of this study were to examine the non-visual effects of artificial skylights and conventional fluorescent lights in a simulated office environment and to clarify the feature effects of the artificial skylights., Methods: Participants were 10 healthy male adults. Non-visual effects were evaluated based on brain arousal levels (α-wave ratio and contingent negative variation [CNV]), autonomic nervous activity (heart rate variability [HRV]), work performance, and subjective responses during daytime exposure to either an artificial skylight or fluorescent lights, as well as nocturnal melatonin secretion., Results: Subjective evaluations of both room lighting-related "natural" and "attractive" items and the "connected to nature" item were significantly higher with the skylight than with the fluorescent lights. Cortical arousal levels obtained from the early component of the CNV amplitude were significantly lower with the skylight than with the fluorescent lights, whereas α-wave ratio and work performance were similar between the two light sources. The HRV evaluation showed that sympathetic nerve tone was lower and parasympathetic nerve tone was higher, both significantly, for the skylight than for the fluorescent lights during daytime. Nocturnal melatonin secretion was significantly greater before and during light exposure at night under the daytime skylight than under the fluorescent lights., Conclusions: Our results suggest that artificial skylights have some advantages over conventional fluorescent lights in maintaining ordinary work performance during daytime with less psychological and physiological stress. The findings also suggest that the artificial skylights would enable built environments to maintain long-term comfort and productivity.

Background: Early electrocardiogram (ECG) changes after breast cancer radiotherapy (RT) have been reported, but their characteristics and associated factors are largely unknown. This study aimed to explore early RT-induced ECG changes and to compare them with echocardiography changes., Materials and Methods: Sixty eligible patients with chemotherapy-naïve left-sided and 20 with right-sided breast cancer were evaluated with echocardiography, blood samples and ECG before and after RT., Results: RT-induced ECG changes in the anterior leads. T-Wave changes were most frequent. T-Wave decline was associated independently with patient age (β=-0.245, p=0.005), mean heart radiation dose (β=1.252, p=0.001) and global systolic strain rate change (β=7.943, p=0.002). T-Wave inversion was associated independently with mean heart radiation dose (β=0.143, p<0.001), global longitudinal strain change (β=0.053, p=0.017) and posterior calibrated integrated backscatter (β=-0.022, p=0.049)., Conclusion: RT-induced ECG changes were prevalent and associated with functional and structural changes in echocardiography. ECG could be used for post-RT cardiac screening., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Purpose: The heart receives high radiation doses during radiation therapy of advanced-stage lung cancer. We have explored associations between overall survival, cardiac radiation doses, and electrocardiographic (ECG) changes in patients treated in IDEAL-CRT, a trial of isotoxically escalated concurrent chemoradiation delivering tumor doses of 63 to 73 Gy., Methods and Materials: Dosimetric and survival data were analyzed for 78 patients. The whole heart, pericardium, AV node, and walls of left and right atria (LA/RA-Wall) and ventricles (LV/RV-Wall) were outlined on radiation therapy planning scans, and differential dose-volume histograms (dDVHs) were calculated. For each structure, dDVHs were approximated using the average dDVH and the 10 highest-ranked structure-specific principal components (PCs). ECGs at baseline and 6 months after radiation therapy were analyzed for 53 patients, dichotomizing patients according to presence or absence of "any ECG change" (conduction or ischemic/pericarditis-like change). All-cause death rate (DR) was analyzed from the start of treatment using Cox regression., Results: 38% of patients had ECG changes at 6 months. On univariable analysis, higher scores for LA-Wall-PC6, Heart-PC6, "any ECG change," and larger planning target volume (PTV) were significantly associated with higher DR (P=.003, .009, .029, and .037, respectively). Heart-PC6 and LA-Wall-PC6 represent larger volumes of whole heart and left atrial wall receiving 63 to 69 Gy. Cardiac doses ≥63 Gy were concentrated in the LA-Wall, and consequently Heart-PC6 was highly correlated with LA-Wall-PC6. "Any ECG change," LA-Wall-PC6 scores, and PTV size were retained in the multivariable model., Conclusions: We found associations between higher DR and conduction or ischemic/pericarditis-like changes on ECG at 6 months, and between higher DR and higher Heart-PC6 or LA-Wall-PC6 scores, which are closely related to heart or left atrial wall volumes receiving 63 to 69 Gy in this small cohort of patients., (Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.)

Previous research investigating the potential influence of geomagnetic factors on human cardiovascular state has tended to converge upon similar inferences although the results remain relatively controversial. Furthermore, previous findings have remained essentially correlational without accompanying experimental verification. An exception to this was noted for human brain activity in a previous study employing experimental simulation of sudden geomagnetic impulses in order to assess correlational results that had demonstrated a relationship between geomagnetic perturbations and neuroelectrical parameters. The present study employed the same equipment in a similar procedure in order to validate previous findings of a geomagnetic-cardiovascular dynamic with electrocardiography and heart rate variability measures. Results indicated that potential magnetic field effects on frequency components of heart rate variability tended to overlap with previous correlational studies where low frequency power and the ratio between low and high frequency components of heart rate variability appeared affected. In the present study, a significant increase in these particular parameters was noted during geomagnetic simulation compared to baseline recordings., (Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.)

Although diagnostically indispensable, magnetic resonance imaging (MRI) has been, until recently, contraindicated in patients with an implantable cardiac device. MR conditional cardiac devices are now widely used, but the mode programming needed for safe MRI has yet to be established. We reviewed the details of 41 MRI examinations of patients with a MR conditional device. There were no associated adverse events. However, in 3 cases, paced beats competed with the patient's own beats during the MRI examination. We describe 2 of the 3 specific cases because they illustrate these potentially risky situations: a case in which the intrinsic heart rate increased and another in which atrial fibrillation occurred. Safe MRI in patients with an MR conditional device necessitates detailed MRI mode programming. The MRI pacing mode should be carefully and individually selected.

This study was carried out to determine the effects of electromagnetic field (EMF) emitted by cellular phones (CPs) on electrocardiograms (ECGs) of guinea pigs. A total of 30 healthy guinea pigs weighing 500-800 g were used. After 1 week of adaptation period, animals were randomly divided into two groups: control group (n = 10) and EMF-exposed group (n = 20). Control guinea pigs were housed in a separate room without exposing them to EMFs of CPs. Animals in second group were exposed to 890-915 MHz EMF (217 Hz of pulse rate, 2 W of maximum peak power and 0.95 wt kg(-1) of specific absorption rate) for 12 h day(-1) (11 h 45 min stand-by and 15 min speaking mode) for 30 days. ECGs of guinea pigs in both the groups were recorded by a direct writing electrocardiograph at the beginning and 10th, 20th and 30th days of the experiment. All ECGs were standardized at 1 mV = 10 mm and with a chart speed of 50 mm sec(-1). Leads I, II, III, lead augmented vector right (aVR), lead augmented vector left (aVL) and lead augmented vector foot (aVF) were recorded. The durations and amplitudes of waves on the trace were measured in lead II. The data were expressed as mean with SEM. It was found that 12 h day(-1) EMF exposure for 30 days did not have any significant effects on ECG findings of guinea pigs. However, this issue needed to be further investigated in a variety of perspectives, such as longer duration of exposure to be able to elucidate the effects of mobile phone-induced EMFs on cardiovascular functions.

Effects of electromagnetic energy radiated from mobile phones (MPs) on heart is one of the research interests. The current study was designed to investigate the effects of electromagnetic radiation (EMR) from third-generation (3G) MP on the heart rate (HR), blood pressure (BP) and ECG parameters and also to investigate whether exogenous melatonin can exert any protective effect on these parameters. In this study 36 rats were randomized and evenly categorized into 4 groups: group 1 (3G-EMR exposed); group 2 (3G-EMR exposed + melatonin); group 3 (control) and group 4 (control + melatonin). The rats in groups 1 and 2 were exposed to 3G-specific MP's EMR for 20 days (40 min/day; 20 min active (speech position) and 20 min passive (listening position)). Group 2 was also administered with melatonin for 20 days (5 mg/kg daily during the experimental period). ECG signals were recorded from cannulated carotid artery both before and after the experiment, and BP and HR were calculated on 1st, 3rd and 5th min of recordings. ECG signals were processed and statistically evaluated. In our experience, the obtained results did not show significant differences in the BP, HR and ECG parameters among the groups both before and after the experiment. Melatonin, also, did not exhibit any additional effects, neither beneficial nor hazardous, on the heart hemodynamics of rats. Therefore, the strategy (noncontact) of using a 3G MP could be the reason for ineffectiveness; and use of 3G MP, in this perspective, seems to be safer compared to the ones used in close contact with the head. However, further study is needed for standardization of such an assumption.

Patients with first acute myocardial infarction (AMI) constitute a demographic that is exposed to significant amounts of low-dose ionizing radiation (LDIR) over a short period. The aim of this study was to describe cardiac LDIR exposure trends among patients with first AMI over a recent approximately 10-year period. Administrative databases were used to identify a cohort of 106,803 patients who had first AMIs in Quebec, Canada, from 1996 to 2004. These patients were followed through 2007, and the use over time of cardiac imaging procedures associated with LDIR was documented using a cumulative exposure variable. Exposure was documented in 2 periods: the acute phase (<1 month after AMI) and the chronic phase (1 month to 3 years after AMI). The mean dose of cardiac LDIR incurred in the acute post-AMI phase increased twofold during the study period, from 6.8 to 11.8 mSv/patient. However, the mean dose of cardiac LDIR incurred in the chronic post-AMI phase decreased, from 8.3 to 7.3 mSv/patient. Overall, there was a 26.4% increase in cumulative cardiac LDIR exposure, to a mean of 19.1 mSv/patient in the 2 years after AMI, which was driven primarily by an increase in percutaneous coronary interventions. When patients were stratified by cumulative LDIR exposure, several predictors of heavier LDIR exposure were identified among the strata of exposed patients, including younger age and the absence of acute and co-morbid conditions, and the heaviest exposed group subsequently had the lowest overall mortality. In conclusion, among patients experiencing first AMI in Canada, exposure to cardiac LDIR increased over a recent approximately 10-year period. However, the observed trend is toward increasing use of therapeutic procedures with proven mortality benefit undertaken earlier in the disease course and away from diagnostic procedures in the subsequent years after AMI., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: This study evaluated the tolerance and therapeutic efficacy of rhenium-188 hydroxyethylidene diphosphonate ((188)Re-HEDP) in patients with different types of advanced cancer suffering from bone pain caused by osseous metastases., Methods: Sixty-four patients received a single injection of escalating doses of (188)Re-HEDP with various dosages. Vital signs were observed before and after treatment for 8 weeks; adverse effects and rebound pain were recorded within 8 weeks after injection. Blood counts, biochemical parameters, and electrocardiogram were also measured over a period of 8 weeks. Clinical follow-up studies including the bone pain score and the Karnofsky performance score were performed. Pain response was scored by a four-point pain-rating scale as complete, marked, mild, and no response., Results: No adverse effects or clinically significant changes in vital signs, electrocardiograms, and biochemical parameters in patients were observed, and there was no statistical change in alkaline phosphate levels in patients before or after treatment. The overall nadir of thrombopenia was at week 4, leucopoenia at week 3, and anemia at week 8. At week 8, the mean level of platelets and leukocytes returned to baseline levels. The pain score descended from 8.11 to 7.74 on the day of therapy, with a nadir of 4.89 at week 4, and up to 6.67 at week 8 after therapy (p < 0.05). The Karnofsky performance score continually increased from 74.81 before therapy to 82.31 at 8 weeks (p > 0.05 Pain palliation was reported by 73.33% of patients, with a mean duration of 6.85 weeks and a mean start time of 4.05 days. Of the specific tumor types, pain relief was achieved in 84.62% of patients with prostate cancer, 78.57% with breast cancer, 62.50% with lung cancer, and 55.56% with liver cancer., Conclusions: (188)Re-HEDP is a useful radiopharmaceutical agent for improving bone pain in patients with advanced cancer with painful bone metastases.

Herein, we report a case of pseudosinus tachycardia resulting from an electromagnetic interference between a mobile phone and treadmill device. Electromagnetic interference from a charging mobile phone connected to the same socket with the exercise device turned the recording of a patient to that of pseudosinus tachycardia at approximately twice the rate of actual basal heart rate. Removal of the mobile phone from the socket resulted in normalization of the electrocardiogram.

Anthracyclines are very potent drugs in the therapy of malignancies in childhood. The major dose limiting adverse effect of these drugs is the risk of dilated cardiomyopathy. We performed a retrospective study on 168 patients who were treated with anthracyclines for a malignant disease with or without chest radiation at the department of Pediatric Hematology and Oncology at the University of Duesseldorf between 2000 and 2004. During and after chemotherapy the patients were screened by echocardiography and ECG examinations prior to each administration of anthracyclines. Only four patients presented with adverse cardiac events, one of whom developed acute cardiac failure. This patient was additionally treated with chest radiation. Three of the four patients showed intermittent arrhythmias, mainly supraventricular tachycardia. One of them presented with atrial ectopic tachycardia and left ventricular dysfunction. We conclude that the frequency of cardiac sequelae after chemotherapy with anthracyclines is low under present guidelines. Detection of early cardiac sequelae may be more difficult than in the past. Only one patient with cardiac sequelae in our study group was diagnosed by regular performed examinations for cardiac sequelae of chemotherapy. We therefore need to modify our screening methods to increase the effectiveness of detection of cardiac dysfunction prior to clinical manifestation.

In MRI, the flow of blood in the patient is subjected to a strong static magnetic field (B(0)). The movement of charge carriers in a magnetic field causes a magnetofluid dynamic (MFD) effect that induces a voltage across the artery. This induced voltage distorts the ECG signal of the patient and appears as an elevation of the T-wave of the ECG signal. Flow of blood through the aortic arch is perpendicular to the magnetic field and coincides with the occurrence of the T-wave of the ECG. Based on these facts, it is proposed that the elevation in the T-wave occurs because of the voltage induced across the aortic arch. In this paper, the elevation is computed mathematically using the equations of MFD. A method is developed to measure this induced voltage based on discretization of the aortic arch and measuring the blood flow profile in the aorta. The results are compared to the ECG signals measured in humans in the bore of 1.5 T imaging magnet. The computed ECG signals at the 12 leads are very similar to the measured values.

With the development of economy and coming of information era, the chance of exposure to electromagnetic fields with various frequencies has been increased for every human. The effects of electromagnetic radiattion on human being's health are versatile. To study the effects of bioelctronic parameters of rats in the electromagnetic radiations of HV transmission line, EEG, ECG and CMAP were measured in rats exposed to simulating high-voltage transmission line electromagnetic radiation for over one year. Brain tissues were studied by Fourier transform infrared spectroscopy. The results showed that no significant difference between exposed group and control group in EEG; however the FT-infrared spectra of brain tissues were different; the ECG of the exposed animals was considerably altered. Significant slowing of heart rate was observed in those rates exposed to EMFs; the latent period of CMAP in exposed group were not different compared with those of control group however there was a significant difference in wave amplitude of CMAP between the exposed group and control group. All results indicated that there must be some effects on bioelectric parameters of rats exposed to electromagnetic radiation of high-voltage transmission line for a long time.

Radiation-induced heart disease (RIHD), characterized by accelerated atherosclerosis and adverse tissue remodeling, is a serious sequelae after radiotherapy of thoracic and chest wall tumors. Adverse cardiac remodeling in RIHD and other cardiac disorders is frequently accompanied by mast cell hyperplasia, suggesting that mast cells may affect the development of cardiac fibrosis. This study used a mast cell-deficient rat model to define the role of mast cells in RIHD. Mast cell-deficient rats (Ws/Ws) and mast cell-competent littermate controls (+/+) were exposed to 18 Gy localized single-dose irradiation of the heart. Six months after irradiation, cardiac function was examined by echocardiography and Langendorff-perfused isolated heart preparation, whereas structural changes were assessed using quantitative histology and immunohistochemical analysis. Mast cell-deficient rats exhibited more severe postradiation changes than mast cell-competent littermates. Hence, mast cell-deficient rats exhibited a greater upward/leftward shift in the left ventricular (LV) diastolic pressure-volume relationship (P = 0.001), a greater reduction in in vivo LV diastolic area (from 0.50 +/- 0.024 cm in age-matched controls to 0.24 +/- 0.032 cm after irradiation; P = 0.006), and a greater increase in LV posterior wall thickness (from 0.13 +/- 0.003 cm in age-matched controls to 0.15 +/- 0.003 cm after irradiation; P = 0.04). Structural analysis revealed more pronounced postradiation accumulation of interstitial collagen III but less myocardial degeneration in hearts from mast cell-deficient rats. These data show that the absence of mast cells accelerates the development of functional changes in the irradiated heart, particularly diastolic dysfunction, and suggest that, in contrast to what has been the prevailing assumption, the role of mast cells in RIHD is predominantly protective.

Static magnetic fields induce flow potentials in arterial flows in and around the heart, that have been detected as distortions in the ECG. The resultant currents flowing through the myocardium could alter the rate or rhythm of the heart. No such changes have been seen in animal experiments, or with humans, in static fields up to 8 T. The possible effects of such currents induced by fields larger than 8 T on cardiac pacemaker rate, and arrhythmogenesis are reviewed, using virtual cardiac tissues-computational models of cardiac electrophysiology. Arrhythmogenesis can be by the initiation of ectopic beats, or by re-entry, whose probability of occurrence is increased by any increase in the electrical heterogeneity, in particular, the action potential duration heterogeneity of the ventricle. Focal ectopic activity would be readily detectable, but since re-entrant arrhythmias are very rare events, even a large increase in their probability of occurrence still leaves them unlikely to be observed. Both of these two arrhythmogenic mechanisms would show a steep sigmoidal, or threshold dependence on induced current intensity, with the threshold for increasing the vulnerability to re-entry less than the threshold for initiating activity. Failure to observe them at fields less than 8 T provides only a lower bound for any threshold for arrhythmogenesis.

Goal: This paper reviews recent studies evaluating human subjects for physiologic or neuro-cognitive function adverse effects resulting from exposure to static magnetic fields of magnetic resonance imaging systems., Materials and Methods: The results of three studies are summarized. Two studies evaluated exposure to a maximum of 8 Tesla (T). The first series studied 25 normal human subjects' sequential vital signs (heart rate, blood pressure, blood oxygenation, core temperature, ECG, respiratory rate) measured at different magnetic field strengths to a maximum of 8 T. A second series of 25 subjects were studied at 0.05 and 8 T (out and in the bore of the magnet), performing 12 different standardized neuro-psychological tests and auditory-motor reaction times. The subjects' comments were recorded immediately following the study and after a three-month interval. The third study contained 17 subjects, placed near the bore of a 1.5 T magnet, and it used six different cognitive, cognitive-motor, or sensory tests., Results: There were no clinically significant changes in the subjects' physiologic measurements at 8 T. There was a slight increase in the systolic blood pressure with increasing magnetic field strength. There did not appear to be any adverse effect on the cognitive performance of the subjects at 8 T. A few subjects commented at the time of initial exposure on dizziness, metallic taste in the mouth, or discomfort related to the measurement instruments or the head coil. There were no adverse comments at 3 months. The 1.5 T study had two of the four neuro-behavioral domains exhibiting adverse effects (sensory and cognitive-motor)., Conclusions: These studies did not demonstrate any clinically relevant adverse effects on neuro-cognitive testing or vital sign changes. One short-term memory, one sensory, and one cognitive-motor test demonstrated adverse effects, but the significance is not clear.

Blood flow in an applied magnetic field gives rise to induced voltages in the aorta and other major arteries of the central circulatory system that can be observed as superimposed electrical signals in the electrocardiogram (ECG). The largest magnetically induced voltage occurs during pulsatile blood flow into the aorta, and results in an increased signal at the location of the T-wave in the ECG. Studies involving the measurement of blood pressure, blood flow rate, heart sounds, and cardiac valve displacements have been conducted with monkeys and dogs exposed to static fields up to 1.5 tesla (T) under conditions producing maximum induced voltages in the aorta. Results of these studies gave no indication of alterations in cardiac functions or hemodynamic parameters. Cardiac activity monitored by ECG biotelemetry during continuous exposure of rats to a 1.5-T field for 10 days gave no evidence for any significant changes relative to the 10 days prior to and following exposure. Theoretical modeling of magnetic field interactions with blood flow has included a complete solution of the equation describing the flow of an electrically conductive fluid in the presence of a magnetic field (the Navier-Stokes equation) using the finite element technique. Magnetically induced voltages and current densities as a function of the applied magnetic field strength have been calculated for the aorta and surrounding tissues structures, including the sinoatrial node. Induced current densities in the region of the sinoatrial node are predicted to be >100 mA/m2 at field levels >5 T in an adult human under conditions of maximum electrodynamic coupling with aortic blood flow. Magnetohydrodynamic interactions are predicted to reduce the volume flow rate of blood in the human aorta by a maximum of 1.3%, 4.9%, and 10.4% at field levels of 5, 10, and 15 T, respectively.

Objective: Our previous investigation indicated that electromagnetic radiation level of city environment in some frequency range has gotten close to national standard limits. This study is to investigate the effects of these frequency electromagnetic waves coexisted in same environment on teenagers' electrocardiogram and blood cells., Methods: Electrocardiogram and blood cells were examined in 106 cases of teenagers by using electrocardiograph and blood counting instruments respectively., Results: There were not significantly different in heart rate, P-R interphase, QRS-wave time, Q-T interphase, blood hemoglobin content and blood platelet number in teenagers between high and low electromagnetic radiation environment (P > 0.05). The total blood leucocyte number in teenagers was statistically lower in high electromagnetic radiation environment than that in low electromagnetic radiation environment (P < 0.05). With regard to classification of blood leucocyte, the blood monocyte number in 14 - 18 years old of teenagers and the blood eosinophil number in boy were significantly higher in high electromagnetic radiation environment than those in low electromagnetic radiationenvironment (P < 0.05)., Conclusion: The electromagnetic radiation nowadays in metropolis environment may have no harmful effects on teenagers' electrocardiogram and have harmful effects on teenagers' blood leucocyte-mainly showing decreased total blood leucocyte number, increased percentages of monocyte and eosinophil number.

In this work the effect of sinusoidal 50 Hz, 0.2 mT magnetic fields on the red blood cells (RBCs) and heart functions of Albino rats were investigated. Twenty-four male Albino rats were equally divided into four groups, A, B, C, and D. Animals from groups B were continuously exposed to the magnetic field for 15 days; and groups C and D, for 30 days. Group A was used as control. Animals from group D were kept after exposure to the magnetic field for a period of 45 days for delayed effect studies. The osmotic fragility and shape of RBCs' membrane and hemoglobin (Hb) structure tests were carried out for all groups. The dielectric relaxation of Hb molecules was measured in the frequency range of 0.1-10 MHz and the dielectric increment (Deltaepsilon), relaxation time (tau), molecular radius (r), and Cole-Cole parameter (alpha) were calculated for all groups. The ECG was measured for all animals before and after exposure to the magnetic field. The results indicated that exposure of the animals to 50 Hz, 0.2 mT magnetic fields resulted in the decrease of RBCs membrane elasticity and permeability and changes in the molecular structure of Hb. The ECG of the exposed animals was considerably altered. The data also indicated that there was no sign of repair in the newly generated RBCs structure and the ECG after removing the animals from the magnetic field, which indicates that the blood generating system was severely injured. The injuries in the heart of the animals were attributed to the loss of some physiological functions of the RBCs as a result of exposures of the rats to the magnetic field., (Copyright 2003 Wiley-Liss, Inc.)

Purpose: We sought to evaluate the radiation exposure of cardiac CT scans with 16-row multidetector computed tomography (MDCT). Additionally the possibility of dose reduction by using a ECG-controlled tube current modulation technique was evaluated., Methods and Material: An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for dose measurements. Effective dose was calculated according to ICRP 60. Exposure was performed on a 16-row MDCT scanner with standard protocols for CT coronary calcium scoring (120 kV, 133 mAs, 12 x 1.5 mm) and CT coronary angiography (120 kV, 400 mAs, 12 x 0.75 mm). Exposure was repeated at a simulated heart rate of 60 bpm with ECG-pulsed tube current modulation., Results: Effective dose was 2.9 mSv (male) and 3.6 mSv (female) for the calcium scoring protocol. CT coronary angiography resulted in an effective dose of 8.1 mSv (male) and 10.9 mSv (female). Using ECG-pulsed tube current modulation radiation exposure can significant reduced: by 46 % (1.6 mSv) in calcium scoring and by 47 % (4.3 mSv) in CT coronary angiography., Conclusion: MDCT of the heart shows a significant radiation exposure, which can significantly be reduced by ECG-pulsed tube current modulation. Radiation exposure of cardiac MDCT is comparable to CT-examinations of chest or abdomen, but seem to be slightly higher compared to conventional coronary angiography.

During magnetic resonance imaging (MRI) pulse-sequences the human body is exposed to switched magnetic gradient fields. These gradients become stronger and are switched faster for fast imaging. Effects resulting from these fields with trapezoidal waveforms are on the one hand sensory perception of induced currents and on the other hand muscular and cardiac stimulation. All three components of the current density induced by gradient pulse sequence were analysed in a high-resolution model of the human torso. The evaluation of the calculated data was performed thoroughly in the region of the heart muscle of the torso model to find out how different waveforms of the switched gradient field influence strength and direction of induced currents.

Geomagnetic variations of partly interplanetary origin, with cyclic signatures in human affairs and pathology include the incidence of various diseases, regarding which this study of healthy subjects attempted to determine an underlying mechanism by worldwide archival and physiological monitoring, notably of heart rate variability (HRV). In the past half-century, the possible health and other hazards of natural, solar variability-driven temporal variations in the earth's magnetic field have become a controversial subject in view of the inconsistent results. Some well-documented claims of associations between geomagnetic storms and myocardial infarction or stroke have been rejected by a study based on more comprehensive data analyzed by rigorous methods - covering, however, only part of a solar cycle in only part of a hemisphere. It seems possible that inter-solar cycle and geographic variability, if not geographic differences, may account for discrepancies. Herein, we examine the start of a planetary study on any influence of geomagnetic disturbances that are most pronounced in the auroral oval, on human HRV. The magnetic field variations exhibit complex spectra and include the frequency band between 0.001-10 Hz, which is regarded as ultra-low frequency by physicists. Since the 'ultra-low-frequency' range, like other endpoints used in cardiology, refers to much higher frequencies than the about-yearly changes that are here shown to play a role in environmental-organismic interactions revealed by HRV, the current designations used in cardiology are all placed in quotation marks to indicate the need for possible revision. Whether or not this suggestion has an immediate response, we have pointed to a need for the development of instrumentation and software that renders the assessment of circadian, infradian and even infra-annual (truly low frequency) modulations routinely feasible. HRV was examined on the basis of nearly continuous 7-day records by ECG between December 10, 1998, and November 2, 2000, on 19 clinically healthy subjects, 21 to 54 years of age, in Alta, Norway. A geomagnetic record was obtained from the Auroral Observatory of the University of Tromsø. First, frequency-domain measures of HRV were compared for each person in 24-hour spans of high geomagnetic disturbance versus quiet conditions. Second, cross-spectra between geomagnetic activity and HRV measures were quantified via the squared coherence spectrum using 7-day time series. A 7.5% increase in the 24-hour average of heart rate, HR (P = 0.00020) and a decrease in HRV were documented on days of high geomagnetic disturbance. The decrease in HRV was validated statistically for the 'total frequency', 'TF' endpoint (18.6% decrease, P= 0.00009). The decrease in spectral power was found primarily in the 'circaminutan frequency', 'VLF' (21.9% decrease, P< 0.000001) in conjunction with the 'minutes-to-hours' component, ultra-low-frequency, 'ULF' (15.5% decrease, P= 0.00865) and circadecasecundan 'low frequency', 'LF' (14.2% decrease, P = 0.00187) regions of the spectrum. Power-law scaling of the power spectra did not show any statistically significant difference. It is noteworthy that most of the decrease in HRV, except for the circaminutan (VLF) component, was observed only in the season in which sunshine alternated with darkness (D/L), a finding suggesting a mechanism influenced by the alternation of light and darkness. The hypothesis of a light-dark-influenced magnetoreception was also supported by cross-spectral analysis. Group-averaged coherence at frequencies coincident with the geomagnetic Pc 6 pulsations (with periods ranging from 10 minutes to 5 hours) differed with a statistical significance (P < 0.000001) among the three natural lighting conditions, the association being weaker during UL or D/D than during D/L. By contrast, no statistically significant differences were found in terms of the circadian and circasemidian frequencies in relation to the alternation of sunshine with darkness or rather circannual rhythm stage. In conclusion, evidence is provided herein that an alteration of HRV is most apparent in the circaminutan ('VLF') region, which is clinically important, because a reduction in its power is a predictor of morbidity and mortality from cardiovascular disease. The circadecasecundan ('LF') component of HRV also decreased in association with geomagnetic disturbance, which may reflect an episodic alteration of arterial pressure related to changes in geomagnetic activity. Lastly, our study suggests the existence of a light-dark-influenced magnetoreception mechanism in humans involving mainly the Pc 6 band of the magnetic field.

To study the interactions among the natural physical environmental cycles and human infradian components of heart rate (HR) and HR variability (HRV), a healthy 49-year-old man in Kiev, who had monitored his electrocardiogram (ECG) around the clock earlier for 50 days, added at a later date with the same ambulatorily wearable device, a record of 70 days. The mean value of the R-R intervals (R-R), their standard deviation (SDNN) and other HRV endpoints, computed over consecutive 5-min intervals, served as markers of the subject's functional associations with the amplitude of fluctuations in atmospheric pressure (FAP) and the planetary Kp index of geomagnetic disturbance. About-weekly and half-weekly cycles in HRV endpoints indicate a reduction in physiological 'preparedness', here described as 'dynamics', of the subject investigated on Saturdays and Sundays and a sharp increase in 'dynamics' on Mondays. The waveform of the weekly oscillation seemed to be influenced by ambient air temperature and FAP. On Mondays, an FAP amplification or a temperature rise was accompanied by a significant decrease in R-R and SDNN, indicating an aggravation of a 'Monday effect' in physiological 'dynamics'. HRV endpoints also revealed about-5-day and about-12-day cyclic components similar to those found in FAP. The infradian pattern in a 70-day record differed from one found earlier in a 50-day record of the same subject. Changes in the natural physical environment (past as well as present), especially in air temperature and FAP, likely influence(d) if not synchronize(d) the amplitude and waveform of infradian weekly and half-weekly physiological cycles. Some of these infradians, their wobbly nature notwithstanding, may have been built into our temporal make-up by an evolutionary integration of life in the non-stationary quasi-periodic natural physical environment, which continues to contribute to variability.

In previous research, intermittent exposure to sinusoidal 60 Hz magnetic fields at a resultant flux density of 28.3 microT was found to alter heart rate variability (HRV) in men during night sleep. When the 24 men in the present study were exposed under similar conditions, HRV was not altered. The previous studies included the hourly collection of blood samples via an indwelling venous catheter, while the present study did not. This may account for the observed differences in results. Further research is needed to determine if field exposure interacts with physiological arousal mechanisms to alter autonomic nervous system control over cardiac rhythms., (Copyright 2000 Wiley-Liss, Inc.)

The effect of increased UV-radiation doses modeling 25 and 50% of ozone layer depletion on sheep's organisms was studied in the field experiment. The character of changes in animal organisms was found to depend on irradiation doses, sensitivity of individual system of living organism to electromagnetic radiation and physiological peculiarities of protection.

Background: Measures of heart rate variability (HRV) are widely recognized as being an important indicator method for autonomical function and cardiovascular neural regulation. The low-frequency component in spectral analysis is increased during conditions of raised sympathetic activation, the high-frequency component is closely correlated with vagal activity. Whole-body infrared-A irradiation (WBIAI) according to von Ardenne is a newly developed version of hyperthermia. In clinical use peripheral vasodilatation with significant increases in heart rate and hypotension were noted as acute effects of WBIAI. In order to evaluate the effect of WBIAI on autonomic function, we measured HRV during serial hyperthermias., Patients and Methods: Power spectral density analysis of HRV during the first and the last of 4 serial WBIAI treatments with 30-60 min endurance was performed in 10 patients with chronic pain disorders. Tympanal body temperature was recorded continuously and was supposed to increase by 1 degrees C during treatment. Electrocardiographic monitoring was performed using a Marquette HoIter ECG. RR data were manually edited and standard frequency domain measures of the first and the last 5 min of treatment computed. The subjective efficacy of the treatment was rated by prestandardized interviews., Results: Body temperature increased by 0.9 degrees C during the first treatment and 1.2 degrees C during the last treatment. In all patients the rise in body temperature due to treatment was accompanied by a significant increase in heart rate and a decrease of arterial blood pressure. During hyperthermia a slight decrease of absolute low-frequency and total power as well as a sharp decrease of high-frequency power and a significant increase of the low/high-frequency ratio could be noted. The rise in low/high-frequency ratio during WBIAI was less distinct at the last treatment compared to the initial treatment. Hyperthermia was regarded as a safe, well-tolerable and effective treatment., Conclusion: The results suggest that the cardiovascular response during WBIAI is accompanied by significant changes in autonomic cardiac regulation: A significant decrease of low-frequency power corresponding to depressed vagal activity results in an increase of Iow/high-frequency ratio. During serial hyperthermias the acute response is diminished suggesting an adaption of the autonomic response to hyperthermia. Further studies are necessary to investigate the long-standing autonomic effects of the treatment and include analysis of influencing factors such as the level of physical activity and constitutional individual conditions.

Spectral analysis of cardiac rhythm has determined characteristics of humoral, sympathetic and parasympathetic regulation in children with cardiac abnormalities and thyroid hyperplasia. The examinees demonstrated low activity of humoral immunity, high sympathetic influences, slight variability of frequency-amplitude characteristics. Sanatorium treatment improved regulation of cardiac activity. Spectral analysis of cardiac rhythm proved efficient for optimization of physiotherapy.

Dog exposure to doses from 39 to 124 Gy results in an increase of heart rate and tension in control of the cardiac rhythm, the extent being dose dependent. An additional physical load on the cardiovascular animals system reveals a high functional control reserves of the cardiovascular system which provides stable functioning even after exposure to the above doses.

Cardiovascular changes in humans exposed to nonionizing radiation [including extremely-low-frequency electromagnetic fields (ELF EMFs) and radiofrequency radiation (RFR)] are reviewed. Both acute and long-term effects have been investigated. In general, if heating does not occur during exposure, current flow appears to be necessary for major cardiovascular effects to ensue, such as those due to electric shock. Whereas most studies have revealed no acute effect of static or time-varying ELF EMFs on the blood pressure, heart rate, or electrocardiogram waveform, others have reported subtle effects on the heart rate. The possible health consequences of these results are unknown. Regarding long-term effects of ELF EMFs, reports from the former Soviet Union in the early 1960s indicated arrhythmias and tachycardia in high-voltage-switchyard workers. Subsequent studies in Western countries, however, did not confirm these findings. These studies are limited by uncertainties regarding exposure durations and appropriate control groups. Investigations of acute cardiovascular changes in humans purposely exposed to RFR have been limited to studies of magnetic resonance imaging (which, in addition to RFR, involves static and time-varying magnetic fields). It has been concluded that such exposures, as presently performed, are not likely to cause adverse cardiovascular effects. Reports of hypertension in workers potentially exposed to high levels of RFR during accidents are considered to be incidental (due to anxiety and posttraumatic stress). Soviet investigators have also indicated that long-term RFR exposure may result in hypotension and bradycardia or tachycardia. Other researchers, however, have been incapable of replicating these results, and some scientists have attributed the effects to chance variations and mishandling of data. In summary, studies have not yielded any obvious cardiovascular-related hazards of acute or long-term exposures to ELF EMFs or RFR at levels below current exposure standards.

Extremely low frequency magnetic fields interact with an animal by inducing internal electric fields, which are in addition to the normal endogenous fields present in living animals. Male rats weighing about 560 g each were anesthetized with ketamine and xylazine. Small incisions were made in the ventral body wall at the chest and upper abdomen to position a miniature probe for measuring internal electric fields. The calibration constant for the probe size was 5.7 mm, with a flat response from at least 12 Hz to 20 kHz. A cardiac signal, similar to the normal electrocardiogram with a heart rate of about 250 bpm, was readily obtained at the chest. Upon analysis of its spectrum, the cardiac field detected by the probe had a broad maximum at 32-95 Hz. When the rats were exposed to a 1 mT, 60 Hz magnetic field, a spike appeared in the spectrum at 60 Hz. The peak-to-peak magnitudes of electric fields associated with normal heart function were comparable to fields induced by a 1 mT magnetic field at 60 Hz for those positions measured on the body surface (where induced fields were maximal). Within the body, or in different directions relative to the applied field, the induced fields were reduced (reaching zero at the center of the animal). The cardiac field increased near the heart, becoming much larger than the induced field. Thus, the cardiac electric field, together with the other endogenous fields, combine with induced electric fields and help to provide reference levels for the induced-field dosimetry of ELF magnetic field exposures of living animals.

The purpose of this study was to determine whether nitric oxide (NO) contributes to the hypotensive state induced by exposure to radiofrequency radiation of millimeter-wavelength (MMW). This was accomplished using a synthetic analogue of L-arginine, N omega-nitro-L-arginine methyl ester (L-NAME), to competitively inhibit NO synthesis. Ketamine-anesthetized rats were instrumented for the measurement of arterial blood pressure, ECG, and temperature at five sites. Animals were exposed to 35-GHz radiofrequency radiation until mean arterial pressure (MAP) decreased to 75 mmHg. MMW exposure was then halted and either saline or L-NAME (1, 2.5, 5, or 10 mg/kg) was administered; each rat received only one dose. Following irradiation, L-NAME at each dose produced a peak increase in MAP that was smaller than that produced by the same dose of L-NAME in nonirradiated rats. There was no difference in post-MMW survival times between L-NAME-and saline-treated rats. These results indicate that bolus administration of L-NAME does not reverse hypotension induced by 35-GHz microwave heating, suggesting that excess levels of NO do not mediate this form of circulatory failure.

The use of laser radiation in a complex of therapeutic measures after acute myocardial infarction promoted improvement in a clinical course of the disease, stabilization of coronary circulation as shown by ECG, intracardiac hemodynamics registered at echo-CG. The latter is able to identify early indications of hemodynamic defects. Basing on these data correction of rehabilitation plan is made.

To determine the potential association of increased 201Tl uptake by the stomach with symptoms referable to gastritis, 39 consecutive patients experiencing chest pain syndromes underwent a routine dipyridamole 201Tl pharmacological stress test. With the patient in a fasting state, dipyridamole was infused intravenously (0.56 mg kg-1), shortly followed by 201Tl infusion and subsequent image acquisition for single photon emission tomography (SPET). The original 32 SPET images over 180 degrees of arc were interpreted without knowledge of clinical data, using a 4-point scoring system. Patients with active symptoms of gastro-oesophageal discomfort (n = 17) were found to have significantly greater 201Tl stomach uptake scores, compared to the little or no uptake in the 22 patients without such active symptoms (P = 0.0001). A stepwise logistic regression analysis was used to determine which factor(s) showed independent predictive value of 201Tl gastric uptake. The only two independent variables identified were the presence of active gastritis symptoms and the use of anti-gastritis medications. Elevated gastric 201Tl uptake may be a clinically useful finding indicative of gastric inflammation that may be of value in the differential diagnosis of chest and epigastric discomfort.

In awaken rats, ECG and EEG were simultaneously analysed in order to quantify the cortical EEG and beat-to-beat heart rate variability (HRV) in response to light onset. The HRV bands LF (40-200 mHz), MF (200-600 mHz) and HF (600-2500 mHz) and the EEG bands delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz) and beta (13-32 Hz) were assessed. Light onset induced a significant arousal reaction in the EEG, manifested by a global decrease in total spectral power and a shift towards theta and beta bands, while total HRV spectral power increased, with a shift to the sympathetic-related MF band. This simultaneous changes in HRV and EEG induced by light onset could be triggered by the same common factor that controls both oscillatory responses.

A group of 10 chinchilla male rabbits were exposed to 800 MHz alternative microwave fields. The data obtained revealed changes in the EEG, ECG and respiration in only 2 rabbits after 5-7 experiments.

Runaway pacemaker occurred in a patient undergoing high-energy neutron radiation therapy despite adherence to published safety guidelines. The very low estimated dose of 0.9 Gy received by the pacemaker demonstrates the extreme sensitivity of integrated circuits to this new modality of radiation therapy.

121 workers who were exposed to RFR (< 30 MHz) over one year were examined. They were divided into two groups: one group was exposed to high electric field intensity (> or = 100 V/m), another to low intensity (< 100 V/m) and both groups were compared to control subjects. No significant changes in the functioning of the autonomic nervous system and blood parameters (Hb, WBC and blood platelets) occurred in the exposed subjects of either group. Some changes in ECG (ST-T interval and abnormal heart rate) were observed in the group exposed to high intensity (> or = 100 V/m) radiation. 100 V/m is suggested as an exposure limit for RF (< 30 MHz) radiation.

This human exposure study examined the relationship between field strength and biological response and tested whether the exposure levels at which the greatest effects occur differ for different endpoints. Three matched groups of 18 men each participated in two 6 h exposure test sessions. All subjects were sham exposed in one session. In the other session, each group of subjects was exposed at a different level of combined electric and magnetic field strength (low group:6 kV/m, 10 microT; medium group:9 kV/m, 20 microT; and high group: 12 kV/m, 30 microT). The study was performed double blind, with exposure order counterbalanced. Significant slowing of heart rate, as well as alternations in the latency and amplitude of event-related brain potential measures derived from the electro encephalogram (EEG), occurred in the group exposed to the 9 kV/m, 20 microT combined field (medium group). Exposure at the other field strength levels had no influence on cardiac measures and differential effects on EEG activity. Significant decrements in reaction time and in performance accuracy on a time estimation task were observed only in the low group. These results provide support for the hypothesis that humans may be more responsive to some combinations or levels of field strength than to others and that such differences in responsivity may depend, in part, on the endpoint of interest.

Purpose: Although spinal irradiation used in the treatment of CNS malignancies includes a portion of the heart in the radiation field, cardiac effects have not been previously reported., Patients and Methods: We compared patients treated for malignancy in childhood with spinal irradiation (n = 26) with patients treated with mediastinal/flank irradiation (n = 47) that included the heart in the radiation field. All patients were more than 1 year from completion of radiation therapy. Patients underwent at least two of the following cardiac evaluations: (1) ECG; (2) 24-hour ambulatory ECG; (3) echocardiogram; and (4) exercise-testing using cycle ergometry., Results: Twelve of 16 patients (75%) in the spinal irradiation group with an assessable exercise test achieved a maximal cardiac index (MCI) below the fifth percentile as compared with 13 of 40 patients (32%) who had received mediastinal/flank irradiation (P = .007). Furthermore, after adjusting for normal heart growth, radiation and anthracycline doses, and follow-up time, the group of patients who received spinal irradiation had significantly higher estimated posterior wall stress (P = .002), expressed as the natural logarithm of the ratio of end-diastolic left ventricular internal diameter (LVID) to left ventricular posterior wall thickness (LVPWT), than the group who had received mediastinal/flank irradiation. Finally, eight of 26 patients (31%) in the spinal group had pathologic Q-waves in the inferior leads versus three of 47 (6.4%) in the mediastinal/flank group (P = .001)., Conclusion: Patients who have received spinal irradiation for pediatric malignancies appear to be at risk for significant cardiac dysfunction. The asymmetric distribution of radiation to a growing heart, as given with spinal irradiation, may be the cause of these findings.

We investigated the clinical, electrophysiological, haemodynamic and angiographic aspects of four patients (two men and two women, aged 31-46 years) who developed complete heart block 13-20 years after therapeutic irradiation of the chest for Hodgkin's disease. The initial cardiac symptom was syncope in three, effort intolerance in one. The electrocardiogram recorded third-degree atrioventricular block in three patients, right bundle branch block and posterior fascicular block in one. The electrophysiological study, performed in three cases, showed that the block was infranodal in two. Three patients had significant coronary arterial stenoses, that involved the ostia in two. All patients had mild-to-moderate aortic and mitral regurgitation. One patient had haemodynamic signs of constriction. Another patient had recurrent pericardial effusions. All had echocardiographic evidence of a thickened pericardium. Cardiac involvement can be extensive in patient with radiation-induced heart block. Because coronary artery disease can be particularly severe, coronary angiography appears to be warranted in such patients.

Investigations of the central haemodynamics and myocardial contractility in 73 men, who took part in repairing after the Chernobyl accident in 1986, in 4 years after the accident have shown the hyperkinetic type of circulation in 60.2%, eukinetic in 23.2%, hypokinetic in 15.6% of the examinees. Such changes of the central haemodynamics, increased frequency of the hyperkinetic type are due to the regulatory disorders decreasing the vascular tone in the major and minor circles, amplifying the venous return to heart and increasing the myocardial contractility.

Summarised electroretinograms (ERGs) of dark-adaptable retina of Rana temporaria were studied in situ with an automated experimental device with programmable control and first and second derivatives electron differentiation. X-rays were shown to induce the ERG composed of two components which were conventionally designated as the first and second roentgen responses (R-1 and R-2). These differ by their parameters from the ERGs induced by red and blue light in the same experiment. Administration of sodium azide, sodium nitrite, monoiodine acetate and other compounds changed the waves of R-1 and R-2 as well as photo-induced ERGs. This suggests their relative independence and different mechanism of initiation, and allows their partial isolation for separate studying.

The effect of excessive UV-radiation with 2-4, 5-6, or 7-8 minimal erythematous doses (MED) on man's health condition was investigated, when the irradiated surface area made 20% or 50% of the body surface area. Before and 1 or 3 days after exposure the following parameters were measured: skin state, skin perspiration, body temperature, fluid consumption, diuresis, ECG, PCG, occlusion plethysmography. The observations allowed the conclusion that 5-8 MEDs were threshold doses inducing early intoxication in response to local irradiation (20% of the body surface area) and upper body irradiation (50% of the body surface area). Irradiation with 7-8 MEDs caused noticeable intoxication: fever, headache, increased body temperature (37 degrees C and over), inhibited perspiration, fluid retention, and altered cardiac function.

Electrocardiographic signs of changes in the myocardium were detected in 93.2 percent of 74 patients with malignant maxillofacial tumors; this was due to the presence of coronary disease, myocardial dystrophy, essential hypertension, respiratory abnormalities. The development and progress of these shifts much depended on radiotherapy and chemoradiotherapy of the tumors. The most frequent findings were deviations in the end section of the ventricular complex, reflecting the metabolic and ischemic changes in the myocardium, associated with a rise in radiation and polychemotherapy dosage. Extracoronarogenic myocardial lesions and coronary disease progression were clinically characterized by augmentation of cardiac insufficiency and various arrhythmias with mild pain syndrome. These specific clinical and electrocardiographic features of myocardial involvement should be borne in mind when choosing and carrying out radio- and polychemoradiotherapy of patients with maxillofacial tumors.

This study examined the safety and dose-response relationships of 632-nm laser irradiation of photosensitized normal coronary arteries in 27 dogs. Fifteen received 2.5 mg/kg dihematoporphyrin ether (DHE), seven received no sensitizer, and five had coronary instrumentation but no laser (sham laser procedures) at nine coronary sites--four sensitized, five non-sensitized. Laser energy of 82 to 1,640 J/cm2 was delivered via a 584 microns diffusing-tip optical fiber, providing estimated tissue fluences of 20 to 410 J/cm2. Serial electrocardiograms and selective coronary arteriograms were performed up to 1 month post laser irradiation. Histologic examination was performed of all treated sites. Tissue fluences less than 200 J/cm2 produced no permanent electrocardiographic or angiographic changes; reversible spasm occurred in 2/8 photosensitized-lased, 0/2 non-photosensitized-lased. Minor medial damage occurred in 1/8 sensitized-lased, 1/2 non-sensitized-lased, and 0/9 sham-lased sites. At tissue fluences greater than 200 J/cm2 4/7 sensitized-lased animals died prematurely--one due to immediate and irreversible coronary spasm and Q wave infarction, one due to fibrillation during 48-hour follow-up coronary angiography (normal angiograms), two with normal electrocardiograms and angiograms within one day of undetermined death; 0/5 non-sensitized-lased animals expired or had coronary spasm; and 3/7 sensitized-lased and 0/5 non-sensitized/lased had significant medial to adventitial histologic damage. Coronary irradiation at less than 200 J/cm2 appears to be safe for photodynamic treatment of atherosclerotic lesions. Pretreatment for coronary spasm is appropriate.

Electrocardiography was used to analyze the results of 4-year investigations of the cardiac activity and reactivity (adrenalin test) in 32 dogs irradiated with high-energy protons (approximately 240 MeV) at absolutely lethal doses of 4 and 5 Gy. The author's and literature data have shown the similarity of cardiac functional features and reactivity in a long-term period in dogs with those in animals after radiation disease caused by exposure to some other types of ionizing radiations.