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The paper contains a description of the "Neurotest7A" signal generator designed for testing the electroencephalography and electrocardiography equipment, including its functional and technical characteristics, structural scheme and operational algorithm.
For the purpose of evaluating cause, frequency, type and seriousness of arrhythmias in dialysis patients, 14 chronic uremics, 8 on bicarbonate-dialysis, 6 on acetate-dialysis underwent a basal ECG, echocardiography and a Holter dynamic electrocardiography (ECGD) for a duration of 96 hours. Before and after dialysis PAO, body weight, serum electrolytes and arterial pH were controlled. In 11 patients (78%) supraventricular and ventricular arrhythmias were discovered of equal frequency and seriousness both in the inter and intra dialytic phase, even if more frequent in ventricular hypertrophic patients (IVSn) the complex ventricular arrhythmias (Lown greater than 2). The seriousness and frequency of ventricular and supraventricular arrhythmias in the dialytic phase did not seem to depend either on the type of tampon or on the presence or absence of cardiopathies while in the inter-dialytic phase the seriousness of ventricular arrhythmias seems to depend upon the presence of cardiopathies. The Authors conclude that the pathogenesis of arrhythmias in uremic patients on dialysis is multifactorial and that their elevated incidence makes the use of a Holter in these patients recommendable.
The biophysical diagnostic methods are an unusual element of evaluation of the fetus state in the time of pregnancy and delivery. Nowadays, the applied methods of fetus supervision during labor don't ensure the permanent analysis and they don't deliver diagnostic information about fetus hypoxia. The purpose of avoiding the risk of fetus injury and its hypoxia should be developed by technologies which allow making a diagnosis of fetus condition and to detection of intralabor hypoxia, So, especially all new methods are indicated, which make easier the diagnostic in a permanent mode and which allow for hypoxia expectation and they also allow to reduce the number of unjustified medical interference. One of these methods is fetus electrocardiography.
AIM: To show possibilities of dipolar electrocardiography (DECG) in diagnosis of left ventricular hypertrophy (LVH). MATERIAL AND METHODS: We made DECG in 151 healthy subjects and 158 hypertensive patients. To characterize DECG quantitatively, we used the integral activation duration index (IADI) calculated as a weighted sum of the areas with different duration of activation, module of the maximal vector QRS, QRSxIADI (IADIM). RESULTS: In patients with left ventricular myocardial mass index (LVMMI) under 150 g/m2, sensitivity of DECG was 38-49%, in the index over 150 g/m2 sensitivity reached 38-75%, specificity 89-98% compared to healthy examinees and 72-82% compared to hypertensive patients without LVH. The IADIM parameter correlates directly (moderate correlation) with duration of QRS complex and LVMMI. CONCLUSION: Possibilities of using parameters IADI and IADIM for assessment of electrophysiological myocardial remodeling and their correlation with other methods need further investigations.
BACKGROUND: Multi-detector spiral computed tomography with retrospective electrocardiography-gated image reconstruction allows detailed anatomic imaging of the heart, great vessels and coronary arteries in a rapid, available and non-invasive mode. OBJECTIVES: To investigate the spectrum of findings in 32 consecutive patients with chest pain who underwent CT coronary angiogram in order to determine the clinical situations that will benefit most from this new technique. METHODS: Thirty-two patients with chest pain were studied by MDCT using 4 x 1 mm cross-sections, at 500 msec rotation with pitch 1-1.5, intravenous non-ionic contrast agent and a retrospectively ECG-gated reconstruction algorithm. The heart anatomy was evaluated using multi-planar reconstructions in the axial, long and short heart axes planes. Coronary arteries were evaluated using dedicated coronary software and the results were compared to those of conventional coronary angiograms in 12 patients. The patients were divided into four groups according to the indication for the study: group A--patients with high probability for coronary disease; group B--patients after CCA with undetermined diagnosis; group C--patients after cardiac surgery with possible anatomic derangement; and group D--symptomatic patients after coronary artery bypass graft, before considering conventional coronary angiography. RESULTS: Artifacts caused by coronary motion, heavy calcification and a lumen diameter smaller than 2 mm were the most frequent reasons for non-evaluable arteries. Assessment was satisfactory in 83% of all coronary segments. The overall sensitivity of 50% stenosis was 74% (85% for main vessels) with a specificity of 96%. Overall, the CTCA results were critical for management in 18 patients. CONCLUSIONS: Our preliminary experience suggests that CTCA is a reliable and promising technique for the detection of coronary artery stenosis as well as for a variety of additional cardiac and coronary structural abnormalities.
UNLABELLED: The purpose of this study was to evaluate myocardial electrocardiography (ECG)-gated 13N-ammonia (13N-NH3) PET for the assessment of cardiac end-diastolic volume (EDV), cardiac end-systolic volume (ESV), left ventricular (LV) myocardial mass (LVMM), and LV ejection fraction (LVEF) with gated 18F-FDG PET as a reference method. METHODS: ECG-gated 13N-NH3 and 18F-FDG scans were performed for 27 patients (23 men and 4 women; mean+/-SD age, 55+/-15 y) for the evaluation of myocardial perfusion and viability. For both 13N-NH3 and 18F-FDG studies, a model-based image analysis tool was used to estimate endocardial and epicardial borders of the left ventricle on a set of short-axis images and to calculate values for EDV, ESV, LVEF, and LVMM. RESULTS: The LV volumes determined by 13N-NH3 and 18F-FDG were 108+/-60 mL and 106+/-63 mL for ESV and 175+/-71 mL and 169+/-73 mL for EDV, respectively. The LVEFs determined by 13N-NH3 and 18F-FDG were 42%+/-13% and 41%+/-13%, respectively. The LVMMs determined by 13N-NH3 and 18F-FDG were 179+/-40 g and 183+/-43 g, respectively. All P values were not significant, as determined by paired t tests. A significant correlation was observed between 13N-NH3 imaging and 18F-FDG imaging for the calculation of ESV (r=0.97, SEE=14.1, P<0.0001), EDV (r=0.98, SEE=15.4, P<0.0001), LVEF (r=0.9, SEE=5.6, P<0.0001), and LVMM (r=0.93, SEE=15.5, P<0.0001). CONCLUSION: Model-based analysis of ECG-gated 13N-NH3 PET images is accurate in determining LV volumes, LVMM, and LVEF. Therefore, ECG-gated 13N-NH3 can be used for the simultaneous assessment of myocardial perfusion, LV geometry, and contractile function.
BACKGROUND: Nominal atrioventricular (AV) interval in dual chamber pacemaker (DDD) is not the best AV delay in the majority of patients with atrioventricular block. To find a simple method for optimizing AV delay adjustment, we assessed surface electrocardiography (ECG) for optimizing AV delay during dual chamber pacing. METHODS: DDD pacemakers were implanted in 46 patients with complete, or almost complete, AV block. Optimal AV delay was achieved by programming an additional delay of 100 ms, to the width of intrinsic P wave or to the interval between pacing spike to the end of P wave on surface ECG. Left ventricular (LV) end diastolic and end systolic volumes, ejection fraction and diastolic parameters were measured by Doppler echocardiography during both nominal and optimal AV delay pacing. RESULTS: Compared to nominal AV delay setting, LV end diastolic volume increased [to (53.2 +/- 11.3) ml from (50.2 +/- 10.2) ml, P < 0.05], end systolic volume decreased [to (26.1 +/- 9.0) ml from (27.9 +/- 8.2) ml, P < 0.05] during adjusted AV delay pacing, resulting in an increase in LV ejection fraction [to (68.2 +/- 5.3)% from (64.5 +/- 4.3)%, P < 0.05]. LV diastolic filling and isovolumic relaxation time were not significantly changed. CONCLUSION: Optimization of AV delay by surface ECG is a simple method to improve LV systolic function during dual chamber pacing.
INTRODUCTION AND OBJECTIVES: In patients with an inferior myocardial infarction (IMI), ST-segment depression in left precordial leads during exercise electrocardiography (ExECG) has been associated with left anterior descending coronary artery (LADCA) disease. The aim of this study was to assess the value of stress echocardiography in identifying LADCA disease in patients with IMI and a highly abnormal ExECG result. METHODS: The study included patients with an IMI and an abnormal ExECG result whose coronary angiography findings were available. A highly abnormal ExECG result was defined as ST-segment depression in three or more leads, including V5. The wall motion score index was calculated and each patient was evaluated echocardiographically for ischemia in LADCA territory. RESULTS: Of 241 patients who underwent stress ECG, 100 (mean age 57 [11] years) met inclusion criteria. Some 38 had significant LADCA stenosis and, in 75, ExECG gave a highly abnormal result. The sensitivity, specificity and accuracy of a highly abnormal ExECG result for detecting LADCA disease were 74% (60%-88%), 26% (15%-37%), and 44% (34%-54%), respectively. Echocardiographic detection of ischemia had similar sensitivity, at 74%, but higher specificity, at 92% (P< .001), and accuracy, at 85% (P< .001). Multivariate analysis of clinical, exercise test, and stress echocardiography variables revealed that the only independent predictors of LADCA disease were age (OR=1.070), recent IMI (OR=0.136), and ischemia in LADCA territory (OR=19.9). CONCLUSIONS: Stress echocardiography is a good noninvasive technique for detecting LADCA disease in patients with an IMI. The diagnostic accuracy of a highly abnormal ExECG result is not sufficient for its use in this clinical setting.
Using Holter electrocardiography, the primary factors affecting the occurrence and severity of ventricular premature systoles (VPS) and the method of treatment of VPS in patients having no apparent heart disease were examined. Pathological significance of catecholamines on the occurrence of VPS was studied in 182 patients. The close correlation between the severity of VPS and the total amount of urinary norepinephrine excretion demonstrated in this study suggests that the occurrence of VPS in patients with no apparent underlying heart disease, especially those over 40 years of age, may be mediated by enhanced endogenous catecholamine activities. This assumption is further substantiated by the fact that beta adrenoceptor blockade was effective against VPS in patients excreting high amounts of catecholamines, but not in patients with normal catecholamine excretion. Antiarrhythmic efficacy of class IA (disopyramide), IB (aprindine, mexiletine), II (propranolol), III (amiodarone) and IV (verapamil) drug was studied in 110 patients having more than 1,000 VPS per day. Judging from these results, we may conclude that: 1) VPS with short coupling intervals should be treated with class I drugs such as mexiletine which have a fast kinetics of unbinding from the inactivated state, 2) VPS with intermediate or long coupling intervals should be treated with class I drugs such as disopyramide and aprindine, which have a slow kinetics of unbinding from the inactivated state, 3) class II drug, propranolol, was effective against VPS associated with an increased sympathetic tone, 4) class III drug, amiodarone, was the most potent antiarrhythmic agent against any type of VPS, and 5) class IV drug, verapamil, appeared effective against VPS in elderly patients.
OBJECTIVE: To evaluate the patterns of electrocardiography (ECG), cardiac risk factors and its clinical consequence in women with epithelial ovarian cancer (EOC) who received paclitaxel and carboplatin (PC) as front line chemotherapy. MATERIAL AND METHOD: The medical records and electrocardiographic data of women with EOC who received paclitaxel (175 mg/min2) and carboplatin (AUC=5) every 3 weeks at Chiang Mai University Hospital between January 2000 and December 2004 were reviewed for cardiac risk factors and clinical consequence. RESULTS: Among 79 women receiving PC for EOC, 43 (54.4%) had cardiac risk factors. Seventy (88.6%) women had normal ECG, the remaining nine had sinus tachycardia (5), bundle branch block (2), mild T inversion (1), and Wolff-Parkinson-White syndrome (1) before the first course of chemotherapy. Among 70 women with normal initial ECG 8 (11.4%) had sinus tachycardia, one (1.4%) had early depolarization, two (2.9%) had sinus bradycardia and three (4.3%) had sinus arrhythmia in subsequent ECG All these cardiac disturbances were asymptomatic and needed no intervention, indicating grade I toxicity. The odds ratio of developing abnormal ECG in women with cardiac risk factor was 1.24 (95% CI = 0.33 to 4.64, p = 0.77). Among nine patients with abnormal ECG before the first course of PC, six (66.7%) had subsequent abnormal ECG but all were asymptomatic and no worsening of abnormal ECG pattern was noted. CONCLUSION: Although paclitaxel and carboplatin chemotherapy could induce abnormal ECG in women with either normal or abnormal prior ECG, its consequence was of no clinical significance. Therefore, the benefit of ECG before each treatment course was theoretically limited.
Signal-averaged electrocardiography is a useful diagnostic tool and screening test for those patients at risk for the development of VT. It is also useful in the evaluation of the patient after MI and the patient with unexplained syncope. The prognostic value of the signal-averaged ECG process is gaining popularity. More investigation is needed, especially in the areas of technique and significance of abnormalities, before the signal-averaged ECG becomes a routine test in diagnosing dysrhythmias. The signal-averaged ECG provides the health care team with a new, non-invasive test. Knowledge of its use and application can provide the clinician with additional information that can aid in the screening process for patients at risk for sudden cardiac death.
Fifteen children and adolescents with muscular dystrophy underwent investigation by Doppler echocardiography and high amplification electrocardiography to evaluate the quality of left ventricular function. High amplification ECG showed minor intra-atrial conduction defects in 3 cases and abnormal late micro potentials without arrhythmogenic late potentials in 3 other cases. Significant abnormalities were observed in 40% of children examined. Doppler echocardiography showed relative conservation of systolic left ventricular function but a decrease in indices of contractility was observed in 46% of cases, especially in patients with Duchenne muscular dystrophy. Abnormalities of left ventricular distensibility were observed earlier and were more common (53% of cases). A significant decrease in cardiac output was found in 50% of patients, especially among the older and more severely affected children irrespective of the type of muscular dystrophy. These two investigations provide complementary information for the evaluation of left ventricular function of children with muscular dystrophy and they are proposed routinely for the follow-up of these patients.
A Mason-Likar (M-L) leads system has been widely used in the exercise electrocardiography (ECG) using treadmill for the detection of myocardial ischemia. In routine treadmill exercise ECG using M-L lead, we often observe different patterns of ST-T forms those of II, III and aVF on bipolar leads. In this study, on 213 patients, conventional 12 lead ECG and the M-L lead placement ECG were recorded both at supine and standing positions. A careful analysis was made on all the records of patterns, durations, and amplitudes of QRS and T waves. We also evaluated the ST trendgram of patients with no ischemic changes proven exercise TI-201 myocardial single photon emission tomography (SPECT). Quantitative examination showed no significant differences between those in precordial leads of the standard and the M-L lead system in any subjects. The augmented amplitude of QRS and T waves, the disappearance of abnormal Q-waves in II, III, aVF lead, the negative inversion in QRS phase in lead aVL an left axis deviation were often recognized with M-L lead placement. In treadmill exercise ECG, ST depression more than 1 mm in II, III, aVF lead was noted 14 out of 17 patients with no ischemic changes. The all ST-T changes showed "not-decrescendo" type in ST trendgram. We concluded that rigorous evaluation for electrical axis, the configuration of ST-T waves and the existence of myocardial ischemia in leads II, III, aVF was necessary on treadmill exercise ECG using M-L lead replacement.
In patients with acute myocarditis, arrhythmias constitute one of the crucial risk factors for morbidity and mortality. To clarify the incidences and the chronological features of arrhythmias and their correlation with the histopathology of the heart, we conducted continuous electrocardiography in an animal model of viral myocarditis, and light microscopy of the heart with special reference to the conduction system. Forty weanling C3H/He mice were divided into an inoculated group (IG) and a control group (CG), of 20 mice each. IG was injected intraperitoneally with coxsackie B3 virus and CG was injected with virus-free culture medium. Thin electrodes were implanted in their chest walls and connected with an electric impulse transmitting device so that they could move freely. ECGs were recorded continuously without anesthesia up to the 14th postinoculation day. The atrial and ventricular myocardium and the conduction system were studied by light microscopy. In CG, no arrhythmia was noted. In IG, various kinds of arrhythmias were documented. The incidences of the arrhythmia in the 20 mice were: sinus arrest 80%, second or third degree atrioventricular (AV) block 30%, premature atrial complexes 30%, premature ventricular complexes 20%, and ventricular tachycardia 10%. Arrhythmias were usually transient and recurrent, and the majority of them developed between the 6th and 13th day, when the histologic changes of the heart were greatest. There seemed to be a correlation between the kind of arrhythmias and the myocarditic lesions. Mice with sinus arrest or AV block developed histopathologic changes in the sinus node or AV conducting tissue, respectively. In the early stage of myocarditis, no inflammatory changes were apparent in the sinus node in the mice with sinus arrest.
Electrocardiography (ECG) and arterial blood gases (ABG) were taken to monitor 90 patients prior to, during and after bronchofiberscopy. PaO2 generally decreased during the procedure without supplemental oxygen. Patients who underwent bronchofiberscopy with PaO2 less then 9.31 kPa were 66.67%. The mean of the decrease of SaO2 was 5.79 +/- 7.74%. 83.33% of the patients developed sinus tachycardia. There were 26.67% of the patients showed abnormal P wave, ST-T wave, Q-T interval etc during the procedure. 93.33% of them were given oxygen via a nasal stuff during the procedure and had an increase of PaO2.
The authors selected 37 permanent pacemaker patients followed for eleven successive months, with symptomatology eventually related to the pacing system. An Holter ambulatory monitorization was performed to all of them during 24 hours. Twenty one had single chamber systems and the others double chamber. Twelve malfunctions were found in ten patients. Six due to "undersensing", 4 related to "oversensing", and 2 from loss of capture. Two patients had tachycardia pacemaker mediated. An inadequate mode of pacing was found in other two cases. Fifteen rhythm disturbances not related to the pacemaker systems were registered in thirteen patients: supra-ventricular in 9; ventricular greater than or equal to 3 degree of lown in 5; and 2nd degree A.V.B. Mobitz type I in one case. Four patients were submitted to surgical intervention in order to modify the mode of pacing. It was also necessary to reprogram ten patients. The Holter Ambulatory Electrocardiography revealed to be an important diagnostic method for the detection of intermittent malfunction of pacing systems. The occasional changes of cardiac rhythm not linked with pacing were also revealed.
The authors report their experience of signal-averaged electrocardiography (SAE) in arrhythmogenic right ventricular dysplasia (ARVD) in a study comparing the results in 40 control subjects, 21 patients with ARVD with episodes of sustained monomorphic ventricular tachycardia (VT) (Group I), 7 patients with ARVD without sustained VT (Group II) and 10 asymptomatic members of the families of patients in Group I (Group III). There were significant differences in the results of SAE in the time domain between the control group and Group I, patients with "classical" ARVD. The RMS 40 (root mean square of the last 40 ms of the QRS complex) was the most sensitive parameter but the specificity was less than the averaged QRS width and the low amplitude signal duration. The results in Group II were more varied, some patients having clearly abnormal SAE and others strictly normal recordings. In Group III, the investigation was normal. Spectral analysis after Fourier transformation did not show significant differences between the 3 groups. A difference was observed between the diffuse and localised forms of ARVD in Groups I and II: the localised forms had a shorter QRS width and low amplitude signal duration than the diffuse forms. Also, there was a relationship in Group I between age and duration of QRS and delayed potential which increased and with the RMS 40 or 50 which decreased. This is an argument in favour of the progressive nature of ARVD with respect to time.
To study the diagnostic values of intrapartum fetal electrocardiography (FECG) and cardiotocography (CTG), 68 patients in labor were monitored at random. One-min Apgar score was chosen as the gold standard. The specificity (87.1%) and accuracy (86.8%) of FECG were found better than those of CTG (54.5% and 57.4% respectively). Fetal hypoxia and acidosis was firstly manifested by shortened P-R interval, FHR deceleration and increase in the T wave amplitude. It suggested that FECG can be a reliable diagnostic method following CTG screening.