Normal P wave signal-averaged electrocardiogram (SAE) values were determined in 120 healthy Japanese adults (56 men, 64 women), aged 44.5±10.2 years (mean±SD). The P wave trigger method was used with a Fukuda FDX6500 recorder. We used bipolar Frank leads (X,Y,Z), and recordings were made with forward and backward digital Butterworth filters [40 Hz (18 dB / oct) -300 Hz (12 dB / oct)]. The recordings were taken for the following five parameters: forward and backward filtered P wave duration [fPd (F); fPd (B)]; bidirectionally corrected fPd [fPd (C)]; and 20 ms of the terminal portions of voltage at forward and backward filtering (RMS20). Overall, fPd (F) was 117.8-136.4 ms, fPd (B) 116.4-134.4 ms, fPd (C) 97.4-115.2 ms, RMS20 (F) 1.6-3.6 μV, and RMS20 (B) was 2.2-5.4 μV. Between the sexes, there were significant differences in fPd (F) (p<0.001) and fPd (B) (p<0.01) and in RMS20 (F) (p<0.05) and RMS20 (B) (p<0.05). Weak positive correlations were observed between fPd (F) and body surface area, fPd (F) and age, fPd (B) and body surface area, fPd (B) and age, fPd (C) and body surface area, and fPd (C) and age. There was no evident correlation, however, between either forward or backward RMS20 and body surface area or between forward or backward RMS20 and age. Differences in the normal P wave values between the sexes and age groups were evaluated in this study.
We compared signal‐averaged electrocardiography (SAE), SAE mapping, and left ventricular catheter mapping in 60 patients with ischemic heart disease. Using the data obtained in patients with no fragmented electrograms (EE) in the left ventricle, the late potential was defined by SAE as a filtered QRS duration > 131 msec or a root mean square voltage < 16 μV for the last 40 msec of the QRS complex. SAE mapping was performed by recording the signal‐averaged electrocardiogram at 48 sites on the body surface. With SAE mapping, the filtered QRS duration and the area in the last 20 msec of the QRS complex were significantly different between the patients with and without EEs. The late potential was defined by SAE mapping as a filtered QRS duration > 136 msec or an area < 28 μV.msec for the last 20 msec of the QRS complex. The sensitivity and specificity of detecting FEs were 46% and 88%, respectively, by the SAE filtered QRS criterion, while they were 66% and 88% by the root mean square criterion. In contrast, SAE mapping gave values of 66% and 92% by the filtered QRS criterion, as well as values of 100% and 92% by the area criterion. Thus, SAE mapping provided better detection of the EE and was more closely correlated with the results of catheter mapping, suggesting its potential for clinical application.
Recently, signal-averaging technique of high resolution electrocardiogram to detect electrical activity from the region of the bundle of His has developed. But this technique has not been commonly used for detection of His bundle activity, compare it with detection of late potentials. We studied suitable lead system, filters, signal averaging counts and high resolution gain to detect surface recording of His bundle activity. We also studied that if we recorded electrogram using late potential detection system, how many people could be detected for His bundle activity. Signal-averaging technique of high resolution electrocardiogram clinically applicated especially in atrio-ventricular block patients. There were significant changes in the frequency of identifying His bundle activity by signal-averaging electrocardiographic system recorded by varying leads system, filters, averaging counts, high resolution gain. When using this technique in a clinical situation, we should use most appropriate device, including its condition.
Signal-averaging of high resolution electrocardiographic data to identify ventricular late potentials, associated with ventricular tachycardia, has emerged as a useful technique for risk stratification following myocardial infarction. Multiple lead system, filters and criteria have been used in clinical trials. As variations in data analysis are introduced, it is important to assess the impact of the final results and to ensure that criteria for normalcy, appropriate for these variation, are developed if needed. This study compares the results produced by four systems and one system with a different filter used for determination of late potential parameters in the time domain. It is concluded that varying technique and filters significant changes in the values used to identify late potentials on high-resolution electrocardiographic records. These change may have clinical impact. When using this technique in a clinical situation, parameters values, appropriate for the device, and its components should be developed, if needed.
A 19 year-old girl with an unusual type of coarctation of the aorta terminating in complete obstruction is presented. At the age of 5 years, she was diagnosed by aortography to have coarctation of the aorta of type IV C according to Edward's classification. No surgical treatment was performed at that time because her growth was good and she didn't have hypertension. During the follow-up period, marked hypertension developed, and she was readmitted. The aortogram revealed a bicuspid aortic valve and total obstruction of the descending thoracic aorta at the site where coarctation was noticed previously. The abdominal aorta distal from the obstruction site was filled through rich collateral circulation. As these angiographic interval changes are very rare, we discussed the genesis of obstruction and operative indication by reviewing the literature.
Signal‐averaged (SA) electrocardiography and SA electrocardiographic mapping were performed in 50 patients with old myocardial infarction, 19 of whom had left ventricular aneurysm and 11 of whom had clinical sustained ventricular tachycardia.The SA electrocardiogram and SA electrocardiographic mapping data were then compared with those obtained by endocardial catheter mapping in patients with or without fragmented electrograms, sustained ventricular tachycardia, and ventricular aneurysm. Compared to SA electrocardiography, the SA map correlates with sustained VT with improved sensitivity but decreased specificity. However, SA electrocar diographic mapping had the advantage of displaying the extent of the body surface area that was positive for late potentials. In addition, the site of the longest endocardial fragmented electrogram could be predicted by SA electrocardiographic mapping, suggesting that this technique deserves wider clinical application.signal‐averaged electrocardiography, signal‐averaged electrocardiographic mapping, late potential, sustained ventricular tachycardia
A 67-year-old male was admitted with cyanosis, digital clubbing and exertional dyspnea. Laboratory data revealed severe polycythaemia with 26 mg/dl hemoglobin, red blood cell; 866 x 10(-4)/mm3, hematocrit 72.8% and PaO2 44.6 mmHg. Selective pulmonary angiography demonstrated a large arteriovenous fistula involving the right middle lobe. After venesection of 1,200 ml of blood, the middle lobectomy was performed safely. In a case of pulmonary arteriovenous fistula with such severe polycythaemia, preoperative venesection is useful to decrease perioperative complications.
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