Biomedical subjects

S Yakubo

Publications and source records attributed to S Yakubo.

8 recordsLinked to original sources

PubMed2000

Normal limits of high-resolution signal-averaged ECG parameters of Japanese adult men and women.

High-resolution signal-averaged electrocardiography (Hi-Res ECG) has been found useful in measuring ventricular late potentials for identifying patients prone to life-threatening ventricular arrhythmias. Several studies have reported cut-off values (normal limits) of Hi-Res ECG parameters, including sex-specific limits, for adult population. However, there are no such studies reporting such limits in the Japanese population. Hi-Res ECGs were recorded from 482 normal healthy patients (204 men; 278 women) with no cardiac disease and normal electrocardiogram. Three Hi-Res ECG parameters filtered QRS duration (FQRSD), low amplitude signal duration under 40 microV of terminal QRS (LASD), and root mean square voltage in the terminal 40 milliseconds (RMSV) were analyzed. FQRSD was longer in men than in women (P < .0001). RMSV was larger in men than in women (P < .0001). There was no significant difference in LASD between men and women. The upper limit (90th percentile) of FQRSD was 116 milliseconds for women. The upper limit of LASD was 42 milliseconds for both men and women. The lower limit (10th percentile) of the RMSV was 14 microV for both men and women. There was no significant difference in the distributions of the Hi-Res ECG parameters between our study and an earlier study on mostly whites from the United States and Europe. The upper limits (90th percentile) of FQRSD and LASD in the Japanese normal patients were nearly the same as for whites. But, the lower limit (10th percentile) of RMSV in our Japanese normals was significantly smaller than that for whites. Therefore, it may be necessary to use race-specific normal limits for late potential analysis. Criteria for abnormal late potentials (defined as abnormal values in at least 2 of the 3 Hi-Res ECG parameters) were met in 18 of 482 (3.7%) normal healthy patients. Further studies are needed to evaluate the role of these criteria in identifying cardiac patients with life-threatening arrhythmias in the Japanese population.

Adolescent↗

PubMed1995

Intra-QRS high-frequency ECG changes with ischemia. Is it possible to evaluate these changes using the signal-averaged Holter ECG in dogs?

The purpose of this experiment is to study the possibility of intra-QRS high-frequency electrocardiographic (HFECG) changes for the evaluation of and recovery from myocardial ischemia in both the time-domain and spectral-turbulence analyses on the signal-averaged ECG using the Holter ECG monitoring (Holter SAECG) system. A balloon catheter was inserted into the left anterior descending coronary artery (LAD of 8 mongrel dogs and was maintained inflated for 2 hours to occlude the LAD and then was deflated to allow for reperfusion. The cardiac signal from the three orthogonal leads of the surface ECG (X, Y, and Z) was recorded and analyzed with a Del Mar Avionics (model 459, Irvine, CA) recorder and analyzer (model 563). The Holter SAECG was assessed before the LAD occlusion phase (control), during the coronary occlusion phase (ischemia), after the reperfusion phase (recovery). To evaluate intra-QRS ECG changes in the time-domain analysis, root-mean-square (RMS) voltage of the entire QRS in 40-250 HZ (40 RMS), 100-250 Hz (100 RMS), and 150-250 Hz (150 RMS) were studied and the vector magnitude of the QRS was depicted. In the spectral-turbulence analysis and spectrocardiogram to study the discordance of the ECG wave front velocity by fast Fourier transformation analysis, the interslice correlation mean (IC mean) and interslice correlation standard deviation (IC SD), which were calculated as the mean and standard deviation of the Pearson correlation coefficient of each time slice with its neighbor, were investigated. In the time-domain analysis, the LAD occlusion by balloon catheter at ischemia produced a reduction in 40 RMS, 100 RMS, and 150 RMS, while a restoration was seen at recovery in 40 RMS and 100 RMS. In the spectral-turbulence analysis, LAD occlusion at ischemia caused a decrease in IC mean and an increase in IC SD. The waveform of the vector magnitude and the spectrocardiogram seen at control showed changes with ischemia and was restored at recovery with the coronary reperfusion. It was thought possible to capture the intra-QRS HFECG changes that occur during myocardial ischemia and recovery from it in the time-domain analysis and spectral-turbulence analysis on the Holter SAECG system in spite of the limitation of this methodology. To evaluate myocardial ischemia and recovery, this method should be useful clinically.

Animals↗

PubMed1995

[Evaluation for micropotential analysis by signal-averaged ECG using Holter monitoring].

The development of signal-averaged electrocardiogram (SAECG) has made possible the examination of ventricular late potentials (LP). Recently, the Holter SAECG system, which uses the tape of Holter monitoring, was produced. In the filtered QRS duration (FQRS), a correlation of R = 0.81 was seen between real time SAE and Holter SAE. Correlation of root mean square voltage of the signals in the last 40 mS of QRS (RMS40) and the duration of low amplitude signals (< 40 microV) in the latter part of the QRS (LAS40) were 0.79 and 0.70, respectively between these two systems. As good correlation was seen among the various indicators on the Holter SAECG and real time SAECG, a comparative study in the evaluation for ventricular tachycardia (VT) was performed on these two SAECG systems. With the Holter SAECG, positive LP were as follows: in myocardial disease with VT, 83.3% were positive LP; in myocardial disease without VT, 7.5% were positive LP; and in the healthy subjects, 0% were positive LP. For assessing VT, either real time SAECG or the Holter SACGE may be considered equally suitable for clinical use. During the treadmill exercise test, myocardial ischemia was investigated by the Holter SAECG system. After exercise, healthy subjects revealed longer FQRS, larger root mean square voltage of the signals in the QRS (RMS Total). While in ischemic heart disease, that had ST depression on the Holter ECG after exercise, decrease in RMS Total was found. For assessing myocardial ischemia, it is believed that Holter SAECG had the possibility of evaluating high frequency component in the entire QRS.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography, Ambulatory↗

PubMed1993

Effect of reperfusion by direct percutaneous transluminal coronary angioplasty on ventricular late potentials in cases of total coronary occlusion at initial coronary arteriography.

The relationship between the time required for reperfusion and the incidence of late potentials was studied in 94 patients who survived a first acute myocardial infarction (AMI) and who showed total occlusion of the infarct-related artery at an initial coronary arteriography. Sixty-three patients who successfully underwent direct percutaneous transluminal coronary angioplasty (PTCA), and 31 who were treated conventionally (controls), underwent signal-averaged electrocardiography. Direct PTCA patients were classified into 5 groups according to the time required for reperfusion: < or = 4, 4-6, 6-8, 8-10, and > or = 10 h. The incidence of late potentials in these groups was 8%, 12%, 14%, 33%, and 43%, respectively, and 48% in the controls. Late potentials were recorded more frequently as the period until successful reperfusion increased: the incidence of late potentials was significantly lower in the < or = 4 and 4-6 h groups than in the controls (p < 0.005 and p < 0.05, respectively). Therefore, reperfusion achieved within 6 h reduced the incidence of late potentials in AMI patients and may be effective for preventing malignant ventricular arrhythmias.

Acute Disease↗

PubMed1992

Detection of late potentials. Comparison of two commercial high-resolution ECG systems.

Signal-averaged electrocardiogram (SAECG) is used for detection of ventricular late potentials (LPs) in cardiac patients. As many commercial SAECG systems become available, it is essential to determine if they provide equivalent diagnostic information. Two high-resolution (Hi-Res) ECG systems (MAC-12, Marquette Electronics, Inc (MEI), Milwaukee, WI and LVP101, Arrhythmia Research Technology (ART), Austin, TX) were tested on 143 subjects (13 controls and 130 cardiac patients, 21 of whom were tested for inducible ventricular tachycardia [VT]). Late potential measurements (total QRS duration, high-frequency low-amplitude signal duration, and root-mean-square voltage) obtained from the two systems were in good agreement in most of the controls and patients. Application of Multicenter criteria for the MEI system and Gomes criteria for the ART system yielded very good agreement in LP diagnosis (at least 2 parameters abnormal). The two Hi-Res systems predicted inducible VT with good accuracy. The MEI system gave slightly higher sensitivity (90% vs 70%) and specificity (91% vs 82%) than the ART system in patients tested for inducible VT. In controls, both systems gave the same specificity (92%) and the LP diagnosis agreed in all controls (100%). Although the number of patients was small, neither sensitivity nor specificity were significantly different between the two systems at p < 0.05. To conclude, MEI and ART Hi-Res systems gave very similar LP diagnoses when appropriate criteria were applied.

Cardiac Pacing, Artificial↗

PubMed1992

[Detection of ventricular late potentials comparison of 4 commercial high-resolution systems].

UNLABELLED: The purpose of this study was to evaluate the methodologic problems of noninvasive registration of ventricular late potentials. METHODS: we compared the results obtained in the same patients with four different systems which were Marquette MAC1, MAC12, ART LP101 and FUKUDA VCM 3000. Filtering was employed digital forward direction, 100-300 Hz in MAC1, digital FFT, 40-250 Hz in MAC12, digital, bidirectional, 40-250 Hz in ART and analogue, forward direction 40-300 Hz in FUKUDA VCM 3000. DEFINITION OF LATE POTENTIALS (LPs): Filtered QRS duration (FQRSD) was 120 msec or more, root mean square voltage in the last 40 msec (RMSV) was 15 microV or less in MAC12 and ART. FQRSD was 130 msec or more, RMSV was 15 microV or less in FUKUDA. FQRSD was 20 msec or more after QRS obtained from low resolution leads in MAC1. SUBJECTS: 163 patients [control 13, PVCs 23, myocardial infarction 55, others 51, IVCD (RBBB, LBBB, IVCD) 21] were included in this study. RESULTS: 17.6% of all patients (except for IVCD) showed LPs with MAC12, 20.0% with ART, 30.3% with FUKUDA, and 14.1% with MAC1. 23.1% of the control group showed LPs with MAC12 and FUKUDA, but no cases showed LPs with ART and FUKUDA. 4.3% of the PVC group showed LPs with MAC12, 13.0% with ART and FUKUDA, but no cases showed LPs with MAC1. 25.5% of the myocardial infarction group showed LPs with MAC12 and MAC1, 30.9% with ART and 36.3% with FUKUDA. All four methods gave corresponding results in 65.4% of patients, 7.0% positive and 58.4% negative findings. FQRSD of MAC12, ART and FUKUDA was 110.2 +/- 18.1 msec, 105.2 +/- 20.4 msec and 125.8 +/- 22.8 msec respectively. Correlation coefficient (r value) in FQRSD was 0.90 between ART and MAC12, 0.74 between ART and FUKUDA, and 0.75 between FUKUDA and MAC12. RMSV of MAC12, ART and FUKUDA was 49.2 +/- 30.2 microV, 43.7 +/- 37.8 microV and 22.5 +/- 10.6 microV respectively. R value in RMSV was 0.59 between ART and MAC12, 0.38 between ART and FUKUDA and 0.43 between FUKUDA and MAC12. R value in high frequency low amplitude signals duration under 40 microV of LPs positive patients in MAC1 was 0.51 between ART and MAC 12, 0.18 between MAC12 and MAC1, and 0.32 between ART and MAC1. Most of the differences result from a different interpretation of the tracings. Especially LPs far from QRS offset could be registered with neither MAC12, ART nor FUKUDA.

Action Potentials↗

PubMed1990

Prospective study of late potentials to predict cardiac sudden death and ventricular tachycardias in patients with myocardial infarction surviving over 4 weeks.

We studied, prospectively, the predictive value of late potentials to cardiac sudden death and sustained ventricular tachycardias in 385 patients with myocardial infarction surviving over 4 weeks. Signal averaged electrocardiogram was performed over a 4 week period from the onset of acute myocardial infarction in all patients. Late potentials were observed in 118 of 385 patients. During the mean follow up period of 24.3 months, 17 patients had cardiac sudden death and 15 patients had symptomatic sustained ventricular tachycardias. In 16 of 17 patients with cardiac sudden death and 14 of 15 patients with sustained ventricular tachycardias, late potentials were observed. Sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy of late potentials to cardiac sudden death in these 385 patients were 94.1%, 72.3%, 13.6%, 99.6% and 73.2% respectively. Also, these predictive values of late potentials to sustained ventricular tachycardias in the group of patients were 93.3%, 71.9%, 11.9%, 99.6% and 72.7%, respectively. We concluded that the clinical usefulness of late potentials in patients with myocardial infarction surviving over 4 weeks in the negative predictive value to cardiac sudden death and sustained ventricular tachycardias is superior to that of positive predictive value. Sensitivity of late potentials to these events is also higher.

Adult↗

PubMed1987

The clinical evaluation of the late potentials in patients with ventricular arrhythmias.

We investigated the recognition of late potentials in patients with and without organic heart diseases and spontaneous ventricular arrhythmias. None of the normal subjects had late potentials and patients with ventricular arrhythmias but no organic heart diseases, also had no late potentials as well as patients with idiopathic ventricular tachycardias. Late potentials in patients with idiopathic cardiomyopathy were noted more frequently in the dilated type than in the hypertrophic type, especially in those with high grades of ventricular arrhythmias. Patients with old myocardial infarctions had a higher rate of late potentials recognition in cases of sudden death or ventricular tachycardias. On the other hand, we observed lower rates in patients during early stage of acute myocardial infarction in spite of the evidence of a higher rate of ventricular electrical instability. There was no association between ejection fractions, wall motion scores and late potentials. However, a higher recognition of late potentials was found in patients with inferior or posterior myocardial infarction and ventricular aneurysm. We concluded that the late potential must be evaluated in each of the different groups of organic heart diseases in order to estimate the clinical value of ventricular arrhythmias.

Adolescent↗