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Results for “Body Surface Potential Mapping”

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PubMed2003

Baseline reconstruction for localization of rapid ventricular tachycardia from body surface potential maps.

Determination of an accurate electrocardiographic (ECG) baseline is generally needed for localization of ventricular arrhythmias with body surface potential mapping (BSPM). We suggest a novel signal processing method for ECG baseline reconstruction during monomorphic ventricular tachycardias (VT). The method is based on an assumption that VT consists of similar ventricular extrasystolic beats with overlapping depolarization and repolarization. The sequential reconstruction algorithm utilizes information of small variations in the heart rate and yields a non-overlapping QRST-signal, provided that the measurement set-up has a high enough temporal resolution to avoid distortions due to sampling differences and misalignment of individual beats. The reconstructed QRST-signal is utilized to subtract overlapping T-waves from the QRS complexes during VT. The use of the method is demonstrated with clinically measured BSPM data.

Body Surface Area↗

PubMed1986

Identification of best electrocardiographic leads for diagnosing anterior and inferior myocardial infarction by statistical analysis of body surface potential maps.

In view of the increasing interest in quantifying and modifying the size of myocardial infarction (MI), it is important to look for clinically practical subsets of electrocardiographic leads that allow the earliest and most accurate diagnosis of the presence and electrocardiographic type of MI. A practical approach is described, taking advantage of the increased information content of body surface potential maps over standard electrocardiographic techniques for facilitating clinical use of body surface potential maps for such a purpose. Multivariate analysis was performed on 120-lead electrocardiographic data, simultaneously recorded in 236 normal subjects, 114 patients with anterior MI and 144 patients with inferior MI, using as features instantaneous voltages on time-normalized QRS and ST-T waveforms. Leads and features for optimal separation of normal subjects from, respectively, anterior MI and inferior MI patients were selected. Features measured on leads originating from the upper left precordial area, lower midthoracic region and the back correctly identified 97% of anterior MI patients, with a specificity of 95%; in patients with inferior MI, features obtained from leads located in the lower left back, left leg, right subclavicular area, upper dorsal region and lower right chest correctly classified 94% of the group, with specificity kept at 95%. Most features were measured in early and mid-QRS, although very potent discriminators were found in the late portion of the T wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗

PubMed2001

Recording locations in multichannel magnetocardiography and body surface potential mapping sensitive for regional exercise-induced myocardial ischemia.

INTRODUCTION: This study aimed to identify the optimal locations in multichannel magnetocardiography (MCG) and body surface potential mapping (BSPM) to detect exercise-induced myocardial ischemia. METHODS: We studied 17 healthy controls and 24 coronary artery disease (CAD) patients with stenosis in one of the main coronary artery branches: left anterior descending (LAD) in 11 patients, right (RCA) in 7 patients, and left circumflex (LCX) in 6 patients. MCG and BSPM signals were recorded during a supine bicycle stress test. The capability of a recording location to separate the groups was quantified by subtracting the mean signal amplitude of the normal group from that of the patient group during the ST segment and at the T-wave apex, and dividing the resulting amplitude difference by the corresponding standard deviation within all subjects. RESULTS: In MCG the optimal location for ST depression was at the right inferior grid for the RCA, at the mid-inferior grid for the LCX, and in the middle of these locations for the LAD subgroup (mean ST amplitudes: CAD -80 +/- 360fT, controls 610 +/- 660fT; p < 0.001). In BSPM it was on the left upper anterior thorax for the LAD, left lower anterior thorax for the RCA, and on the lower back for the LCX subgroup (mean ST amplitudes: CAD -39 +/- 61 microV and controls 38 +/- 38 microV; p < 0.001). In MCG the optimal site for T-wave amplitude decrease was the same as the one for the ST depression. In BSPM it was on the middle front for the LAD, on the back for the LCX and on the left abdominal area for the RCA group. In accordance with electromagnetic theory, the largest ST segment and T-wave amplitude changes took place in MCG in locations orthogonal to those in BSPM. CONCLUSION: This study identified magnetocardiographic and BSPM recording locations which are sensitive for detecting transient myocardial ischemia by evaluation of the ST segment as well as the T-wave. These locations strongly depend on ischemic regions and are outside the conventional 12-lead ECG recording sites.

Aged↗

PubMed1988

Electrocardiographic body surface potential maps of the QRS and T of normal young men. Qualitative description and selected quantifications.

A qualitative and quantitative analysis of the Body Surface Potential Maps (BSPM) of 40 young men, ages 19-41, is presented utilizing a 180 electrode system, with 135 anterior leads and 45 posterior leads. Evidence for epicardial right ventricular breakthrough was demonstrated in 36/40 at 27.9 +/- 6.8 ms, whereas our previous studies on normal children (average age 12.5 years) have demonstrated evidence for epicardial right ventricular breakthrough at 25.0 +/- 8.9 ms. The peak-to-peak magnitude at maximal potential (at 42.3 +/- 4.8 ms) was not significantly different from that of the children (4,430 +/- 1,165 microV), and the peak-to-peak magnitude of ST-T was virtually the same as that of the children (1,182 +/- 376.2 microV). The terminal activation pattern of late QRS on the body surface map appeared in the true posterior, anterior superior, posterior right superior and/or right anterior superior positions, in order of frequency. There were other regions appearing less frequently. In contrast, this pattern in children was seen only in the anterior superior, right anterior superior, posterior right superior, and true posterior in order of frequency. In 18/40, the body surface manifestation of repolarization was seen an average of 9.4 +/- 4.8 ms before the end of the QRS. A new pseudocolor display with 31 color levels representing body surface potentials allowed excellent resolution of isopotential detail.

Adult↗

PubMed1989

Body surface potential mapping to monitor the effects of thrombolytic therapy following acute myocardial infarction.

The authors demonstrate the value of body surface potential mapping (BSPM) and a limited lead system in monitoring complete ECG evolution following myocardial infarction (MI) and the effects of thrombolytic therapy. They produced ST-segment isopotential maps, which indicate the site and extent of myocardial injury. Pathological Q wave maps were also produced, which intimate the extent of myocardial necrosis. Analysis of a sequence of maps recorded during the acute phase of MI revealed sudden changes attributed to reperfusion, reinfarction or "silent" events.

Adult↗

PubMed1996

Evaluation of body surface potential mapping changes after successful percutaneous transluminal coronary angioplasty.

OBJECTIVE: To assess the progress of chronic myocardial ischemia after successful percutaneous transluminal coronary angioplasty (PTCA) using body surface potential mapping (BSPM). DESIGN: For BSPM analysis the following kinds of maps were used: isopotential repolarization maps corresponding to 70% of ST-T interval's duration and isointegral maps corresponding to 0% to 20% of ST-T duration. BSPM measurements were taken before the PTCA and usually one to six days after this intervention. In 17 patients BSPM was carried out within two days after PTCA. Eleven to 14 BSPM examinations were usually carried out during six months of follow-up. Control coronary angiography was performed after six months in all but three patients. RESULTS: Substantial focal decrease of positive potential in repolarization caused by myocardial ischemia recovered gradually after successful PTCA. This appeared to be caused by the regression of "hibernating myocardium'. An increase of positive potential was statistically significant (P < 0.01) after the fifth week of PTCA intervention. There was a positive correlation between BSPM findings and chest discomfort of patients after PTCA. Chronic myocardial ischemia could be observed on isopotential and/or isointegral maps examined before the PTCA in 21 of 25 cases (sensitivity 84%).

Adult↗

PubMed2006

The effect of psychoemotional load on ventricular repolarization reflected in integral body surface potential maps.

The aim of the present study was to investigate the reflection of psychoemotional stress in the body surface potential distribution as documented by isointegral maps of cardiac activation and recovery. In 72 young men (18.3+/- 7.3 y.) with no cardiovascular history body surface potential maps (BSPMs) at rest and during the test of mental arithmetic were recorded. The digitalized data for each point of the QRS, STT and QRST integral maps, for each subject in both situations, were processed and evaluated by methods of univariate as well as spatial mathematical and statistical modeling. The results showed during MA a significant decrease of repolarization integral values over the sternum and right precordium, which contributed to analogically localized decrements also in the QRST BSM. The decrease occurred in more than 2/3 of lead points. The most pronounced changes were observed in the right precordial area, where potentials decreased in more than in 70 % of subjects. In conclusion, the discriminative power of the difference STT and QRST integral maps was strong enough to distinguish the mental arithmetic induced changes in the superficial cardiac electric field. These adrenergic transient alterations in ventricular recovery may be of importance in subjects at risk for ventricular arrhythmias.

Body Surface Potential Mapping↗

PubMed1988

Body surface potential maps with low-level exercise in isolated left anterior descending coronary artery disease.

One hundred and twenty-lead body surface potential maps (BSPMs) were recorded at rest, at immediate cessation of exercise and after 1 (early) and 5 minutes (late) of recovery in 14 patients with isolated, critical, left anterior descending (LAD) coronary artery stenosis. Exercise endpoints, at an average peak rate of 98 +/- 13, were usual pain worsening in 13 LAD patients, and diagnostic ST depression in lead V5 in 1 patient. Twelve patients also had positive thallium scans. BSPMs were also recorded in 8 normal subjects who exercised to peak heart rates similar to those of the LAD subjects. Spatially, there were similar exercise changes in QRS and ST-segment integral patterns over the precordium and inferior torso in both groups. These were transient in the control group but persisted to late recovery in the LAD group, particularly for ST integral. Quantitatively, multivariate analysis revealed significant temporal differences between the 2 groups. However, the only independent BSPM variable was the sum of ST integral decrease, averaging --2,323 +/- 1,809 microV.s for normal patients between rest and immediate cessation of exercise, compared with -3,828 +/- 2,329 microV.s for the LAD patients (p less than 0.05). Late recovery minus rest difference averaged -1,264 +/- 1,080 microV.s for normal subjects and -2,575 +/- 1,844 microV.s for LAD patients (p less than 0.01). To control for the physiologic changes of exercise, the ST integral temporal differential maps of the normal subjects were subtracted from those of the LAD patients and the sum of negative intergroup differences was assumed to reflect only ischemia. Correlation of ST integral ischemia values at immediate cessation of exercise and late recovery was high (r = 0.88); however, intertechnique correlations of the BSPM variables with quantitative angiographic scores and thallium perfusion scan scores revealed generally low r values (range 0 to 0.52). These data demonstrate that ischemic repolarization changes are detectable and quantifiable by BSPM at low levels of cardiac stress in patients with 1-vessel disease when the usual electrocardiographic criteria of myocardial ischemia are frequently absent. The data further suggest that ST integral changes reflective of myocardial ischemia persist well after the exercise recovery period and that they are complementary to, rather than substitutionary for, other indirect measures of myocardial ischemia.

Adult↗

PubMed1980

Total body surface potential mapping during exercise: QRS-T-wave changes in normal young adults.

Total body surface potential distributions were recorded from 20 normal young adults, 20-35 years old, during multistage maximal exercise testing on a bicycle ergometer. Using a system for measuring total body surface potential distributions from measurements at 24 locations, high-quality potential maps were obtained during exercise without requiring wave form averaging or special modes of exercise. Serial maps recorded at 1-msec intervals throughout QRS-T during exercise and during recovery from exercise were compared with corresponding maps recorded with the subjects at rest. During and after exercise, consistent changes appeared in the map patterns during early QRS and the ST segment and in the magnitude of the T-wave potentials. Increases in QRS duration (0-10 msec) also appeared during exercise. The changes in map patterns during early QRS in exercise strongly suggested changes in the initial sequence of activation in the ventricles. The results demonstrate the importance of analyses of total body surface potential distributions in understanding ECG changes during exercise.

Adult↗

PubMed1990

Exercise body surface potential mapping in single and multiple coronary artery disease.

Body surface ST integral maps were recorded in 36 coronary artery disease (CAD) patients at: rest; peak, angina-limited exercise; and, 1 and 5 min of recovery. They were compared to maps of 15 CAD patients who exercised to fatigue, without angina, and eight normal subjects. Peak exercise heart rates were similar (NS) in all groups. With exercise angina, patients with two and three vessel CAD had significantly (p less than 0.05) greater decrease in the body surface sum of ST integral values than patients with single vessel CAD. CAD patients with exercise fatigue, in the absence of angina, had decreased ST integrals similar (NS) to patients with single vessel CAD who manifested angina and the normal control subjects. There was, however, considerable overlap among individuals; some patients with single vessel CAD had as much exercise ST integral decrease as patients with three vessel CAD. All CAD patients had persistent ST integral decreases at 5 min of recovery and there was a direct correlation of the recovery and peak exercise ST changes. Exercise ST changes correlated, as well, with quantitative CAD angiographic scores, but not with thallium perfusion scores. These data suggest exercise ST integral body surface mapping allows quantitation of myocardium at ischemic risk in patients with CAD, irrespective of the presence or absence of ischemic symptoms during exercise. A major potential application of this technique is selection of CAD therapy guided by quantitative assessment of ischemic myocardial risk.

Adult↗

PubMed2002

Body surface potential mapping in patients with Brugada syndrome: right precordial ST segment variations and reverse changes in left precordial leads.

OBJECTIVE: The aim of this study was to perform quantitative signal analysis of high-resolution body surface potential mapping (BSPM) recordings to assess its usefulness for the electrocardiographic characterization of patients with Brugada syndrome. The diagnostic value of the QRS integral and of the gradient of the ST segment have not been elucidated in Brugada syndrome. METHODS: In 27 subjects (16 with Brugada syndrome and 11 healthy subjects), 120-lead BSPMs were recorded at baseline and after pharmacological provocation with intravenous administration of ajmaline (1 mg/kg). The recordings were analyzed for two regions outside the positions of the standard ECG leads: the right precordial leads (RPL) on the second and third intercostal space (high RPL) and the left precordial leads (LPL) between the fifth and seventh intercostal space (low LPL). RESULTS: At baseline, in high RPL regions, patients with Brugada syndrome showed more positive QRS integrals (-5+/-8 vs. -16+/-8 mV ms) and a steeper negative ST segment gradient (-0.62+/-0.41 vs. -0.29+/-0.40 mV/s) compared to healthy subjects, P<0.001. In contrast, in low LPL regions, reduced QRS integrals and positive ST segment gradients were observed. These ECG signs were even more pronounced after intravenous ajmaline and showed a better discrimination for patients with Brugada syndrome than differences in RPL or LPL during baseline, respectively. CONCLUSIONS: In the left precordial leads, patients with Brugada syndrome showed ECG changes which were reversed in relation to the ECG changes observed in right precordial leads. BSPM measurement is a useful tool to improve the understanding of the electrocardiographic changes in the Brugada syndrome.

Adult↗

PubMed1995

Electric instability after myocardial infarction displayed in body surface potential maps.

A longitudinal study during the first year after myocardial infarction (MI) was performed in 12 patients (pts) to evaluate the reversibility of the electric heart field changes occurring during the acute phase by means of body surface potential mapping (BSPM). Using correlation coefficients we showed that the inversion of electric processes in myocardial depolarization and/or repolarization during acute phase of MI displays irreversible damage of the myocardium that means high risk for the pt and that the healing of infarcted heart is not completed within 6 months after MI at least from the electrical point of view.

Body Surface Potential Mapping↗

PubMed2002

Dipyridamole body surface potential mapping: noninvasive differentiation of syndrome X from coronary artery disease.

Up to 20% to 30% of patients with angina and abnormal stress test have normal coronary arteries at angiography or syndrome X (Sy X). We tested whether body surface potential mapping (BSPM) with intravenous dipyridamole could differentiate patients with Sy X from patients with coronary artery disease (CAD). We compared the effects of intravenous dipyridamole (0.28 mg/kg over 4 min) on BSPM in 17 healthy volunteers (controls) and in 2 groups of patients with angina and abnormal ergometric tests who were referred for angiography: 27 patients with obstructive disease (> or =70% diameter stenosis) in the CAD group, and 17 patients with Sy X. Control subjects were easily differentiated from patients with CAD or Sy X by markedly smaller baseline BSPM DeltaST-T < or = LSD departure areas (P <.001), but the Sy X and CAD groups had similar ST-T departure areas. The average potential integral difference after dipyridamole (APID) differentiated Sy X and CAD patients: the mean APID increased in patients with Sy X and trended negative in the CAD group. The APID(20%-40%) (integrated over 20% to 40% of the ST-T interval) mean value was 0.59 +/- 0.67 microVs in the Sy X group and -0.18 +/- 0.59 microVs in the CAD group (P <.01). At a threshold APID(20%-40%) > 0.17 microVs, the sensitivity and specificity for Sy X was 71% and 78%, respectively; the area under the receiver operating characteristic curve was 0.79 (95% CI 0.64, 0.93). Dipyridamole BSPM is a promising noninvasive diagnostic modality to differentiate patients with Sy X from those with CAD.

Body Surface Potential Mapping↗

PubMed2004

QT dispersion estimated from 80 body surface potential map leads and from standard 12-leads ECG in psychiatric patients treated with dosulepin.

The aim of the study was to detect changes of the QT dispersion (QTd) due to cardiotoxicity of tricyclic antidepressant dosulepin. Electrocardiographic and body surface potential mapping (BSPM) recordings were obtained using Cardiag 112.2 diagnostic system from 27 psychiatric outpatients treated with prophylactic doses of dosulepin and compared to those obtained from 37 healthy volunteers. From these recordings the QTd and the dispersion of heart rate-corrected QT interval QTc were evaluated. These parameters were estimated both from 80 BSPM leads and from 12 standard ECG leads. Acquired data were statistically correlated by Spearman rank order correlation coefficient with dosulepin plasma levels. The average QTd evaluated from BSPM leads (+/-SD) in the dosulepin group was significantly higher [70 (+/-21) ms] than that in the control group [34 (+/-12) ms] (P< 0.001). Moreover, the correlation between QTd and the dosulepin plasma level was statistically significant as well (P< 0.001) with the value of correlation coefficient 0.7871. The QTd evaluated from standard 12 ECG leads was increased in dosulepin group as well [46 (+/-18) ms vs. 28 (+/-10) ms - P< 0.05] but we have not found any significant correlation of the QTd with the dosulepin plasma level. According to the above-mentioned results we can conclude that the QTd estimated from BSPM leads (but not that estimated from 12-lead ECG) could be used as a marker of the dosulepin effect on the myocardium.

Adult↗

PubMed2002

Late QRS activity in signal-averaged magnetocardiography, body surface potential mapping, and orthogonal ECG in postinfarction ventricular tachycardia patients.

BACKGROUND: Delayed electrical activity necessary for re-entrant ventricular tachycardia (VT) is detectable noninvasively with high resolution techniques. We compared high resolution signal-averaged analysis of magnetocardiography (MCG), body surface potential mapping (BSPM), and orthogonal three-lead ECG (SA-ECG) in the identification of patients prone to VT after myocardial infarction (MI). METHODS: Patients with remote myocardial infarction and cardiac dysfunction were studied, 22 with (VT group) and 22 without VT (control group). MCG with seven channels and BSPM with 63 and SA-ECG with three orthogonal leads were registered. After signal-averaging and highpass filtering, three time domain analysis (TDA) parameters describing late electrical activity were computed: QRS duration (QRSd), root mean square amplitude (RMS) of the last 40 ms of QRS, and the duration of the low-amplitude QRS end (LAS). RESULTS: All parameters by each method were significantly different between the patients' groups. For example, LAS parameter in MCG was 59 (SD 22) ms in the VT group vs. 37 (SD 13) ms in controls (P < 0.001), 77 (SD 22) ms vs. 56 (SD 19) ms in BSPM (P = 0.002), and 60 (SD 24) ms vs. 39 (SD 22) ms in SA-ECG (P = 0.005). The combination of LAS parameter in MCG and SA-ECG resulted in improved performance in comparison to any single parameter with 95% sensitivity and 68% specificity. CONCLUSIONS: All three high resolution methods identified VT propensity among post-MI patients with cardiac dysfunction and between-method differences were small. Information in MCG and SA-ECG may be complementary and their combination could be of value in postinfarction arrhythmia risk assessment.

Aged↗

PubMed1985

Myocardial infarction diagnosis with body surface potential mapping, electrocardiography, vectorcardiography and thallium-201 scintigraphy: a correlative study with left ventriculography.

In 35 subjects with typical or atypical angina and/or documented myocardial infarction (MI), body surface potential maps (BSPMs), ECG, VCG and rest Thallium-201 (T1-201) have been compared to left ventriculography (LVG). BSPMs were recorded with 26 ECGs, and BSPM abnormalities for MI cases were considered to be areas of normally positive potentials that have become negative. Subjects with MI were classified according to the segmental localization and degree of asynergy on LVG. Moderate anterolateral and apical asynergy were found to correlate with BSPM diagnosis of anterolateral MI and ischemia, severe anterolateral and apical asynergy with BSPM diagnosis of anterolateral MI and ischemia, and moderate diaphragmatic and/or posterobasal asynergy with BSPM diagnosis of posterior MI. Simultaneous anterior and posterior asynergy were found for BSPM diagnosis of anterior with posterior MI. Subjects with no LVG asynergy had normal BSPMs. BSPM diagnosis had the highest correlation coefficient with the LVG diagnosis (r = 0.88). ECG and VCG showed similar results with r = 0.65 and 0.71 respectively, while T1-201 had r = 0.55. The examination of our BSPMs, as well as the ECG, VCG and T1-201, did not permit to detect apical damage in presence of anterior MI, and posterobasal damage in the presence of inferoposterior MI. It is concluded that BSPMs are slightly superior to ECG and VCG for diagnosis of MI.

Adult↗

PubMed2006

Spatial distribution of repolarization and depolarization abnormalities evaluated by body surface potential mapping in patients with Brugada syndrome.

BACKGROUND: Mutations in sodium channel gene, SCN5A, have been identified in Brugada syndrome, but it is still unclear as to how sodium channel dysfunction relates to arrhythmogenesis. We examined spatial distribution of both repolarization and depolarization abnormalities in patients with Brugada syndrome by using 87-leads body surface potential mapping (BSPM). METHODS: BSPM was recorded under baseline condition and after pharmacological interventions in 28 patients with Brugada syndrome (27 males, 49 +/- 14 years). The ST-segment amplitude 20 ms after the end of QRS (ST20), QRS duration, and corrected recovery time (RTc) were measured in all 87-leads, and averaged among 6-leads (D-F, 5-6) reflecting right ventricular outflow tract (RVOT) potentials and the other 81-leads. RESULTS: The ST20 was elevated at baseline, normalized by isoproterenol, and augmented by pilsicainide in only the RVOT. The RTc was longer at baseline and increased by pilsicainide in only the RVOT. On the other hand, the QRS duration was slightly widened at baseline, further increased by pilsicainide, but not changed by isoproterenol in both leads. CONCLUSIONS: The ST-segment elevation and the RTc prolongation were localized and modulated by agents only in the RVOT region, while the slight QRS widening at baseline and further increase by pilsicainide were observed homogeneously. Our data suggest that depolarization abnormalities are distributed homogeneously, whereas repolarization abnormalities are localized in the RVOT.

Adolescent↗

PubMed1997

Additional data on body surface potential maps of ventricular repolarization in normal adults.

To date most published studies on normal basic data of the potential distribution of cardiac activity have been restricted to ventricular depolarization. Only a few papers have dealt with ventricular repolarization in normal subjects. This is an attempt to establish the basic data of the body surface potential maps (BSPM) of ventricular repolarization in normal adults. BSPM of ventricular repolarization utilizing 87 electrodes through the heart potential map system designed by Toyama et al. were studied in 50 normal Chinese male adults. The following information on BSPMs was obtained: (1) In the initial phase of ventricular repolarization, the potential maximum was located on the precordial area and the potential minimum appeared on the right-superior portion of the back; (2) The movement of potentials was counterclockwise and stable during the later portion of the T loop; (3) The magnitudes of the potentials changed in a spindle pattern with the drifting of ventricular repolarization. They first increased and then decreased with the largest value being around the peak period of the T wave; (4) The absolute value was greater in the potential maximum than the potential minimum throughout ventricular repolarization. There was no "reversal" potential distribution pattern. This parameter may be of importance clinically; (5) There were usually multiple potential maxima and multiple potential minima during the ST segment and early phase of the T wave; (6) The largest potential maximum and potential minimum were 0.93 +/- 0.28 mV and 0.35 +/- 0.19 mV, respectively. The potential maximum and potential minimum at the peak T wave were 0.91 +/- 0.23 mV and 0.35 +/- 0.17 mV, respectively. Obviously, this study offers valuable basic data on the BSPM in normal adults and will be helpful to our understanding of the BSPM in various heart diseases.

Adult↗