Ventricular injury in acute left circumflex occlusion: Exploration using precordial bipolar leads and regional vectorcardiograms.

BACKGROUND: Precordial Bipolar Leads (PBLs) provide new electrocardiographic information derived from standard 12­lead ECG recordings. OBJECTIVES: To explore the usefulness of PBLs in patients with acute circumflex coronary artery (CxCA) occlusion. METHODS: Twelve patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA) were studied before and after acute CxCA occlusion and their data were processed with new methods based on PBLs. RESULTS: The findings were: 1. In right PBL V2-V1, a strong systolic current of injury moving in the left-to-right direction coexists with a strong right-to-left current of injury displayed in left standard unipolar precordial leads (V4, V5 and V6). 2. Ischemic changes lead to a significant increase (approximately 10 ms) in the QRS duration in different leads, although changes in the QRS loop rotation and folding were absent. 3. In the transverse, sagittal, and frontal planes, superimposing two PBLs and the corresponding Regional VCG facilitates the location of the J-point. 4. In the Regional VCGs of this group of patients, J-point and ST segment shifts produced an image that reminds the Greek letter omega (Ω). 5. The currents of injury flowing in opposite directions could result in electrical cancellation that minimizes ECG changes in the standard 12­lead recordings. CONCLUSIONS: Computerized processing of digital, standard 12­lead ECG recordings, provides new valuable diagnostic data in patients with acute CxCA occlusion. The loops revealed important information related to systolic currents of injury. Because these methods use routine 12­lead ECG data, the procedure is based only in software applications. CONDENSED ABSTRACT: Twelve patients undergoing PTCA were studied before and after acute CxCA occlusion and their data were processed with the new methods based on Precordial Bipolar Leads (PBLs) to explore their usefulness. The results showed strong systolic currents of injury in different and sometimes opposite directions in the right-to-left axis and ischemic alterations in the time and amplitude of the QRS waves. The superimposition of two-dimensional coordinates planes (x-y, x-z or z-y) helped to locate the J-point and to display the Regional VCG omega sign (Ω) of myocardial injury. In conclusion, computerized processing of digital ECG data provides new diagnostic information in patients with acute CxCA occlusion.

Right ventricle injury in RCA occlusion: Exploration using precordial bipolar leads and surrogate vectorcardiograms.

BACKGROUND: Precordial Bipolar Leads (PBL) provide new electrocardiographic information derived from standard 12­lead ECG recordings. OBJECTIVES: To explore the usefulness of PBL in patients with acute right coronary artery (RCA) occlusion. METHODS: Sixteen patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA) were studied before and after RCA occlusion and their data were processed with new methods based on PBL. RESULTS: The findings were: 1. In PBL V2-V1, strong systolic currents of injury moving in the left to right direction coexist with those directed towards leads II, III and aVF. 2. Changes in the time of the peaks of the QRS waves do not alter the duration of the QRS. 3. The QRS loops of the surrogate VCG generated show that, during ischemia, the time changes in the peak of the QRS waves displayed in one axis are the consequence of an increase in the amplitude of the waves observed in the perpendicular axis. 4. The use of two simultaneous dimensions (transverse and frontal planes) facilitates the location of the J-point. 5. In the surrogate VCGs of this group of patients, J-point and ST segment shifts produced an image that reminded the Greek letter omega (Ω). 6. The QRS wave changes, in time and amplitude, explained the rotational changes and the ischemic distortions of the surrogate VCG loops. CONCLUSIONS: Computerized processing of ECG data appears to provide new and valuable diagnostic data in patients with acute RCA occlusion. The loops revealed important information related to systolic currents of injury. Because these methods use routine 12­lead ECG data, the procedure is based only in software applications.

Abnormal Myocardial Activation as a Cause of ST elevation: A Study Using Precordial Bipolar Leads (PBL).

OBJECTIVES: The purpose of the study was to describe the ischemic changes occurring during percutaneous transluminal coronary angioplasty (PTCA) using a new method based on Precordial Bipolar Leads (PBL) and Precordial Unipolar Leads (PUL). BACKGROUND: Ischemic ECG changes have been attributed to both systolic and diastolic injury currents. The relation between ST-segment shift and QRS changes is unclear and there is a discussion about its significance. METHODS: Twelve-lead electrocardiograms (ECGs) were performed in 16 patients before PTCA balloon inflation and immediately after balloon deflation in the proximal left anterior descending coronary artery (LAD). Also, ECG data was used to generate V2-V1 PBL, average V1+V2 lead, and the correspondent loop to explore ECG and spatial vector changes. RESULTS: (1) The V2-V1 Vs Average V1+V2 loop rotation changed from counterclockwise (CCW) to clockwise (CW) in 14 of 15 patients (93%). (2) In 12 of 16 patients (75%), there was an abrupt change of QRS vector direction, producing a "folding" of the loop. In 10 of these cases, the change occurred between 32 and 49 milliseconds after the QRS initiation. (3) In 3/16 patients the final part of the loop was "transported", without folding, to the turning point. (4) The "folding" of the loop changed the direction of the final QRS forces and the J point and ST-segment were displaced to the left and forward. (5) For this reason, repolarization began from an abnormal anterior location. CONCLUSIONS: (1) Ischemic changes in the QRS loop have a cornerstone point in which the whole loop changes. (2) Once the loop has changed its direction, there are no major modifications in the loop development, but the forces do not aim anymore to the isoelectric point. (3) Alterations of myocardial activation appear to be responsible for ST elevation in hyperacute ischemia.

Right-to-left T-wave discordance in acute myocardial infarction: A new electrocardiographic sign of apical and left lateral infarction.

INTRODUCTION: A new ECG method producing Precordial Bipolar Leads (PBL) enables a computerized subtraction of the electrical activity detected by the precordial V1 lead from that of the V6 electrode (V6-V1 PBL). This calculation can also be performed manually using measurements from standard simultaneous 12 lead ECG (SS12LECG) tracings. We compared the magnitude of T-waves generated by PBL V6-V1 (measured by computer) to the SS12LECG V6-V1 T-waves (measured on the tracing) to determine whether these measurements are equivalent. Although Lead I and Lead V6-V1 PBL examine almost the same right-to-left axis, we noted that Lead I and Lead V6-V1 PBL sometimes have opposite T-wave polarities. We investigated this observation further using a database containing control and patient data. MATERIAL AND METHODS: Records of 79 patients and 52 controls from the Physionet database were used to generate the V6-V1 PBL for comparison to manual calculations from the V1 and V6 unipolar T-wave measurements on the tracings. The accuracy of these measurements was validated against the computer measurements by correlation and paired t-tests. RESULTS: The T-wave automated and manual measurements in patients were strongly correlated (0.9895), consistent with the premise that measurements from tracings are accurate. The V6-V1 T-wave calculation was positive in 48 of the 52 control subjects. Nearly half of the acute myocardial infarction (AMI) patients had discordant T-wave polarity between Lead I and V6-V1 PBL; ventriculography results on 24 of these patients identified 13 patients with apical and 11 with lateral wall motion abnormalities. CONCLUSION: A discordant T-wave in Lead I and in the V6-V1 PBL is a potential diagnostic criterion for apical or left-lateral infarction.

Nuevos Métodos Electrocardiográficos: Un Estudio Basado en Electrodos Bipolares Precordiales / NEW ELECTROCARDIOGRAPHIC METHODS: A NEW STUDY BASED IN PRECORDIAL BIPOLAR ELECTRODES

En este artículo se presentan varios métodos nuevos de exploración electrocardiográfica. Todos ellos se basan en la modificación del procesamiento de la información que rutinariamente recoge el ECG standard de 12 canales, sin electrodos o cables adicionales. Se basan en derivaciones bipolares precordiales que miden el desfase en tiempo y amplitud entre los electrodos que van de V1 a V6, y muestran, en forma magnificada y con mucho más detalle, las anormalidades en el eje derecha a izquierda (como lo hace DI). El ECG se realiza rutinariamente y sus resultados son los trazados habituales. No obstante, usando los datos ya recogidos, se obtienen derivaciones precordiales bipolares, coordenadas polares, subderivaciones y derivaciones ponderadas nuevas. Los nuevos trazados permiten apreciar con claridad fenómenos difíciles de apreciar en los trazados de rutina del ECG de 12 canales.

Several new methods of electrocardiographic exploration are presented in this work. All are based on processing the information already obtained when a standard 12-channel ECG is performed. They need no additional electrodes or cables. They are based on precordial bipolar leads measuring time - amplitude mismatch among V1 to V6 unipolar electrodes, and present, with much more detail and magnified, abnormalities on the right to left axis. ECG is performed in the usual way producing the classic 12 tracings. However, using the data already collected, bipolar precordial leads, polar coordinates, sub derivations and new weighted derivations can be obtained. The new methods allow seeing clearly some phenomena difficult to appreciate in the routine tracings of the 12-channel ECG.

Precordial bipolar leads: A new method to study anterior acute myocardial infarction.

INTRODUCTION: A new ECG method produces Precordial Bipolar Leads (PBL) generated by subtraction of measurements of Standard Precordial Unipolar Leads (SPUL). This procedure brings new information about time/amplitude mismatch among SPUL, presenting it as tracings and local VCG loops exploring the precordial left-to-right axis on the horizontal plane. In this study, results of V2-V1 bipolar precordial derivation V2-V1 (right to left) and its relationship with the anteroposterior axis are presented. MATERIAL AND METHODS: Records of 37 patients and 15 controls from Physionet database were used to create new PBL and compare between V1 and V2 SPUL. So, bipolar V2-V1 was obtained by subtracting V1 measurements from V2, always having as positive the V2 SPUL and as negative V1. The algorithm used was subtracting, in every millisecond, the voltage recorded by the right electrode from the simultaneously recorded left electrode. Combination of SPUL and PBL can be presented as tracings or local loops, showing detailed information of the electric horizontal plane of the heart at retrosternal location. PBL V2-V1 reflects right ventricle and septal electric activity. RESULTS: The new method is able to detect changes in vectors and differences of milliseconds between SPUL and presents new and important information about the right-to-left electric axis. Right ventricle and interventricular septum electric activity can be differentiate in anterior AMI and LBBB. CONCLUSION: Time/amplitude mismatch between SPUL could be the source of abundant and new information about cardiac depolarization and repolarization. As data to obtain PBL and new loops are already obtained in any ECG device that records simultaneously 12 leads, the system can be added to ECG software algorithms without any additional cable or recording work.