Introduction: Prior accurate PVC localization improves the time and outcome of ablative procedures. We developed a new manual Vector Technique (VcT) to localize the PVC origin to cardiac anatomy regions. In contrast, our Cardiac Isochrone Positioning System (CIPS) is a computer based system that localizes the PVC to patient specific cardiac anatomy from the MRI and electrode positions from the 3D Camera. Hypothesis: We hypothesize that this new VcT can rapidly quantitate the location of PVC to anatomical regions whereas CIPS localizes the PVCs to more specific cardiac anatomical segments. Method: The VcT assumes the frontal plane leads are formatted on the chest as an equilateral triangle and the horizontal leads as a partial sphere. Using the concept that a lead recording perpendicular to a dipole vector is zero, the QRS axis vectors of the PVC were calculated manually within 3.8 to 7.5 degrees in the frontal and horizontal planes. CIPS computed the electrode positions by registration of the MRI derived torso model with the 3D image of the patient. The ECG signals were used by both methods to localize the PVC origin to the cardiac anatomy. Result: In 12 patients (below), this manual VcT separated without overlap in the horizontal plane the PVC into Left Ventricle (LV 30-45°), Right Ventricular (RV 308-348°), and Papillary Muscle (PM 128-150°) regions, but not in the frontal plane. CIPS localized 10 PVCs to the same and 2 to adjacent anatomical segments while the vector techn

Vectorcardiographic QRS loops illustrate the electrical activation of the left ventricle (LV) in 3-dimensional space; however, the individual variability in these loops is not well understood. The left bundle-branch fan distributes the initial activation to the LV and has been shown to distribute its fascicles between the LV papillary muscles. Computer models of LV activation using papillary muscle as the initial electrical activation points accurately predict QRS duration and frontal plane axis.Twelve healthy adults received standard 12-lead electrocardiograms and 1.5-T cardiac magnetic resonance imaging. A software developed by ECG-TECH Corp (Huntington Station, NY) generated 3-dimensional QRS vector loops for each subject. Short- and long-axis papillary muscle positions were measured for each subject using cardiac magnetic resonance images. A theoretical plane equidistant from the endocardial origins of each papillary muscle was constructed. Vectors perpendicular to the QRS vector loop and the theoretical plane termed the plane identifier were used for comparison. Spearman rank correlation was used to compare the azimuth and elevation of the plane identifiers of the QRS vector loop and the theoretical plane.No correlation was found between the azimuth or elevation of the theoretical plane and the QRS vector loops with Spearman rank correlation coefficients of ρ = 0.11 (P = .71) and ρ = 0.22 (P = .49), respectively. Subgroup analysis by QRS vector loop morphology (planar vs

Often students think of ECGs (electrocardiograms) as a diagnostic tool for heart attacks. In this activity, students are able to develop an approach to examine an ECG in order to determine what is known as the mean electrical axis (MEA) of their ventricle. In doing so, they not only learn another use for ECGs, they are able to see a real-world application and gain an understanding of dipoles and of vector analysis.

Traditionally, "ECG" refers to a 12-lead ECG taken while lying down as discussed below. However, other devices can record the electrical activity of the heart, Electrocardiography is the process of using an electrocardiograph (a device) to produce an electrocardiogram (a recording, often called an ECG or EKG) that shows a line graph of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart using electrodes placed on the skin. These Defibrillation… Electrodes are the actual conductive pads attached to the body surface. Any pair of electrodes can measure the electrical potential difference between the two corresponding locations of attachment. Such a pair forms a lead. However, "leads" can also be formed between a physical electrode and a virtual electrode, which is the average of numerous leads. All clinical ECGs use Wilson's central terminal (WCT) as the virtual electrode from which the precordial leads are measured, whose potential is defined as the average potential measured by the three standard limb leads. Commonly, 10 electrodes attached to the body are used to form 12 ECG leads, with each lead measuring a specific electrical potential difference. Together with leads I, II, and III, augmented limb leads aVR, aVL, and aVF form the basis of the hexaxial reference system, which is used to calculate the heart's electrical axis in the frontal plane. Older versions of the nodes (VR, VL, VF) use Wilson's central terminal as the negative pole, but the amplitude is too small for the thick lines of old ECG machines. The Goldberger terminals scale up (augments) the Wilson results by 50%, at the cost of sacrificing physical correctness by not having the same negative pole for all three. depolarization of the heart toward the positive electrode produces a positive deflection depolarization of the heart away from the positive electrode produces a negative deflection repolarization of the heart toward the positive electrode produces a negative deflection repolarization of the heart away from the positive electrode produces a positive deflection Thus, the overall direction of depolarization and repolarization produces positive or negative deflection on each lead's trace. For example, depolarizing from right to left would produce a positive deflection in lead I because the two vectors point in the same direction. In contrast, that same depolarization would produce minimal deflection in V1 and V2 because the vectors are perpendicular, and this phenomenon is called isoelectric. Normal rhythm produces four entities – a P wave, a QRS complex, a T wave, and a U wave – that each have a fairly unique pattern. Th…

<h4>Background</h4>Twelve-lead electrocardiography (ECG) is essential in human cardiology but remains poorly investigated in equine medicine due to a lack of standardization and inconsistent findings.<h4>Hypothesis/objectives</h4>Describe the normal vectorcardiogram (VCG) variation in horses at rest and during exercise using Delta 12-lead ECG, including repeatability and intra- and interobserver variations.<h4>Animals</h4>One hundred two healthy Warmblood horses, aged 3-20 years, were examined at rest, of which 30 also during exercise.<h4>Methods</h4>Prospective, observational study. Electrocardiograms were recorded using a Δ 12-lead configuration with precordial electrodes positioned at atrial and mid-ventricular levels. Data were processed with custom MATLAB scripts to generate mean ECG and VCG patterns. Repeatability and intra- and interobserver reliability were assessed using cross-correlation and circular statistics in R.<h4>Results</h4>Electrocardiographs were obtained during sinus rhythm. The Δ 12-lead configuration and derived VCG showed high repeatability, with significant intra- and interobserver reliability at rest and during exercise. The mean directions of the P wave and the QRS complex were similar during rest and exercise. The P loop and the initial QRS showed leftward and caudoventral orientation on VCG, while the remainder of the QRS loop was oriented in a dorsocranial direction and slightly to the left or right.<h4>Conclusions and clinical importance</h4>The Δ 12-lead configuration and the derived VCG show consistent patterns during sinus rhythm, both at rest and during exercise. These features hold promise for improving the diagnosis of atrial and ventricular arrhythmias, particularly because the orthogonal XYZ-leads offer a format that is easier for practicing veterinarians to interpret.