First don't think when you get a pet scan it will work. Download figureDownload PowerPointFigure 7. The presence of a q wave in lead I was nearly uniformly identified on EPI pace maps and was also noted to be highly specific criteria. Only the QRSd and the SRS complex duration were observed to be significantly longer from the EPI than from the ENDO. Red arrows point out q waves in lead I, representing the initial rightward activation from the EPI to the ENDO. Whether this suggested algorithm would enhance the value of the single morphological criteria alone remains to be determined with certainty. Similarly, raising the cutoff for IDT from ≥85 ms to ≥90 ms increased the specificity for the diagnosis of EPI pace map origin from 70% to 79%, with a slight decrease in the sensitivity (from 83% to 76%). The analysis of the pace maps and VTs was performed with the reviewer blinded to the patient number as well as whether the VT was localized to the epicardium or endocardium. In all patients, a decision was made to undergo an EPI ablation because of an unsuccessful ENDO LV ablation before or at the time of the EPI procedure. Patients with NICM frequently have an EPI origin for VT. Because an EPI ablation procedure requires a different level of risk and resources, it is imperative to identify which patients are likely to benefit from an EPI approach with their initial procedures. Patient is a UK registered trade mark. Download figureDownload PowerPointFigure 2. See the first reference in 'Further reading & references' below for an easy-to-read-and-understand guide to basic interpretation of ECG timing, with sample traces. Twelve-lead ECG showing characteristic morphological features of VT originating from epicardium versus endocardium. To assess results in a different population, we prospectively applied ECG criteria in a second cohort of 11 consecutive patients with NICM undergoing ENDO and EPI catheter mapping and ablation for drug-refractory ventricular arrhythmias. The following ECG features were assessed in each pace map and VT: (1) QRS duration (QRSd); (2) pseudo-delta wave (PdW), intrinsicoid deflection time (IDT), shortest RS complex (SRS), and maximum deflection index (MDI); and (3) presence of q waves in lead I (QWL1) and presence of q wave in inferior leads (Figure 2). The new ECG algorithm applied to this validation population correctly identified the origin in 19 of 21 VTs (93% sensitivity and 86% specificity for EPI origin). Pace mapping focused on low bipolar voltage areas. This is defined as >3 ventricular extrasystoles in a row at >120 bpm (at 100-120 bpm it is termed accelerated idioventricular rhythm). every QRS complex is preceded by a P-wave) but the P-waves are inverted (negative in aVF), therefore this is an atrial tachycardia Blue arrows show inferior q waves with ENDO pacing. A 3-lead ECG (paper speed, 25 mm/sec; sensitivity, 10 mm/mV) demonstrating a single VPC (arrow) followed by 2 sinus complexes, then an abrupt onset of rapid monomorphic ventricular tachycardia. The electrograms were not only low in amplitude but were also typically fractionated and late. Previously reported cutoff values for PdW, IDT, and SRS interval criteria tended to lack specificity in identifying EPI origin for VTs (specificity was ≈50% for all 3 measurements). The study population was composed of 13 men and 1 woman, with an average age of 59�14 years. Customer Service © American Heart Association, Inc. All rights reserved. Such an approach can help to distinguish between events such as fast atrial fibrillation (irregular) and other atrial arrhythmias such as supraventricular tachycardia (SVT) (regular). B, Left posterior oblique view of a bipolar EPI voltage map in sinus rhythm from another patient also showing low-voltage (<1.0 mV) abnormalities on the epicardium in proximity to the mitral valve. By using this site you agree to our use of cookies. Support Desktop, Tablet and Mobile with responsive design. All patients underwent magnetic electroanatomic voltage map during basal rhythm as previously described. What could be causing your pins and needles? Baseline clinical characteristics of the population are shown in Table 1. Endocardial abnormal voltage was defined by low bipolar voltage (<1.5 mV) during baseline rhythm (Figure 1). Published morphology criteria: q wave in lead I (QWLI) and no q waves in inferior leads and interval criteria: pseudo-delta wave ≥34 ms, intrinsicoid deflection time ≥85 ms, shortest RS complex ≥121 ms, and maximum deflection index ≥0.55 were assessed for ability to identify EPI origin. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Red arrows show q waves in lead I with EPI pacing. This study determined prospectively the value of previously published interval and morphology ECG criteria for identifying an EPI VT site of origin in patients with NICM. 1-800-242-8721 Of importance, low electrogram amplitudes have been described around the atrioventricular groove as well as surrounding the coronary arteries as a result of the normal distribution of fat tissue in the EPI. We analyzed the 12-lead surface ECG of all the VTs that were demonstrated to originate from the basal superior and lateral LV (Josephson sites 8, 10, and 12; Figure 1). The reference value for defining abnormal electrograms recorded from the LV EPI was recently established based on voltage maps in 8 patients with normal LV.11 Normal EPI electrograms were defined as >1 mV, which corresponds to 95% of the signals from normal EPI LV recorded at a distance of at least 1 cm from a defined large coronary vessel. This allows you to compare it to the normal range for the event and decide whether or not it is abnormal. The electrical signals causing this rapid beating originate in the ventricles. C and D, Pace maps performed from superior basal and superior-lateral basal regions in the directly opposite EPI LV. Given the limitations observed when using the individual interval criteria for the diagnosis of pace map or VT originating from the EPI in patients with NICM, we sought to create a multistep algorithm that might optimize recognition of the site of origin. myocardial irritability. MDI was defined as the interval measured from the earliest ventricular activation (or from the stimulation artifact) to the peak of the largest amplitude deflection in each precordial lead (taking the lead with shortest time) divided by the QRSd. This 4-step algorithm identified the origin in 109 of 115 pace maps (95%), 21 of 24 VTs (88%) in the study population, and 19 of 21 VTs (90%) in validation cohort. Twelve-lead ECG showing characteristic morphological features of VT originating from epicardium versus endocardium. In these patients, as with the first group of patients, a decision was made to undergo an EPI ablation because of an unsuccessful ENDO LV ablation before or at the time of the EPI mapping ablation procedure.

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