Interpretation of Isopotential Surface Maps in Patients with Ostium Primum and Secundum Atrial Defects

Abstract

The purpose of this study was to determine if there were consistent differentiating patterns in body surface potential maps in children with normal hearts and in those with ostium primum versus ostium secundum atrial septal defects. A second purpose was to interpret the isopotential surface maps in terms of the position of intracardiac electrical wave fronts.Body surface activity throughout QRS demonstrated three major intervals: developing, transitional, and declining potentials. Patients with both types of atrial septal defects demonstrated complex distributions (multiple maxima) during the transitional interval which were not encountered in normal subjects. In the primum group, the distribution of positive and negative potentials sequentially changed in an inverted pattern as compared to the pattern in those patients with secundum defects. Furthermore, during the transitional interval the potential distribution was considerably more complex in the primum group. In two additional patients, body surface maps were helpful in clarifying misleading and atypical conventional electrocardiograms.The presence of simultaneous multiple maxima could only be accounted for by the existence of multiple wave fronts simultaneously present within the heart. In particular the emergence of two widely separated anterior chest maxima in patients with secundum atrial defect indicated the simultaneous presence of prominent left and right ventricular wave fronts. Also, the marked differences in the relative positions of the major body surface maximum and minimum could be accounted for only by considerable differences in the position and extent of intracardiac wave fronts. For example, the target distribution, consisting of an isolated minimum surrounded by multiple maxima and positive potentials over the upper body, in the ostium primum patients, indicated epicardial breakthrough in a wave front positioned in the anterosuperior portion of the heart. In contrast, normal subjects and patients with secundum defect had distributions indicating antero-inferior wave front position at the time of right ventricular epicardial breakthrough. Additional Indexing Words: Intracardiac electrical wave fronts PRESENTATION of body surface potential distributions (body surface maps) provides a picture of cardiac electrical events as projected on the body surface. Surface maps differ from selective scalar leads by providing Body surface activity an integrated picture containing more information for predictions concerning single or multiple intracardiac wave fronts than is available from viewing scalar leads alone. From an electrophysiologic point of view, an From the

Resolution of Abnormal Body Surface Maps in Children with Atrial Septal Defect after Intracardiac Repair

“…Typical findings in BSMs during the depolarization process in preoperative ASD patients were compatible with delayed RV conduction 5–8,13,14 . Blumenschein et al 5 showed delayed RV excitation in patients with ASD.…”

“…31 Typical findings in BSMs during the depolarization process in preoperative ASD patients were compatible with delayed RV conduction. [5][6][7][8]13,14 Blumenschein et al 5 showed delayed RV excitation in patients with ASD. Liebman et al 7,8,13 reported BSMs of RV overload as the terminal conduction delay of RV.…”

“…The common standard ECG findings in patients with ASD are the rsR' pattern in lead V 1 1 and isolated negative T wave in the precordial leads 2–4 . Various studies have examined the possible genesis of these ECG abnormalities in patients with ASD, which mainly are attributed to abnormalities in depolarization 5–8 . However, the possibility of abnormal repolarization processes associated with these ECG changes has not been explored, particularly in association with their resolution following intracardiac repair with hemodynamic improvement.…”

Χαρτογραφηση Εμφραγματος Του Οπισθιου Τοιχωματος Του Μυοκαρδιου

“…Το 1963 ό Taccardi 1 χρησιμοποίησε 240 προκάρδιες απαγωγές σέ φυσιολογικά άτομα για νά δείξει οτι πολλαπλά μέγιστα και ελάχιστα μπορούν νά υπάρχουν στο προ κάρδιο κατά τή διάρκεια τοΰ καρδιακού κύκλου.Ή παρακολούθηση τών ηλεκ τρικών φαινομένων της καρδιάς σέ κάθε msec τοΰ συμπλέγματος QRS μέ τή βοήθεια ηλεκτρονικού υπολογιστή τόσο σέ φυσιολογικά άτομα όσο και σέ ασθενείς μέ διάφορες καρδιακές παθήσεις (μεσοκολπικό έλλειμα, υπερτροφία, έμφραγμα) επέτρεψε τήν απόκτηση χαρτών, οί όποιοι δίνουν πληροφορίες επιπλέον εκείνων τοΰ κοινού ΗΚΓ και τοΰ άνυσματοκαρδιογραφήματος. 2 , 19 , 20 , 21 Περαιτέρω ή χαρτογράφηση χρησιμοποιήθηκε κυρίως για τον υπολο γισμό της εκτάσεως και τοϋ μεγέθους τοΰ εμφράγματος καθώς και τήν εκτί μηση της επιδράσεως διαφόρων φαρμακολογικών και αίμοδυναμικών πάρα-γόντων πάνω στην Ισχαιμία καί το έμφραγμα. Ώς δείκτης του μεγέθους του εμφράγματος ελήφθη το άθροισμα των ανασπάσεων του ST όλων των απα γωγών σέ χιλστ.…”