A Case of Lown-Ganong-Levine Syndrome: Due to an Accessory Pathway of James Fibers or Enhanced Atrioventricular Nodal Conduction (EAVNC)?

BACKGROUND Lown-Ganong-Levine syndrome, includes a short PR interval, normal QRS complex, and paroxysmal tachycardia. The pathophysiology of this syndrome includes an accessory pathway connecting the atria and the atrioventricular (AV) node (James fiber), or between the atria and the His bundle (Brechenmacher fiber). Similar features are seen in enhanced atrioventricular nodal conduction (EAVNC), with the underlying pathophysiology due to a fast pathway to the AV node, and with the diagnosis requiring specific electrophysiologic criteria. CASE REPORT A 17-year-old man presented with a history of recurrent narrow-complex and wide-complex tachycardia on electrocardiogram (ECG). An electrophysiologic study showed an unusually short atrial to His (AH) conduction interval and a normal His to ventricle (HV) interval, without a delta wave. Two stable AH intervals coexisted in the same atrial pacing cycle length. In the recovery curve study, this pathway had a flat conduction curve without an AH increase until the last 60 ms, before reaching the effective refractory period. These ECG changes did not respond to an adenosine challenge. When this pathway became intermittent, there was a paradoxical response to adenosine challenge with conduction via a short AH interval, but without conduction block. Catheter ablation of the AV nodal region resulted in a normalized AH interval, decremental conduction properties, and resulted in a positive response to an adenosine challenge. CONCLUSIONS In this case of Lown-Ganong-Levine syndrome, electrophysiologic studies supported the role of the accessory pathway of James fibers.

Duración del QRS y deterioro hemodinámico precoz tras cirugía de revascularización coronaria / QRS Duration and Early Hemodynamic instability after coronary Revascularization Surgery

Introducción y objetivos. La duración del intervalo QRS en el ECG es un marcador de disfunción ventricular y peor pronóstico. Su valor en pacientes sometidos a cirugía de revascularización coronaria no ha sido establecido. Métodos. Estudiamos a 203 pacientes consecutivos (64 ± 9 años de edad; el 74% varones) programados para cirugía electiva coronaria. Se registró la duración máxima del intervalo QRS en el ECG de 12 derivaciones preoperatorio. Definimos inestabilidad hemodinámica como la aparición de muerte cardiaca, insuficiencia cardiaca, uso de fármacos inotrópicos intravenosos o balón de contrapulsación intraaórtico durante el postoperatorio. Resultados. La aparición de inestabilidad hemodinámica (n = 94 [46%]) se asoció a una mayor duración del intervalo QRS preoperatorio (97,5 ± 21,14 frente a 88,5 ± 16,9 ms; p = 0,001). El QRS fue mayor en quienes apareció insuficiencia cardiaca (n = 23; 104,3 ± 22,9 frente a 91,1 ± 18,5 ms; p = 0,002), precisaron inotrópicos intravenosos (n = 77; 96,5 ± 20,5 frente a 90,1 ± 18,2 ms; p = 0,007) o sufrieron fibrilación auricular postoperatoria (n = 58; 98,2 ± 23,8 frente a 90,4 ± 17 ms; p = 0,018). El bloqueo de rama se asoció a mayor necesidad de balón de contrapulsación (el 29 frente al 12%; p = 0,012), inotrópicos (el 58 frente al 35%; p = 0,014) y mayor incidencia de inestabilidad hemodinámica (el 69 frente al 42%; p = 0,006). Tras el ajuste multivariable, los predictores de inestabilidad hemodinámica fueron la duración del QRS (odds ratio [OR] = 1,49; intervalo de confianza [IC] del 95%, 1,11-2; p = 0,007), la ausencia de injerto arterial (OR = 3,6; IC del 95%, 1,14-11,6; p = 0,029) y el tiempo de circulación extracorpórea (OR = 1,013; IC del 95%, 1,003-1,023; p = 0,013), con independencia de otros factores de riesgo. Conclusiones. El retraso de la conducción intraventricular o duración del intervalo QRS se asocia a mayor riesgo de inestabilidad hemodinámica durante el post-operatorio de cirugía coronaria (AU)

Introduction and objectives. The duration of the QRS interval measured by ECG is a marker of ventricular dysfunction and indicates a poor prognosis. Its value in patients undergoing coronary revascularization surgery has not been established.Methods. The study involved 203 consecutive patients (age 64±9 years, 74% male) scheduled for elective coronary surgery. The maximum QRS duration measured on a preoperative 12-lead ECG was recorded. Hemodynamic instability was defined as the occurrence of cardiac death, heart failure, or a need for intravenous inotropic drugs or intra-aortic balloon counterpulsation during the postoperative period.Results. The occurrence of hemodynamic instability (n=94, 46%) was associated with a longer preoperative QRS duration (97.5±21.14 ms vs 88.5±16.9 ms; P=.001). The QRS duration was also longer in patients who developed heart failure (n=23; 104.3±22.9 ms vs. 91.1±18.5 ms; P=.002), needed inotropic drugs (n=77; 96.5±20.5 ms vs. 90.1±18.2 ms; P=.007) or developed postoperative atrial (..) (AU)

Ablation therapy of supraventricular tachycardia in elderly persons.

Ablation of supraventricular tachycardia in elderly persons presents a challenging problem to electrophysiologists. Friable cardiac structures, prone to catheter perforation, comorbid cardiovascular disease, and the propensity to develop atrial fibrillation and thromboembolic complications, place these patients at high risk. Newer techniques for cardiac mapping and ablation, the establishment of precise ablation lines, and safer approaches to the ablation mechanism (particularly for atrial fibrillation) are presented in this review. In addition, a novel rapid ablation method to permanently cure atrial ventricular nodal re-entry tachycardia is demonstrated.

[Ventricular pre-excitation: electrophysiopathology, criteria for interpretation and clinical diagnosis. References for geriatrics]. / La pre-eccitazione ventricolare: elettrofisiopatologia, criteri interpretativi e inquadramento clinico. Riferimenti di Geriatria.

The authors review the state-of-the-art on ventricular pre-excitation in medical and arrhythmological literature in order to facilitate the recognition of the various clinical forms, like classic and occult Wolff Parkinson withe syndrome and Lown Ganong Levine syndrome. A historical introduction reviews our electrophysiopathological knowledge of the electrical activation and conduction of ventricular pre-excitation compared to normal, starting from the anatomic discovery of conduction pathways to the possible use of transesophageal electrostimulation and endocavity mapping to study electric potentials. Avantgarde technologies have also been developed to eliminate anomalous pathways firstly by using a direct current dirscharge and secondly radiofrequency. Atrioventricular electric activation has been widely illustrated in normal subjects in order to create a model for comparison with pathological ventricular pre-excitation: the upper left portion of the septum is no longer the first zone to trigger the kinetic mechanism compared to the early fascicular fraying of the homonymous branch. Instead the upper right part of the septum is activated earlier owing to the anomalous fascia connected on this side to the right branch through their septal arborisations. As a result, this new conduction pathway activates the ventricular masses earlier through an anomalous route, given that there is no further contact with the atrioventricular nodes which act as a control. A similar situation is found in the left branch block where the ventriculogram is late with a normal PR, unlike pre-excitation when an early delta wave is present with a short PR. Electric conduction is also illustrated based on new knowledge of the circuit structures and the rings theory. Orthodromic tachycardia is distinguished from the antidromic form, double accessory pathway tachycardia, ectopic reciprocant atrial fibrillation tachycardia and occult bundle tachycardia which is studied using transesophageal stimulation with a time threshold of 70 ms for ventricular-atrial retrograde activation. The stimulation techniques using single or repeated extrastimulus are explained for this purpose, as well as those with serial extrastimulation and the physical characteristics of the circuit based on the ratio between voltage and resistance. The authors also report the practical aims of electrostimulation for determining the electric threshold of the anomalous circuit in terms of refractoriness, electric atrial stability, reciprocity and the occurrence of the macro re-entry. Lastly, the authors describe electric conduction by anomalous pathways based on the criterion of conduction and activation, both of which are analysed and compared on the basis of the intrinsicoid deflection morphology on the surface ECG: the aberrant qRs usually suggests an antidromic ventricular activation and retrograde conduction between atrium and ventricle, while normal intrinsicoid deflection demonstrates that the activation is orthodromic and the conduction anterograde, namely ventricle-atrial. Having been reproduced in a synoptic synthesis, these manifestations show a regular electrophysiological pattern because they are dissimilar from the behaviour of the monophasic bioelectric potential of the cardiac cells specialised in the conduction of the stimulus, whether they represent a normal or pathological electric pathway. The study is rounded off by the analysis of the reciprocant tachycardias and their re-entry varieties related to the type of the anomalous bundles. A number of types of re-entry can be identified: sinusal re-entry (micro re-entry), atrial re-entry, re-entry in the atrio-ventricular node, re-entry tachycardia and the so-called triggered type. The discussion of the electrophysiopathological aspects of pre-excitation is followed by the clinical forms of ventricular pre-excitation that can be divided into 3 main types. The different ECG clinical pictures are set out in the summary table, together with the type of shunt and activation and possible variants, following Rosenbaum s classic paint: the common type B, the rare type A and a last variant, the C type. This section also describes the positional peculiarities of the Kent-Paladino bundle, the left ventricular, septal (anterior and posterior) and the multiple-bundle ones. The authors also illustrate the criterion and meaning of endocavity mapping in the search for anomalous bioelectric potentials that identify the pathway or the location of the endocardiac bundle and/or foci to be eliminated. A new echocardiographic technique is described with a conventional M mode, digitalised 2D and tissular Doppler which has a comparable ability to identify the anomalous pathways of electric conduction using a non-invasive method. (ABSTRACT TRUNCATED)