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.

A novel gain-of-function KCNJ2 mutation associated with short-QT syndrome impairs inward rectification of Kir2.1 currents.

AIMS: Short-QT syndrome (SQTS) is a recently recognized disorder associated with atrial fibrillation (AF) and sudden death due to ventricular arrhythmias. Mutations in several ion channel genes have been linked to SQTS; however, the mechanism remains unclear. This study describes a novel heterozygous gain-of-function mutation in the inward rectifier potassium channel gene, KCNJ2, identified in SQTS. METHODS AND RESULTS: We studied an 8-year-old girl with a markedly short-QT interval (QT = 172 ms, QTc = 194 ms) who suffered from paroxysmal AF. Mutational analysis identified a novel heterozygous KCNJ2 mutation, M301K. Functional assays displayed no Kir2.1 currents when M301K channels were expressed alone. However, co-expression of wild-type (WT) with M301K resulted in larger outward currents than the WT at more than -30 mV. These results suggest a gain-of-function type modulation due to decreased inward rectification. Furthermore, we analysed the functional significance of the amino acid charge at M301 (neutral) by changing the residue. As with M301K, in M301R (positive), the homozygous channels were non-functional, whereas the heterozygous channels demonstrated decreased inward rectification. Meanwhile, the currents recorded in M301A (neutral) showed normal inward rectification under both homo- and heterozygous conditions. Heterozygous overexpression of WT and M301K in neonatal rat ventricular myocytes exhibited markedly shorter action potential durations than the WT alone. CONCLUSION: In this study, we identified a novel KCNJ2 gain-of-function mutation, M301K, associated with SQTS. Functional assays revealed no functional currents in the homozygous channels, whereas impaired inward rectification demonstrated under the heterozygous condition resulted in larger outward currents, which is a novel mechanism predisposing SQTS.

Lown-Ganong-Levine syndrome in a 3-month-old infant with isolated left ventricular noncompaction.

This report describes a 3-month-old boy with isolated left ventricular noncompaction admitted to a medical facility due to heart failure and dysrhythmia. His electrocardiogram showed a short PR interval and a normal QRS complex after abortion of supraventricular tachycardia in favor of Lown-Ganong-Levine syndrome or enhanced atrioventricular nodal conduction.

Electrocardiographic changes in patients with spontaneous pneumothorax.

The aim of the study was to evaluate the prevalence of electrocardiography (ECG) abnormalities in subjects with spontaneous pneumothorax. Forty consecutive patients (mean age 43.7 +/-19.1 years) with spontaneous pneumothorax participated in the study. There were 22 cases of left-sided and 18 cases of right-sided pneumothorax. The mean relative volume of pneumothorax was 51.4 +/-24.7% according to the Light's index and 53.5 +/-22.9% according to the Rhea method. Heart rate was significantly higher in patients with pneumothorax than after lung re-expansion (91 +/-20 bpm vs. 72 +/-16 bpm; P<0.001). Abnormal left axis deviation was found in 3 patients with left-sided and in 1 with right-sided pneumothorax, while abnormal right axis deviation was found in 2 patients with left-sided pneumothorax. Relevant QRS abnormalities (incomplete RBBB and T-wave inversion) were found in 4 patients (10%). QRS amplitude in V2-V6 leads was significantly decreased in left-sided pneumothorax, while the right-sided pneumothorax was associated with an increase in QRS amplitude in V5-V6. We conclude that ECG in subjects with pneumothorax often reveals significant abnormalities. The most significant abnormalities were seen in patients with massive right-sided pneumothorax.

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.

Lown-Ganong-Levine syndrome in pregnancy.

BACKGROUND: Lown-Ganong-Levine syndrome is characterized by paroxysmal supraventricular tachycardia, a short PR interval, and normal QRS. CASE: A gravida 3, para 2 was diagnosed with Lown-Ganong-Levine syndrome at 16 weeks' gestation after an episode of chest pain and shortness of breath. She was hospitalized and treated with digoxin, and her symptoms subsided. The remainder of her pregnancy was uneventful. CONCLUSION: Lown-Ganong-Levine Syndrome is a rare complication most commonly seen in young to middle-aged women. This syndrome can be treated and controlled medically with a good outcome.

[Atypical symptoms of Fabry's disease: sudden bilateral deafness, lymphoedema and Lown-Ganong-Levine syndrome]. / Nietypowe objawy choroby Fabry'ego--nagla obustronna utrata sluchu, obrzek limfatyczny i zespól Lowna, Ganonga i Levine'a.

A 40-year-old man with Fabry disease, confirmed by decreased leukocyte alpha-galactosidase A activity in 2001, complained of sudden bilateral deafness, as evidenced by clinical history and audiometry. Magnetic resonance of the brain revealed features typical of Fabry disease. Other clinical manifestations of the disease included: angiokeratoma, mild proteinuria with normal renal function, lymphoedema of the lower limbs, pre-excitation syndrome, myocardial hypertrophy.

[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)

Ventricular preexcitation in children and young adults: atrial myocarditis as a possible trigger of sudden death.

BACKGROUND: Sudden death (SD) in ventricular preexcitation (VP) syndrome is believed to be the result of atrial fibrillation with rapid ventricular response over the accessory pathway. Previous reports are anecdotal and often lack autopsy validation. METHODS AND RESULTS: Prevalence and clinicopathological features of VP were investigated in a series of 273 SDs in children and young adults (aged

Continuous vectorcardiographic monitoring of ischemia during coronary angioplasty in patients with bundle-branch block.

BACKGROUND: Patients with the combination of bundle-branch block and ischemic heart disease have a poor outcome. There is no established criterion for detection of transient ischemia when bundle-branch block is present. OBJECTIVE: To elucidate vectorcardiographic changes during coronary angioplasty of patients with bundle-branch block. DESIGN AND METHODS: The QRS complex and ST-segment changes of 29 patients with bundle-branch block were studied during elective coronary angioplasty using continuous vectorcardiography. Data for the patients with bundle-branch block were compared with data for narrow-QRS-complex controls, matched for the vessel dilated, sex, and age. RESULTS: Patients with bundle-branch block were found to have more pronounced changes in the QRS-vector difference as a response to coronary occlusion than did controls. ST-vector magnitude responded in a similar way during coronary occlusion of patients with and without bundle-branch block but from different baselines. ST change-vector magnitude was found to be the most sensitive parameter for detection of ischemia in patients with bundle-branch block as well as for controls. CONCLUSION: Monitoring of transient ischemia during coronary angioplasty for patients with bundle-branch block is feasible using continuous vectorcardiography. A change in ST vector magnitude > 100 microV is suggested to indicate significant ischemia in the presence of bundle-branch block.

[Use-dependence of propafenone. Clinical demonstration of the hypothesis of modulated receptors]. / Uso-dependencia con propafenona. Demonstración clínica de la hipótesis de los receptores modulados.

UNLABELLED: The aim of this study was to assess use-dependence in patients with ventricular premature contractions (VPC's) treated with propafenone, by means of the increase in heart rate using transesophageal atrial pacing. It was also analyzed whether this phenomenon was related to the antiarrhythmic effect. Fifteen patients with more than 30 symptomatic VPC's/sour were evaluated. Esophageal pacing was performed with cycles of 600 and 400 msec during periods of 1 min and with simultaneous recording of 2 or 3 EKG leads with a paper speed of 100 mm/sec. Holter monitoring (HM) was carried out in all patients. Propafenone was administered in doses of 450 and 900 mg/day, during 5-7 days, at which moment another HM and esophageal stimulation were repeated. The QRS duration (pre-treatment) was 82.6 +/- 13.5 msec (basal) and 82.4 +/- 13 msec during pacing with 600 msec cycle length (p: NS). The QRS duration with P (900 mg/day) was 96.6 +/- 20 msec (basal) (p:NS vs. pre-treatment) but during atrial pacing with 600 msec cycle length it increased to 109.3 +/- 23 msec (p < 0.0004). This use-dependence was also observed with pacing at 600 msec in patients receiving doses of 450 mg/day: 95.3 +/- 13 msec (p < 0.0001 vs. baseline QRS) (Table 1). IN CONCLUSION: 1) there was no significant increase in the QRS duration with P without pacing; 2) propafenone showed use-dependence during atrial stimulation, even with cycle length of 600 msec and with the lower doses.

Enhanced A-V nodal conduction (Lown-Ganong-Levine syndrome) by congenitally hypoplastic A-V node.

The basic anatomical substrate of enhanced A-V nodal conduction, manifesting or not as Lown-Ganong-Levine syndrome, is still a controversial issue. We describe the case of a 34-year-old man who presented episodes of ventricular fibrillation. Electrophysiological studies showed that the AH interval was 55 ms, and increased by only 20 ms at paced cycle lengths of 300 ms; atrial pacing induced atrial fibrillation, with a shortest RR interval of 240 ms. Despite verapamil therapy, this patient died suddenly at home. Histological study disclosed a severe A-V node hypoplasia that was evidently congenital in nature; the rest of the conduction system was normal, and no accessory A-V pathways were present. We suggest that enhanced A-V nodal conduction in this patient was due to the developmental defect in the A-V node; this abnormality caused a loss of specific impulse-delaying function, and thus allowed rapid, unfiltered atrial impulses to reach the lower A-V junction and ventricles.

The preexcitation syndrome: epidemiological and genetic study.

A sample of 4210 subjects of both sexes aged 35-54 years was examined, chosen at random from six regions of Croatia. An electrocardiogram at rest was performed in all subjects and changes analyzed by the Minnesota code. A short P-R interval together with a widening QRS complex and a delta wave was found in 0.05%, while 42 (1.0%) of the examinees had a short P-R interval, but only 0.21% were symptomatic. Three years after the first examination 0.06% of the subjects had preexcitation with a delta wave, and in one subject it appeared after three years. 0.35% of the subjects had a short P-R interval after three years but only 0.18% were symptomatic and in 22 (0.65%) it had disappeared in three years. After 13 years these subjects did not appear for an examination, and the short P-R interval did not appear in any of other subjects during this period. There were more short P-R intervals: 3.22% in females and 1.96% in males, but 0.33% only were symptomatic. Antigens of the human leukocyte group A (HLA) system were analyzed in 46 patients: the Wolff-Parkinson-White syndrome was found in 35, while 11 had the Lown-Ganong-Levine syndrome. Antigens of the HLA-A, HLA-B and HLA-DR locuses were determined by the microlymphocytotoxicity method. The results of the frequency of HLA system antigens were compared to the results of the control group of a Croatian population consisting of 175 people. There was an increased frequency of HLA-A9 and HLA-B5 (P = 0.026 and 0.0092) in the investigated population as a whole. The participation of HLA-A3 antigen was significantly less among patients (P = 0.03), while HLA-B14 antigen was not found in patients with preexcitation. Within 10 HLA-DR locuses, HLA-DR7 antigen was rather more frequently present, although this was not statistically significant (P = 0.173).

Pulmonary developmental anomaly associated with Klippel-Feil syndrome and anomalous atrioventricular conduction.

We report the findings in a patient with Klippel-Feil syndrome and associated agenesis of right upper and middle lobes, hypoplasia of the right lower lobe of the lung, and Lown-Ganong-Levine syndrome. To our knowledge, such an association has not been previously described.