Electrophysiologic characteristics and radiofrequency ablation of concealed nodofascicular and left anterograde atriofascicular pathways.

INTRODUCTION: True nodoventricular or nodofascicular pathways and left-sided anterograde decremental accessory pathways (APs) are considered rare findings. METHODS AND RESULTS: Two unusual patients with paroxysmal supraventricular tachycardia were referred for radiofrequency (RF) ablation. Both patients had evidence of dual AV nodal conduction. In case 1, programmed atrial and ventricular stimulation induced regular tachycardia with a narrow QRS complex or episodes of right and left bundle branch block not altering the tachycardia cycle length and long concentric ventriculoatrial (VA) conduction. Ventricular extrastimuli elicited during His-bundle refractoriness resulted in tachycardia termination. During the tachycardia, both the ventricles and the distal right bundle were not part of the reentrant circuit. These findings were consistent with a concealed nodofascicular pathway. RF ablation in the right atrial mid-septal region with the earliest atrial activation preceded by a possible AP potential resulted in tachycardia termination and elimination of VA conduction. In case 2, antidromic reciprocating tachycardia of a right bundle branch block pattern was considered to involve an anterograde left posteroseptal atriofascicular pathway. For this pathway, decremental conduction properties as typically observed for right atriofascicular pathways could be demonstrated. During atrial stimulation and tachycardia, a discrete AP potential was recorded at the atrial and ventricular insertion sites and along the AP. Mechanical conduction block of the AP was reproducibly induced at the annular level and at the distal insertion site. Successful RF ablation was performed at the mitral annulus. CONCLUSION: This report describes two unusual cases consistent with concealed nodofascicular and left anterograde atriofascicular pathways, which were ablated successfully without impairing normal AV conduction system.

Decremental conduction properties in overt and concealed atrioventricular accessory pathways.

AIM: Most atrioventricular accessory pathways (AV-APs) exhibit Kent bundle physiology characterized by fast and non-decremental conduction properties. In contrast, atriofascicular APs, which are only capable of reaching slow levels of long antegrade decremental conduction, are uncommon. The aim of this study was to describe antegrade and/or retrograde AV-APs with unusual decremental properties. METHODS AND RESULTS: Five patients with unusual decremental AV-APs underwent electrophysiological evaluation and radiofrequency catheter ablation for symptomatic tachycardias. Three were found to have structural heart disease, and three latent decremental AV-APs in the anterograde and/or retrograde direction that could not be demonstrated by routine electrophysiological testing. In Case 1, a right posteroseptal AV-AP with bidirectionally latent decremental conduction was associated with clinical antidromic circus movement tachycardia (CMT) mimicking ventricular tachycardia and orthodromic CMT, the latter inducible only with isoprenaline. In Case 2, incessant orthodromic CMT was due to a latent retrograde left posterolateral AV-AP. In both cases, double atrial responses to a single paced ventricular beat, initiating orthodromic CMT, were observed. In Case 3 with latent preexcitation unmasked by adenosine and atrial pacing, retrograde latent decremental conduction over a right posteroseptal AV-AP could be shown only with isoprenaline. This patient and the remaining two with overt preexcitation demonstrated anterograde decremental AP conduction that was discontinuous over a right posteroseptal AV-AP in Cases 3 and 4 and was continuous over a midseptal AV-AP in Case 5. In the latter case, the site of decremental conduction could be localized at the proximal AP origin. All five AV-APs were successfully ablated at the annulus level. CONCLUSION: AV-APs with unusual decremental properties that are either latent, demonstrable only during CMT or overt, exhibiting functional longitudinal dissociation are described. These APs could be identified and successfully ablated after detailed electrophysiological analysis.

Radiofrequency ablation of a concealed nodoventricular Mahaim fiber guided by a discrete potential.

INTRODUCTION: We present the case of a 17-year-old woman who underwent an electrophysiological study and radiofrequency (RF) ablation of supraventricular tachycardia refractory to medical treatment. Two right-sided, concealed, nondecremental atrioventricular accessory pathways (AV-APs) involved in orthodromic circus movement tachycardias were identified. After RF ablation of both AV-APs, evidence of bidirectional dual AV nodal conduction was demonstrated and regular narrow complex tachycardia was induced. METHODS AND RESULTS: During the tachycardia, retrograde slow and fast AV nodal pathway conduction with second-degree ventriculoatrial (VA) block and VA dissociation were observed. During the tachycardia with second-degree VA block, ventricular extrastimuli elicited during His-bundle refractoriness advanced the next His potential or terminated the tachycardia. Mapping the right atrial mid-septal region, a distinct high-frequency activation P potential was recorded in a discrete area, two thirds of the way from the His bundle toward the os of the coronary sinus. Detailed electrophysiologic testing with the recordable P potential demonstrated that the tachycardia utilized a concealed nodoventricular AP arising from the proximal slow AV nodal pathway. CONCLUSION: The tachycardia with slow 1:1 VA conduction could be reset by ventricular extrastimuli elicited during His-bundle refractoriness advancing the subsequent activation P potential and atrial activation. RF ablation guided by recording of the activation P potential resulted in elimination of both the slow AV nodal pathway and the nodoventricular connection with preservation of the normal AV conduction system.

[Chronic right heart failure after implantation of a cava filter]. / Chronische Rechtsherzbelastung nach Implantation eines Kavasperrfilters.

HISTORY AND CLINICAL FINDINGS: A 39-year-old woman complained of dyspnoea and increasing abdominal pressure sensation. A Greenfield filter had been implanted into her inferior vena cava (IVC) 4 years previously because of pulmonary embolism from a deep vein thrombosis after a hysterectomy with abscess formation. Physical examination revealed neck vein congestion, jaundiced sclerae, a tense abdominal wall, ascites and a soft machinery murmur in the paraumbilical region. INVESTIGATIONS: Transaminase activities were slightly raised (GOT 38 U/I, GPT 20 U/I), but total bilirubin and direct bilirubin were markedly elevated (2.9 mg/dl and 1.1 mg/dl, respectively). There was no evidence of cholestasis or decreased liver synthesis. Ultrasound showed marked dilatation of the IVC and hepatic veins, and echocardiography revealed right ventricular enlargement with grade II tricuspid regurgitation. Calculated pulmonary arterial systolic pressure averaged 50 mmHG. Colour-coded Doppler sonography demonstrated an aorto-caval shunt at the level of the filter in the IVC and penetration of a filter strut into the aortic lumen. TREATMENT AND COURSE: After removing the ascitic fluid by fluid and sodium restriction, and administration of an aldosterone antagonist and a loop diuretic, the A-V fistula was closed surgically and the filter removed. Three months after operation she was put on phenprocoumon (Quick value 20-30%). At the latest outpatient examination, 6 months after the operation, she was free of symptoms. CONCLUSION: As filter implantation in the IVC may produce severe complications, indications for it need to be demonstrated by further studies of its efficacy.

Intermittent edema of the upper and lower extremities and the abdominal wall caused by membranous stenosis of the superior vena cava and membranous obstruction of the inferior vena cava.

We report on a 38-year-old patient with intermittent edema of the lower legs, arms and abdominal wall. The cause for his tendency to develop edema was a membranous obstruction of the inferior vena cava and a membranous stenosis of the superior vena cava. The etiology of these anomalies of the vena cava suggests a congenital malformation. In consideration of the cases of inferior and/or superior vena cava-anomalies published to date the patient received an anticoagulant therapy (coumarin) and treatment with graduated compression stockings. He now complains from time to time of a sensation tension in the lower legs after prolonged standing or sitting. Edema of the upper and lower extremities and the abdominal wall have disappeared.