Radiofrequency catheter ablation of atriofascicular and nodoventricular Mahaim tracts.

Grogin, Harlan R.; Lee, R J; Kwasman, Michael; Epstein, Laurence M.; Schamp, David J.; Lesh, Michael D.; Scheinman, Melvin M.

doi:10.1161/01.cir.90.1.272

Cited by 78 publications

(59 citation statements)

References 11 publications

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“…An interesting finding was the appearance of a tachycardic rhythm induced by RF pulse and ceasing after it was maintained for some time. Its occurrence is similar to a phenomenon observed during RF application in tissues with intrinsic automaticity, such as the sinus node, the AV node and accessory nodes 20 . These observations suggest that atrial structures with automaticity could be involved in the mechanism of AF in some patients 21 .…”

Section: Discussionsupporting

confidence: 67%

Radiofrequency catheter ablation in patients with atrial fibrillation

Scanavacca¹,

Sosa²,

d’Ávila³

et al. 1999

Arq. Bras. Cardiol.

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this novel technique, as well as to caution against the risk of developing pulmonary veno-occlusive syndrome, observed in one patient submitted to radiofrequency catheter ablation.Case 1 -The first patient was a 36 year-old male who had presented with occasional episodes of paroxistic AF for the past ten years, and daily recurrences for the past two years. He had failed to respond to quinidine associated to digoxine, amiodarone, sotalol and subsequently propafenone associated to atenolol. After clinical and echocardiographic evaluation, no systemic or structural heart disease was documented. Rest ECG was normal, but ambulatory Holter monitoring displayed several episodes of non-sustained AF following atrial premature beats and frequent episodes of atrial tachycardia.In June, 1998, an EP study was undertaken under deep sedation with propofol, midazolam and fentanyl. Three catheters were inserted percutaneously into the right femoral artery. A decapolar catheter was positioned at the lateral wall of the right atrium. An octapolar catheter was inserted into the coronary sinus, and a quadripolar catheter with a 4 mm tip was inserted in the left atrium, through a transeptal approach ( fig. 1). An intravenous bolus of heparin (5000 IU) was given, followed by a 1000 UI/hr continuous infusion.AF was recorded in left atrial electrograms, whereas right atrium electrograms were organized and regular ( fig. 2). Three direct current shocks (200 J) were delivered in an attempt to restore sinus rhythm, but that was maintained for only a few seconds, with AF recurrence (fig. 3). With the catheter positioned at the right inferior pulmonary vein, we observed that AF initiated after an atrial premature beat occurring earlier at that site when compared to the right atrial and coronary sinus signals. However, it did not precede peripheral P wave. The catheter was subsequently manipulated towards the left superior pulmonary vein (LSPV) ostium and another direct current 200 J shock delivered. After AF recurred, it could be observed that the atrial beat initiating the tachycardia was about 100 msec earlier at this site than the P wave preceding the tachycardia (fig. 4). A Recent reports have demonstrated that, in some patients, atrial fibrillation is triggered by ectopic foci originated from the pulmonary veins and that these foci can be effectively treated by radiofrequency pulses. In this report we confirm these findings in three patients with paroxistic atrial fibrillation refractory to antiarrhythmic drugs, while we caution against the occurrence of pulmonary veno-occlusive syndrome, observed in one of the patients after the second attempt to treat atrial fibrillation with RF ablation. We concluded that although RF pulses are effective to interrupt focal atrial fibrillation, multiple applications in the pulmonary veins can produce significant pulmonary vein stenosis. The significance of these findings remains to be determined after a longer follow-up.Atrial fibrillation (AF) is one of the most frequently found cardiac arrhythmia in...

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Section: Discussionsupporting

confidence: 67%

Radiofrequency catheter ablation in patients with atrial fibrillation

Scanavacca¹,

Sosa²,

d’Ávila³

et al. 1999

Arq. Bras. Cardiol.

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Section: Nodoventricular or Atriofascicular?mentioning

confidence: 99%

“…Catheter ablation is accomplished by identifying the proximal Mahaim Accessory Pathways and distal insertions and, ideally, the recording of a proximal pathway potential at the tricuspid annulus or a distal one on the right ventricular free wall (see Figure 6). 5,[13][14][15][16][17] Pathway potential recording may be facilitated during atrial pacing. Since most of the Mahaims are mapped on the lateral tricuspid annulus or right free wall underneath the valve, the use of supportive long sheaths that stabilise the ablating catheter may be very helpful.…”

Section: 13mentioning

confidence: 99%

“…[2][3][4][5][12][13][14][15][16][17] However, posteroseptal locations could also be found, 7,14 and true nodoventricular fibres have been identified (see Figure 5). 1,14,16 In addition, some of these pathways, so-called 'short'as opposed to 'long' Mahaims, may insert at the ventricle near rather than in the RBB. [5][6][7]18 Thus, pathways with Mahaim characteristics can be atriofascicular, atrioventricular, nodofascicular and nodoventricular, depending on their variable proximal and distal insertions.…”

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confidence: 99%

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Mahaim Accessory Pathways

Katritsis

Wellens

Josephson

2017

Arrhythmia &Amp; Electrophysiology Review

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In 1941, Mahaim and Winston described the histology of anomalous connections that arise from the AV node and insert into the right ventricle.1 This was the first description of nodoventricular or so-called Mahaim accessory pathways. Accessory pathways with decremental conduction properties that connected the atrium to the right bundle branch (RBB) were subsequently mapped mainly at the lateral aspect of the tricuspid annulus, and thus the term atriofascicular was also adopted. [2][3][4] We know now that decrementally conducting connections can be between the right atrium or the AV node and the right ventricle in or close to the RBB. 5-7 Thus, although they are anatomically distinct from the initially described nodoventricular pathway, they present with similar electrocardiographic and electrophysiological characteristics and the term 'Mahaim' has been adopted to describe pathways with the following features: Electrocardiographic Features ECG During Sinus RhythmDuring sinus rhythm overt pre-excitation is usually absent (see Figure 1). Only subtle ECG abnormalities, such as an rS pattern in lead III, absence of septal Q waves in leads I and V6, and terminal QRS slurring or notching, suggest the presence of Mahaim conduction. 9,10However, patients with short, rapidly conducting fibres may have typical pre-excitation. 10 ECG during tachycardiaAlthough, typically, antidromic atrioventricular reentrant tachycardia over a Mahaim fibre has a left bundle branch (LBBB) morphology (see Figure 2), various QRS patterns and axis may occur (see Figure 3). 6,7 It seems that these pathways insert into or near the RBB, and variations in the frontal plane axis can be explained by the location of the exit of the RBB and a variable degree of fusion of ventricular activation between anterograde conduction over the pathway and, following retrograde invasion into the RBB, partial anterograde left ventricular activation over the left-sided conduction system, especially the anterior fascicle (see Figure 4). The various QRS patterns and rate changes seen during the change from short to long V-A tachycardia can be explained by the mode of retrograde conduction over the bundle branch system. 6,7 Electrophysiological Properties Nodoventricular or Atriofascicular?Although the first case of this arrhythmia was studied electrophysiologically by Wellens and published in 1971, and considered to be based on a nodo-ventricular pathway, 11 with the advent of surgical and then catheter ablation in the 1980s, it was discovered that most fibres with Mahaim conduction characteristics originated at the lateral aspect of the tricuspid annulus, and the term atriofascicular pathway was adopted. [2][3][4][5][12][13][14][15][16][17] However, posteroseptal locations could also be found, 7,14 and true nodoventricular fibres have been identified (see Figure 5). 1,14,16 In addition, some of these pathways, so-called 'short'as opposed to 'long' Mahaims, may insert at the ventricle near rather than in the RBB. [5][6][7]18 Thus, pathways with Mahaim characteristic...

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“…Recently, most of these pathways have been classified as atriofascicular fibers that connect the right atrium to distal portions of the right branch of the His bundle with decremental properties 7,8 . Because they have different anatomical and electrophysiological characteristics, the following special ablation techniques have been considered: 1) atrial stimulation (pace-mapping) along the tricuspid ring, looking for the shortest "spike-Delta" interval 9 ; 2) mapping with extrastimuli during antidromic tachycardia, searching for the point of greatest "preexcitation" of the subsequent QRS; and 3) mapping of the activation potential of the fiber in sinus rhythm [10][11][12][13] . The latter has been considered more precise than the others; however, due to the rarity of this type of fibers, little experience has been reported in the medical literature.…”

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confidence: 99%