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. 2003 Apr 1;3(2):47-59.

Mahaim fibre tachycardia: recognition and management

Eduardo Back Sternick  1
Affiliations

Mahaim fibre tachycardia: recognition and management

Eduardo Back Sternick. Indian Pacing Electrophysiol J. .
No abstract available

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Figures

Figure 1
Figure 1
A: Atriofascicular pathway: baseline ECG discloses minimal preexcitation with a 0.12 s PR interval. During atrial pacing LBBB with âQRS= -20°, QRS 130 msec wide. B: Atrioventricular pathway in Ebstein's disease: baseline ECG without preexcitation and disclosing RBBB with normal PR interval. During atrial pacing manifest preexcitation with LBBB (âQRS= -30°), QRS 160 msec wide with a slurred initial r wave in V1
Figure 2
Figure 2
Three cases of fasciculoventricular pathways: PR intervals are 0,08 sec, 0,09 sec and 0,10 sec respectively. QRS is wider in the first ECG and <0.11 sec in the others 2 cases, and frontal plane axis are +30°, +75° and +45°. QRS transition occurs in V3, V2 and V2, respectively.
Figure 3
Figure 3
Atrioventricular pathway: high right atrial (HRA) pacing at 450 msec causes Wenckebach block on the accessory pathway. Progressive prolongation of AV interval (80-120-150-block) is due to prolongation of A-AP potential (40-80-115-block). Preexcitation degree increases from the first to the second QRS complex and remains constant in the third QRS despite further prolongation of the A-APP interval.
Figure 4
Figure 4
Antidromic tachycardia. Late (S) atrial extrastimuli delivered from the lateral high right atrium without disturbing AA timing at the His bundle recording advances QRS complex by 20 msec and His deflection by 30 msec, proving that the pathway is extra nodal and participates on the circuit.
Figure 5a
Figure 5a
Baseline ECG disclosing a normal PR interval (0,16 sec) and a preexcited QRS complex consistent with a right posteroseptal decremental AP
Figure 5b
Figure 5b
During atrial pacing a brief pulse (1 sec) of radiofrequency current delivered at a site with "M" potential yield a transient complete AV block followed by an escape rhythm without preexcitation (30-35 b/min). Preexcitation resumed in 14 seconds
Figure 6
Figure 6
Three examples of "M" potentials (TA- tricuspid annulus electrograms): from left to right: first two cases with His-like potentials and the third with narrow and low amplitude potential. Ablation was successful in each of those sites.
Figure 7
Figure 7
Radiofrequency catheter ablation during atrial pacing: MAT starts immediately after current delivery (RF-ON) and lasted for 8 seconds. Preexcitation is no longer present when MAT terminates.
Figure 8
Figure 8
Radiofrequency ablation of recurrent atriofascicular pathway conduction: during ablation salvos of automatic and irregular rhythms with the same QRS morphology as the preexcited one. The salvos persisted even after abolition of preexcitation (*) and fade out until complete disappearance.
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References

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