The various manifestations of concealed nodofascicular/nodoventricular bypass tracts.

BACKGROUND: The various arrhythmic manifestations of concealed nodofascicular (NF)/nodoventricular (NV) bypass tracts (BPTs) are poorly understood. OBJECTIVE: The purpose of the study was to define diagnostic criteria for supraventricular tachycardias (SVTs) associated with concealed nodal pathways (NPs). METHODS: We reviewed 11 patients with concealed NPs who underwent electrophysiology study and ablation for symptomatic SVT. RESULTS: Of 11 patients 7 (64% women; mean age 54 ± 16 years), NF/NV BPTs were active bystanders during atrioventricular nodal reentrant tachycardia (atypical [n = 4]; typical [n =2]) or participants during orthodromic NF/NV reentrant tachycardia (n = 5). The majority (10 of 11 [91%]) had nodal origin in the slow pathway (SP) and 7 of 11 (64%) presented as long RP SVT. Ablation of the SP targeting the right (n = 10) or left (n = 1) inferior extension eliminated concealed NP-associated SVTs in all patients. CONCLUSION: Concealed NF/NV BPTs are active bystanders equally as common as participants during SVT. They typically insert into the SP and often present as long RP SVT. SP ablation eliminates concealed NF/NV BPT-associated SVTs regardless of the mechanism.

Electrophysiological features differentiating the atypical atrioventricular node-dependent long RP supraventricular tachycardias.

BACKGROUND: Diagnosing atypical atrioventricular node-dependent long RP supraventricular tachycardias (SVTs) can be challenging. METHODS AND RESULTS: Nineteen patients with 20 SVTs (atypical atrioventricular nodal reentrant tachycardia without [n=11]/with [n=3] a bystander nodofascicular [NF] accessory pathway, orthodromic reciprocating tachycardia [ORT] using a decremental atrioventricular [permanent form of junctional reciprocating tachycardia; n=4] or NF [NF reentrant tachycardia; n=2]) accessory pathway underwent electrophysiological study. Postpacing interval (PPI)-tachycardia cycle length (TCL), corrected PPI, VA (ventriculoatrial), HA (His-atrial), AH (atrio-His) values, and responses to His-refractory ventricular premature depolarizations were studied. Compared with atrioventricular nodal reentrant tachycardia, ORT patients were younger (42±13 years versus 54±19 years; P=0.036) and were women (5/6 [83%] versus 3/14 [21%]; P=0.036); TCLs were similar (435 ms versus 429 ms; 95% confidence interval, -47.5 to 35.5). PPI-TCL was shorter for ORT (118 ms versus 176 ms; 95% confidence interval, 26.3-89.7) but only 50% had PPI-TCL <115 ms, whereas 5 of 6 (83%) had PPI-TCL <125 ms (sensitivity, 83%; specificity, 100%). Corrected PPI <110 ms, VA <85 ms, and HA <0 ms had equivalent sensitivity (67%) and 100% specificity for ORT. Compared with permanent form of junctional reciprocating tachycardia, NF reentrant tachycardia/atrioventricular nodal reentrant tachycardia had longer AH (29 ms versus 10 ms; 95% confidence interval, 3.03-35.0) or AH(SVT)