RESUMO
BACKGROUND: Superior-type fast-slow (sup-F/S-) atrioventricular nodal reentrant tachycardia (AVNRT) is a rare AVNRT variant using a superior slow pathway (SP) as the retrograde limb. Its intracardiac appearance, characterized by a short atrio-His (AH) interval and the earliest site of atrial activation in the His-bundle, is an initial indicator for making a diagnosis. METHODS: Among 22 consecutive patients with sup-F/S-AVNRT, 3 (age, 68-81 years) patients had an apparent slow-fast (S/F-) AVNRT characterized by a long AH interval and the earliest site of atrial activation in or superior to the His-bundle region (tachy-long-AH). RESULTS: The diagnosis of sup-F/S-AVNRT was based on the standard criteria in 2 patients and on the occurrence of Wenckebach-type atrioventricular block during tachycardia, which was attributable to a block at the lower common pathway (LCP) below the circuit of the AVNRT, detected owing to the lower common pathway potentials, in one patient. As with the typical S/F-AVNRT, tachy-long-AH was induced after a jump in the AH interval. In contrast to typical S/F-AVNRT, fluctuation in the ventriculoatrial interval was observed during the tachy-long-AH. Ventricular overdrive pacing was unable to entrain or terminate the tachy-long-AH. Moreover, the tachy-long-AH reciprocally transited to/from sup-F/S-AVNRT spontaneously or was triggered by ventricular contractions while the atrial cycle length and earliest site of atrial activation remained unchanged. Both tachycardias were cured by ablation at a single site in the right-side para-Hisian region of 2 patients and the noncoronary aortic cusp of one patient. Collectively, the essential circuit of both tachycardias was identical, and the tachy-long-AH was diagnosed as another phenotype of sup-F/S-AVNRT accompanied by sustained antegrade conduction via another bystander slow pathway breaking through the His-bundle owing to the repetitive antegrade block at the lower common pathway, thus representing a long AH interval during the ongoing sup-F/S-AVNRT. CONCLUSIONS: An unknown sup-F/S-AVNRT phenotype exists that apparently mimics the typical S/F-AVNRT and is also an unknown subtype of apparent S/F-AVNRT.
Assuntos
Fascículo Atrioventricular/fisiopatologia , Técnicas Eletrofisiológicas Cardíacas , Frequência Cardíaca , Taquicardia Ventricular/diagnóstico , Potenciais de Ação , Idoso , Idoso de 80 Anos ou mais , Fascículo Atrioventricular/cirurgia , Ablação por Cateter , Feminino , Humanos , Masculino , Fenótipo , Valor Preditivo dos Testes , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/cirurgia , Fatores de Tempo , Resultado do TratamentoRESUMO
INTRODUCTION: Electrophysiological properties of reentry circuits of fast-slow atrioventricular nodal reentrant tachycardia (F/S-AVNRT) may contribute to cyclic variability after atrial induction. METHODS: In 156 atrial inductions of 33 patients with F/S-AVNRT, we measured the atrio-His (AH) and His-atrial (HA) intervals in the first cycle after the induction (AH[1] and HA[1], respectively), those in the second cycle (AH [2] and HA [2], respectively), and those during tachycardia that maintained a stable cycle length AH[T] and HA[T], respectively), and calculated the value of AH(1) minus AH(T) [ΔAH] and the value of HA(1) minus HA(T) [ΔHA] in each induction. According to the sum of ΔAH and ΔHA, tachycardia variability was classified as incremental (<-20), balanced (-20 to 20), or decremental (>20). RESULTS: ΔAH and ΔHA were significantly different between the three responses: 6 ± 28 and -67 ± 39 in 55 inductions (35%) with an incremental response, 20 ± 10 and -23 ± 28 in 59 (38%) with a balanced response, and 54 ± 44 and 4 ± 50 in 42 (27%) with a decremental response, respectively. Incremental response was reproducibly and consistently observed in 33% of patients. HA(2) was similar to HA(T) in inductions with an incremental response. These results suggest that incremental response can be manifested only in the first cycle when HA(1) is excessively shortened, approximating a retrograde conduction time over a slow pathway, in contrast, and far superior to a decremental delay of AH(1). CONCLUSION: In specific patients with F/S-AVNRT, poorly recognized, electrophysiological properties of shortening a retrograde conduction time over a slow pathway was manifested during atrial induction.
Assuntos
Potenciais de Ação , Estimulação Cardíaca Artificial , Técnicas Eletrofisiológicas Cardíacas , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Adulto , Idoso , Nó Atrioventricular/fisiopatologia , Fascículo Atrioventricular/fisiopatologia , Ablação por Cateter , Feminino , Átrios do Coração/fisiopatologia , Sistema de Condução Cardíaco/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Taquicardia por Reentrada no Nó Atrioventricular/fisiopatologia , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia , Fatores de Tempo , Resultado do TratamentoRESUMO
We report a case of atypical fast-slow atrioventricular nodal reentrant tachycardia (AVNRT) using a slow pathway variant extending to the superoanterior right atrium. The AVNRT diagnosis was confirmed by using standard electrophysiological criteria that exclude a diagnosis of atrial tachycardia and atrioventricular reentrant tachycardia. The earliest atrial activation during tachycardia was found in the superoanterior right atrium adjacent to the tricuspid annulus, where the first delivery of radiofrequency energy terminated and eliminated the inducibility of the tachycardia.
Assuntos
Ablação por Cateter/métodos , Técnicas Eletrofisiológicas Cardíacas/métodos , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Trifosfato de Adenosina/administração & dosagem , Trifosfato de Adenosina/uso terapêutico , Assistência ao Convalescente , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Eletrocardiografia , Feminino , Átrios do Coração/fisiopatologia , Humanos , Taquicardia por Reentrada no Nó Atrioventricular/fisiopatologia , Taquicardia por Reentrada no Nó Atrioventricular/terapia , Taquicardia Supraventricular/diagnóstico , Taquicardia Supraventricular/tratamento farmacológico , Resultado do TratamentoAssuntos
Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Taquicardia Supraventricular/diagnóstico , Adulto , Nó Atrioventricular/fisiopatologia , Ablação por Cateter , Diagnóstico Diferencial , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Feminino , Humanos , Taquicardia por Reentrada no Nó Atrioventricular/fisiopatologia , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia , Taquicardia Supraventricular/fisiopatologia , Taquicardia Supraventricular/cirurgiaAssuntos
Complexos Atriais Prematuros/complicações , Fibrilação Ventricular/etiologia , Potenciais de Ação , Complexos Atriais Prematuros/diagnóstico , Complexos Atriais Prematuros/fisiopatologia , Complexos Atriais Prematuros/terapia , Desfibriladores Implantáveis , Cardioversão Elétrica/instrumentação , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Frequência Cardíaca , Humanos , Masculino , Fatores de Tempo , Resultado do Tratamento , Fibrilação Ventricular/diagnóstico , Fibrilação Ventricular/fisiopatologia , Fibrilação Ventricular/terapiaRESUMO
After entrainment pacing, the postpacing interval of a diastolic potential may be misinterpreted if the distal tip of the ablation catheter captures a remote bystander pathway adjacent to the critical isthmus of a complex reentrant circuit in a structurally diseased heart. We discuss this possible pitfall of entrainment mapping of reentrant ventricular tachycardia, observed after a healed myocardial infarction.
Assuntos
Estimulação Cardíaca Artificial/métodos , Técnicas Eletrofisiológicas Cardíacas , Sistema de Condução Cardíaco/fisiopatologia , Taquicardia Ventricular/diagnóstico , Potenciais de Ação , Idoso , Autopsia , Ablação por Cateter , Evolução Fatal , Sistema de Condução Cardíaco/patologia , Sistema de Condução Cardíaco/cirurgia , Humanos , Masculino , Infarto do Miocárdio/complicações , Valor Preditivo dos Testes , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/cirurgia , Fatores de TempoRESUMO
The length of the slow pathway (SP-L) in atrioventricular (AV) nodal reentrant tachycardia (NRT) has never been measured clinically. We studied the relationship among (a) SP-L, i.e., the distance between the most proximal His bundle (H) recording and the most posterior site of radiofrequency (RF) delivery associated with a junctional rhythm, (b) the length of Koch's triangle (Koch-L), (c) the conduction time over the slow pathway (SP-T), measured by the AH interval during AVNRT at baseline, and (d) the distance between H and the site of successful ablation (SucABL-L) in 26 women and 20 men (mean age 64.6 ± 11.6 years), using a stepwise approach and an electroanatomic mapping system (EAMS). SP-L (15.0 ± 5.8 mm) was correlated with Koch-L (18.6 ± 5.6 mm; R 2 = 0.1665, P < 0.005), SP-T (415 ± 100 ms; R 2 = 0.3425, P = 0.036), and SucABL-L (11.6 ± 4.7 mm; R 2 = 0.5243, P < 0.0001). The site of successful ablation was located within 10 mm of the posterior end of the SP in 38 patients (82.6 %). EAMS-guided RF ablation, using a stepwise approach, revealed individual variations in SP-L related to the size of Koch's triangle and AH interval during AVNRT. Since the site of successful ablation was also correlated with SP-L and was usually located near the posterior end of the SP, ablating anteriorly, away from the posterior end, is not a prerequisite for the success of ablation procedures.