Assuntos
Bloqueio de Ramo/fisiopatologia , Complexos Cardíacos Prematuros/fisiopatologia , Sistema de Condução Cardíaco/fisiopatologia , Idoso , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/efeitos adversos , Bisoprolol/administração & dosagem , Bisoprolol/efeitos adversos , Bloqueio de Ramo/diagnóstico por imagem , Bloqueio de Ramo/tratamento farmacológico , Complexos Cardíacos Prematuros/diagnóstico por imagem , Complexos Cardíacos Prematuros/tratamento farmacológico , Ablação por Cateter/métodos , Eletrocardiografia , Enalapril/administração & dosagem , Enalapril/efeitos adversos , Sistema de Condução Cardíaco/diagnóstico por imagem , Sistema de Condução Cardíaco/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/fisiopatologia , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/fisiopatologia , Masculino , Taquicardia Supraventricular/complicações , UltrassonografiaRESUMO
BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) often terminate spontaneously, presumably due to changes in the electrophysiological properties of the reentrant circuit. However, the mechanism of spontaneous termination of these arrhythmias is incompletely understood. METHODS: We included 70 consecutive patients with reentrant supraventricular tachycardias (35 AVNRT, 35 AVRT) in whom the arrhythmia ended spontaneously during the electrophysiologic study. We determined in each patient the duration of the induced arrhythmia, site of block, beat-to-beat oscillations in tachycardia cycle-length (CL), A-H, H-V, H-A and V-A intervals. RESULTS: In 21/34 (62%) patients with AVNRT and 19/30 (63%) with orthodromic AVRT, tachycardia termination was preceded by progressive increase in tachycardia CL due to prolongation of the A-H interval (Mobitz type-I pattern). In 13/34 patients with AVNRT (38%) and 11/30 with orthodromic AVRT (37%), termination occurred suddenly without a preceding change in CL, with block ensuing retrogradely either in the fast AV nodal pathway or the accessory pathway (Mobitz type-II pattern). In 4/5 patients with antidromic AVRT the tachycardia ended at the retrograde limb with previous prolongation of the VA interval. CONCLUSION: Spontaneous termination of AVNRT and AVRT is a time-related phenomenon. Despite different pathways being involved in these two reentrant tachycardias, termination can follow antegrade or retrograde block in similar ratio (60% antegradely and 40% retrogradely). Antegrade block is preceded by prolongation of the AH interval (Mobitz type-I), whereas retrograde block occurs unexpectedly in the retrograde limb (Mobitz type-II). Fatigue of conduction appears to be involved in this phenomenon.
Assuntos
Nó Atrioventricular/fisiopatologia , Fascículo Atrioventricular/fisiopatologia , Eletrocardiografia , Taquicardia por Reentrada no Nó Atrioventricular/fisiopatologia , Taquicardia Paroxística/fisiopatologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Remissão Espontânea , Estudos Retrospectivos , Adulto JovemAssuntos
Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/fisiopatologia , Eletrocardiografia/métodos , Sistema de Condução Cardíaco/anormalidades , Defeitos dos Septos Cardíacos/diagnóstico , Defeitos dos Septos Cardíacos/fisiopatologia , Humanos , MasculinoRESUMO
It has recently been reported that a high-degree right bundle branch block (RBBB) may conceal the electrocardiographic manifestations of the Brugada ECG pattern. An 82-year-old with recent onset palpitations was seen in clinic. The resting ECG showed sinus rhythm, high-degree RBBB, and an irregular idioventricular rhythm. Some fusion beats between sinus rhythm and idioventricular rhythm occurred spontaneously depicting incomplete RBBB pattern and a clear cut elevation of the ST-segment was unveiled, giving rise to a suspicious Brugada ECG pattern. The mechanisms and implications of these findings are discussed.
Assuntos
Ritmo Idioventricular Acelerado/fisiopatologia , Síndrome de Brugada/fisiopatologia , Eletrocardiografia , Idoso de 80 Anos ou mais , Antiarrítmicos , Humanos , MasculinoAssuntos
Ajmalina , Síndrome de Brugada/diagnóstico , Síndrome de Brugada/prevenção & controle , Eletrocardiografia/métodos , Complicações Cardiovasculares na Gravidez/diagnóstico , Complicações Cardiovasculares na Gravidez/prevenção & controle , Convulsões/prevenção & controle , Feminino , Humanos , GravidezRESUMO
BACKGROUND: The aim of this study was to compare the outcome of 3 months vs. 18 months of amiodarone treatment after atrial fibrillation (AF) conversion in patients who experienced the first episode of persistent AF. METHODS: We included 51 patients who experienced the first episode of persistent AF receiving amiodarone (600 mg) daily for 4-6 weeks. If AF persisted, electrical cardioversion (ECV) was performed. All patients received amiodarone (200 mg daily) for 3 months and then were randomized to amiodarone (Group I) or placebo (Group II) and followed for 15 months. The control group comprised 9 untreated patients undergoing ECV. Treatment effectiveness was evaluated using a Bayesian model. RESULTS: Eighteen months after AF reversion, 22 (81.5%) patients in Group I, 13 (54.2%) patients in Group II, and 1 (11.1%) patient in the control group remained in sinus rhythm. No differences were found between Group I patients who required ECV and Group II patients. Sinus rhythm was preserved in all Group I patients when it was achieved during amiodarone administration. Limiting adverse effects occurred in 3 (11.1%) patients in Group I. CONCLUSIONS: In patients regaining sinus rhythm after the first episode of persistent AF, a 3-month amiodarone treatment after reversion is a reasonable option for rhythm control.