Short head-up tilt test potentiated with oral nitroglycerine: comparison with a conventional test using isoproterenol.

Conventional tilt test protocols are time consuming and there is no consensus regarding the optimal duration of the test and the provocative drug to be used. This study evaluated the diagnostic power of a short nitroglycerine test against a conventional isoproterenol protocol. A cohort of 128 patients with unexplained syncope was studied. A group of 64 consecutive patients were tilted with a short nitroglycerine test consisting of a passive phase of 15 minutes and if this proved negative, 400 microg of sublingual nitroglycerin spray for a further 15 minutes. The control group consisted of 64 patients tilted with a conventional isoproterenol protocol with a passive phase of 30 minutes and a drug-challenge phase of 20 minutes. In the nitroglycerine protocol 39 (60.9%) patients showed a positive response versus 27(42.2%) in the isoproterenol group (P = 0.034). The duration of the protocol was 23.2 +/- 7.2 minutes in the nitroglycerine group versus 41.1 +/- 15.5 minutes with isoproterenol (P = 0.001). The time until syncope was 18.87 +/- 6.1 versus 29 +/- 18, respectively (P = 0.002). For evaluating unexplained syncope the short tilt test protocol with nitroglycerine is less time consuming, easier to perform, and has a higher rate of positive response than a conventional isoproterenol protocol.

Electrocardiographic recognition of the epicardial origin of ventricular tachycardias.

BACKGROUND: Some ventricular tachycardias (VTs) originating from the epicardium are not suitable for endocardial radiofrequency ablation and require an epicardial approach. The aim of this study was to define the ECG characteristics that may identify an epicardial origin of VTs. METHODS AND RESULTS: We analyzed the 12-lead ECG recordings during epicardial and endocardial left ventricular pacing in 9 patients to verify the hypothesis that the epicardial origin of the ventricular activation widens the initial part of the QRS complex. Then, we analyzed the ECG pattern in 14 VTs successfully ablated from the epicardium after a failed endocardial approach (group A), in 27 VTs successfully ablated from the endocardium (group B), and in 28 additional VTs that could not be ablated from the endocardium (group C). Four distinct intervals of ventricular activation were defined and measured: (1) the pseudodelta wave, (2) the intrinsicoid deflection time in V2, (3) the shortest RS complex, and (4) the QRS complex. VTs from groups A and C showed a significantly longer pseudodelta wave, intrinsicoid deflection time, and RS complex duration compared with VTs of group B. There was no difference between groups A and C. A pseudodelta wave of > or =34 ms has a sensitivity of 83% and a specificity of 95%, an intrinsicoid deflection time of > or =85 ms has a sensitivity of 87% and a specificity of 90%, and an RS complex duration of > or =121 ms has a sensitivity of 76% and a specificity of 85% in identifying an epicardial origin of the VTs. CONCLUSIONS: ECG suggests VTs originating from the epicardium and those with an unsuccessful radiofrequency ablation from the endocardium.

Nonsurgical transthoracic epicardial radiofrequency ablation: an alternative in incessant ventricular tachycardia.

OBJECTIVES: The purpose of this study was to analyze the feasibility, efficacy, and safety of epicardial radiofrequency (RF) ablation in patients with incessant ventricular tachycardia (VT). BACKGROUND: Management of patients with incessant VT is a difficult clinical problem. Drugs and RF catheter ablation are not always effective. A nonsurgical transthoracic epicardial RF ablation can be an alternative in patients refractory to conventional therapy. METHODS: Epicardial RF ablation was performed in 10 patients who presented with incessant VT despite the use of two or more intravenous antiarrhythmic drugs. RESULTS: In eight patients, endocardial ablation (EdA) failed to control the tachycardia. In the remaining two patients, epicardial ablation (EpA) was first attempted because of left ventricular thrombus and severe artery disease, respectively. Eight patients had a diagnosis of coronary artery disease with healed myocardial infarction. One patient had dilated cardiomyopathy, and one patient had idiopathic, incessant VT. In patients with structural heart disease, the mean ejection fraction was 0.28 +/- 0.10%. Four patients previously received an implantable defibrillator. The EpA effectively terminated the incessant tachycardia in eight patients, which represents a success rate of 80%. In them, after a follow-up of 18 +/- 18 months, a single episode of a different VT was documented in one patient. No significant complications occurred related to the procedure. CONCLUSIONS: In patients with incessant VT despite the use of drugs or standard EdA, the epicardial approach was very effective and should be considered as an alternative in this life-threatening situation.

[Radiofrequency ablation in the treatment of focal atrial fibrillation using circumferential mapping and segmentary disconnection of pulmonary veins]. / Ablación por radiofrecuencia para el tratamiento de la fibrilación auricular focal a través de cartografía circunferencial y aislamiento segmentario de las venas pulmonares.

INTRODUCTION: The treatment of paroxysmal atrial fibrillation in patients without structural heart disease using radiofrequency ablation of pulmonary veins is a recently developed procedure with a good clinical success rate, although there have only been a few published series. We analyzed our results with this technique. METHOD: The procedure was performed in 33 highly symptomatic patients with focal atrial fibrillation that had probably originated in the pulmonary veins. The electrophysiological study was carried out with a decapolar catheter inserted by transeptal catheterization. Ablation was performed using a 4-mm catheter and directed to the segments of the ostium of pulmonary veins where venous potentials with greatest precocity were recorded. Subsequent radiofrecuency applications were performed until pulmonary vein disconnection was achieved. RESULTS: Venous electrical activity was recorded in 59 of 115 pulmonary veins that were mapped (58 were disconnected). During a median follow-up of 180 days, 8 patients recurred and only 2 of these continue with repeat episodes. The success rate at short term was 74.2% and at mid-term was 93.5%. Nineteen patients continue to receive antiarrhythmic treatment innefective before the procedure. Two patients showed complications related to catheter manipulation during tansseptal catheterization, probably due to air embolism, that was resolved spontaneously without consequences. No patient showed pulmonary stenosis. CONCLUSIONS: Teatment of focal atrial fibrillation using circumferential mapping and radiofrecuency application in segments of the ostium of pulmonary veins is a highly effective procedure in selected patients and has potentially severe although infrequent complications.

Ablación por radiofrecuencia para el tratamiento de la fibrilación auricular focal a través de cartografía circunferencial y aislamiento segmentario de las venas pulmonares / Radiofrequency ablation in the treatment of focal atrial fibrillation using circumferential mapping and segmentary disconnection of pulmonary veins

Introducción. El tratamiento de la fibrilación auricular paroxística en pacientes sin cardiopatía estructural a través de la ablación con radiofrecuencia de las venas pulmonares es un procedimiento reciente y con una tasa de éxito clínico importante, aunque las series publicadas son escasas. Analizamos nuestros resultados. Método. Fueron sometidos al procedimiento 33 pacientes muy sintomáticos y en fibrilación auricular de probable origen focal en venas pulmonares. Se realizó cartografía con un catéter decapolar por punción transeptal. Se utilizó un catéter de 4 mm para ablación de los segmentos del ostium de las venas donde se registraba el potencial eléctrico venoso con mayor precocidad, y se aplicó radiofrecuencia hasta obtener la desconexión de la vena pulmonar. Resultados. Se registró actividad eléctrica en 59 de 115 venas pulmonares cartografiadas (58 fueron desconectadas). Durante un seguimiento medio de 180 días, 8 pacientes presentaron recurrencia de la arritmia y de éstos sólo dos siguen con episodios repetitivos. La tasa de éxito a corto plazo fue del 74,2 por ciento y a medio plazo, del 93,5 por ciento. Diecinueve pacientes reciben tratamiento antiarrítmico antes inefectivo. Dos pacientes presentaron complicaciones en relación con el manejo de catéteres durante la punción transeptal, probablemente por embolia gaseosa, que se resolvieron espontáneamente sin secuelas. Ningún paciente presentó signos o síntomas de estenosis pulmonar. Conclusiones. El tratamiento de la fibrilación auricular focal a través de cartografía circunferencial y aplicación de radiofrecuencia en segmentos del ostium de las venas pulmonares es un procedimiento de gran eficacia en pacientes seleccionados y con complicaciones potencialmente graves pero infrecuentes (AU)