[Systemic embolism after reversion to sinusal rhythm of persistent atrial flutter]. / Embolismo sistémico tras reversión a ritmo sinusal del aleteo auricular persistente.

BACKGROUND: The incidence of embolism in atrial flutter has been underestimated in the routine clinical practice. PATIENTS AND METHODS: In this study the incidence of thromboembolic events after restoration of sinus rhythm (by catheter ablation or cardioversion) was compared in two groups of consecutive patients, with a different anticoagulation protocol. A total of 169 patients were evaluated. A first retrospective analysis of 79 non anticoagulated patients (group I). A second prospective group of 90 patients who were treated with an anticoagulation protocol (group II) similar to that for patients with atrial fibrillation. All had typical atrial flutter of at least one month's duration before the procedure. RESULTS: The mean age of patients in group I was 61 12 years and the mean left ventricular ejection fraction was 57 6%. Patients in group II had a mean age of 61 10 years and the mean left ventricular ejection fraction was 56 9%. No differences were observed regarding prevalence of structural cardiopathy, arterial hypertension, diabetes mellitus, left ventricular dysfunction, atrial size or atrial fibrillation between the two groups of patients. Four patients in the retrospective analysis (5%) had an embolic event associated with the procedure, compared with 0 (0%) in the group of patients treated with the anticoagulation protocol. The efficient anticoagulation was associated with a lower risk of thromboembolic events (p < 0.05). CONCLUSIONS: The incidence of embolic events after reversion to sinusal rhythm of persistent atrial flutter can be decreased. These patients should follow the same recommendations of anticoagulation that apply for patients with persistent atrial fibrillation that are going to be reverted to sinus rhythm.

Embolismo sistémico tras reversión a ritmo sinusaldel aleteo auricular persistente / Systemic embolism after reversion to sinusal rhythm of persistent atrial flutter

Pacientes y métodos. En este estudio se compara la incidencia de eventos tromboembólicos después de restaurar el ritmo sinusal (por ablación con catéter o cardioversión) en dos grupos consecutivos de pacientes con un protocolo de anticoagulación diferente. Se evaluaron 169 pacientes. Un primer análisis retrospectivo de 79 pacientes no anticoagulados (grupo I). Un segundo grupo prospectivo de 90 pacientes se trató con un protocolo de anticoagulación (grupo II) similar al de los pacientes con fibrilación auricular. Todos presentaban aleteo auricular típico de al menos un mes de duración antes del procedimiento. Resultados. Grupo I: la edad media fue 61ñ12 años y la fracción de eyección ventricular izquierda media de 57 ñ 6 por ciento. Grupo II: tuvo una edad media 61 ñ 10 años y fracción de eyección ventricular izquierda media de 56 ñ 9 por ciento. No hubo ninguna diferencia en la prevalencia de cardiopatía estructural, hipertensión arterial, diabetes mellitus, disfunción ventricular izquierda, tamaño auricular o fibrilación auricular entre los dos grupos de pacientes. Cuatro pacientes del análisis retrospectivo (5 por ciento) presentaron un episodio embólico asociado con el procedimiento, comparado con 0 (0 por ciento) de los pacientes tratados con un protocolo de anticoagulación. La anticoagulación eficaz se asoció con un menor riesgo de tromboembolismo (p < 0,05). Conclusiones. Es posible reducir la incidencia de eventos embólicos después de la reversión a ritmo sinusal del aleteo auricular persistente. Estos pacientes deben seguir las mismas recomendaciones de anticoagulación que los pacientes con fibrilación auricular persistente que van a ser revertidos a ritmo sinusal (AU)

[Evaluation of the anatomopathological characteristics and the safety of radiofrequency lesions at the atrial level with two different systems of irrigated tip catheters on an experimental level]. / Estudio de las características anatomopatológicas y la seguridad de las lesiones producidas en la aurícula con dos diferentes sistemas de catéteres de punta irrigada en un modelo experimental.

INTRODUCTION AND OBJECTIVES: We performed this study to evaluate the security and efficacy in the lesions produced on the atrial wall by different irrigated catheters in an experimental model. We evaluated the anatomopathologic characteristics of the lesions produced by two different systems of irrigated tip catheters, with opened or closed circuit. METHODS: This study was performed in 16 pigs applying 60 sec radiofrequency pulses with three different energy levels (15, 25 y 50 Watts). Two different systems of radiofrequency ablation irrigated catheters were used, opened and closed. We used 4 pigs in which we performed ablation with a standard catheter as a control group. Under fluoroscopic guidance, catheters were placed on the high and low right atrial lateral wall, where lesions were produced. After 7 days, animals were sacrificed for anatomopathological study. RESULTS: A total of 27 lesions were performed with irrigated catheters (11 closed circuit and 16 opened) and 6 with standard catheters in the control group. We did not find significant differences in the lesion characteristics between the two different systems of irrigated tip catheter used, nevertheless lesions performed with the closed system were slightly greater. Th lesions produced with irrigated catheters were always superior in the control group. Transmurality in the free atrial wall is frequent with both systems. We did not see any perforation in the atrial wall. CONCLUSIONS: We did not find significant differences in the size of the lesions produced with the two systems of irrigated catheters used. These data from an experimental model can provide useful information for atrial tachycardia radiofrequency ablation procedures in humans.

[Macroscopic and microscopic study of the right coronary artery after radiofrequency catheter ablation of cavotricuspid isthmus in an experimental model]. / Estudio macro y microscópico de la arteria coronaria derecha tras ablación con catéter y radiofrecuencia del istmo cavotricuspídeo en un modelo experimental.

INTRODUCTION AND OBJECTIVES: The right coronary artery (RCA) is found in the AV groove, just below the ablation target of atrial flutter, the cavotricuspid isthmus (ICT). After radiofrequency (RF) ablation with standard catheters, there have been no reports of complications, but it may not be successful in 10% of the cases. However, the use of irrigated tip catheters, which create deeper lesions, might potentially damage the coronary tree. METHODS: We analyzed the effects of ICT RF ablation on the coronary tree, with macroscopic and microscopic anatomopathological study. Ablation on ICT was performed using an irrigated tip catheter in 16 pigs and was randomly compared with a standard ablation catheter. There were no clinical problems, modifications of ST or new arrhythmias during the ablation. The heart was extracted at 1 week. RESULTS: The macroscopic study demonstrated that the right coronary artery was preserved, along the ICT, surrounded by the epicardial fat. The microscopic study showed an inflammatory reaction in the epicardial fat that reached the adventitia of the coronary artery, but never produced necrosis in 14 cases. The muscular wall of the artery had signs of focal inflammation without endothelium involvement in 2 cases. However, we found a subepicardial vein completely damaged by the radiofrequency. CONCLUSIONS: Although the right coronary artery is located just below the isthmus, no necrosis was observed in any case. However, there was an inflammatory reaction that focally reached the muscular wall. The veins may be damaged in RF ablation, perhaps due to the different blood flow of each vessel.

[Anatomopathological and biochemical correlation of lesions produced by standard and irrigated 4 mm radiofrequency catheters]. / Correlación anatomopatológica y bioquímica de las lesiones producidas por la radiofrecuencia con catéteres estándar e irrigados de 4 mm.

INTRODUCTION AND OBJECTIVES: The influence on the size of radiofrequency lesions by cooling of the tip of the electrode remains unclear. Moreover, the possible effects of two different cooling systems, closed and open, have not been well differentiated. We designed this study to compare both systems of irrigated-tip catheters and the lesions produced with standard 4 mm catheters and also to evaluate the pathological and biochemical marker release correlation (cardiac troponin I) in an experimental model. METHODS: The study was performed in 20 pigs. Applying between 1-8 radiofrequency pulses, at a power of 15, 25 or 50 watts, for 15-60 seconds to each animal. After 7 days, the pigs were sacrificed for anatomopathological study. RESULTS: A total of 54 lesions were produced, 25 with standard catheters and 29 with irrigated catheters. The mean volume of the lesions produced with standard catheters was 146 +/- 110 microl and with irrigated-tip catheters 856 +/- 864 microl (p < 0.001). Peak values of cardiac troponin I were also higher for irrigated catheters (18 +/- 15 ng/ml) than for standard (6.5 +/- 3 ng/ml). The correlation between the size of the lesion and the levels of cardiac troponin I were 0.86 and 0.79 with the standard and irrigated-tip catheters, respectively. The incidence of cratering was higher with standard catheters (60%) than with irrigated (27%). CONCLUSIONS: The lesions produced with an irrigated catheter are greater than those observed with standard catheters. The mean peak value of postablation cardiac troponin demonstrate a good correlation with the real size of the necrosis.

[Recurrent ventricular fibrillation during a febrile illness in a patient with the Brugada syndrome]. / Fibrilación ventricular recurrente durante un proceso febril en un paciente con síndrome de Brugada.

Different situations have been involved in the origin of ventricular arrhythmic events in patients with the Brugada syndrome such as bradycardia, alcohol consumption and mental stress. We present a 30 year old male with recurrent ventricular fibrillation due to a febrile illness with intense sweating. He had been previously studied at our Unit in 1995 because of an episode of resuscitated cardiac arrest due to ventricular fibrillation. The twelve-lead electrocardiogram showed the typical characteristics of a patient with the Brugada syndrome. Different invasive and non-invasive tests performed were normal. He received a defibrillator and had no recurrences during 4 years of follow up. In March,1999, after an upper respiratory tract infection he had high fever treated with paracetamol but at down he had sweating and chills, followed by 3 defibrillator shocks. Late interrogation showed 5 episodes of ventricular fibrillation, two of them non-sustained, and the rest adequately treated by the defibrillator. Activation and inactivation kinetics for early INa are twofold faster at higher temperature, and shift activation and steady-state inactivation. This may explain the role of the temperature as a trigger for ventricular arrhythmias in our patient.

Biochemical markers and cardiac troponin I release after radiofrequency catheter ablation: approach to size of necrosis.

BACKGROUND: We designed this study to determine the value of serum levels of several cardiac markers in patients who underwent radiofrequency ablation and to establish the utility of cardiac troponin I (cTnI). After radiofrequency ablation there is always a small localized endomyocardial necrosis. The volume of the necrosis may be estimated by the rise of several biochemical marker levels, classically creatinine kinase (CK) and CK-MB. cTnI is a newly available biochemical marker with a high cardiac specificity. METHODS AND RESULTS: We analyzed the data from 51 patients who underwent radiofrequency ablation and from 16 control patients who underwent an electrophysiologic study without ablation. The levels of CK, CK-MB mass, cTnI, and myoglobin were compared with clinical findings, ST-T wave abnormalities, and the presence of arrhythmias. The study shows that there is a higher release of cTnI compared with the standard markers CK, CK-MB, and myoglobin. A pathologic value of cTnI was found in 92% of the patients of the ablation group. CK-MB had a lower sensitivity (63%). The area under the receiver operating characteristic curve for cTnI was 0.9375, significantly superior to the other biochemical markers (P <.05). We found a moderate level of correlation between the number of radiofrequency pulses and cardiac cTnI release (r = 0.69, P <.0001). CONCLUSIONS: The serum level of cTnI detects the minor myocardial damage produced by radiofrequency ablation. This would be useful information to have in patients who might have the potential for other ischemic events. The other biochemical or ablation parameters usually reported, including the radiofrequency ablation parameters, have no good correlation with the size of the myocardial necrosis. Therefore we suggest that monitoring of cTnI is the best way to detect and quantify the size of myocardial necrosis created by radiofrequency ablation.

[Electromagnetic interference between automatic defibrillators and digital and analog cellular telephones]. / Interferencias electromagnéticas entre los desfibriladores automáticos y los teléfonos móviles digitales y analógicos.

BACKGROUND AND OBJECTIVES: Functional pacemaker interference by mobile telephones has been described with analogical systems and with possible greater influence, digital systems, including inhibition and inadequate pacing. The influence of both system has not been extensively studied in patients with implantable cardioverter defibrillators (ICD). PATIENTS AND METHODS: We studied the influence of mobile phones, both digital and analogic network, on the performance of several models of defibrillators, in a standardised test set up designed to provide high sensitivity. The purpose of our study was to establish whether there are any influences on ICD functions, both in in vivo and in in vitro models. Several mobile phones, with different transmission powers, were moved towards the defibrillator and the electrode, under continuous documentation of defibrillator sensing and interrogation afterwards. The experimental model was performed with the aid of an arrhythmia simulator (Intersim) and demo-defibrillators. The tests were repeated both in and out of a solution of saline water with an impedance within normal human limits. RESULTS: Partial loss of telemetry was found in 14 patients, 8 with analogical phones and 6 with digital phones. Fourteen patients showed alterations only on the surface electrocardiogram channel and five on the intracavitary channel. The same results were reproduced in the in vitro model. However, the in vitro test allowed us to simulate multiple ventricular arrhythmias, and demonstrate the normal sensing and functioning of the defibrillator during a "spontaneous" arrhythmia. After testing, we demonstrate that no real oversensing/undersensing was documented in any device. There was no evidence of ICD reprogramming or pacing inhibition. In particular, no inadequate therapies were delivered. CONCLUSIONS: a) in our series, we have not demonstrated clinically significant electromagnetic interferences with mobile phones of digital or analogical networks: b) the in vitro model allowed us to conclude that even if a spontaneous arrhythmia appears, the function of the defibrillator is not altered; c) the use of mobile phones seems to be safe for defibrillator patients, and d) however, some basic rules, such as to maintain the phone at least 15 cm away from the defibrillator, are advised.