Respuesta al ECG de noviembre de 2019 / Response to ECG, November 2019

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ECG de noviembre de 2019 / ECG, November 201

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Caracterización de la vía lenta nodular en pacientes con taquicardia por reentrada nodular: implicaciones clínicas para guiar la ablación / Characterization of the nodal slow pathway in patients with nodal reentrant tachycardia: clinical implications for guiding ablation

Introducción y objetivos La ablación de vía lenta nodular es el tratamiento de elección de la taquicardia por reentrada nodular. No hay descritas variables demográficas, anatómicas ni electrofisiológicas que predigan una localización exacta de la vía lenta dentro del nódulo auriculoventricular ni su proximidad a la vía rápida. El objetivo es estudiar estas variables. Métodos Se incluyó prospectivamente a 54 pacientes (17 varones; media de edad, 55 ± 16 años) sometidos a ablación efectiva de vía lenta. Se midieron los periodos refractarios de ambas vías y su tiempo de conducción diferencial. Se calculó las distancias desde la región hisiana (correspondiente a la localización de la vía rápida) hasta el ostium del seno coronario (con lo que se obtuvo una estimación de la longitud anteroposterior del triángulo de Koch) y también hasta la zona de la vía lenta. Resultados El tiempo de conducción diferencial (139 ± 98 ms) no se correlacionó con las distancias His-seno coronario (19 ± 6 mm; p = 0,6) ni His-vía lenta (14 ± 4 mm; p = 0,4). A mayor distancia His-seno coronario, se estableció mayor distancia His-vía lenta (r = 0,652; p < 0,01) y se confirmó la correlación anatómica entre las dimensiones del triángulo y la separación entre ambas vías. En los pacientes mayores de 70 años, se observaron menor tamaño del triángulo y menor distancia entre ambas vías (p < 0,001). Conclusiones Una mayor dimensión anteroposterior del triángulo de Koch se asocia a una localización de vía lenta más alejada de la rápida, encontrándose ambas más próximas entre sí (mayor riesgo de bloqueo auriculoventricular) en los pacientes de edad avanzada (AU)

Introduction and objectives: Nodal slow pathway ablation is the treatment of choice for nodal reentrant tachycardia. No demographic, anatomic, or electrophysiologic variables have been reported to predict an exact location of the slow pathway in the atrioventricular node or its proximity to the fast pathway. The purpose of this study was to analyze these variables. Methods: The study prospectively included 54 patients (17 men; mean age, 55 [16] years) who had undergone successful slow pathway ablation. The refractory periods of both pathways and their differential conduction time were measured, and calculations were performed to obtain the distance from the His-bundle region (location of the fast pathway) to the coronary sinus ostium (to estimate the anteroposterior length of the triangle of Koch) and to the slow pathway area. Results: The differential conduction time (139 [98] ms) did not correlate with the His-coronary sinus distance (19 [6] mm; P = .6) or the His-slow pathway distance (14 [4] mm; P = .4). When the Hiscoronary sinus distance was larger, the His-slow pathway distance was also larger (r = 0.652; P < .01) and the anatomic correlation between the triangle dimensions and the separation between the two pathways was confirmed. In patients older than 70 years, smaller triangle sizes and a shorter distance between both pathways were observed (P < .001). Conclusions: A greater anteroposterior dimension of the triangle of Koch is associated with a slow pathway location farther from the fast pathway. In elderly patients the two pathways are closer together (higher risk of atrioventricular block) (AU)

Characterization of the nodal slow pathway in patients with nodal reentrant tachycardia: clinical implications for guiding ablation.

INTRODUCTION AND OBJECTIVES: Nodal slow pathway ablation is the treatment of choice for nodal reentrant tachycardia. No demographic, anatomic, or electrophysiologic variables have been reported to predict an exact location of the slow pathway in the atrioventricular node or its proximity to the fast pathway. The purpose of this study was to analyze these variables. METHODS: The study prospectively included 54 patients (17 men; mean age, 55 [16] years) who had undergone successful slow pathway ablation. The refractory periods of both pathways and their differential conduction time were measured, and calculations were performed to obtain the distance from the His-bundle region (location of the fast pathway) to the coronary sinus ostium (to estimate the anteroposterior length of the triangle of Koch) and to the slow pathway area. RESULTS: The differential conduction time (139 [98] ms) did not correlate with the His-coronary sinus distance (19 [6] mm; P=.6) or the His-slow pathway distance (14 [4] mm; P=.4). When the His-coronary sinus distance was larger, the His-slow pathway distance was also larger (r=0.652; P<.01) and the anatomic correlation between the triangle dimensions and the separation between the two pathways was confirmed. In patients older than 70 years, smaller triangle sizes and a shorter distance between both pathways were observed (P<.001). CONCLUSIONS: A greater anteroposterior dimension of the triangle of Koch is associated with a slow-pathway location farther from the fast pathway. In elderly patients the two pathways are closer together (higher risk of atrioventricular block).

Pulmonary hemorrhage after cryoballoon ablation for pulmonary vein isolation in the treatment of atrial fibrillation.

Pulmonary vein isolation has evolved over the past years as an alternative for the treatment of symptomatic recurrences of atrial fibrillation refractory to antiarrhythmic drug treatment. Both radiofrequency energy and cryoballoon ablation have proven useful in this setting. We present the case of a 55-year-old male patient undergoing cryoballoon ablation complicated with pulmonary hemorrhage. The cause of this rare complication may be found in the damage of vascular venous structures near the ablation zone or, alternatively, in hemorrhagic damage of the pulmonary vein surrounding tissue (or less probably to direct injury of the lingular bronchus). The extremely low temperatures achieved in this case (which are often associated with deep balloon position inside the veins) are alarming and should alert the physician about the possibility of an excessively intrapulmonary vein deployment of the cryoablation balloon.

Comparison of epicardial cryoablation and irrigated radiofrequency ablation in a Swine infarct model.

UNLABELLED: Epicardial Cryoablation in Swine. INTRODUCTION: Cryoablation is an alternative to radiofrequency (RF) energy used in some ablation procedures. Its role and effectiveness compared to irrigated RF in epicardial tissue and epicardial substrates is not yet fully established. METHODS AND RESULTS: Using a swine chronic infarct model, we compared RF lesions produced by an open-irrigated 3.5 mm tip catheter with those produced by an 8 mm tip cryocatheter in epicardial infarct border zone, epicardial normal tissue, and normal endocardium. In the infarct border zone, cryolesions were larger than RF lesions in maximum diameter (9.3 ± 2.9 mm vs 6.2 ± 2 mm, P < 0.001) and volume (171.7 ± 173.1 mm(3) vs 77 ± 53.5 mm(3) , P = 0.021). In normal epicardial tissue, cryolesions were larger in maximum diameter (11.2 ± 4.3 mm vs 7.7 ± 3.1 mm, P = 0.012), depth (5.8 ± 1.6 mm vs 4.7 ± 1.4 mm, P = 0.034), and volume (274.7 ± 242.2 mm(3) vs 112 ± 102.9 mm(3) , P = 0.002). In normal endocardium, no significant differences were found. CONCLUSIONS: Epicardial cryoablation with an 8 mm tip cryocatheter led to larger lesion volume in infarcted myocardium compared to a 3.5 mm irrigated RF catheter. This is likely related to a combination of cryoadherence, more efficient energy delivery with horizontal orientation, and lack of warming by circulating blood. Cryoablation merits further investigation as a modality for treating ventricular tachycardia of epicardial origin in humans. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1016-1023, September 2012).

Ablation of ventricular arrhythmias arising near the anterior epicardial veins from the left sinus of Valsalva region: ECG features, anatomic distance, and outcome.

BACKGROUND: Left ventricular outflow tract tachycardia/premature depolarizations (VT/VPDs) arising near the anterior epicardial veins may be difficult to eliminate through the coronary venous system. OBJECTIVE: To describe the characteristics of an alternative successful ablation strategy targeting the left sinus of Valsalva (LSV) and/or the adjacent left ventricular (LV) endocardium. METHODS: Of 276 patients undergoing mapping/ablation for outflow tract VT/VPDs, 16 consecutive patients (8 men; mean age 52 ± 17 years) had an ablation attempt from the LSV and/or the adjacent LV endocardium for VT/VPDs mapped marginally closer to the distal great cardiac vein (GCV) or anterior interventricular vein (AIV). RESULTS: Successful ablation was achieved in 9 of the 16 patients (56%) targeting the LSV (5 patients), adjacent LV endocardium (2 patients), or both (2 patients). The R-wave amplitude ratio in lead III/II and the Q-wave amplitude ratio in aVL/aVR were smaller in the successful group (1.05 ± 0.13 vs 1.34 ± 0.37 and 1.24 ± 0.42 vs 2.15 ± 1.05, respectively; P = .043 for both). The anatomical distance from the earliest GCV/AIV site to the closest point in the LSV region was shorter for the successful group (11.0 ± 6.5 mm vs 20.4 ± 12.1 mm; P = .048). A Q-wave ratio of <1.45 in aVL/aVR and an anatomical distance of <13.5 mm had sensitivity and specificity of 89%, 75% and 78%, 64%, respectively, for the identification of successful ablation. CONCLUSIONS: VT/VPDs originating near the GCV/AIV can be ablated from the LSV/adjacent LV endocardium. A Q-wave ratio of <1.45 in aVL/aVR and a close anatomical distance of <13.5 mm help identify appropriate candidates.