Eduardo Caballero

Noninvasive Identification of Ventricular Tachycardia-Related Conducting Channels Using Contrast-Enhanced Magnetic Resonance Imaging in Patients With Chronic Myocardial Infarction Comparison of Signal Intensity Scar Mapping and Endocardial Voltage Mapping

OBJECTIVES We performed noninvasive identification of post-infarction sustained monomorphic ventricular tachycardia (SMVT)-related slow conduction channels (CC) by contrast-enhanced magnetic resonance imaging (ceMRI). BACKGROUND Conduction channels identified by voltage mapping are the critical isthmuses of most SMVT. We hypothesized that CC are formed by heterogeneous tissue (HT) within the scar that can be detected by ceMRI. METHODS We studied 18 consecutive VT patients (SMVT group) and 18 patients matched for age, sex, infarct location, and left ventricular ejection fraction (control group). We used ceMRI to quantify the infarct size and differentiate it into scar core and HT based on signal-intensity (SI) thresholds (>3 SD and 2 to 3 SD greater than remote normal myocardium, respectively). Consecutive left ventricle slices were analyzed to determine the presence of continuous corridors of HT (channels) in the scar. In the SMVT group, color-coded shells displaying ceMRI subendocardial SI were generated (3-dimensional SI mapping) and compared with endocardial voltage maps. RESULTS No differences were observed between the 2 groups in myocardial, necrotic, or heterogeneous mass. The HT channels were more frequently observed in the SMVT group (88%) than in the control group (33%, p < 0.001). In the SMVT group, voltage mapping identified 26 CC in 17 of 18 patients. All CC corresponded, in location and orientation, to a similar channel detected by 3-dimensional SI mapping; 15 CC were related to 15 VT critical isthmuses. CONCLUSIONS SMVT substrate can be identified by ceMRI scar heterogeneity analysis. This information could help identify patients at risk of VT and facilitate VT ablation.

Transcatheter occlusion of complex atrial septal defects

Percutaneous device occlusion of secundum atrial septal defects (ASDs) is becoming an accepted alternative to surgical closure. This method allows us to evaluate patients with complex conditions for treatment. From a total of 70 patients with ASD evaluated for percutaneous closure, we selected for analysis 28 who had complex conditions. The mean age was 36 ± 23 yr (range, 4–72). Six had heart failure, and of these six, three had atrial fibrillation. At cardiac catheterization, the pulmonary pressure was 47 ± 24 mm Hg, and the QP/QS was 1.7 ± 0.4; two patients had bidirectional shunt and systemic pulmonary pressure. Two patients received a buttoned device and 26 an Amplatzer septal occluder. The groups of patients with complex conditions were separated into the following groups. Group I (n = 4) underwent combined treatment of associated anomalies. Two patients had pulmonary stenosis, one had mitral stenosis, and one had an aortic root–left atrium fistula. They were treated in or during with the same procedure by combined transcatheter techniques (balloon valvuloplasty and fistula occlusion) before ASD occlusion. Group II (n = 9) had multiple defects (cribiform or two separate holes). They were treated with a single device in five instances and with two separate devices in four cases. Group III (n = 14) had large (32 ± 3 mm) single defects. Nine of them underwent successful implantation using a device 33 ± 3 mm in diameter; in the remaining five patients the device was removed because of instability. Group IV (n = 3) had residual defects after previous partial device occlusion. All three defects were successfully occluded with a second device. No movement or interference with the first device was observed. Group V (n = 6) had severe pulmonary hypertension (86 ± 16 mm Hg). Immediately after ASD occlusion we observed significant relief in these patients (67 ± 14 mm Hg; P < 0.01). There were no major complications; all 23 patients with successful implants were discharged without symptoms 2–7 days later; one patient with atrial fibrillation recovered sinus rhythm. The follow‐up (8 ± 5 mo) Doppler echo study showed complete ASD occlusion in 22 patients and a peak pulmonary pressure of 30 ± 14 mm Hg. We conclude that transcatheter occlusion of ASDs is an effective and safe treatment for patients with complex anatomic or physiopathologic conditions, as evaluated by short‐term follow‐up. Cathet. Cardiovasc. Intervent. 51:33–41, 2000.

Influence of stent treatment strategies in the long-term outcome of patients with long diffuse coronary lesions

Diffuse coronary lesions (length > 20 mm) are still considered high risk for percutaneous intervention even in the current stent era. We compared the 2‐year outcome of patients with long diffuse stenosis treated by three different stent strategies. In addition, we also analyzed the possible factors influencing a favorable late outcome. Our series is constituted by 232 patients with 247 long lesions treated between May 1994 and April 1999; 82 patients received one single long stent (group 1), 71 patients were treated by overlapped multiple stents (group 2), and 79 with multiple nonoverlapped stents (group 3). The mean age was 59 ± 11 years. There were not significant differences between groups in terms of age, risk factors, clinical presentation, type of lesion, or adjunctive medical therapy. Patients from group 1 had shorter lesions (29 ± 10 mm) than patients from groups 2 (41 ± 15 mm) and 3 (36 ± 14; P < 0.05). Major cardiac events (death, acute myocardial infarction, or repeat revascularization) at 24 ± 12 months follow‐up took place in 39 patients (17%). The probabilities of being free of major events at follow‐up were 71%, 78%, and 80% for group 1, 2, and 3 respectively (P = NS). Only three variables were identified as significant predictors of these late events: smaller vessel size, smaller minimal lumen diameter after stenting, and the type of lesion being restenotic as compared with native stenosis. Patients with diffuse lesions treated by single long stents did not have a better late outcome than those who received multiple stents. The best late outcome was observed in those patients who had bigger vessel size, larger poststent lumen dimensions and native lesions, regardless of the stent deployment strategy used. Cathet Cardiovasc Intervent 2003;58:293–300.

Técnica de la doble guía para el implante del electrodo venoso ventricular izquierdo en pacientes con anatomía venosa coronaria desfavorable

Introduccion y objetivos El implante de un electrodo ventricular izquierdo a traves del seno coronario plantea, en ocasiones, cierta dificultad debido a obstaculos anatomicos que limitan el acceso a la vena diana. El objetivo es analizar la experiencia del Hospital Universitario de Gran Canaria Dr. Negrin con la tecnica de la doble guia en el implante de un electrodo venoso ventricular izquierdo. Metodos De 170 pacientes consecutivos (67 ± 9 anos, 72% varones) a los que se implanto un dispositivo de resincronizacion se recurrio, en 20 de ellos (12%), al uso de una segunda guia hidrofilica en paralelo para el implante del electrodo en la vena diana, dada la imposibilidad de implante sin esta tecnica. Resultados Las causas de imposibilidad de implante con la tecnica convencional fueron: tortuosidad extrema del vaso en su desembocadura (5 pacientes, 25%), angulo marcado en la desembocadura de la vena diana (7 pacientes, 35%), presencia de una valvula venosa en dicha localizacion (8 pacientes, 40%) y, finalmente, escaso soporte del cateter guia (4 pacientes, 20%), bien por valvula de Tebesio fenestrada (2 pacientes) o por valvula de Vieussens restrictiva (2 pacientes) que no permitia el avance del cateter guia y/o del electrodo. En 4 casos (20%) hubo mas de un factor. En todos los casos, tras avanzar una segunda guia hidrofilica se pudo realizar el implante en la vena diana sin complicaciones. Conclusiones El uso de una segunda guia en paralelo (tecnica de la doble guia) es un procedimiento seguro y eficaz para el implante del electrodo ventricular izquierdo en pacientes con anatomia desfavorable.

Successful slow pathway ablation for atrioventricular nodal re-entrant tachycardia via a hypoplastic inferior vena cava in a patient with an azygos continuation.

Catheter ablation of the slow pathway for atrioventricular nodal re-entrant tachycardia (AVNRT) is not always possible due to congenital or acquired obstruction of the inferior vena cava (IVC). Although a superior access has been proposed as an alternative approach, a poor manoeuvrability and a lower stability of the ablation catheter may be potential problems. We report a case of slow pathway ablation for AVNRT in a patient with an azygos continuation using a hypoplastic but uninterrupted IVC.

Concepto y pronóstico de insuficiencia cardiaca con fracción de eyección normal

Aproximadamente un 40-50% de los pacientes con insuficiencia cardiaca presenta una fraccion de eyeccion normal. Hoy dia se asume que la disfuncion diastolica es la causa del cuadro, pero persiste cierto grado de controversia derivado de la dificultad que entrana su valoracion ecocardiografica y de una elevada tasa de errores diagnosticos. Se han descrito diferencias epidemiologicas respecto a los pacientes con insuficiencia cardiaca sistolica, aunque la presentacion clinica y el pronostico son similares, con una elevada mortalidad a medio plazo condicionada por una alta prevalencia de comorbilidad y la ausencia de ensayos clinicos aleatorizados que hayan probado terapias eficaces para modificar el curso de la enfermedad. Incluso en pacientes con disfuncion diastolica asintomatica – condicion frecuente en la poblacion general – se ha observado un incremento significativo de la mortalidad por todas las causas.

Utilidad de la senovenografía de retorno con hiperemia para el estudio de la anatomía venosa coronaria previo al implante de dispositivos de resincronización cardiaca

Introduccion y objetivos El implante de un electrodo a traves del seno coronario (SC) puede ser dificultoso debido a obstaculos anatomicos que limitan el acceso a la vena. Por ello es fundamental conocer la anatomia venosa coronaria. El objetivo es analizar la utilidad de la senovenografia de retorno con hiperemia en el implante de dispositivos de resincronizacion cardiaca comparandolo con la senovenografia oclusiva retrograda. Metodos Se estudio la anatomia venosa coronaria en 200 pacientes, mediante la filmacion del retorno venoso coronario optimizado con la induccion de hiperemia y mediante senovenografia oclusiva, puntuandose la visibilidad de las distintas porciones del sistema venoso coronario. Resultados En general, se obtuvo una informacion anatomica adecuada en el 99,5% de los individuos. Las puntuaciones de visibilidad para el SC y la vena lateral fueron ligeramente superiores en el grupo estudiado mediante senovenografia oclusiva retrograda, aunque no hubo diferencias significativas entre ambas tecnicas. Por el contrario, la vena cardiaca media y la vena interventricular anterior se visualizaron con mayor detalle mediante la senovenografia de retorno. No hubo complicaciones en el grupo estudiado mediante senovenografia de retorno, mientras que en 3 pacientes estudiados con senovenografia oclusiva se produjo la diseccion de la gran vena cardiaca, aunque no impidio el implante del electrodo. Conclusiones La angiografia coronaria de retorno define con precision la anatomia venosa de la region lateral del ventriculo izquierdo y permite anticipar el nivel de dificultad del implante del electrodo.

Double-Wire Technique for Implanting a Left Ventricular Venous Lead in Patients With Complicated Coronary Venous Anatomy

INTRODUCTION AND OBJECTIVES Occasionally, implanting a left ventricular pacing electrode for cardiac resynchronization therapy via the coronary sinus may be complicated by the presence of anatomical structures that obstruct the access to the target vein. Our objective was to report on experience using a double-wire technique for implanting left ventricular venous leads gained at the Dr Negrín Hospital in Gran Canaria, Spain. METHODS In 20 (12%) of 170 consecutive patients (67 [9] years, 72% male) undergoing implantation of a cardiac resynchronization device, a second parallel hydrophilic guidewire had to be used during lead implantation in the target vein as implantation was impossible without using this technique. RESULTS Implantation using a conventional approach was impossible because there was severe tortuosity at the vessel entrance in five patients (25%), a sharp angle at the entrance to the target vein in seven (35%), a venous valve at the vessel entrance in eight (40%), and, finally, poor support for the guiding catheter in four (20%), due to the presence of either a fenestrated Thebesian valve (two patients) or a restrictive Vieussens valve (two patients) that blocked passage of the guiding catheter or electrode. In four patients (20%), there was more than one factor. In all these cases, implantation was achieved in the target vein without complications after passage of a second hydrophilic guidewire. CONCLUSIONS The use of a second parallel guidewire (i.e., the double-wire technique) provides a safe and effective way of implanting left ventricular venous pacing electrodes in patients with anatomical complications.

Late failure of left ventricular leads stabilized using the retained guidewire technique in patients undergoing cardiac resynchronization therapy

The retained guidewire technique has been proposed as an alternative method for stabilizing the left ventricular lead in patients who experience repetitive intraoperative dislocation. This article concerns three patients, out of a total of 185 (1.6%) undergoing cardiac resynchronization therapy, who had to be treated using the retained guidewire technique because of demonstrable recurrent lead dislocation. Electrode parameters were all within normal limits. Although lead dislocation could not be demonstrated macroscopically, sensing and pacing parameters were found to have changed 6 months to 1 year after implantation, with a marked elevation in impedance. Laboratory analysis showed deformation and fracture of the coil electrodes as well as deterioration of the insulation coating. In conclusion, our experience shows that the retained guidewire technique should not be used because delayed electrode damage can occur.

Usefulness of Hyperemic Venous Return Angiography for Studying Coronary Venous Anatomy Prior to Cardiac Resynchronization Device Implantation

INTRODUCTION AND OBJECTIVES Implantation of electrodes via the coronary sinus (CS) can be very challenging because access to the target vessel is restricted by anatomical obstacles. Consequently, prior knowledge of coronary venous anatomy is crucial. The objective of this study was to evaluate the usefulness of hyperemic venous return angiography relative to that of occlusive retrograde venography prior to cardiac resynchronization device implantation. METHODS Coronary venous anatomy was studied in 200 patients both by videoing venous coronary return, which was optimized by inducing hyperemia, and by occlusive venography. The visibility of different portions of the coronary venous system was scored. RESULTS Overall, sufficient anatomic information was obtained in 99.5% of patients. Visibility scores for the CS and the lateral vein of the left ventricle were slightly higher in the group studied using occlusive venography, though there was no significant difference between the two techniques. In contrast, the middle cardiac vein and the anterior interventricular vein could be visualized in greater detail using venous return angiography. There were no complications in the group studied using venous return angiography whereas dissection of the great cardiac vein occurred in three patients studied using occlusive venous angiography, though this did not prevent electrode implantation. CONCLUSIONS With venous return angiography, it was possible to visualize accurately the venous anatomy of the lateral wall of the left ventricle and, consequently, to anticipate the level of difficulty posed by electrode implantation.