Miguel Abecasis

Epicardial radiofrequency applications: in vitro and in vivo studies on human atrial myocardium

OBJECTIVESnTo obtain a better understanding of tissue damage induced in human atria by epicardial radiofrequency ablation and its correlation with intra-tissue temperatures measured sub-epicardially and sub-endocardially.nnnMETHODSnRadiofrequency (RF) currents were delivered to human atrial tissues using experimental set-ups to simulate surgical RF epicardial ablation at 80, 85 and 90 degrees C. Sub-endocardial and sub-epicardial temperatures were measured with thermocouples during the ablations. Twelve samples from in vitro epicardial ablations were histologically assessed. Localized RF epicardial ablations at same temperatures were performed on 38 mitral patients with concomitant atrial fibrillation (AF) before full cardiopulmonary bypass and samples histologically assessed. All patients had endocardial RF ablation at 70 degrees C to treat AF.nnnRESULTSnIn vitro Sub-endocardial temperatures were lower than 50 degrees C except on thin atria (approximately 2-3 mm) in ablations at 80 and 85 degrees C and on thicker atria (approximately 5 mm) in ablations at 90 degrees C. Lesions measured 0.85-1.98 mm, all showed epicardial and myocardial damage but none were transmural. Mitral patients: Lesions measured 0.38-3.25 mm and 13/25 induced at 70 degrees C, 2/8 at 80 degrees C, 1/4 at 85 degrees C and 0/1 at 90 degrees C were confined to the epicardium leaving the myocardium undamaged. The remaining had damage of the epicardium and of variable portions of the myocardium, and three were transmural.nnnCONCLUSIONSnThe application temperature and the intra-tissue temperature are not the sole factors that determine lesion depth. The thickness and the composition of the epicardium and of the myocardium are major determinants in the formation of the lesion.

Ventral cardiac denervation reduces the incidence of atrial fibrillation after coronary artery bypass grafting

OBJECTIVESnBecause the autonomic nervous system is an important determinant in the appearance of atrial fibrillation, we have assessed the role of ventral cardiac denervation for its prevention.nnnMETHODSnPatients undergoing low-risk coronary artery surgery were enrolled. No routine antiarrhythmic drugs were administered before or after the operation. Ventral cardiac denervation was performed in 207 patients, and 219 patients were used as control subjects. Denervation was performed before cardiopulmonary bypass. The groups were comparable regarding demographic, clinical, and operative variables.nnnRESULTSnThe additional time for the denervation was 5 +/- 2 minutes, and there were no associated complications. Postoperative atrial fibrillation was present in 15 (7%) patients undergoing ventral cardiac denervation (95% confidence interval, 4%-12%) and in 56 (27%) control subjects (95% confidence interval, 18%-35%). Patients submitted to ventral cardiac denervation had fewer and less severe episodes of atrial fibrillation, and no patient had atrial fibrillation after discharge. Ventral cardiac denervation was the most significant predictor of postoperative atrial fibrillation (odds ratio, 0.42; confidence interval, 0.23-0.78; P =.006). Age of greater than 65 years (odds ratio, 1.67; confidence interval, 0.96-2.9; P =.067) was a highly suggestive predictor. The analysis of the effect of ventral cardiac denervation correlated with the patients age showed a more pronounced effect in patients younger than 70 years (odds ratio, 0.43; confidence interval, 0.22-0.86; P =.022)nnnCONCLUSIONSnVentral cardiac denervation is a fast and low-risk procedure. Its use significantly reduces the incidence and severity of atrial fibrillation after routine coronary artery bypass surgery. Patients younger than 70 years of age are expected to have a higher success rate than those older than 70 years.

Subacute left ventricle free wall rupture after acute myocardial infarction: awareness of the clinical signs and early use of echocardiography may be life-saving

Left ventricular free wall rupture (LVFWR) is a fearful complication of acute myocardial infarction in which a swift diagnosis and emergency surgery can be crucial for successful treatment. Because a significant number of cases occur subacutely, clinicians should be aware of the risk factors, clinical features and diagnostic criteria of this complication. We report the case of a 69 year-old man in whom a subacute left ventricular free wall rupture (LVFWR) was diagnosed 7 days after an inferior myocardial infarction with late reperfusion therapy. An asymptomatic 3 to 5 mm saddle-shaped ST-segment elevation in anterior and lateral leads, detected on a routine ECG, led to an urgent bedside echocardiogram which showed basal inferior-wall akinesis, a small echodense pericardial effusion and a canalicular tract from endo to pericardium, along the interface between the necrotic and normal contracting myocardium, trough which power-Doppler examination suggested blood crossing the myocardial wall. A cardiac MRI further reinforced the possibility of contained LVFWR and a surgical procedure was undertaken, confirming the diagnosis and allowing the successful repair of the myocardial tear. This case illustrates that subacute LVFWR provides an opportunity for intervention. Recognition of the diversity of presentation and prompt use of echocardiography may be life-saving.

Lipomatous hypertrophy of the interatrial septum: report of two cases where histological examination and surgical intervention were unavoidable.

Lipomatous hypertrophy of the interatrial septum (LHIS) is an increasingly recognized heart condition characterized by fatty deposits in the interatrial septum with sparing of the fossa ovalis. Its distinctive characteristic features by imaging techniques, benign nature, and the fact that most patients remain asymptomatic, has limited the need for histological confirmation and operative intervention in most cases. In this report, we describe two cases of LHIS where cardiac surgical intervention was indispensable: in the first patient, due to the presence of an additional left atrial tumour found out as mixoma and in the second, to relief a superior vena cava obstruction together with bypass grafts for severe coronary artery disease. Histological samples of the interatrial septal lesion were obtained in both cases either because of uncertainty of the diagnosis (Case 1) or to confirm the diagnosis (Case 2).

The large septal arteries in normal hearts, in aortic valve disease, and in tetralogy of Fallot

BACKGROUNDnSeveral surgical techniques such as the Ross operation or total correction of tetralogy of Fallot require incisions of the upper ventricular septum. Very few reports on the anatomy of the septal arteries of the pathologic heart can be found in the literature. To get a more precise knowledge of the large septal arteries in pathologic hearts, we have compared the anatomy of normal hearts with that of hearts with aortic valve disease and of tetralogy of Fallot.nnnMETHODSnTwenty-six normal heart specimens (group A), 11 with aortic valve disease (group B), and 4 with tetralogy of Fallot (group C) were dissected.nnnRESULTSnIn groups B and C a single large septal artery was always found. The large septal artery had the orientation previously described for normal hearts. Still, its course in the lower border of the anterior extension of the septomarginal trabecula was deeper. The anterior extension of the septomarginal trabecula was 4 +/- 3 mm deep in group A, 6 +/- 2 mm in group B, and 3 mm in group C. The interventricular septum was much thicker in groups B and C than in group A.nnnCONCLUSIONSnThe position of the large septal artery can be predicted from coronary angiography and from the morphology of the anterior extension of the septomarginal trabecula. Knowledge of its position can improve the safety of operations performed on the outflow of the interventricular septum.

Tratamiento quirúrgico sin circulación extracorpórea de la fibrilación auricular aislada para la prevención secundaria de accidentes cerebrovasculares isquémicos agudos

Introduccion La fibrilacion auricular (FA) se asocia a un aumento de mortalidad cardiovascular y accidentes cerebrovasculares (ACVA) por embolos de la orejuela izquierda (OI). El tratamiento con anticoagulantes orales (ACO) reduce el riesgo de ACVA, pero los pacientes permanecen susceptibles a nuevos fenomenos tromboembolicos. Material y metodos Seis pacientes con edad media 56 anos, FA aislada y ACVA, sometidos a ABVP (argon a –170° y cateter Cryocath Surgifrost®, durante 3 min dos veces en cada conjunto de venas pulmonares) y exclusion externa de la OI sin CEC. La ABVP se realizo bajo ecocardiograma transesofagico. Se practico estudio electrofisiologico (EEF) mediante cables epicardicos implantados durante la intervencion. Las areas aisladas fueron comparadas con las no aisladas en relacion con las amplitudes del electrograma y umbrales de captura auricular. Los pacientes fueron medicados con antiarritmicos y ACO. Resultados No hubo mortalidad hospitalaria. En las zonas aisladas la amplitud del electrograma fue menor que en las no aisladas (0,3xa0±xa00,1 y 1,4xa0±xa00,8; pxa0=xa00,0075). Los umbrales de captura auricular fueron mas altos en las zonas aisladas que en las no aisladas (15,3xa0±xa010,5 y 8,7xa0±xa03,8; pxa0=xa00,14). El seguimiento medio fue 16,5 (12-18) meses. Todos los pacientes estaban en RS el dia del alta y 1 ano despues y no presentaron nuevos episodios tromboembolicos. Un paciente presento episodios de FA paroxistica autolimitada en los primeros 3 meses sin repercusion. Conclusiones Nuestra experiencia inicial en el tratamiento de la FA aislada mediante ABVP con argon y sin CEC ofrece buenos resultados. Debe documentarse la persistencia del efecto y su eficacia en la reduccion de los fenomenos tromboembolicos.

Surgical Bailout Therapy after Implantation of a Medtronic CoreValve Bioprosthesis.

Moderate-to-severe paraprosthesic leak causing hemodynamic deterioration and left ventricular remodeling can occur after transcatheter aortic valve implantation (TAVI). We present the case of a 75-year-old woman who underwent TAVI with a 26u2009mm CoreValve prosthesis complicated with an acute left ventricle dilatation due to a severe paravalvular leak. Patient was unresponsive to elective balloon post-dilatation, and therefore she was successfully treated with open-heart surgery to remove the malfunctioning CoreValve bioprosthesis and perform standard aortic valve replacement.

NT-PROBNP ASSAY MAY PRECLUDE THE NEED FOR ROUTINE ENDOMYOCARDIAL BIOPSY TO DETECT CARDIAC ALLOGRAFT REJECTION, BUT NOT EARLY AFTER TRANSPLANTATION

Background: Endomyocardial biopsy (EMB) remains the standard for the diagnosis of rejection after heart transplantation (HTx). Very high levels of the N-terminal fragment of B-type natriuretic peptide (NT-proBNP), an established marker for the diagnosis of heart failure, are common in the first 3 months after HTx. The aim of this study was to determine whether the NT-proBNP assay may detect or exclude cardiac allograft rejection.