Olga Medina

Incidence and Clinical Significance of Multiple Consecutive, Appropriate, High-Energy Discharges in Patients With Implanted Cardioverter-Defibrillators

BACKGROUND Some patients with an automatic implantable cardioverter-defibrillator (ICD) suffer multiple appropriate, consecutive, high-energy discharges (MCDs) during follow-up. Such events might represent resistant ventricular arrhythmias and might have prognostic significance. METHODS AND RESULTS Eighty consecutive patients with an ICD were followed up for up to 82 months (mean, 21 +/- 19 months). Thirty-eight patients had survived an out-of-hospital cardiac arrest and 42 had recurrent ventricular tachycardia. During follow-up, 16 patients had MCD (group A), 26 patients had episodes of single appropriate discharges (group B), and 38 patients had no appropriate discharges (group C). Group A patients had worse functional status (P = .001), lower left ventricular ejection fractions (LVEFs) (P = .001), and lower survival rates (log rank, P = .003) than the remaining two groups of patients. Cox analysis showed LVEF (P = .001) to be an independent predictor of MCD. Independent predictors of death or heart transplant were MCD (P = .001), female sex (P = .001), age (P = .001), history of cardiac arrest (P = .003), and functional status (P = .003). The only independent predictor of total mortality was female sex (P = .002). Independent predictors of cardiac death were MCD (P = .007) and female sex (P = .018). Independent predictors of arrhythmic death were age (P = .001), female sex (P = .02), and MCD (P = .023). CONCLUSIONS In patients with an ICD, the development of MCD is an independent predictor of cardiac and arrhythmic mortality. If this finding is confirmed in larger studies, it may help to identify patients in whom other therapeutic alternatives, ie, heart transplantation, should be considered during follow-up after ICD implantation.

Identification of concealed posteroseptal Kent pathways by comparison of ventriculoatrial intervals from apical and posterobasal right ventricular sites.

BACKGROUND The differential diagnosis of supraventricular tachycardia with concentric atrial activation usually requires the inducibility of sustained tachycardia and needs a complex and time-consuming electrophysiological evaluation. To develop a simple test to establish if ventriculoatrial conduction uses a posteroseptal accessory pathway or the normal conduction system, we compared the ventriculoatrial intervals during right ventricular pacing from apical and posterobasal sites. METHODS AND RESULTS Continuous pacing was performed from an apical and a posterobasal right ventricular site in 34 patients with retrograde conduction over the normal conduction system (group A) and in 22 patients with conduction over a posteroseptal accessory pathway (group B). During apical pacing, ventriculoatrial intervals in group A (176 +/- 40 milliseconds) were not significantly different than those in group B (197 +/- 47 milliseconds, P = NS). During posterobasal pacing, group B patients had significantly shorter ventriculoatrial intervals than group A patients (158 +/- 46 versus 197 +/- 39 milliseconds, P < .01). The difference between the ventriculoatrial interval obtained during apical pacing and that obtained during posterobasal pacing (ventriculoatrial index) discriminated between the two groups without overlapping: It was positive in all group B patients (39 +/- 19; range, +10 to +70 milliseconds) and negative in all except two group A patients (-21 +/- 13; range, -50 to +5 milliseconds; P < .001). CONCLUSIONS This ventriculoatrial index can identify accurately and in the absence of tachycardia whether concentric retrograde conduction is proceeding over a posteroseptal accessory pathway or over the normal conduction system.

Utilidad en la práctica clínica del tratamiento antiarrítmico tras cardioversión eléctrica en pacientes sin cardiopatía estructural

Introduccion y objetivos Conocer en la practica clinica el uso de antiarritmicos tras cardioversion electrica en pacientes sin cardiopatia y su repercusion en el mantenimiento del ritmo sinusal. Metodos Se realizo un seguimiento a un ano de 528 pacientes con fibrilacion auricular persistente sin cardiopatia significativa tras una cardioversion electrica efectiva en 96 hospitales espanoles, con controles clinicos 1, 3, 6 y 12 meses despues. Se analizo el uso y la utilidad de los farmacos antiarritmicos en la prevencion de recurrencias de fibrilacion auricular persistente. Resultados Se trato al alta con farmacos antiarritmicos al 80% de los pacientes, y el mas utilizado fue la amiodarona. Ningun factor clinico se relaciono con un mayor uso de antiarritmicos. El 37% de los pacientes siguio en ritmo sinusal en todos los controles. En el control a los 12 meses, se mantuvo el tratamiento antiarritmico al 59% de los pacientes que seguian en ritmo sinusal. En el analisis multivariable de la regresion de Cox, el peso (hazard ratio [HR] por cada kilo = 1,01; p = 0,04) y la ausencia de tratamiento antiarritmico (HR = 1,59; p = 0,001) fueron factores independientes relacionados con la recurrencia de fibrilacion auricular persistente. La amiodarona tendia a ser superior a los otros antiarritmicos. Conclusiones En la practica clinica habitual, tras una cardioversion electrica efectiva, la gran mayoria de los pacientes sin cardiopatia estructural recibe farmacos antiarritmicos, especialmente amiodarona, que es el principal factor relacionado con el mantenimiento del ritmo sinusal 1 ano mas tarde.