José Moríñigo

Seguridad y eficacia clínica de la estimulación con el modo AAI en la disfunción del nodo sinusal: seguimiento a largo plazo

Introduction and objectives. Although atrial pacing is a more physiological mode of stimulation in sinus node dysfunction, the pacing modes most often are used DDD and VVI. The aim of our study was to demonstrate that AAI/AAIR pacing is effective and safe by analyzing the complications and mortality of this pacing mode in a longterm follow-up study. Patients and method. Between 1982 and 2000 definitive AAI-mode pacemakers were implanted for sinus node dysfunction in mode AAI in 160 patients. We analyzed the clinical characteristics, evolution, and complications of the AAI pacing mode during a follow-up of 5.4 ± 4.5 years. Results. The sample was made up of 104 women and 56 men with an average age of 72 ± 12 years. During follow-up, it was necessary to change the pacing mode for symptomatic bradycardia in 11 patients (annual incidence 1.2%), which was caused by second or third-degree atrioventricular block in 7 patients (annual incidence 0.8%), and chronic atrial fibrillation with bradycardia in 4 patients (annual incidence 0.4%). During follow-up, atrial arrhythmias occurred in 32 patients (annual incidence 3.7%), stroke in 4 patients (annual incidence 0.4%), and 27 patients (annual incidence 3.1%) died. Conclusions. The AAI/AAIR pacing mode was safe and effective in sinus node dysfunction, with a low percentage of pacing changes required for progression to atrioventricular block, low incidence of atrial arrhythmias, stroke and low mortality during long term follow-up.

Influence of beta-blocker therapy on antitachycardia pacing effectiveness for monomorphic ventricular tachycardias occurring in implantable cardioverter-defibrillator patients: a dose-dependent effect

AIMS To determine, in a non-selected population of 282 implantable cardioverter-defibrillator (ICD) patients with left ventricular dysfunction, the influence of the dose of beta-blockers on antitachycardia pacing (ATP) effectiveness and on the incidence of shock due to monomorphic ventricular tachycardias (VT). METHODS AND RESULTS We followed 282 ICD patients along 26 +/- 19 months. Antitachycardia pacing and shock programming were standardized. We determined the indexed dose equivalent of beta-blockers (IDE-BB), using metoprolol as a reference, at each VT presentation. The median of IDE-BB was 55 mg/m(2)/day. We analysed 846 VT occurred in 100 patients. The ATP success rate was 84%. Upon classification of the events into three groups (IDE-BB = 0, IDE-BB < 55, and IDE-BB > or = 55), the frequency of effective ATP increased with the IDE-BB: 75 vs. 83 vs. 92% (P < 0.001). According to logistic regression, IDE-BB remained as an independent predictor of effective ATP (P < 0.001) and VT-related shock (P = 0.001). Both the mean ATP effectiveness per patient (67 vs. 80 vs. 91%, P = 0.007) and the mean survival time free of VT-related shock (583 vs. 847 vs. 1158 days, P = 0.019, log-rank test) increased linearly with the dose of beta-blockers. CONCLUSION Beta-blockers increase the effectiveness of ATP through a dose-dependent effect. As a result, they reduce the incidence of shocks due to VT.

Early Reduction of QT Dispersion after Primary Percutaneous Intervention in ST-Segment Elevation Acute Myocardial Infarction

Objectives: To determine, in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI), the mechanisms and clinical implications of the acute changes in QT dispersion (QTd). Methods: In this prospective study we included 216 patients admitted with a STEMI of <12 h of evolution. All were treated with PPCI. QTd was measured prior to PPCI and within 1 h after. Results: The ratio of QTd reduction after PPCI (QTd-R) – defined as [(QTd before PPCI – QTd after PPCI)/QTd before PPCI] ×100 – was significantly correlated with the percentage of ST-segment elevation resolution (ST-R; p < 0.001). To determine the significance of the different values of QTd-R, we further subdivided our population into 3 groups according to the tertiles of QTd-R (<10, 11–49, ≥50%). Patients with longer QTd-R had higher percentages of ST-R: 32 ± 43 for QTd-R <10% vs. 60 ± 21 for 11–49% vs. 71 ± 12 for ≥50% (p < 0.05). By logistic regression, patients with QTd-R ≥50% had a reduction of 75% in the adjusted frequency of death or severe heart failure during hospitalization (95% CI 13–73%, p = 0.03). Conclusion: QTd-R after PPCI occurs early, is closely related to the restoration of reperfusion at the microvascular level and provides additional prognostic information.

Influence of cycle length variations on antitachycardia pacing effectiveness among ICD patients

BACKGROUND Antitachycardia pacing (ATP) fails to terminate 5% to 25% of ventricular tachycardias (VTs) occurring in implantable cardioverter-defibrillator patients. We speculated that small fluctuations in VT cycle length (CL) may be related to the efficacy of subsequent ATP. OBJECTIVE The purpose of this study was to determine the relationship between the R-R variations of the last 12 R-R intervals before ATP and the efficacy of the first ATP attempt. METHODS We studied 551 VTs (CL 329±35 ms) occurring in 67 patients. We also analyzed the percentage of variation (P-RR), which was calculated by dividing the mean difference between each R-R interval and the next one by the CL (×100), and the acceleration index (AI), which was calculated by dividing the CL of the first 6 R-R intervals by the CL of the next 6. RESULTS The effectiveness of the first ATP therapy was 81%, being higher in VTs with AI<1 (85% vs 64%; P<.001). After classifying the events according to the tertiles of P-RR, ATP efficiency was better in higher values of P-RR (VTs with AI<1): 99% (third tertile) vs 85% (second tertile) vs 76% (first tertile), P<.001; and for VTs with AI≥1: 94% vs 68% vs 42% (P<.001). By logistic regression, P-RR (%; odds ratio 2.37; P<.001), and AI<1 (odds ratio 4.17; P<.001) were found to be independent predictors of successful first ATP attempts. CONCLUSION Small changes in CL increase the effectiveness of ATP significantly. VTs with lower degrees of R-R fluctuations, especially when the pattern is a progressive CL shortening, are infrequently terminated by ATP.

Relationship between the duration of the basal QRS complex and electrical therapies for ventricular tachycardias among ICD patients.

Background: In implantable cardioverter‐defibrillators (ICD) patients, the duration of the basal QRS complex (QRSd) is not associated with a greater risk of developing ventricular tachyarrhythmias. QRSd could be inversely related to the effectiveness of antitachycardia pacing (ATP) because it may be associated with longer conduction times of the paced‐impulses and hence, with a greater propensity to require shocks to terminate ventricular tachycardias (VTs).

Valor pronóstico tardío de la troponina I en los pacientes ingresados en una unidad coronaria por angina inestable

Introduccion y objetivos La troponina I (TnI) es un marcador de dano miocardico utilizado en la estratificacion pronostica del sindrome coronario agudo. El objetivo del estudio fue analizar el valor pronostico tardio del nivel maximo de TnI obtenido en las 48 h tras el ingreso en una unidad coronaria por angina inestable. Metodos Se incluyo a 149 pacientes consecutivos. Se realizaron determinaciones seriadas de la fraccion MB de la creatincinasa (CK-MB) y TnI. Los pacientes sin elevacion de la CK-MB fueron clasificados en dos grupos, en funcion de la presencia de TnI elevada (n = 58) o normal (n = 91). Se analizaron prospectivamente los factores clinicos y evolutivos relacionados con la probabilidad de muerte, nuevo episodio agudo coronario o revascularizacion coronaria tras un ano de seguimiento. Resultados No se observaron diferencias entre los dos grupos en relacion con las caracteristicas clinicas, salvo la edad, que fue mayor en el grupo con TnI elevada (69 frente a 64 anos; p = 0,01). Tras un ano de seguimiento no se apreciaron diferencias en la incidencia de nuevos acontecimientos coronarios agudos ni en la revascularizacion; sin embargo, la mortalidad fue mayor en el grupo con TnI elevada (el 13 frente al 4%; p = 0,01). Los predictores independientes de mortalidad fueron el infarto previo (riesgo relativo [RR] = 3), TnI elevada (RR = 3,2), fraccion de eyeccion 70 anos (RR = 15). Conclusiones En la angina inestable, un valor elevado de TnI dentro de las primeras 48 h del ingreso se asocia con un aumento de la mortalidad al ano de seguimiento.

Morphology of Far-Field Electrograms and Antitachycardia Pacing Effectiveness Among Fast Ventricular Tachycardias Occurring in ICD Patients: A Multicenter Study

Fast ventricular tachycardias (FVT) are less likely to be terminated by antitachycardia pacing (ATP). No information is available regarding the ability of far‐field electrogram (Ff‐EG) morphology (Ff‐EGm) in predicting the result of the subsequent ATP. Our objective is to determine the relationship between Ff‐EGm and ATP efficacy.

Taquicardia ventricular y hemocromatosis cardíaca

La hemocromatosis esta caracterizada por un excesivo deposito de hierro en una variedad de tejidos. La afeccion cardiaca sucede en un tercio de los pacientes con hemocromatosis y se produce como consecuencia de una acumulacion de ferritina en el musculo cardiaco que induce por un lado una alteracion en la funcion ventricular sistolica y diastolica y por otro un sustrato arritmogenico. Las manifestaciones clinicas pueden estar indistintamente relacionadas con taquiarritmias auriculares, ventriculares, bloqueos auriculoventriculares y/o con insuficiencia cardiaca congestiva, siendo mas frecuentes las primeras. Presentamos el caso de una paciente con hemocromatosis secundaria a transfusiones repetidas por anemia sideroblastica con afeccion cardiaca y cuyas primeras manifestaciones cardiacas fueron taquiarritmias auriculares recurrentes y taquicardia ventricular sostenida sincopal, por lo que se implanto un desfibrilador automatico.

Fragmentation of the paced QRS complex: a marker of antitachycardia pacing effectiveness among ICD patients.

The presence of notches in the paced QRS complex (P‐QRS) from the right ventricular apex (RVA) reflects delays in the activation of the left ventricle and may therefore be associated with longer times of stimulus conduction. Our objective was to determine prospectively the relationship between the duration of a notch ≥0.1 mV in the P‐QRS (DN) and the effectiveness of antitachycardia pacing (ATP).

An Adult With a Double-Chamber Right Ventricle

Rev Esp Cardiol. 2005;58(2):217 217 We report the case of a 56-year-old asymptomatic man with a pulmonary grade III/VI holosystolic murmur. No electrocardiographic changes were observed. On echocardiography, the left ventricle was normal with normal systolic function, and the right ventricle (RV) was hypertrophic with a midventricular gradient (maximum, 56; mean, 33 mm Hg) and a perimembranous ventricular septal defect (VSD). On magnetic resonance imaging, the RV was seen to be divided into 2 chambers (pRV: proximal chamber, dRV: distal chamber) separated by a muscle band (Figure 1) and the VSD (Figure 2). A hemodynamic study showed an intraventricular (not transvalvular) gradient of 50 mm Hg and a VSD with a pulmonaryto-systemic flow ratio of 1.4. Since the patient was asymptomatic and the obstruction was not severe, the initial decision was to clinically follow-up the patient. IM AG E S I N CA R D I O L O G Y