Isabel Trapero

Prognostic value of a comprehensive cardiac magnetic resonance assessment soon after a first ST-segment elevation myocardial infarction.

OBJECTIVES To evaluate the prognostic value of a comprehensive cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI). BACKGROUND CMR allows for a simultaneous assessment of wall motion abnormalities (WMA), WMA with low-dose dobutamine (WMA-dobutamine), microvascular obstruction, and transmural necrosis. This approach has been proven to be useful to predict late systolic recovery soon after STEMI. Its prognostic value and the relative prognostic weight of these indexes are not well-defined. METHODS We studied 214 consecutive patients with a first STEMI treated with thrombolytic therapy or primary angioplasty discharged from hospital. In the first week (7 +/- 1 day after infarction), with CMR we determined the extent (number of segments) of WMA, WMA-dobutamine, microvascular obstruction, and transmural necrosis. RESULTS During a median follow-up of 553 days, 21 major adverse cardiac events (MACE) including 4 cardiac deaths, 6 nonfatal myocardial infarctions, and 11 readmissions for heart failure were documented. The MACE was associated with a larger extent of WMA (8 +/- 4 segments vs. 5 +/- 3 segments, p < 0.001), WMA-dobutamine (6 +/- 4 segments vs. 4 +/- 3 segments, p = 0.004), microvascular obstruction (3 +/- 3 segments vs. 1 +/- 2 segments p <0.001), and transmural necrosis (7 +/- 3 segments vs. 3 +/- 3 segments, p < 0.001). In a complete multivariate analysis that included baseline characteristics, electrocardiogram, biomarkers, angiography, ejection fraction, left ventricular volumes, and all CMR indexes, WMA/segment (hazard ratio: 1.29 [95% confidence interval: 1.11 to 1.49], p = 0.001) and the extent of transmural necrosis/segment (hazard ratio: 1.30 [95% confidence interval: 1.12 to 1.51], p < 0.001) were the only independent prognostic variables. CONCLUSIONS A comprehensive CMR assessment is useful for stratifying risk soon after STEMI, but only the extent of systolic dysfunction and of transmural necrosis provide independent prognostic information.

Modification of Ventricular Fibrillation Activation Patterns Induced by Local Stretching

Introduction: We hypothesize that local modifications in electrophysiological properties, when confined to zones of limited extent, induce few changes in the global activation process during ventricular fibrillation (VF). To test this hypothesis, we produced local electrophysiological modifications by stretching a circumscribed zone of the left ventricular wall in an experimental model of VF.

Resultados de la estrategia farmacoinvasiva y de la angioplastia primaria en la reperfusión del infarto con elevación del segmento ST. Estudio con resonancia magnética cardiaca en la primera semana y en el sexto mes

INTRODUCTION AND OBJECTIVES Pharmacoinvasive strategy represents an attractive alternative to primary angioplasty. Using cardiovascular magnetic resonance imaging we compared the left ventricular outcome of the pharmacoinvasive strategy and primary angioplasty for the reperfusion of ST-segment elevation myocardial infarction. METHODS Cardiovascular magnetic resonance was performed 1 week and 6 months after infarction in two consecutive cohorts of patients included in a prospective university hospital ST-segment elevation myocardial infarction registry. During the period 2004-2006, 151 patients were treated with pharmacoinvasive strategy (thrombolysis followed by routine non-immediate angioplasty). During the period 2007-2008, 93 patients were treated with primary angioplasty. A propensity score matched population was also evaluated. RESULTS At 1-week cardiovascular magnetic resonance, pharmacoinvasive strategy and primary angioplasty patients showed a similar extent of area at risk (29±15 vs. 29±17%, P=.9). Non-significant differences were detected by cardiovascular magnetic resonance at 1 week and at 6 months in infarct size, salvaged myocardium, microvascular obstruction, ejection fraction, end-diastolic volume index and end-systolic volume index (P>.2 in all cases). The same trend was observed in 1-to-1 propensity score matched patients. The rate of major adverse cardiac events (death and/or re-infarction) at 1 year was 6% in pharmacoinvasive strategy and 7% in primary angioplasty patients (P=.7). CONCLUSIONS A pharmacoinvasive strategy including thrombolysis and routine non-immediate angioplasty represents a widely available and logistically attractive approach that yields identical short-term and long-term cardiovascular magnetic resonance-derived left ventricular outcome compared to primary angioplasty.

Pharmacological modifications of the stretch-induced effects on ventricular fibrillation in perfused rabbit hearts

Stretch induces modifications in myocardial electrical and mechanical activity. Besides the effects of substances that block the stretch-activated channels, other substances could modulate the effects of stretch through different mechanisms that affect Ca(2+) handling by myocytes. Thirty-six Langendorff-perfused rabbit hearts were used to analyze the effects of the Na(+)/Ca(2+) exchanger blocker KB-R7943, propranolol, and the adenosine A(2) receptor antagonist SCH-58261 on the acceleration of ventricular fibrillation (VF) produced by acute myocardial stretching. VF recordings were obtained with two epicardial multiple electrodes before, during, and after local stretching in four experimental series: control (n = 9), KB-R7943 (1 microM, n = 9), propranolol (1 microM, n = 9), and SCH-58261 (1 microM, n = 9). Both the Na(+)/Ca(2+) exchanger blocker KB-R7943 and propranolol induced a significant reduction (P < 0.001 and P < 0.05, respectively) in the dominant frequency increments produced by stretching with respect to the control and SCH-58261 series (control = 49.9%, SCH-58261 = 52.1%, KB-R7943 = 9.5%, and propranolol = 12.5%). The median of the activation intervals, the functional refractory period, and the wavelength of the activation process during VF decreased significantly under stretch in the control and SCH-58261 series, whereas no significant variations were observed in the propranolol and KB-R7943 series, with the exception of a slight but significant decrease in the median of the fibrillation intervals in the KB-R7943 series. KB-R7943 and propranolol induced a significant reduction in the activation maps complexity increment produced by stretch with respect to the control and SCH-58261 series. In conclusion, the electrophysiological effects responsible for stretch-induced VF acceleration in the rabbit heart are reduced by the Na(+)/Ca(2+) exchanger blocker KB-R7943 and by propranolol but not by the adenosine A(2) receptor antagonist SCH-58261.

La suma de la elevación del segmento ST predice mejor la obstrucción microvascular en pacientes tratados con éxito con una intervención coronaria percutánea primaria. Un estudio de resonancia magnética cardiovascular

Introduccion y objetivos La utilidad de la resolucion del segmento ST (RST) para la prediccion de la reperfusion epicardica esta bien establecida. La asociacion de los cambios del segmento ST con la obstruccion microvascular (OMV) observada en la resonancia magnetica cardiovascular (RMC) tras una intervencion coronaria percutanea primaria (ICPp) en el infarto de miocardio con elevacion del ST (IMEST) no se ha aclarado todavia. Metodos Estudiamos a 85 pacientes consecutivos ingresados por un primer IMEST y tratados con una ICPp que tenian una arteria relacionada con el infarto permeable. Se registro un ECG al ingreso, tras 90 min y tras 6, 24, 48 y 96 h de la ICPp. Se calculo la RST y la suma de la elevacion del ST (sumEST) en todas las derivaciones. Resultados La RMC revelo una OMV en 37 pacientes. En los infartos con OMV, el valor de la sumEST antes y despues de la revascularizacion fue mayor que en los infartos sin OMV (p ≤ 0,001 en todos los casos). En cambio, no hubo diferencias significativas en la cantidad de RST entre los infartos con y sin OMV a los 90 min de la revascularizacion (p = 0,1), sino solo a partir de las 6 h (p 3 mm a los 90 min de la ICPp, pero no una RST ≥ 70%, predijo de manera independiente la OMV observada en la RMC ( odds ratio = 3,1; intervalo de confianza del 95%, 1,2-8,4; p = 0,02). Conclusiones La OMV se asocio a un valor significativamente superior de la sumEST en todos los momentos de valoracion tras la revascularizacion. La diferencia en la cantidad de RST entre los infartos con OMV y sin OMV solo fue significativa a partir de las 6 h tras la revascularizacion. La OMV se predijo mejor con una sumEST > 3 mm a los 90 min de la ICPp.

Interleukin 6 and cognitive dysfunction.

The interleukin-6 (IL-6) is a pleiotropic cytokine that plays a key role in interaction between immune and nervous system. Although IL-6 has neurotrophic properties and beneficial effects in the CNS, its overexpression is generally detrimental, adding to the pathophysiology associated with CNS disorders. The source of the increase in peripheral IL-6 remains to be established and varies among different pathologies, but has been found to be associated with cognitive dysfunction in several pathologies. This comprehensive review provides an update summary of the studies performed in humans concerning the role of central and peripheral IL-6 in cognitive dysfunction in dementias and in other systemic diseases accompained by cognitive dysfuction such as cardiovascular, liver disease, Behçet’s disease and systemic lupus erythematosus. Further research is needed to correlate specific deficits in IL-6 and its receptors in pathologies characterized by cognitive dysfunction and to understand how systemic IL-6 affects high cerebral function in order to open new directions in pharmacological treatments that modulate IL-6 signalling.

The sum of ST-segment elevation is the best predictor of microvascular obstruction in patients treated successfully by primary percutaneous coronary intervention. Cardiovascular magnetic resonance study.

INTRODUCTION AND OBJECTIVES The usefulness of ST-segment elevation resolution (STR) for predicting epicardial reperfusion is well established. However, it is still not clear how ST-segment changes are related to microvascular obstruction (MVO) observed by cardiovascular magnetic resonance (CMR) after primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction (STEMI). METHODS The study involved 85 consecutive patients admitted for a first STEMI and treated by pPCI who had a patent infarct-related artery. An ECG was recorded on admission and 90 min and 6, 24, 48 and 96 h after pPCI. Thereafter, STR and the sum of ST-segment elevation (sumSTE) in all leads were determined. RESULTS Overall, CMR revealed MVO in 37 patients. In infarcts with MVO, sumSTE was greater both before and after revascularization than in infarcts without MVO (P≤.001 at all times). In contrast, there was no significant difference in the magnitude of STR between infarcts with and without MVO 90 min after revascularization (P=.1), though there was after 6 h (P< .05 at all times). The area under the receiver operating characteristic curve for detecting MVO was greater for sumSTE than STR (P< .05 for all measurements). On multivariate analysis, after adjusting for clinical, angiographic and ECG characteristics, a sumSTE >3 mm 90 min after pPCI was an independent predictor of MVO on CMR, while an STR ≥70% was not (odds ratio=3.1; 95% confidence interval, 1.2-8.4; P=.02). CONCLUSIONS MVO was associated with a significantly increased sumSTE at all times after revascularization. The difference in the magnitude of STR between infarcts with and without MVO was significant only >6 h after revascularization. The best predictor of MVO was a sumSTE >3 mm 90 min after pPCI.

Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental

INTRODUCTION AND OBJECTIVES The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. METHODS Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. RESULTS Linear regression analysis showed that there was a good correlation between the dominant frequency obtained using the two signal analysis methods: frequency (spectral analysis) = 1.01 x frequency (time-frequency analysis) -- 0.4 (r=0.9; P< .0001; standard error of the estimate, 2.2 Hz). In all cases except one, the dominant frequency exhibited a significant temporal variation on a short timescale (time-frequency analysis); the coefficient of variation was between 0.19 (0.06) and 0.24 (0.07) (NS). In all cases, there were significant differences between regions. The location at which the frequency was highest varied according to the timepoint considered, though it was predominantly in the apical or anterior zone. CONCLUSIONS In the absence of external modulating factors, the frequency of ventricular fibrillation exhibits temporal and spatial variations which can be observed at short timescales. In the free wall of the left ventricle, the dominant frequency is highest in the apical and anterior zones, and the maximum frequencies are most often found in these zones.Introduccion y objetivos El analisis de la variabilidad de la frecuencia durante la fibrilacion ventricular ha aportado resultados no uniformes. En un modelo experimental de fibrilacion ventricular se analiza, en una escala temporal reducida, las variaciones de la frecuencia y su distribucion espacial. Metodos En 10 preparaciones de corazon aislado y perfundido de conejo, se efectuan registros epicardicos de la fibrilacion ventricular con un electrodo multiple (240 electrodos unipolares) y se aplican metodos de analisis espectrales y de tiempo-frecuencia para obtener la frecuencia dominante en la pared anterolateral del ventriculo izquierdo. Resultados La recta de regresion obtenida al relacionar los valores de la frecuencia dominante obtenidos con los 2 metodos de analisis muestra una buena correlacion entre ambos: frecuencia (metodo espectral) = 1,01 × frecuencia (metodo tiempo-frecuencia) – 0,4 (r = 0,9; p Conclusiones En ausencia de factores moduladores externos, la fibrilacion ventricular presenta variaciones temporales y espaciales de la frecuencia que se objetivan en escalas de tiempo reducidas. En la pared libre del ventriculo izquierdo, la frecuencia dominante es mayor en las zonas apicales y anteriores, zonas en las que se ubican con mayor frecuencia los valores maximos.

Modifications of mechanoelectric feedback induced by 2,3-butanedione monoxime and Blebbistatin in Langendorff-perfused rabbit hearts.

Myocardial stretching is an arrhythmogenic factor. Optical techniques and mechanical uncouplers are used to study the mechanoelectric feedback. The aim of this study is to determine whether the mechanical uncouplers 2,3‐butanedione monoxime and Blebbistatin hinder or modify the electrophysiological effects of acute mechanical stretch.

Effects of chronic exercise on myocardial refractoriness : a study on isolated rabbit heart

Aim:  To determine whether chronic physical training increases atrial and ventricular refractoriness in isolated rabbit heart.