Estimulación eléctrica permanente en región septal en pacientes con insuficiencia cardíaca secundaria a estimulación en ápex de ventrículo derecho / Permanent septal pacing in patients suffering secondary heart failure compared to right ventricular apical pacing

Resumen Introducción: Independientemente de la modalidad de estimulación (VVI o DDD), el mayor porcentaje de estimulación ventricular derecha deteriora la función contráctil izquierda. Por ello se han estudiado diferentes sitios de estimulación. Objetivo: Describir las diferencias electrocardiográficas y ecocardiográficas entre la estimulación en la región apical y la región septal del ventrículo derecho (VD)0. Métodos: Se estudió a 24 pacientes, 2 mujeres y 22 hombres, con fracción de eyección deprimida (≤ 35%) secundaria a estimulación en punta de VD. Se realizó electrocardiograma durante estimulación en ápex de VD y en seguimiento de estimulación septal. También ecocardiografía en ambos momentos. Resultados: La fracción de eyección se incrementó desde 31 ± 3.1% hasta 45 ± 12% (p = 0.0041) con estimulación septal; esta mostró mejor grado de sincronía mecánica. Conclusiones: La estimulación septal puede constituir un sitio de elección en pacientes con disfunción sistólica de ventrículo izquierdo secundaria a estimulación en ápex de VD, los cuales presenten QRS estrecho en su conducción intrínseca, pues en la muestra estudiada produce una mejoría en la sincronía electromecánica, demostrándose incrementos significativos en la fracción de eyección.

Abstract Introduction: Regardless of the type of electrical stimulation (VVI or DDD) the highest percentage of right ventricular apical pacing can cause left ventricular failure. For this reason, studies have been performed in different sites on right ventricle pacing. Objective: To describe differences between electrocardiography and echocardiography variables during right ventricular apical pacing and septal pacing. Methods: A total of 24 patients were studied, 2 women and 22 men, with heart failure due to conventional pacing on right ventricular (ejection fraction ≤ 35%). An electrocardiogram as well as an echocardiogram, was performed during right ventricular apical pacing and when patients were paced on septal area. Results: The ejection fraction increased from 31 ± 3.1% to 45 ± 12% (P=.0041) on septal pacing, showing higher degree of mechanic synchronisation. Conclusions: Pacing on septal area could be a good site for those patients that suffer heart failure due to right ventricular apical pacing. These must show narrow QRS on their intrinsic electrocardiographic conduction. This kind of pacing can produce an improvement in electro- mechanical synchronisation, as well as show an increased left ventricular ejection fraction.

Evaluación de la respuesta a la terapia de resincronización cardíaca en un grupo de pacientes que asisten a un programa de falla cardíaca / Evaluation of the response to cardiac resynchronisation therapy in a group of patients taking part in a heart failure program

Resumen Introducción: la terapia de resincronización cardiaca es una de las estrategias de tratamiento actuales para pacientes con insuficiencia cardiaca y función sistólica deprimida, que ha demostrado producir un alivio significativo en los síntomas, así como mejoría en la función ventricular izquierda y en la supervivencia a largo plazo. Objetivo: evaluar la respuesta a la terapia de resincronización cardíaca después de seis meses de seguimiento. Metodología: estudio observacional analítico de cohorte retrospectivo, con análisis anidado de casos y controles, en el que se incluyeron pacientes mayores de 18 años pertenecientes a una clínica de falla cardíaca y que fueran portadores de un dispositivo de resincronización cardíaca. Se realizó análisis univariado de las características clínicas y ecocardiográficas y posteriormente un análisis bivariado a las variables relacionadas con la respuesta a la terapia. Resultados: se incluyeron 92 pacientes con historia de falla cardíaca e indicación de terapia de resincronización; el 32,6% de los pacientes tenían cardiopatía isquémica y el 67,4% no isquémica, con una fracción de eyección promedio de 18,9%. Durante el seguimiento a los 6 primeros meses no se presentó ningún caso de muerte ni de trasplante cardíaco. Se definieron como respondedores el 47,8% de los pacientes, en tanto que el 52,2% restante fue clasificado como no respondedores. El porcentaje de pacientes que no requirieron hospitalizaciones luego de la terapia fue del 51,1%, y el 65,2% mejoró la clase funcional y 68,5% la fracción de eyección. Conclusión: en el 47,8% de la población estudiada se observó una respuesta a la terapia de resincronización cardiaca adecuada evaluada de forma combinada con parámetros clínicos y ecocardiográficos, hecho que se tradujo en una mejoría relevante en términos de fracción de eyección y clase funcional, además de menor número de hospitalizaciones por falla cardíaca, al igual que ausencia de requerimiento de trasplante cardíaco y de muertes por causa cardiovascular.

Abstract Introduction: Cardiac resynchronisation therapy (CRT) is one of the current strategies for patients with heart failure and depressed systolic dysfunction. It has shown to produce a significant reduction in the symptoms, as well as an improvement in left ventricular function and long-term survival. Objective: To evaluate the response to CRT after 6 months of follow-up. Materials and method: A retrospective, observational, analytical cohort study, with nested case-control analysis, was conducted, which included patients over 18 years of age attending a heart failure clinic, and were carriers of a CRT device. A univariate analysis was performed on the clinical and echocardiographic characteristics. A bivariate analysis was subsequently performed on the variables associated to the treatment response. Results: The study included 92 patients with a history of heart failure and an indication of CRT, of whom 32.6% had ischaemic heart disease, and with a mean ejection fraction of 18.9%. There no deaths or heart transplants during the first 6 months of follow-up. Just under half (47.8%) of the patients were considered responders to the therapy, with the remaining 52.2% classified as non-responders. The percentage of patients that did not require hospital admission after the therapy was 51.1%, 65.2% improved functional class, and 68.5% their ejection fraction. Conclusion: Just under half (47.8%) of the population studied had an adequate response to CRT, when evaluated combined with the clinical and echocardiographic parameters. This led to a significant improvement in terms of ejection fraction and functional class, including a lower number of hospital admissions due to heart failure, as well as the absence of heart transplants and deaths by cardiovascular cause.

Assesment of Myocardial Ischemia by Combination of Tissue Synchronisation Imaging and Dobutamine Stress Echocardiography

BACKGROUND AND OBJECTIVES: Dobutamine stress echocardiography (DSE) is an important non-invasive imaging method for evaluating ischemia. However, wall motion interpretation can be impaired by the experience level of the interpreter and the subjectivity of the visual assessment. In our study we aimed to combine DSE and tissue syncronisation imaging to increase sensitivity for detecting ischemia. SUBJECTS AND METHODS: 50 patients with indications for DSE were included in the study. In 25 patients we found DSE positive for ischemia and in the other 25 patients we found it to be negative. The negative group was accepted as the control group. There was no significant difference in terms of risk factors and echocardiographic parameters between the two groups, except for wall motion scores. In both groups, left ventricular dyssychrony was accepted as the difference between time to peak systolic velocity (Ts) in the reciprocal four couple of non-apical segments at rest and during peak stress. Timings were corrected for heart rate. We compared the differences of the dyssynchronisation value at rest and during peak stress to determine the distinctions within the groups and between the groups of DSE positive and negative patients. RESULTS: We found that stress and ischemia did not create any significant difference over the left intraventricular dyssynchrony with DSE, although at the segmenter level it prolonged the time to peak systolic velocity (p<0.05). These alterations did not show any significant difference between positive and negative DSE groups. CONCLUSION: As a result, this segmenter dyssynchrony and the time to peak systolic velocity, which is corrected for heart rate, did not enhance any new value over DSE for detecting ischemia.

Comparison between two progesterone sources and two oestradiol formulations in a Heatsynch protocol for postpartum cycling dairy cows in pasture

To compare an injectable progesterone (MAD-4) with an intravaginal device (IPD), and natural O17 with synthetic oestradiol (OB) in a synchronisation protocol, 51 cows were divided into four groups. Each group was treated with one of the two sources of progesterone and one of the two oestradiol formulations. Oestrus behaviour, follicle diameter, and pregnancy rates were evaluated. Oestrus behaviour (p = 0.902), numbers of cows in oestrus (p = 0.917), follicle diameter (p = 0.416), and pregnancy rates (p = 0.873) were similar among the four groups. More cows in the group treated with the IPD and OB scored > 200 oestrus behaviour points compared to the other groups (p = 0.038). A longer interval between the end of treatment and oestrus was observed among cows treated with MAD-4 than cows given the IPD (p = 0.030), but no differences were found between animals receiving the two oestradiol formulations (OB and O17). While the use of MAD-4 requires further testing, similar responses to natural oestradiol observed in the present study could allow the use of this formulation in reproductive protocols because it is not associated with the potential human health risks of OB.