Novel set of electrocardiographic left ventricular hypertrophy markers

La hipertrofia ventricular izquierda (HVI) induce cambios en las fases de despolarización y repolarización cardíaca. No obstante, pocos marcadores electrocardiográficos ncluyen parámetros de la repolarización en su diagnóstico. Objetivo de este estudio fue evaluar si la repolarización mejora el diagnóstico electrocardiográfico de la HVI. Material y Métodos: Se estudiamos los vectores QRS y T en el plano horizontal definido por las derivaciones precordiales V1 -V6 y el plano frontal definido por las derivaciones I-aVF en una serie de 40 pacientes con HVI y 34 sujetos control. Resultados: Los índices de HVI se construyeron como combinaciones de parámetros asociados a los vectores de despolarización y repolarización y su rendimiento se comparó con el rendimiento de los criterios de Sokolow-Lyon y Cornell. Los índices que incluyeron parámetros de repolarización mejoraron la sensibilidad de dichos criterios. Sobre los mismos, se construyeron estimativos a partir de medidas directas de amplitud del ECG, con el fin de obtener criterios de fácil medición en la práctica clínica. Para un 90% de especificidad, el mejor criterio, consistiendo en el voltaje de repolarización en la derivación V6 , produjo un 56% de sensibilidad, por encima del 30% de Sokolow-Lyon y el 40% de Cornell. Conclusiones: la repolarización contribuyó al diagnóstico electrocardiográfico de HVI y alentamos la búsqueda de nuevos índices en esta dirección.Left ventricular hypertrophy (LVH) induces changes in both depolarization and repolarization phases. However, little efforts were made to include repolarization features in its diagnosis. The aim of this study was to evaluate whether the repolarization improves ECG diagnosis of LVH. Methods: To do this, we studied the QRS and T vectors in the horizontal plane (HP) defined by the chest leads V1 -V6 and the frontal plane (PF) defined by the limb leads I-aVF in a series of 40 LVH patients and 34 control subjects. Results: LVH indices were constructed as combinations of parameters associated with depolarization and repolarization vectors and their performance was compared to the performance of Sokolow-Lyon and Cornell. Those indices, which included repolarization parameters, improved the sensitivity of these criteria. The latter were selected to construct estimates from direct measurements of ECG amplitudes, in order to obtain easy measurement criteria in the clinical practice. The best estimate, consisting of the repolarization voltage on lead V6 , produced a 56% sensitivity at 90% specificity, above Sokolow-Lyon (sensitivity 30%) and Cornell (sensitivity 40%). Conclusions: repolarization contributed to the electrocardiographic diagnosis of LVH and we encourage the search for new indices in this direction.Fil: Bonomini, Maria Paula. Universidad de Buenos Aires; ArgentinaFil: Ingallina, Fernando Juan. Universidad de Buenos Aires; ArgentinaFil: Barone, Valeria. Universidad de Buenos Aires; ArgentinaFil: Antonucci, Ricardo. Universidad de Buenos Aires; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderon; Argentin

Cardiac Thyrotropin-releasing Hormone Inhibition Improves Ventricular Function and Reduces Hypertrophy and Fibrosis After Myocardial Infarction in Rats

Background: Cardiac thyrotropin-releasing hormone (TRH) is a tripeptide with still unknown functions. We demonstrated that the left ventricle (LV) TRH system is hyperactivated in spontaneously hypertensive rats and its inhibition prevented cardiac hypertrophy and fibrosis. Therefore, we evaluated whether in vivo cardiac TRH inhibition could improve myocardial function and attenuate ventricular remodeling in a rat model of myocardial infarction (MI). Methods and Results: In Wistar rats, MI was induced by a permanent left anterior descending coronary artery ligation. A coronary injection of a specific small interfering RNA against TRH was applied simultaneously. The control group received a scrambled small interfering RNA. Cardiac remodeling variables were evaluated one week later. In MI rats, TRH inhibition decreased LV end-diastolic (1.049 ± 0.102 mL vs 1.339 ± 0.102 mL, P <.05), and end-systolic volumes (0.282 ± 0.043 mL vs 0.515 ± 0.037 mL, P <.001), and increased LV ejection fraction (71.89 ± 2.80% vs 65.69 ± 2.85%, P <.05). Although both MI groups presented similar infarct size, small interfering RNA against TRH treatment attenuated the cardiac hypertrophy index and myocardial interstitial collagen deposition in the peri-infarct myocardium. These effects were accompanied by attenuation in the rise of transforming growth factor-β, collagen I, and collagen III, as well as the fetal genes (atrial natriuretic peptide, B-type natriuretic peptide, and beta myosin heavy chain) expression in the peri-infarct region. In addition, the expression of Hif1α and vascular endothelial growth factor significantly increased compared with all groups. Conclusions: Cardiac TRH inhibition improves LV systolic function and attenuates ventricular remodeling after MI. These novel findings support the idea that TRH inhibition may serve as a new therapeutic strategy against the progression of heart failure.Fil: Schuman, Mariano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Peres Diaz, Ludmila Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Aisicovich, Maia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Ingallina, Fernando Juan. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Toblli, Jorge Eduardo. Hospital Aleman; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Landa, Maria Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Garcia, Silvia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Hospital Aleman; Argentin

Comparison of electrocardiographic and vectorcardiographic planes on a set of left ventricular hypertrophy patients

Most common electrocardiographic diagnostic criteria for left ventricular hypertrophy (LVH) are based on depolarization information. However, reports support that LVH also alters repolarization. Two measures relate depolarization/ repolarization: the angle between the QRS-complex and the T-wave in a plane; the planar QRST (QRST p) and the vector obtained from the cross sum of the depolarization and repolarization vectors (RTa and RTm). We compared the performance of these measures as hypertrophy markers in two sets of planes: the ECG frontal plane (FP) versus the VCG frontal plane (XYP) and the ECG horizontal plane (HP) versus the VCG horizontal plane (XZP). The horizontal views picked up a significant increase of the QRSTp (HP controls vs LVH: 40.18±41.20° vs 66.50±51.65°, p<0.05; XZP controls vs LVH: 43.87±39.76° vs 66.35±38.30°, p<0.05) and a consistent behaviour in the frontal views (XYP controls vs LVH: 17.71±37.23° vs 35.60±47.98°, p<0.005). On the other hand, the angle of the equivalent RT vector significantly increased in the HP (HP controls vs LVH: 24.28±26.50° vs 33.53±22.42°, p<0.05). In conclusion, the angular information in their two forms (QRSTp and RTα) relating depolarization and repolarization was the most informative parameter and should be regarded for the construction of more sensitive electrocardiographic LVH indexes.Fil: Bonomini, Maria Paula. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Ingallina, Fernando Juan. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Barone, V.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Valentinuzzi, M.. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaVI Congreso Latinoamericano de Ingeniería BiomédicaParanáArgentinaUniversidad Nacional de Entre Río

Left ventricular hypertrophy index based on a combination of frontal and transverse planes in the ECG and VCG: Diagnostic utility of cardiac vectors

The changes that left ventricular hypertrophy (LVH) induces in depolarization and repolarization vectors are well known. We analyzed the performance of the electrocardiographic and vectorcardiographic transverse planes (TP in the ECG and XZ in the VCG) and frontal planes (FP in the ECG and XY in the VCG) to discriminate LVH patients from control subjects. In an age-balanced set of 58 patients, the directions and amplitudes of QRS-complexes and Twave vectors were studied. The repolarization vector significantly decreased in modulus from controls to LVH in the transverse plane (TP: 0.45±0.17mV vs. 0.24±0.13mV, p<0.0005; XZ: 0.43±0.16mV vs. 0.26±0.11mV, p<0.005) while the depolarization vector significantly changed in angle in the electrocardiographic frontal plane (Controls vs. LVH, FP: 48.24±33.66◦ vs. 46.84±35.44◦ , p<0.005, XY: 20.28±35.20◦ vs. 19.35±12.31◦ , NS). Several LVH indexes were proposed combining such information in both ECG and VCG spaces. A subset of all those indexes with AUC values greater than 0.7 was further studied. This subset comprised four indexes, with three of them belonging to the ECG space. Two out of the four indexes presented the best ROC curves (AUC values: 0.78 and 0.75, respectively). One index belonged to the ECG space and the other one to the VCG space. Both indexes showed a sensitivity of 86% and a specificity of 70%. In conclusion, the proposed indexes can favorably complement LVH diagnosisFil: Bonomini, Maria Paula. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Ingallina, Fernando Juan. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Barone, Valeria. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Antonucci, Ricardo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Valentibuzzi, Maximo E.. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaXX Congreso Argentino de Bioingeniería y IX Jornadas de Ingeniería ClínicaSan NicolásArgentinaSociedad Argentina de Bioingenieri

Modelling of the electrocardiographic signal during an angioplasty procedure in the right coronary artery

Dynamical models are useful tools to generate sets of varied morphological signals by synthesizing human electrocardiograms (ECGs). These signals are used for testing and improving algorithms of ECG delineation, patient monitoring and heart disease detection. This work presents a procedure based on the ECGSYN model to synthesize ECG morphological changes induced by a percutaneous transluminal coronary angioplasty (PTCA) procedure in the right coronary artery. We provide a set of parameters to be used in ECGSYN and generate heartbeats with altered ST-T complexes. These characteristic model parameters were obtained through a non-linear fitting algorithm applied to every available heartbeat. To extend these parameters, normal distributions were generated with their means and standard deviations obtained from the STAFF III database. Parameters were presented for P, QRS and T-waves at leads II, III and aVF. The synthesis procedure shows an average correlation and positive predictive value of 92.2% and 88.2%, respectively. In conclusion, we provide a technique capable of synthesizing electrocardiographic ischemic morphology with physiological plausibility. Then, the generation of data sets for algorithm testing can benefit from this system of ECG signal synthesis.Fil: Rincon Soler, Anderson Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Fernández Biscay, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Ingallina, Fernando Juan. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentin