ABSTRACT
Resumo Fundamento A terapia de ressincronização cardíaca (TRC) pode beneficiar pacientes com insuficiência cardíaca (IC) avançada. O índice de excentricidade anormal por gated SPECT está relacionado a alterações estruturais e funcionais do ventrículo esquerdo (VE). Objetivo O objetivo do presente estudo foi avaliar a viabilidade do implante de eletrodos do VE guiado por análise de fase e sua relação com o remodelamento ventricular. Métodos Dezoito pacientes com indicação de TRC foram submetidos à cintilografia miocárdica para orientar o implante, avaliando-se os parâmetros de excentricidade e forma ventricular. P < 0,05 foi adotado como significância estatística. Resultados Na linha de base do estudo, a maioria dos pacientes foi classificada como NYHA 3 (n = 12). Após a TRC, 11 dos 18 pacientes foram reclassificados para um menor grau de limitação funcional. Além disso, a qualidade de vida dos pacientes melhorou após a TRC. Foram observadas reduções significativas na duração do QRS, intervalo PR, índice de forma diastólica final, índice de forma sistólica final, volume sistólico e massa miocárdica pós-TRC. O eletrodo do VE da TRC foi posicionado concordante, adjacente e discordante em 11 (61,1%), 5 (27,8%) e 2 (11,1%) pacientes, respectivamente. A excentricidade sistólica e diastólica final demonstrou remodelamento reverso após a TRC. Conclusões O implante de eletrodo do VE em TRC guiado por cintilografia gated SPECT é viável. A colocação do eletrodo concordante ou adjacente ao último segmento a se contrair foi um determinante do remodelamento reverso.
Abstract Background Cardiac resynchronization therapy (CRT) may benefit patients with advanced heart failure (HF). Abnormal eccentricity index by gated SPECT is related to structural and functional alterations of the left ventricle (LV). Objective The aim of this study is to evaluate the feasibility of LV lead implantation guided by phase analysis and its relationship to ventricular remodeling. Methods Eighteen patients with indication for CRT underwent myocardial scintigraphy for implant orientation, and eccentricity and ventricular shape parameters were evaluated. P < 0.05 was adopted as statistical significance. Results At baseline, most patients were classified as NYHA 3 (n = 12). After CRT, 11 out of 18 patients were reclassified to a lower degree of functional limitation. In addition, patients' quality of life was improved post-CRT. Significant reductions were observed in QRS duration, PR interval, end-diastolic shape index, end-systolic shape index, stroke volume, and myocardial mass post-CRT. The CRT LV lead was positioned concordant, adjacent, and discordant in 11 (61.1%), 5 (27.8%), and 2 (11.1%) patients, respectively. End-systolic and end-diastolic eccentricity demonstrated reverse remodeling post-CRT. Conclusions LV lead implantation in CRT guided by gated SPECT scintigraphy is feasible. The placement of the electrode concordant or adjacent to the last segment to contract was a determinant of reverse remodeling.
ABSTRACT
Resumen La estimulación apical permanente del ventrículo derecho (VD) puede producir asincronía del ventrículo izquierdo (VI) desde los puntos de vista eléctrico y mecánico. Este fenómeno es efecto de una alteración de la activación normal del VI que lleva al deterioro de la función sistólica y la aparición de insuficiencia cardíaca y sus efectos deletéreos relacionados. Para el estudio de la asincronía eléctrica del VI se ha propuesto en fecha reciente el nuevo sistema electrocardiográfico no invasivo Synchromax, que puede cuantificar el grado de asincronía eléctrica que causa una subsecuente asincronía mecánica. Esta última se ha estudiado casi siempre mediante la ecocardiografía transtorácica bidimensional (ETT2D) a través del Doppler tisular y la deformación miocárdica y ahora con la ecocardiografía tridimensional transtorácica en tiempo real (E3DTR). La relación entre estos fenómenos ha sido motivo de estudio a fin de identificar a los pacientes que se benefician de la transición a un tratamiento de resincronización cardíaca. Conclusiones: La estimulación artificial permanente del VD produce asincronía eléctrica del VI que puede cuantificarse mediante el nuevo sistema electrocardiográfico Synchromax y desencadenar asincronía mecánica estudiada mediante la ecocardiografía transtorácica para reconocer a los pacientes que pueden beneficiarse de un tratamiento de resincronización cardíaca.
Abstract Permanent apical pacing of right ventricle (RV) can produce dyssynchrony of the left ventricle (LV) from an electrical and mechanical point of view. This phenomenon is caused by an alteration in the normal activation of LV leading to a deterioration of systolic function and the appearance of heart failure and its associated deleterious effects. For the study of the electrical asynchrony of the LV, a new noninvasive electrocardiographic system Synchromax has recently been proposed, being able to quantify the degree of electrical asynchrony that leads to a subsequent mechanical dyssynchrony. The latter has been traditionally studied by two-dimensional transthoracic echocardiography (2DTTE) through tissue Doppler and myocardial deformation and lately by real-time 3-dimensional echocardiography (RT3DE). The relationship between these phenomena has been the subject of study to predict those patients who benefit from an upgrade to cardiac resynchronization therapy. Conclusions: Permanent apical pacing of the RV produces electrical dyssynchrony of the LV that can be quantified using a new electrocardiographic system Synchromax and trigger mechanical asynchrony studied through transthoracic echocardiography allowing to predict those patients who benefit from cardiac resynchronization therapy.
Subject(s)
Humans , Cardiac Pacing, Artificial/adverse effects , Ventricular Dysfunction, Left/etiology , Echocardiography , Cardiac Pacing, Artificial/methods , Echocardiography, Doppler , Ventricular Dysfunction, Left/diagnostic imaging , Echocardiography, Three-Dimensional , Cardiac Resynchronization Therapy/methodsABSTRACT
BACKGROUND AND OBJECTIVES: Left ventricular (LV) dyssynchrony has been commonly detected among hypertensive patients with normal LV systolic function and no evidence of congestive heart failure. The purpose of our study was to assess the changes in LV systolic dyssynchrony (SDSLV) among hypertensive patients after antihypertensive treatment, and to determine the relationship between SDSLV and other conventional echocardiographic parameters. SUBJECTS AND METHODS: Forty one hypertensive patients with normal LV ejection fraction were enrolled. By performing a conventional echocardiographic study, the SDSLV was measured as the time difference between the shortest and longest time of the peak myocardial systolic velocities among 12 segments of the basal and mid-levels of the 3 apical views, and radial dyssynchrony of the basal (RDSbase) and mid-levels (RDSmid) measured as the time difference between the earliest and latest peak values on the radial strain curves of each level of the parasternal short-axis views. RESULTS: Compared to baseline after six months of antihypertensive treatment, the SDSLV improved significantly (48.7+/-37.9 ms vs. 29.5+/-34.1 ms, p=0.020). Also the RDSbase and RDSmid improved significantly in respect to the baseline values (129.9+/-136.3 ms vs. 38.8+/-45.4 ms, p=0.002 and 75.2+/-63.8 ms vs. 28.2+/-37.7 ms, respectively, p<0.001). CONCLUSION: The severity of SDSLV improved with antihypertensive treatment, and was associated with the regression of LV mass. Furthermore, it might precede improvement in the mitral inflow pattern, as assessed by conventional echocardiography, so that early detection of the benefit of antihypertensive treatment may be possible.
Subject(s)
Humans , Echocardiography , Heart Failure , Hypertension , Sprains and StrainsABSTRACT
BACKGROUND: Functional mitral regurgitation (FMR) occurs commonly in patients with dilated cardiomyopathy (DCM). This study was conducted to explore the role of left ventricular (LV) dyssynchrony in developing FMR in patients with DCM in comparison with geometric parameters of the mitral apparatus. METHODS: Twenty patients without FMR and 33 patients with FMR [effective regurgitant orifice area (ERO) = 0.17 +/- 0.10 cm2] were enrolled. MR severity was estimated with ERO area. Dyssynchrony indices (DI) were measured using the standard deviations of time to peak myocardial systolic velocity between eight segments. Using real time 3D echocardiography, mitral valve tenting area (MVTa), anterior (APMD) and posterior papillary muscle distances (PPMD), LV sphericity, and tethering angle of anterior (Aalpha) and posterior leaflets (Palpha) were estimated. All geometrical measurements were corrected (c) by the height of each patient. RESULTS: The patient with FMR had significantly higher cDI, cMVTa, cAPMD and cPPMD, LV sphericity, Aalpha, and Palpha than the patients without FMR (all p < 0.05). With multiple logistic regression analysis, cMVTa (p = 0.017) found to be strongest predictor of FMR development. In patients with FMR, cMVTa (r = 0.868), cAPMD (r = 0.801), cPPMD (r = 0.742), Aalpha (r = 0.454), LV sphericity (r = 0.452), and DI (r = 0.410) showed significant correlation with ERO. On multivariate regression analysis, cMVTa and cAPMD (p < 0.001, p = 0.022, respectively) remained the strongest determinants of the degree of ERO and cAPMD (p < 0.001) remained the strongest determinant of the degree of cMVTa. CONCLUSION: Displacement of anterior papillary muscle and consequent mitral valve tenting seem to play a major role in developing FMR in DCM, while LV dyssynchrony seems to have no significant role.