Viabilidade do Implante de Eletrodo Ventricular Esquerdo na Terapia de Ressincronização Cardíaca Guiada por Gated SPECT e Remodelamento Ventricular / Feasibility of Left Ventricle Lead Implantation in Cardiac Resynchronization Therapy Guided by Gated SPECT and Ventricular Remodeling

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.

La asincronía ventricular izquierda como resultado de la estimulación apical permanente por dispositivos en el ventrículo derecho / Left ventricular dyssynchrony as result of right ventricular permanent apical pacing

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.

Renal sympathetic denervation inhibites the development of left ventricular mechanical dyssynchrony during the progression of heart failure in dogs / 中华超声影像学杂志

Objective To investigate whether transcatheter renal sympathetic denervation (RSD) by radiofrequency ablation interfere with the development of left ventricular (LV) mechanical dyssynchrony during the progression of heart failure (HF).Methods Nineteen beagles were randomly divided into sham-operated group (six dogs),control group (seven dogs),and RSD group (six dogs).Sham-operated group were implanted with pacemakers without pacing;Control group were implanted with pacemakers and underwent 3 weeks of rapid right ventricular pacing;and RSD group underwent catheter-based RSD bilaterally and were simultaneously implanted with pacemakers.LV dyssynchrony was analyzed via 2D speckle-tracking strain echocardiography to evaluate LV function.Longitudinal dyssynchrony was determined as the standard deviation for time-to-peak speckle-tracking strain on apical 4-and 2-chamber views.Radial and circumferential dyssynchrony was determined as the standard deviation for time-to-peak speckle-tracking strain in mid-and base-LV short-axis views.LV systolic pressure (LVSP) and LV end-diastolic pressure (LVEDP) were measured.The LV interstitial fibrosis was determined by histological analysis.Results After 3 weeks,all of the dogs in both the control and RSD groups showed greater LV end-diastolic volume compared with the sham-operated group;however,the dogs in the RSD group had a higher LV ejection fraction (LVEF) than the dogs in the control group (P ＜0.001).The LV systolic strains were higher in the RSD group than in the control group (P ＜0.001 for longitudinal,circumferential and radial strain,respectively).The levels of LV dyssynchrony were lower in the RSD group than in the control group (P ＜ 0.001 for longitudinal,circumferential and radial dyssynchrony,respectively).Compared with control group,RSD group had lower LV end-diastolic pressures and less fibrous tissue.Conclusions RSD inhibites the development of left ventricular mechanical dyssynchrony during the progression of heart failure in dogs.

Evaluation on the ventricular dyssynchrony in patients with pulmonary hypertension using velocity vector imaging / 中华超声影像学杂志

Objective To determine whether strain and strain rate derived from velocity vector imaging ( VVI) allowed assessment of regional and global right ventricular ( RV) dysfunction and intra‐and inter‐ventricular dyssynchrony in patients with pulmonary hypertension ( PHTN) . Methods Ninety‐nine patients were enrolled , including 35 controls and 64 PHTN patients . All participants underwent echocardiography examinations and off line strain/strain rate analysis . Bi‐ventricular regional peak systolic strain ,strain rate ,and the time‐to‐peak systolic variables were measured at the RV free wall ,inter‐ventricular septum ,and LV lateral wall in apical four chamber views . Standard deviations of the time‐to‐peak systolic strain (SD‐Ts) and strain rate (SD‐Tsr) at six RV and three left ventricular (LV) segments were calculated to define intra‐and inter‐ventricular dyssynchrony . Results Compared with the controls , segmental and global peak systolic strain and strain rate decreased in the PHTN patients . And intra‐right ventricular dyssynchrony was present in the PHTN patients [SD‐Ts:(28 ± 20)ms in controls vs (61 ± 62) ms in patients , P = 0 .003 ] . The difference between the time‐to‐peak systolic strain rate at the basal segment of RV free wall and LV lateral wall indicated earlier RV free wall contraction in PHTN patients , relativetoLVlateralwall,particularlyinthoseseverePHTNpatients[(13±13)msincontrolsvs( -49± 14) ms in patients , P < 0 .01] . Conclusions PHTN impairs RV myocardial contraction and induces to ventricular mechanical dyssynchrony .VVI could monitor RV function during the treatment of PHTN .

La estimulación septal del ventrículo derecho generaría igual disincronía biventricular que la estimulación apical en pacientes con fracción de eyección conservada / Right ventricular septal stimulation would produce similar bi-ventricular dyssynchrony as does apical stimulation in patients with normal ejection fraction

Objetivo: Determinar si la estimulación medioseptal genera menor disincronía interventricular e intraventricular que la apical evaluada mediante ecocardiografía en pacientes con fracción de eyección conservada sometidos al implante de marcapasos VVI. Método: Estudio prospectivo que incluyó a 19 pacientes > 70 años, con indicación de implante de marcapasos VVI por bloqueo auriculoventricular completo degenerativo, frecuencia ventricular ≤ 50 lpm y fracción de eyección ≥ 45%. Se excluyeron portadores de fibrilación auricular, insuficiencia cardiaca, aquellos que en ritmo sinusal presentaron QRS > 120 mseg o bloqueo de rama izquierda. Se aleatorizaron 19 pacientes a 2 grupos: grupo A (47%) a implante apical y grupo B (53%) a implante septal. Resultados: La edad media fue de 75 años (± 8). Ninguno tuvo diagnóstico de insuficiencia cardiaca o cardiopatía isquémica. La disincronía intraventricular fue de A: 14.44 ± 19.76 mseg vs. B: 9 ± 36.45 mseg; A: 6.11 ± 62.11 mseg vs. B: 13 ± 38.31 mseg; A: 77 ± 53.51 mseg vs. B: 24.29 ± 80.90 mseg, p = NS. La disincronía interventricular fue de A: 46.44 ± 19.76 mseg vs. B: 42.20 ± 29.56 mseg; A: 45.33 ± 45.67 mseg vs. B: 29.80 ± 44.66 mseg; A: 46.38 ± 20 .mseg vs. B: 21 ± 27.20 mseg, p = NS) a las 48 h, 5 y 48 meses, respectivamente. Conclusión: El sitio de estimulación no generó diferencias en la disincronía biventricular. La estimulación septal presentó una tendencia no significativa a menor disincronía interventricular.

Objective: To determine in patients with normal ejection fraction, undergoing permanent VVI pacing, if medial septal stimulation has lower dyssynchrony than apical stimulation assessed by echocardiography. Method: A prospective trial, 19 patients > 70 years old, scheduled for VVI pacemaker implantation for complete degenerative atrioventricular block, ventricular frequency < 50 beat per minute and ejection fraction ≥ 45%. Patients with atrial fibrillation, heart failure, left bundle branch block and QRS durations longer than 120 milliseconds in surface electrocardiogram with sinus rhythm were excluded. Patients were randomized to apical implantation group A: 47% and septal implantation group B: 53%. Echocardiographic parameters were measured previous to the implant, 48 h, 5 and 48 months after implantation. Results: No patients had diagnosis of ischemic cardiomyopathy or heart failure. Echocardiographic parameters for interventricular dyssynchrony between groups were A: 14.44 ± 19.76 msec vs. B: 9 ± 36.45 msec; A: 6.11 ± 62.11 msec vs. B: 13 ± 38.31 msec; A: 77 ± 53.51 msec vs. B: 24.29 ± 80.90 msec, P = NS). For interventricular dyssynchrony were A: 46.44 ± 19.76 msec vs. B: 42.20 ± 29.56 msec; A: 45.33 ± 45.67 msec vs. B: 29.80 ± 44.66 msec; A: 46,38 ± 20 msec vs. B: 21 ± 27.20 msec, P = NS) at 48 h, 5 and 48 months, respectively. Conclusion: Apical site of stimulation does not increase ventricular dyssynchrony rate in patients with preserved ejection fraction. Septal stimulation showed decreased trend in interventricular dyssynchrony.

Role of Dyssynchrony on Functional Mitral Regurgitation in Patients with Idiopathic Dilated Cardiomyopathy: A Comparison Study with Geometric Parameters of Mitral Apparatus

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.

Improvement in Left Ventricular Systolic Dyssynchrony in Hypertensive Patients After Treatment of Hypertension

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.