Left Ventricular Synchronicity Research Articles

Synchronicity of LV Contraction as a Determinant of LV Twist Mechanics: Serial Speckle-Tracking Analyses in WPW Syndrome Before and After Radiofrequency Catheter Ablation

This study set out to investigate the isolated impact of synchronous patterns of left ventricular (LV) contraction (i.e., LV synchronicity) on LV twist behavior. Although the relationships between LV loading status/LV contractility and twist are well-established, no data are available regarding the relation between LV twist and LV synchronicity, without any interference by changes in LV pre-load, afterload, and contractility. Serial assessment of patients with Wolff-Parkinson-White syndrome before and after radiofrequency catheter ablation (RFCA) allows this to be explored. Of the 40 Wolff-Parkinson-White patients initially screened, 34 were enrolled. Two-dimensional and Doppler echocardiography along with speckle tracking-derived LV twist mechanics, apical-basal rotation delay, and left ventricular dyssynchrony index (LVdys) were obtained before and after RFCA. The LVdys was defined as the maximal delay in time-to-peak radial strain of different LV segments at the papillary muscle level. Overall, no significant changes were demonstrated in LV volumes, systolic and diastolic function, and end-systolic wall stress before versus after RFCA. After RFCA, median value of LVdys was attenuated from 33.5 (interquartile range [IQR]: 14.0 to 84.3) to 14.0 (IQR: 11.5 to 21.8) (p = 0.002), which was accompanied by a reduction in apical-basal rotation delay from 9.7% (IQR: 3.5 to 23.7) to 3.3% (IQR: 1.3 to 8.0) (p = 0.004). In contrast, LV twist increased from 14.2° (IQR: 9.1° to 18.4°) before to 19.7° (IQR: 15.0° to 22.6°) after RFCA (p = 0.002). Delta LV twist pre- to post-RFCA displayed a significant inverse correlation with changes in apical-basal rotation delay (r = -0.42, p = 0.01) and Delta LVdys (r = -0.39, p = 0.02). The LV synchronous contraction is significantly related to LV twist.

Right Ventricular Outflow Tract Pacing Reveals a Different Left Ventricular Synchronization According to the Degree of the Atrio-Ventricular Conductivity

Background: We previously reported right ventricular outflow tract (RVOT) pacing results in a greater cardiac output comparing with mid-septal (RVMS) and apical (RVA) pacing. However, the precise mechanism of the RVOT pacing predominance is unknown. [Purpose] We aimed to clarify the pacing-site-dependent differences in left ventricular (LV) synchronization, and compared them according to the atrio-ventricular conductivity. Methods: In 76 patients, the LV wall motion was visualized by 2D strain echocardiography (2DSE) and the SD in the time-to-peak systolic strain was measured in 18 LV segments. The differences in the LV synchronization were assessed between the sick sinus syndrome (SSS) and complete atrio-ventricular block (cAVB) patient groups. Results: The SD in the time to peak systolic strain was smaller with RVOT pacing than RVMS or RVA with no remarkable difference between the RVMS and RVA. In the SSS group (n=31), RVOT pacing tended to minimize the SD compared with RVMS and RVA (69.9±4.3, 77.8±4.7 vs. 82.8±5.4 ms), whereas the cAVB group (n=24) exhibited no significant difference in the SD among the three pacing positions (68.8±3.0, 73.9±4.4 vs. 76.0±3.7 ms). Conclusion: The beneficial effect of RVOT pacing was depicted clearly by 2DSE. However, the superiority of the RVOT over the RVMS and RVA differed according to the atrio-ventricular conductivity.

Echocardiographic study of left ventricular 3-dimension displacement during different ventricular pacing in vivo:a canine model

Objective To evaluate the changes of left ventricular(LV) 3-dimension peak displacement (3D-D) during different cardiac pacing patterns. To provide a reliable mechanical data base for the optimization cardiac pacing. Methods Cardiac pacings in open-chest Beagle canine models( n = 10) were performed using three patterns[I, e. , right ventricular apical pacing (RVA-P), LV lateral pacing (LVL-P)and LV apical pacing(LVA-P)],3D full volumetric real-time imaging were acquired in a completed cardiac cycle. The 3D-D,3D-D peak time (3D-DTc) and the standard deviation of TC(3D-DTSD) were calculated and analyzed in different pacing patterns for difference and spatial correlationship. Results ① The 3D-D of LVL-P and LVA-P state decreased compared with BASE and RVA-P state, there were significant 3D-D difference of mid anterior,mid anteriorspetal, mid interior,mid posterior, mid lateral between LVL-P and BASE, RVA-P patterns( P ＜0.05). There were significant 3D-D difference of mid anterior,mid lateral,mid posterior between LVA-P and RVA-P patterns groups( P ＜0.05). There were significant 3D-D difference of all segments in apical level between LVL-P,LVA-P and BASE, RVA-P states( P ＜0.05). ② Corrected by the heart rate,the 3D-DTC of different cardiac pacing patterns were shorter than BASE state. ③ There were no significant 3D-DTSD difference between different cardiac pacings and BASE patterns. There were significant 3D-DTSD difference between RVA-P and LVA-P patterns (P ＜ 0.05). Conclusions LV mechanical activation and synchronization could be maintained during RVA-P rather than LVA-P and LVL-P. Echocardiographic study of left ventricular 3D-D can actually reveal myocardial mechanical state during different cardiac pacings and BASE patterns. Key words: Echocardiography; three-dimensional; Cardiac pacing, artificial; Ventricular function, left

Evaluation of Left Ventricular Synchronicity in Hypertensive Patients With Overweight or Obesity

The left ventricular synchronicity in hypertensive patients with overweight or obesity has not been well elucidated. This study was designed to evaluate the left ventricular synchronicity in these patients. Tissue Doppler imaging was performed in 126 hypertensive patients and 25 control subjects. The hypertensive patients were divided into three groups according to BMI: normal weight group (BMI <25 kg/m(2), n = 32, H-NW group), overweight group (BMI 25-29.9 kg/m(2), n = 64, H-OW group), and obese group (BMI >or=30 kg/m(2), n = 30, H-OB group). Left ventricular systolic and diastolic synchronicity were determined by measuring the maximal differences in time to peak myocardial systolic contraction (T(s)-diff) and early diastolic relaxation (T(e)-diff) between any two of the left ventricular segments and the standard deviation of time to peak myocardial systolic contraction (T(s)-SD) and early diastolic relaxation (T(e)-SD) of all 12 segments. Compared with the control group, the indexes of synchronicity including T(s)-diff, T(s)-SD, T(e)-diff, and T(e)-SD were significantly prolonged in the hypertensive patients. Furthermore, although the indexes of blood pressure had no difference among the hypertensive groups, the impaired systolic and diastolic synchronicity including T(s)-diff, T(s)-SD, and T(e)-SD was obviously aggravated with the increasing BMI. Stepwise multivariate analysis revealed BMI as an independent predictor of T(s)-SD and T(e)-SD. Therefore, the impairment of left ventricular synchronicity was aggravated with increasing BMI in hypertensive patients. Overweight and obesity may be important factors to impact the left ventricular synchronicity.

Evaluation of left ventricular deformation and synchronicity before and after coronary artery bypass graft in patients with coronary artery disease using strain rate imaging

Objective To evaluate the capability of strain rate imaging(SRI)for monitoring regional systolic deformation and synchronicity of left ventricle after coronary artery bypass graft(CABG)and for evaluating effect of surgery and predicting restenosis.Methods The values of systolic strain rate(SRsys),systolic strain(Ssys)and post systolic strain index(PSI)in 5 segments supplied by left anterior descending coronary artery were measured in study group(60 patients with coronary artery disease)at 1 day before and 10 days,1 month,3 months and 6 months after CABG.Forty healthy participants served as a baseline control group.The regional myocardial function before and after CABG was compared and analyzed.Results The peak values of SRsys and Ssys decreased before CABG in study group.In 52 of the 60 patients,SRsys and Ssys in the graft segments increased gradually and showed statistical significance in most studied segments at 3 and 6 months after surgery.In the above 52 patients,value of PSI increased before CABG and reduced significantly in all analyzed segments at 6 months after surgery.The restenosis of graft artery was suspected in 8 patients by SRI and the positive predictive value was 75%.The diagnosis sensitivity of SRI parameter method was higher than that of 2-dimensional echocardiography and the sensitivity of Ssys was higher than that of SRsys.Conclusions SRI can be used to quantitatively assess the regionsl systolic deformation and synchronicity and monitor the improvement of myocardial function after CABG and determine the effect of surgery and predict restenosis of graft artery. Key words: Echocardiography; coronary artery bypass; Ventricular function,left; Strain rate imaging

Impact of Left Ventricular Dyssynchrony Early on Left Ventricular Function After First Acute Myocardial Infarction

The impact of left ventricular (LV) dyssynchrony after acute myocardial infarction (AMI) on LV ejection fraction (EF) is unknown. One hundred twenty-nine patients with a first ST-elevation AMI (58 + or - 11 years, 78% men) and QRS duration <120 ms were included. All patients underwent primary percutaneous coronary intervention. Real-time 3-dimensional echocardiography and myocardial contrast echocardiography were performed to assess LV function, LV dyssynchrony, and infarct size. LV dyssynchrony was defined as the SD of the time to reach the minimum systolic volume for 16 LV segments, expressed in percent cardiac cycle (systolic dyssynchrony index [SDI]). Myocardial perfusion at myocardial contrast echocardiography was scored (1 = normal/homogenous; 2 = decreased/patchy; 3 = minimal/absent) using a 16-segment model; a myocardial perfusion index, expressing infarct size, was derived by summing segmental contrast scores and dividing by the number of segments. SDI in patients with AMI was 5.24 + or - 2.23% compared to 2.02 + or - 0.70% of controls (p <0.001). Patients with AMI and LVEF <45% had significantly higher SDI compared to patients with LVEF > or = 45% (4.29 + or - 1.44 vs 6.95 + or - 2.40, p <0.001). At multivariate analysis, SDI was independently related to LVEF; in addition, the impact of SDI on LV systolic function was incremental to infarct size and anterior location of AMI (F change 16.9, p <0.001). In conclusion, LV synchronicity is significantly impaired soon after AMI. LV dyssynchrony is related to LVEF and has an additional detrimental effect on LV function, beyond infarct size and the anterior location of AMI.

Evaluation of pacing site in dogs with naturally occurring complete heart block

Objective To compare left ventricular synchronization and systolic performance with transvenous pacing of the right ventricular apex (RVA), left ventricular free wall (LVF) or simultaneous pacing of the RVA and LVF (BiV). Animals, materials and methods Seven canine patients with complete heart block. Prospective study evaluating effect of pacing site. Twenty four hours following implantation of transvenous BiV pacing systems, electrocardiograms and echocardiograms were assessed during pacing from the: (1) Right Atrial Appendage/RVA (RAA/RVA), (2) RAA/LVF, and (3) RAA/BiV. Results QRS duration was significantly shorter with BiV pacing versus LVF pacing ( p < 0.001), or RVA pacing ( p < 0.001). Echocardiographic indices of systolic performance fractional shortening (FS), ejection fraction (EF), cardiac output (CO) were significantly higher with BiV pacing than with pacing from the RVA ( P = 0.023, 0.006, and 0.002 respectively). Cardiac output, measured by the biplane Simpson's method, was higher with LVF versus RVA pacing ( P = 0.036). There was no difference in FS or EF when comparing LVF to RVA pacing. Tissue Doppler measurements of synchronization and systolic performance did not show any difference between pacing mode, but a significantly increased number of segments were seen to contract following aortic valve closure during LVF pacing ( P = 0.0268) and RVA pacing ( P = 0.0197) as compared to BiV pacing. Conclusions Findings suggest that BiV pacing improves cardiac output and systolic performance versus RVA pacing. This improvement however, is not reflected in tissue Doppler indices of synchronization and systolic performance.

Three-dimensional echocardiographic assessments of exercise-induced changes in left ventricular shape and dyssynchrony in patients with dynamic functional mitral regurgitation

Left ventricular (LV) shape and LV dyssynchrony are two cofactors associated with functional mitral regurgitation (MR) in patients with heart failure. Both can be accurately examined by real-time three-dimensional echocardiography (3DE). We examined the relationship between dynamic MR and exercise-induced changes in LV shape and synchronicity using 3DE. Fifty patients with systolic LV dysfunction underwent 2D and 3D quantitative assessment of LV function, shape, and synchronicity at rest and during symptom-limited exercise test. According to the magnitude of change in MR, patients were divided into EMR group (15 patients, 30%), if the degree of MR increased during test, and NEMR group. During exercise, the changes in LV volumes and ejection fraction were similar in both groups, whereas changes in mitral valvular deformation parameters, in LV sphericity index, and in the extent of LV dyssynchrony were more pronounced in the EMR group. At rest, only the 3D sphericity index could distinguish the two groups. By stepwise multiple regression model, dynamic changes in the systolic dyssynchrony index, sphericity index, and coaptation distance were associated with dynamic MR (r(2) = 0.45, P = 0.012). Dynamic MR during exercise is related to the 3D changes in LV shape and in LV synchronicity.

Assessment of the left ventricular systolic synchronization and global systolic function in patients with implantation of DDD mode cardiac pacemakers by real-time three-dimensional echocardiography

Objective To assess the left ventricular synchronization and global systolic function in patients with implanted dual-chamber (DDD) mode cardiac pacemakers by real-time three-dimensional echocardiography(RT-3DE). Methods Left ventricular systolic synchronization and global function were evaluated in 20 patients with implanted DDD mode cardiac pacemakers and 20 normal people by RT-3DE. The left ventricular end-diastolic volume (LEDV), end-systolic volume ( LESV), stroke volume (SV), left ventricular ejection fraction (LVEF), the mean value of time from the start of electrocardiographic QRS wave to the point of minimal systolic volume (Tmean) of the 17 segments and those standard deviation(T-SD),the maximal difference of time among all 17 segments(Tmax) were obtained by RT-3DE. Results Compared with control group, LESV was significantly increased,SV, LVEF were significantly decreased and T-SD,Tmax were significantly prolonged (P 0.05). In patients group,LVEF correlated closely with T-SD (r =-0.674, P<0.05) and Tmax (r = - 0. 634, P < 0. 05). Conclusions There were left ventrieular systolic asychronization and global systolic dysfunction in patients with implanted dual-chamber (DDD) mode cardiac pacemakers,which could be assessed by RT-3DE. Key words: Echocardiography, real-time three-dimensional; Cardiac pacing, artificial; Myocardial contraction; Ventrieular function, left

DDDR pacing results in left ventricular asynchrony with preservation of ejection fraction and NT-proBNP: A prospective study in sick sinus syndrome and normal ventricular function

Desynchronization induced by right ventricular pacing may increase the risk for heart failure. We aimed to compare left ventricular (LV) function, synchrony and left atrial size along with NT-proBNP levels, in 2 different modes of pacing: AAIR versus DDDR. This was a prospective study of 60 patients with sick sinus syndrome, preserved LV function and normal atrioventricular conduction. Each pacing mode lasted at least 2months, in every patient, after which period every patient was switched to the alternate pacing mode. Intraventricular asychrony was assessed by: 1) M-Mode septal-to-posterior wall motion delay (SPWMD), and 2) Tissue Doppler imaging (TDI) septal to lateral delay. NT-proBNP was measured at the end of each pacing mode. LV ejection fraction and left atrial diameter were not different in the 2 pacing modes, although asynchrony was induced in the DDDR arm (p<0.001 for TDI). NT-proBNP was lower in the DDDR compared to the AAIR mode (p=0.003, F=9.64). The NT-proBNP was inversely correlated to LV ejection fraction in the DDDR mode (p=0.0001, R=-0.75), whilst it was significantly correlated to the TDI septal-lateral delay and SPWMD (p=0.007, R=0.4 and p=0.002, R=0.5) in the AAIR mode. In conclusion in sick sinus syndrome with preserved LV function the DDDR mode does not compromise LV systolic function although it causes asynchrony. The NT-proBNP is lower when the right ventricle is paced, is inversely related to LV function and it is related to the degree of LV synchronization in the AAIR mode.

Impaired left ventricular synchronicity in patients with metabolic syndrome, regardless of hypertension

To assess the left ventricular (LV) diastolic and systolic synchronicity in patients with metabolic syndrome. Tissue Doppler echocardiography was performed in 235 individuals (135 with metabolic syndrome and 100 controls). Diastolic and systolic synchronicity was determined by measuring the SD of time to peak myocardial early diastolic relaxation and systolic contraction and the maximal difference in time to peak myocardial early diastolic relaxation and systolic contraction with six basal and six middle LV segments. Compared with controls, patients with metabolic syndrome showed significantly prolonged SD of time to peak myocardial early diastolic relaxation (20.79 +/- 11.29 vs. 16.33 +/- 5.67 ms, P < 0.001) and SD of time to peak myocardial early systolic contraction (24.50 +/- 15.27 vs. 17.27 +/- 5.46 ms, P < 0.001) and prolonged maximal difference in time to peak myocardial early diastolic relaxation (66.76 +/- 40.81 vs. 45.59 +/- 17.78 ms, P < 0.001) and maximal difference in time to peak myocardial early systolic contraction (71.47 +/- 49.19 vs. 47.64 +/- 17.25 ms, P < 0.001) among all the 12 left ventricular segments. Multiple regression analysis revealed waist-to-hip ratio, fasting blood glucose, age and LV mass for height to the power 2.7 as independent predictors of impaired diastolic synchronicity in metabolic syndrome, with age and LV mass for height to the power 2.7 as independent predictors of impaired systolic synchronicity. Subgroup analyses indicated that there was no difference of LV synchronicity between nonhypertensive and hypertensive subgroups in metabolic syndrome patients. Patients with metabolic syndrome have impaired LV diastolic and systolic synchronicity. Obesity, hyperglycemia and age play important roles in it, whereas hypertension is not the key factor to cause the impaired synchronicity.

The Impact of Atrio-Biventricular Pacing on Hemodynamics and Left Ventricular Dyssynchrony Compared With Atrio–Right Ventricular Pacing Alone in the Postoperative Period After Cardiac Surgery

The aims of this study were to test the hypotheses that in the postoperative period after coronary artery bypass graft surgery (1) atrio-right ventricular (RA-RV) pacing induces a decrease in cardiac output compared with RA pacing alone and (2) atrio-biventricular (RA-BiV) pacing improves CO compared with RA-RV pacing. A prospective observational study. A single-center university hospital. Patients referred for coronary artery bypass graft surgery. Patients were studied during atrial, RA-RV, and RA-BiV pacing. Cardiac output (echocardiography) and left ventricular dyssynchrony were assessed at each step. RA-RV pacing induced a significant decrease in cardiac output (4.3 +/- 1.0 to 3.7 +/- 0.8 L/min, p < 0.01) and a significant increase in left ventricular dyssynchrony (13 +/- 12 to 80 +/- 25 milliseconds, p < 0.01). Biventricular pacing induced a significant increase in cardiac output (3.7 +/- 0.8 to 4.5 +/- 1.0 L/min, p < 0.01) and a significant decrease in left ventricular dyssynchrony compared with right ventricular pacing (80 +/- 25 to 21 +/- 16 milliseconds, p < 0.05). RA-BiV pacing improves cardiac output compared with RA-RV pacing in the postoperative period after coronary artery bypass graft surgery. This improvement is related to an improvement in left ventricular synchronicity.

Abstract 2838: Sequential Changes of Left Ventricular Systolic and Diastolic Synchronicity in Acute ST-Elevation Myocardial Infarction after Primary Coronary Intervention

The aims of this study were to assess the sequential changes of left ventricular (LV) systolic and diastolic synchronicity in patients with acute myocardial infarction (AMI) and to assess their relation with LV recovery and remodeling. Forty-patients with acute ST-elevation MI were examined within 2days, 6weeks and 6months after primary coronary intervention. Fifteen-age matched subjects were enrolled for normal control. The time from the onset of QRS complex to peak systolic velocity (Ts) and to peak early diastolic velocity (Te) were measured on color-coded tissue Doppler imaging. To assess LV synchronicity, SDs of Ts (Ts-SD) and Te (Te-SD) of all 12 segments were calculated (within 2days, at 6weeks and 6months; SD1, SD2 and SD3, respectively). LV recovery was defined as the improvement of wall motion at least more than two segments at 6 weeks. In all AMI patients, the wall motion score index was 1.72±0.27 and LV ejection fraction was 45.9±9.9%. The Ts-SD1 was higher in AMI patients than in controls (45.4±13.5 vs 29.4±13.3ms, p&lt;0.05), but Te-SD1 was not different (18.7±6.9 vs 16.2±10.0). Twenty-two patients (group1) showed a recovery and 18 patients (group2) showed no recovery. The Ts-SD1 was smaller in group1 than in group2 (43.4±12.6 vs 47.9±11.7 ms, p&lt;0.05). In group1, Ts-SD were much decreased as follow up (Ts-SD2, 3; 36.6±14.0 and 31.1±9.5, respectively, p&lt;0.05). In contrast, in group2, Ts-SD was not significantly changed (Ts-SD2,3; 46.7±13.2 and 43.7±8.8, respectively) but Te-SD was increased as follow up (Te-SD1,2,3; 17.8±5.5, 20.4±4.3 and 25.0±3.8, respectively, p&lt;0.05). The LV end-diastolic and systolic volume were increased and the deceleration time of early diastolic mitral inflow velocity was shortened in group2 (p&lt;0.05). This clinical study shows: 1) in acute phase, the regional wall motion abnormalities of AMI had an impact on LV systolic synchronicity; 2) the AMI patients with LV recovery showed better LV systolic synchronicity; 3) the LV systolic synchronicity became better as regional wall motion was improved; and 4) in chronic phase, the LV diastolic synchronicity became worse in AMI patients with no recovery, which might be related to LV remodeling and worsening of LV diastolic function.

Abstract 4556: Magnetic Resonance Imaging in Evaluating Left Ventricular Rotation and Synchronization in Patients with Congenital Single Ventricle Disease

Rotational motion of the left ventricular (LV) myocardium has recently received attention as an index of ventricular function. Echocardiographic methods for evaluation of ventricular mechanics are limited by image quality. We developed a method for evaluating cardiac mechanics on gradient cine magnetic resonance imaging (MRI) studies. Twelve adult single ventricle (SV) patients were retroactively selected to compare with 11 randomly selected relatively normal patients who had undergone cardiac MRI study. Detailed SSFP cine images were acquired at several levels in short axis views using Philips and GE MRI systems. Images from each study were evaluated at the apex and papillary muscle levels using VVI (Siemens) for degree of rotation and circumferential strain rate (CSR). Maximal time difference between each segment was recorded as well as the average degree of rotation. When compared with normal patients, SV patients had less rotation at both apex and papillary muscle levels and more dispersion of peak rotation: average rotation: 1.79° ± 0.81° vs. 3.60° ± 1.38°, p &lt; 0.0001, peak rotation: 3.10° ± 1.25° vs 5.71°± 2.63°, p &lt; 0.0001. In contrast, maximum wall motion delay between the segments of each level for data obtained from both rotation and CSR was greater for SV pathology than normals: rotational segment delay, 181.55 ± 76.06 ms vs. 66.86 ± 47.11 ms, p &lt; 0.0001; CSR delay, 90.73 ± 61.98 ms vs. 44.23 ± 37.14 ms, p = 0.004. Average CSR for SV was −8.87 ± 7.30 s −1 and for normals, −18.02 ± 7.31 s −1 . Our MRI mechanics study showed decreased CSR in SVs compared to normal LVs, and also a marked decrease in and segmental dyssynchrony of rotation.

Tomographic Left Ventricular Volumetric Emptying Analysis by Real-Time 3-Dimensional Echocardiography

Background— The sequence of left ventricular (LV) systolic emptying is not completely understood. Using real-time 3-dimensional echocardiography, we investigated this sequence and LV synchronicity in physiological and pathological conditions. Methods and Results— The study population consisted of 116 healthy volunteers, 20 top-level athletes, 35 patients with LV dysfunction, and 84 patients with LV dysfunction and left bundle-branch block (LBBB). We subdivided the LV into 16 volumetric segments for regional analysis and into apical, middle, and basal regions to calculate the mean of end-systolic times and the time to minimum systolic volume of each region. In healthy volunteers and in top-level athletes, the emptying systolic times increased smoothly from apex to base. These differences determined an apex-to-base time gradient in the LV emptying sequence. In patients with LV dysfunction and without LBBB, this gradient was maintained with a relatively higher LV dyssynchrony. However, in patients with LV dysfunction and LBBB, there was no clear sequence in LV emptying volumes, and this group had the highest LV dyssynchrony. Conclusions— Real-time 3-dimensional echocardiography tomographic slicing of the LV enables accurate analysis of LV emptying in physiological conditions and in conditions of LV dysfunction with and without electrical dyssynchrony. Progressive dilation of LV produces deterioration in LV synchronicity. However, it is the presence of LV dysfunction in combination with LBBB that determines the loss of the apex-to-base time gradient in LV emptying.

A single session of haemodialysis improves left ventricular synchronicity in patients with end-stage renal disease: a pilot tissue synchronization imaging study

Mechanical left ventricular (LV) dyssynchrony impairs cardiac function in patients with heart failure and LV hypertrophy (LVH) and may be a factor contributing to the high incidence of cardiac deaths in patients with end-stage renal disease (ESRD). Objectives. To evaluate the possible presence of LV dyssynchrony in ESRD patients, and acute effect of haemodialysis (HD) on LV synchronicity using a tailored echocardiographic modality, tissue synchronization imaging (TSI). In 13 clinically stable ESRD patients (7 men; 65 +/- 10 years) with LVH, echocardiography data were acquired before and after a single HD session for subsequent off-line TSI analysis enabling the retrieval of regional intraventricular systolic delay data. Six basal and six midventricular LV segments were evaluated. Dyssynchrony was defined as a regional difference in time to peak systolic velocity >105 ms. Before HD, all patients had at least one dyssynchronous LV segment. The percentage of delayed segments correlated positively to LV end-diastolic diameter (r = 0.68, P < 0.05). HD induced a substantial decrease in the percentage of delayed segments from 36 +/- 25% to 19 +/- 14% (P < 0.01), reduced average maximal mechanical systolic LV delay from 300 +/- 89 to 225 +/- 116 ms (P < 0.05) and completely normalized LV synchronicity in three patients (23%). LV dyssynchrony appears to be present frequently in ESRD patients with LVH. The severity of LV dyssynchrony correlates with LV end-diastolic diameter and decreases after a single session of HD suggesting a mechanistic relevance of volume overload and possibly other toxins accumulating in HD patients.

Impaired left ventricular synchronicity in hypertensive patients with ventricular hypertrophy

The influence of left ventricular hypertrophy (LVH) on left ventricular synchronicity, and the prevalence of left ventricular dyssynchrony in hypertensive patients with LVH are unknown. The purpose of this study was to determine the influence of LVH on left ventricular synchronicity in hypertensive subjects. Tissue Doppler imaging (TDI) was performed in 115 hypertensive and 30 control individuals. Hypertensive patients were divided into a LVH group and a non-LVH group according to the left ventricular mass index (LVMI). Diastolic and systolic asynchrony was determined by measuring the maximal differences in time to peak myocardial systolic contraction (Ts-max) and early diastolic relaxation (Te-max) between any two of the left ventricular segments and the standard deviation of time to peak myocardial systolic contraction and early diastolic relaxation of all 12 segments. Ts-max was greater in both the non-LVH and LVH groups than in controls, (96.68 +/- 26.21 versus 79.30 +/- 25.19 versus 53.20 +/- 15.24 ms, both P < 0.001) and in the LVH group than in the non-LVH group (96.68 +/- 26.21 versus 79.30 +/- 25.19 ms, P < 0.01). Te-max was prolonged in both patient groups, being most advance in the LVH group (67.39 +/- 11.01 versus 57.18 +/- 11.42 versus 46.72 +/- 13.24 ms, both P < 0.001 versus control group and P < 0.001 versus non-LVH group). LVH patients had shown a greater prevalence of both systolic and diastolic asynchrony than non-LVH patients. A Ts-max value greater than 88 ms had 68% sensitivity and 71% specificity for detecting hypertensive patients with LVH. Left ventricular systolic synchronicity was impaired in hypertensive patients with LVH. TDI was shown to be useful for the detection of myocardial abnormalities in such patients.

Impaired Left Ventricular Systolic Synchronicity in Hypertensive Patients with Ventricular Arrhythmias

Left ventricular (LV) systolic synchronicity is impaired in hypertensive patients. Ventricular arrhythmias often co-exist in hypertensive patients; hypertension and ventricular arrhythmias have an adverse impact on cardiac function. However, the influence of ventricular arrhythmias on LV synchronicity was not clear. The objective of the present study was to investigate the influence of ventricular arrhythmias on LV synchronicity in hypertensive patients. Tissue Doppler imaging (TDI) was performed in 136 subjects. Group 1 consisted of 74 hypertensives without any arrhythmias; group 2 consisted of 30 hypertensive patients with ventricular arrhythmias; and the control group consisted of 32 normal subjects. Using three apical views, LV synchronicity was assessed by the maximal differences in time to peak myocardial systolic contraction (T(s)) and early diastolic relaxation (T(e)) between any two of the LV segments (T(s)-max, T(e)-max) and the standard deviation of T(s) (T(s)-SD) and T(e) (T(e)-SD) of all 12 segments. T(s)-max was significantly prolonged in group 2 compared with group 1 and the control group (93.70 +/- 20.97 ms vs. 79.48 +/- 25.46 ms [p<0.01] or 53.83 +/- 15.42 ms [p<0.001], respectively). T(s)-SD was also significantly prolonged in group 2 compared with group 1 and the control group (38.16 +/- 5.82 ms vs. 33.37 +/- 6.04 ms [p<0.05] or 24.01 +/- 3.58 ms [p<0.001], respectively). In conclusion, LV systolic synchronicity was impaired in hypertensive patients with ventricular arrhythmias, and TDI was shown to be useful for the detection of myocardial abnormalities in such patients.

Asynchrony of Left Ventricular Systolic Performance After the First Acute Myocardial Infarction in Patients with Narrow QRS Complexes: Doppler Tissue Imaging Study

Left ventricular (LV) electromechanical delay results in asynchronized contraction. However, it is not known if the presence of cardiac diseases without QRS prolongation may result in interventricular or intraventricular asynchrony. Doppler tissue imaging is now established for detecting regional contractile abnormalities and asynchrony in the LV. The aim of the study was to assess the degree of LV asynchrony after the first acute myocardial infarction (AMI) in patients with a narrow QRS complex using Doppler tissue imaging and correlate this with the site and extent of the infarction. Echocardiography with Doppler tissue imaging was performed within 1 week of AMI in 155 patients and compared with 50 age- and sex-matched healthy volunteers. Regional myocardial velocities were assessed at the 4 mitral annular sites, and the corresponding systolic velocity (Sm), early diastolic velocity (Em), time to peak Sm (Ts), and time to peak Em (Te) were measured. To assess LV synchronicity, SDs of Ts (Ts-SD) and Te (Te-SD) of all the 4 mitral annular sites were computed. Location and size of infarct were confirmed by echocardiographic wall-motion score index. QRS complex duration was normal in all patients. Wall-motion score index was significantly higher in patients with anterior than inferior AMI (2.02 +/- 0.34 vs 1.24 +/- 0.21, P < .001). Ts-SD was significantly higher in patient than control group, and in patients with anterior than inferior AMI (38.21 +/- 2.59 vs 21.06 +/- 0.52 milliseconds and 43.18 +/- 3.77 vs 33.24 +/- 1.4 milliseconds, respectively, P < .001 for each), whereas Te-SD did not differ significantly among these groups (20.35 +/- 1.77 vs 18.17 +/- 1.14 milliseconds and 21.6 +/- 1.35 vs 19.1 +/- 1.11 milliseconds, respectively, P > .05 for each). A strong positive correlation was detected between LV systolic asynchrony (Ts-SD) and wall-motion score index (r = .77), LV mass (r = .67), LV end-systolic dimension (r = .65), and LV end-diastolic dimension (r = .5). The correlation was negative with LV ejection fraction (r = -.70) and Sm (r = -.6); the correlation was weak with Em (r = -.33) (P < .001 for all). In multivariate logistic regression analysis, infarct size was found to be the most independent predictor for systolic asynchrony (odds ratio 3.59, 95% confidence interval [1.43-9.33], P < .001). AMI has a significant impact on regional myocardial contractility and LV systolic (but not diastolic) synchronicity early in the course even in the absence of QRS widening or bundle branch block. The degree of LV systolic asynchrony is greater with anterior than inferior AMI and mainly determined by infarct size.

Ventricular mechanical dyssynchrony and resynchronization therapy in heart failure: a new indication for Fourier analysis of gated blood-pool radionuclide ventriculography

In patients with decreased left ventricular ejection fraction and conduction disease, ventricular mechanical dyssynchrony has been demonstrated. To date, resynchronization by biventricular pacing is increasingly used since it improves ventricular function and exercise capacity in patients with heart failure. To optimize and evaluate the effect of resynchronization therapy and to identify patients who may benefit from biventricular pacing the assessment of left ventricular synchronicity is essential. Therefore, a non-invasive and reproducible technique to obtain information on ventricular synchrony is clinically valuable. In this review, the technical background and the role of phase analysis of gated blood-pool nuclear ventriculography in the assessment of ventricular mechanical synchrony, especially in heart failure patients subjected to biventricular pacing, will be discussed.