Amplitudes, durations, and timings of apically directed left ventricular myocardial velocities: II. Systolic and diastolic asynchrony in patients with left ventricular hypertrophy

The reduction of the left ventricular long-axis early diastolic peak velocity (e') evident by early-middle age occurs in the absence of aging-related slowing of active relaxation

PURPOSE

A decrease in the left ventricular (LV) long-axis early diastolic peak velocity (e') is evident by early-middle age, but it is unknown to what extent this decrease is due to slowing of the speed of active relaxation versus a reduction in LV long-axis excursion during early diastole (EDExc).

METHODS

Pulsed-wave tissue Doppler imaging (TDI) signals were acquired from the septal and lateral borders of the mitral annulus in 62 healthy adult subjects of age 18-45 years. EDExc and LV systolic excursion (SExc) were measured as the integrals of the respective TDI signals. The speed of active relaxation was indirectly assessed using time interval measurements related to the TDI early diastolic signal, including the isovolumic relaxation time (IVRT'), the acceleration time (EDAT), and the duration (EDDur). Multiple linear regression analyses were performed to identify the relationships between e', age, EDExc, SExc, and time intervals.

RESULTS

The findings were similar for both LV walls. Age was negatively correlated with e' and EDExc, but was not correlated with SExc, IVRT', EDAT, or EDDur. The closest correlate of EDExc was SExc, and EDExc was independently correlated with both SExc and age. e' was also positively correlated with SExc, but the closest correlate of e' was EDExc, and when combined with EDExc, EDDur became an independent predictor of e'.

CONCLUSION

The aging-related decrease in e' evident by early-middle age occurs in the absence of aging-related slowing of active relaxation and therefore can be largely attributed to the accompanying reduction in EDExc.

Mechanical dispersion is a superior echocardiographic feature to predict exercise capacity in preclinical and overt heart failure with preserved ejection fraction

BACKGROUND

Heart Failure with Preserved Ejection Fraction (HFpEF) is a syndrome characterized by different degrees of exercise intolerance, which leads to poor quality of life and prognosis. Recently, the European score (HFA-PEFF) was proposed to standardize the diagnosis of HFpEF. Even though Global Longitudinal Strain (GLS) is a component of HFA-PEFF, the role of other strain parameters, such as Mechanical Dispersion (MD), has yet to be studied. In this study, we aimed to compare MD and other features from the HFA-PEFF according to their association with exercise capacity in an outpatient population of subjects at risk or suspected HFpEF.

METHODS

This is a single-center cross-sectional study performed in an outpatient population of 144 subjects with a median age of 57 years, 58% females, referred to the Echocardiography and Cardiopulmonary Exercise Test to investigate HFpEF.

RESULTS

MD had a higher correlation to Peak VO2 (r=-0.43) when compared to GLS (r=-0.26), MD presented a significant correlation to Ventilatory Anaerobic Threshold (VAT) (r=-0.20; p = 0.04), while GLS showed no correlation (r=-0.14; p = 0.15). Neither MD nor GLS showed a correlation with the time to recover VO2 after exercise (T1/2). In Receiver Operator Characteristic (ROC) analysis, MD presented superior performance to GLS to predict Peak VO2 (AUC: 0.77 vs. 0.62), VAT (AUC: 0.61 vs. 0.57), and T1/2 (AUC: 0.64 vs. 0.57). Adding MD to HFA-PEFF improved the model performance (AUC from 0.77 to 0.81).

CONCLUSION

MD presented a higher association with Peak VO2 when compared to GLS and most features from the HFA-PEFF. Adding MD to the HFA-PEFF improved the model performance.

Model Embraced Electromechanical Coupling Time for Estimation of Heart Failure in Patients With Hypertrophic Cardiomyopathy

Objective

This study aimed to establish a model embraced electromechanical coupling time (EMC-T) and assess the value of the model for the prediction of heart failure (HF) in patients with hypertrophic cardiomyopathy (HCM).

Materials and Methods

Data on 82 patients with HCM at Shaanxi Provincial People’s Hospital between February 2019 and November 2021 were collected and then formed the training dataset (n = 82). Data were used to screen predictors of HF using univariate and multivariate analyses. Predictors were implemented to discover the optimal cut-off value, were incorporated into a model, and shown as a nomogram. The cumulative HF curve was calculated using the Kaplan–Meier method. Additionally, patients with HCM at other hospitals collected from March 2019 to March 2021 formed the validation dataset. The model’s performance was confirmed both in training and validation sets.

Results

During a median of 22.91 months, 19 (13.38%) patients experienced HF. Cox analysis showed that EMC-T courses in the lateral wall, myoglobin, PR interval, and left atrial volume index were independent predictors of HF in patients with HCM. Five factors were incorporated into the model and shown as a nomogram. Stratification of patients into two risk subgroups by applying risk score (<230.65, ≥230.65) allowed significant distinction between Kaplan–Meier curves for cumulative incidence of HF events. In training dataset, the model had an AUC of 0.948 (95% CI: 0.885–1.000, p < 0.001) and achieved a good C-index of 0.918 (95% CI: 0.867–0.969). In validation dataset, the model had an AUC of 0.991 (95% CI: 0.848–1.000, p < 0.001) and achieved a strong C-index of 0.941 (95% CI: 0.923–1.000). Calibration plots showed high agreement between predicted and observed outcomes in both two datasets.

Conclusion

We established and validated a novel model incorporating electromechanical coupling time courses for predicting HF in patients with HCM.

Comparison of left ventricular subclinical systolic dysfunction between hemodialysis patients and renal transplant recipients using real time three-dimensional echocardiography

AIMS

The relationship between chronic kidney disease and development of heart failure is a well-known clinical entity. Systolic dyssynchrony index (SDI_16) is a new diagnostic tool for detection of subclinical left ventricular (LV) systolic dysfunction by using three-dimensional echocardiography (3DE). We aimed to investigate this parameter in patients with end-stage renal disease who were receiving hemodialysis and patients with renal transplant compared to healthy control subjects.

MATERIAL AND METHODS

Forty-five hemodialysis patients, 45 patients with renal transplant and 45 age-sex matched healthy control subjects included in the study. All participants were evaluated with 3DE in the interdialytic phase for measurement of LV volumes, ejection fraction and SDI_16 parameter.

RESULTS

Both LV diastolic and systolic volumes were significantly higher in hemodialysis group compared to renal transplant group and healthy controls, but this finding did not translate to a statistically significant difference for LVEF measurements between groups (58.71 ± 3.53 vs. 57.17 ± 2.97 vs. 59.23 ± 3.26, p = .16 for renal transplant and hemodialysis and healthy control groups, respectively). Mean value of SDI_16 parameters was significantly higher in hemodialysis group compared to renal transplant group (7.93 ± 2.50 vs. 3.72 ± 1.71, p < .001) and healthy controls (7.93 ± 2.50 vs. 3.00 ± .99, p < .001); whereas, it was similar between renal transplant group and control subjects (3.72 ± 1.71 vs. 3.00 ± .99, p = .10).

CONCLUSION

SDI_16 was significantly higher in hemodialysis patients compared to patients with renal transplant and healthy controls.

Right ventricular systolic function is associated with health-related quality of life: a cross-sectional study in community-dwelling populations

Background

Considerable evidence has been presented that heart and health-related quality of life are directly linked in patients with various diseases. This exploratory study investigated whether cardiac structure and function were associated with health-related quality of life in the general population.

Methods

This cross-sectional study was performed in five villages of Shunyi, a suburban district of Beijing, from June 2013 to April 2016. All inhabitants aged 35 years or older living in five villages of Shunyi were invited to participate. Exclusion criteria were individuals who declined participation, who had incomplete Health-related quality of life (HRQoL) data, and who had suboptimal echocardiograms. HRQoL was evaluated by the Mandarin version of SF-36. The association between the echocardiography-derived cardiac structure and function and each domain of SF-36 was analyzed by the multivariate linear regression analysis after adjusted for conventional risk factors affecting HRQoL.

Results

The baseline data of 990 individuals were analyzed. The median age of the participants was 57 (50–63) years, and 367 (37.1%) were male, the average physical and mental component summary scores were 89.3 (79.8–94.3) and 90 (83.5–95) respectively. Tricuspid annular plane systolic excursion, an echocardiography-derived right ventricular parameter, was associated with all the subscales and summarized scores of SF-36 (all P<0.05). The independent association between tricuspid annular plane systolic excursion and physical/mental component summary scores remained after adjusting for age, gender, body mass index, education level, annual personal income, smoking and drinking status, and comorbidities (β=0.65, 95% confidence interval 0.30–1.01, P<0.01 and β=0.49, 95% confidence interval 0.23–0.76, P<0.01 for physical and mental component summary scores respectively). Compared with the participants with tricuspid annular plane systolic excursion ≥21 mm, the participants with tricuspid annular plane systolic excursion <21 mm had lower adjusted scores of physical and mental component summary scores (81.8 vs. 84.5, P=0.015, and 85.5 vs. 88.1, P<0.01 for physical and mental component summary scores respectively).

Conclusions

In this population-based study, right ventricular systolic function assessed by tricuspid annular plane systolic excursion was independently associated with health-related quality of life assessed by SF-36.

Precise safety pharmacology studies of lapatinib for onco-cardiology assessed using in vivo canine models

Cancer chemotherapies have improved prognosis in cancer patients, resulting in a large and rapidly increasing number of cancer survivors. "Onco-cardiology" or "cardio-oncology" is a new discipline for addressing the unanticipated cardiac side effects of newly developed cancer drugs. Lapatinib, a tyrosine kinase inhibitor suppressing the epidermal growth factor receptor and ErbB2, has been used in advanced or metastatic breast cancer treatment. Reportedly, lapatinib has induced cardiovascular adverse events including QT-interval prolongation and heart failure. However, they have not been predicted by preclinical studies. Hence, a new method to assess the tyrosine kinase inhibitor-induced adverse effects needs to be established. Here, we intravenously administered lapatinib to halothane-anaesthetised dogs, evaluating cardiohemodynamic, electrophysiological, and echocardiographic profiles for pharmacological safety assessments. We intravenously administered lapatinib to chronic atrioventricular block beagle dogs to assess its proarrhythmic potential. The therapeutic concentration of lapatinib significantly increased total peripheral vascular resistance, QT, QTc, monophasic action potential (MAP)_90(sinus), MAP_90(CL400), effective refractory period, and plasma concentration of cardiac troponin I (cTnI), suggesting that lapatinib prolonged the ventricular repolarization without inducing lethal ventricular arrhythmia. Careful monitoring of plasma cTnI concentration and an electrocardiogram could be supportive biomarkers, predicting the onset of lapatinib-induced cardiovascular adverse events.

Effect of different ranges of systolic blood pressure on left ventricular structure and diastolic function in a Chinese population: a cross-sectional population-based Shunyi study

OBJECTIVES

To evaluate the effect of different ranges of systolic blood pressure (SBP) on left ventricular (LV) geometry and diastolic function in Chinese population.

DESIGN

Cross-sectional study.

SETTING

Peking Union Medical College Hospital in Beijing, China.

PARTICIPANTS

All inhabitants aged 35 years or older, living in five villages of Shunyi were invited. Exclusion criteria included individuals who declined participation, presence of moderate to severe valvular heart disease, persistent atrial fibrillation and suboptimal echocardiograms.

INTERVENTIONS

The baseline data of 1051 participants were analysed. The relationship between SBP and LV geometric and diastolic function assessed by echocardiography was analysed after adjusting for conventional cardiac risk factors.

RESULTS

The adjusted value of SBP was independently associated with LV hypertrophy (LVH) and LV diastolic dysfunction (LVDDF) (all p<0.01). Setting individuals with SBP <120 mm Hg as the reference group (group 1), those with SBP between 120 mm Hg and 140 mm Hg (group 2) had higher risk odds of LVH and those with SBP ≥140 mm Hg (group 3) had higher risk odds of LVH and LVDDF (all p<0.01). With the increase of SBP, LV mass index (LVMI) and E/e' stepwise increased and e' stepwise decreased significantly from group 1 to 3 (all p<0.05). In the whole population, SBP was independently correlated with LVMI, LVEDD, Left Atrial Volume Index, e', and E/e' (all p<0.01).

CONCLUSIONS

SBP was independently related to LVH and LVDDF, SBP between 120 and 140 mm Hg was independently related to worse LV remodelling and diastolic function, these findings indicated the potential benefit of intensive SBP control.

Excitation-Contraction Coupling Time is More Sensitive in Evaluating Cardiac Systolic Function

Background:

Pressure overload-induced myocardial hypertrophy is a key step leading to heart failure. Previous cellular and animal studies demonstrated that deteriorated excitation–contraction coupling occurs as early as the compensated stage of hypertrophy before the global decrease in left ventricular ejection fraction (LVEF). This study was to evaluate the cardiac electromechanical coupling time in evaluating cardiac systolic function in the early stage of heart failure.

Methods:

Twenty-six patients with Stage B heart failure (SBHF) and 31 healthy controls (CONs) were enrolled in this study. M-mode echocardiography was performed to measure LVEF. Tissue Doppler imaging (TDI) combined with electrocardiography (ECG) was used to measure cardiac electromechanical coupling time.

Results:

There was no significant difference in LVEF between SBHF patients and CONs (64.23 ± 8.91% vs. 64.52 ± 5.90%; P = 0.886). However, all four electromechanical coupling time courses (Qsb: onset of Q wave on ECG to beginning of S wave on TDI, Qst: onset of Q wave on ECG to top of S wave on TDI, Rsb: top of R wave on ECG to beginning of S wave on TDI, and Rst: top of R wave on ECG to top of S wave on TDI) of SBHF patients were significantly longer than those of CONs (Qsb: 119.19 ± 35.68 ms vs. 80.30 ± 14.81 ms, P < 0.001; Qst: 165.42 ± 60.93 ms vs. 129.04 ± 16.97 ms, P = 0.006; Rsb: 82.43 ± 33.66 ms vs. 48.30 ± 15.18 ms, P < 0.001; and Rst: 122.37 ± 36.66 ms vs. 93.25 ± 16.72 ms, P = 0.001), and the Qsb, Rsb, and Rst time showed a significantly higher sensitivity than LVEF (Rst: P =0.032; Rsb: P = 0.003; and Qsb: P = 0.004).

Conclusions:

The cardiac electromechanical coupling time is more sensitive than LVEF in evaluating cardiac systolic function.

Early diastolic dyssynchrony in relation to left ventricular remodeling and function in hypertension

BACKGROUND

Cardiac synchronization is important in maintaining myocardial performance, but the mechanism of diastolic dyssynchrony leading to failing myocardium is unclear. We aim to study the relation of left ventricular (LV) diastolic dyssynchrony with diastolic dysfunction in patients with hypertension.

METHODS

Two-D, three-D and Doppler echocardiography were performed using the GE Vivid E9 system on 230 subjects. Among them, 154 patients with hypertension were divided into group 1 (86 patients with mild to moderate hypertension, BP 152 ± 8/91 ± 11 mm Hg) and group 2 (68 patients with severe hypertension, BP 188 ± 12/105 ± 24 mm Hg), age 76, gender matched normotensive subjects (119 ± 6/76 ± 9 mm Hg) as control. The routine 2D and Doppler parameters were measured and LV systolic and diastolic dyssynchrony indices were determined as the standard deviation of the time interval from the peak R of the QRS complex to peak myocardial systolic strain rate (Ts-SD), and to early diastolic strain rate (Te-SD) of 12 LV segments.

RESULTS

LV relative wall thickness, mass index, and Te-SD were significantly higher in patients with hypertension than in control group (p<0.0001), but Ts-SD showed no significant differences. Te-SD and diastolic dysfunction worsened progressively with increasing severity of hypertension (p<0.05). Te-SD was significantly and independently associated with parameters of LV remodeling and diastolic function.

CONCLUSION

Our study demonstrated that LV diastolic dyssynchrony was associated with LV remodeling, which seems to contribute to diastolic dysfunction in hypertension. This diastolic dyssynchrony index derived from speckle tracking echocardiography can be used as a marker for studying the LV function and effects of therapy in hypertensive heart disease.

Left ventricular systolic function and systolic asynchrony in patients with septic shock and normal left ventricular ejection fraction

Few studies were performed to investigate the association between tissue Doppler imaging parameters about left ventricular (LV) systolic function and LV systolic asynchrony and prognosis in patients with septic shock and normal LV ejection fraction (LVEF). This prospective study was performed from January 2010 to April 2012 in a medical intensive care unit. Fifty-one patients with septic shock and LVEF greater than or equal to 50% were analyzed. The clinical variables and transthoracic echocardiography data were obtained on admission. The mean value of the peak myocardial systolic velocity (Sm-mean) was measured in the four LV basal segments. Tissue Doppler imaging-based parameter (Ts-SD) was used to evaluate LV intraventricular asynchrony. The 28-day all-cause mortality was 43.1%. The nonsurvivors exhibited higher baseline heart rate and Sm-mean and lower mean arterial blood pressure and Ts-SD. A cutoff value of Sm-mean greater than or equal to 6.2 cm/s in identifying 28-day mortality was determined by the receiver operating characteristic curve analysis. The patients with Sm-mean greater than or equal to 6.2 cm/s or Ts-SD less than 33 ms had higher 28-day mortality. In the Cox multivariate analysis, Sm-mean, Ts-SD, and mean arterial blood pressure emerged as independent predictors for 28-day mortality. We concluded that LV systolic dysfunction and systolic asynchrony assessed by tissue Doppler imaging were associated with improved 28-day all-cause mortality in patients with septic shock and normal LVEF.

The impact of change in volume and left-ventricular hypertrophy on left-ventricular mechanical dyssynchrony in children with end-stage renal disease

Left-ventricular dyssynchrony (LVD) adversely affects systolic performance and has not been previously evaluated in children with end-stage renal disease (ESRD). We hypothesized (1) that LVD in children with ESRD would be significantly increased compared with controls and (2) that volume load and left-ventricular hypertrophy (LVH) would be associated with increased LVD. This was a prospective observational study in which real-time three-dimensional echocardiographic data were acquired in 27 stable children with ESRD (13 peritoneal dialysis [PD] and 14 hemodialysis [HD]) and 29 normal controls. Data were acquired before and after an HD session. Dyssynchrony index (SDI) was defined per standard formulae and was normalized to cardiac cycle duration (SDIp). Left-ventricular mass (LVM) was obtained from M-mode echocardiography and was normalized to height(2.7) (LVM index). The mean age (13.8 vs. 11.3 years) and SDI, SDIp, LVM, and LVM index were significantly greater among children with ESRD than among controls (p < 0.05). Demographics and heart rates were comparable between HD and PD subgroups, whereas SDI 16 and 12 segments, SDIp 16 segments, and LVM were significantly greater in the HD group. SDI and SDIp 16 segments improved after an HD session (p < 0.05); LVM and LVM index remained unchanged. LVD was significantly greater in patients with LVH compared with those without LVH. Children with ESRD had significant LVD and increased LVM compared with controls. Increased LVD in those undergoing HD rather than PD, as well as the improvement in synchrony after HD, suggest that volume may modulate LVD. LVD was increased in children with LVH. LVD in children with ESRD may have pathogenic implications.

Incremental value of global systolic dyssynchrony in determining the occurrence of functional mitral regurgitation in patients with left ventricular systolic dysfunction

AIMS

The aim of this study was to assess the contribution of left ventricular (LV) systolic dyssynchrony to functional mitral regurgitation (MR).

METHODS AND RESULTS

Patients (n = 136) with LV systolic dysfunction (ejection fraction <50%) and at least mild MR were prospectively recruited. The effective regurgitant orifice area (EROA) was assessed by the proximal isovelocity surface area method. Left ventricular global systolic dyssynchrony [the maximal difference in time to peak systolic velocity among the 12 LV segments (Ts-Dif)] and regional systolic dyssynchrony (the delay between the anterolateral and posteromedial papillary muscle attaching sites) were assessed by tissue Doppler imaging. Left ventricular global and regional remodelling, systolic function, indices of mitral valvular and annular deformation were also measured. The size of the EROA correlated with the degrees of mitral deformation, LV remodelling, systolic function, and systolic dyssynchrony. By multivariate logistic regression analysis, the mitral valve tenting area (OR = 1.020, P < 0.001) and the Ts-Dif (OR = 1.011, P = 0.034) were independent determinants of significant functional MR (defined by EROA ≥20 mm(2)). From the receiver-operating characteristic curve, the tenting area of 2.7 cm(2) (sensitivity 83%, specificity 82%, AUC 0.86, P < 0.001) and the Ts-Dif of 85 ms (sensitivity 66%, specificity 72%, AUC 0.74, P < 0.001) were associated with significant functional MR. The assessment of Ts-Dif showed an incremental value over the mitral valve tenting area for determining functional MR (χ(2) = 53.92 vs.49.11, P = 0.028).

CONCLUSION

This cross-sectional study showed that LV global, but not regional systolic dyssynchrony, is a determinant of significant functional MR in patients with LV systolic dysfunction, and is incremental to the tenting area that is otherwise the strongest factor for mitral valve deformation.

The prognostic value of left ventricular systolic function measured by tissue Doppler imaging in septic shock

INTRODUCTION

Left ventricular (LV) dysfunction is common in septic shock. Its association with the clinical outcome is still controversial. Tissue Doppler imaging (TDI) is a useful tool to quantify LV function; however, little knowledge is available about the prognostic value of these TDI variables in septic shock. Therefore, we performed this prospective study to determine the role of TDI variables in septic shock.

METHODS

Patients with septic shock in a medical intensive care unit were studied with transthoracic echocardiography with TDI within 24 hours after the onset of septic shock. Baseline clinical, laboratory, and echocardiographic variables were prospectively collected. Independent predictors of 90-day mortality were analyzed with the Cox regression model.

RESULTS

During a 20-month period, 61 patients were enrolled in the study. The 90-day mortality rate was 39%; the mean APACHE IV score was 84 (68 to 97). Compared with survivors, nonsurvivors exhibited significantly higher peak systolic velocity measured at the mitral annulus (Sa) (11.0 (9.1 to 12.5) versus 7.8 (5.5 to 9.0) cm/sec; P < 0.0001), lower PaO2/FiO2 (123 (83 to 187) versus 186 (142 to 269) mm Hg; P = 0.002], higher heart rate (120 (90 to 140) versus 103 (90 to 114) beats/min; P = 0.004], and a higher dose of norepinephrine (0.6 (0.2 to 1.0) versus 0.3 (0.2 to 0.5) μg/kg/min; P = 0.007]. In the multivariate analysis, Sa > 9 cm/sec (hazard ratio (HR), 5.559; 95% confidence interval (CI), 2.160 to 14.305; P < 0.0001), dose of norepinephrine (HR, 1.964; 95% CI, 1.338 to 2.883; P = 0.001), and PaO2/FiO2 (HR, 0.992; 95% CI, 0.984 to 0.999; P = 0.031) remain independent predictors of 90-day mortality in septic-shock patients.

CONCLUSIONS

Our study demonstrated that LV systolic function as determined by TDI, in particular, Sa, might be associated with mortality in patients with septic shock.

Ventricular dyssynchrony of idiopathic versus pacing-induced left bundle branch block and its prognostic effect in patients with preserved left ventricular systolic function

The extent of left ventricular (LV) dyssynchrony might not be comparable between right ventricular pacing-induced left bundle branch block (RV-LBBB) and idiopathic LBBB (iLBBB), despite the morphologic analogy on the electrocardiogram. The objectives of the present study were to elucidate the differences in the LV dyssynchrony index (LVdys) between RV-LBBB and iLBBB, and to assess the prognostic implication of LV dyssynchrony. The conventional echocardiographic parameters, LVdys, and LV end-systolic wall stress were evaluated in 20 healthy volunteers and 21 patients with iLBBB and 20 with RV-LBBB with preserved LV systolic function. Three types of LVdys were evaluated: LVdys-6, LVdys-2, and LVdys-standard deviation. The patients were clinically followed up for about 3 years. The prevalence of LV dyssynchrony was not rare in those with either iLBBB or RV-LBBB, but it was more prevalent in the patients with iLBBB than in those with RV-LBBB. The patients with iLBBB had greater LVdys than those with RV-LBBB (84 ± 55 vs 55 ± 50 for LVdys-6, 51 ± 49 vs 31 ± 40 for LVdys-2, 37 ± 24 vs 24 ± 22 for LVdys-standard deviation in iLBBB vs RV-LBBB). LVdys displayed significant correlations with QRS duration, LV volumes, LV ejection fraction, LV end-systolic wall stress, and mitral inflow E/mitral annular E' velocity ratio. Multivariate logistic regression analysis showed that the LV end-diastolic volume and LV end-systolic wall stress were independent determinants of the presence of LV dyssynchrony. During follow-up, no cardiovascular death or hospitalization for heart failure was reported in either group. In conclusion, despite similarities in electrocardiographic morphology, the extent of LV dyssynchrony were greater in patients with iLBBB, with LV preload and afterload the main determinants. No association was found between the presence of LV dyssynchrony and prognosis.

Right-heart function related to the results of acute pulmonary vasodilator testing in patients with pulmonary arterial hypertension caused by connective tissue disease

BACKGROUND

Acute pulmonary vasodilator testing is important for patients with pulmonary arterial hypertension, but little is known about the predictors of response to such testing.

METHODS

Forty-eight patients (mean age, 41.3 ± 11.6 years; 91.7% women) with pulmonary arterial hypertension associated with connective tissue diseases who underwent right-heart catheterization and acute pulmonary vasodilator testing were prospectively recruited. Echocardiography was performed before and immediately after testing.

RESULTS

There were 14 responders (29.2%) to acute pulmonary vasodilator testing. Responders had lower pulmonary vascular resistance, higher peak systolic velocity of the lateral tricuspid valve annulus (right ventricular [RV] S') and tricuspid annular plane systolic excursion, and smaller RV end-diastolic area. After vasodilator testing, mean pulmonary artery pressure and pulmonary vascular resistance decreased significantly in both groups, cardiac index increased significantly in responders, and RV function improved significantly in nonresponders. Receiver operating characteristic curve analysis identified an optimal cutoff value for RV S' of ≥10.5 cm/sec to predict response, with sensitivity of 71% and specificity of 71%. There were more responders among patients with RV S' ≥ 10.5 cm/sec (45.5% vs 15.4%, P = .02). On multivariate logistic regression analysis, RV S' ≥ 10.5cm/sec emerged as an independent predictor of response (odds ratio, 4.58; 95% confidence interval, 1.18-17.79; P = .02).

CONCLUSIONS

Right-heart function is better in responders to acute pulmonary vasodilator testing than in nonresponders among patients with pulmonary arterial hypertension associated with connective tissue diseases, and pulmonary vasodilators may improve RV function in nonresponders and cardiac index in responders. RV S' is a simple and clinically useful tool for predicting the results of pulmonary vasodilator testing.

Effects of the aging process on left ventricular systolic and diastolic synchronicity indexes: insights from 160 "completely" healthy volunteers

BACKGROUND

Growing attempt to use left ventricular (LV) systolic (LVSIsys) and diastolic (LVSIdia) synchronicity indexes in the process of selecting potential responders to cardiac resynchronization therapy has created a need for normative reference values.

HYPOTHESIS

This study sought: (1) to determine normal reference ranges for LVSIsys and LVSIdia, and (2) to assess their relationships to age and conventional parameters reflecting LV systolic and diastolic functions.

METHODS

We recruited 160 healthy volunteers (104 men) free of any systemic or cardiovascular disease. Maximal difference and standard deviation of time to peak systolic and peak early diastolic myocardial velocities for LVSIsys and LVSIdia were measured using 6 and 12 segment models.

RESULTS

Normal ranges for LVSIsys and LVSIdia obtained in this study were slightly higher than previously reported. The normal aging process did not significantly change LVSIsys, whereas LVSIdia progressively and consistently increased with age. Significant correlations were observed between LVSIdia and parameters representing LV diastolic function, that is, early mitral inflow velocity and its deceleration time, and early mitral annulus velocity. A physiologic increase in LV mass/Ht²·⁷ showed a weak, but significant correlation with LVSIdia (r = 0.15-0.22), but not with LVSIsys. On multivariate analysis, an age-dependent increase in LVSIdia was confirmed.

CONCLUSIONS

In this study, we propose age-specific reference ranges for LVSIsys and LVSIdia. LVSIsys remains stable throughout age groups, whereas LVSIdia progressively increases with age. We believe that the reference values provided here will be useful for defining abnormal LV synchronous contraction and relaxation.

Echocardiographic detection of cardiac ectopy: a possible alternative to electrophysiological mapping?

PURPOSE

Three-dimensional (3-D) visualization of ventricular activation sequence is imperative for the diagnosis and treatment of malignant cardiac arrhythmias. Modern mapping systems that serve as the gold standard for detection and localization of the focus are costly and require an invasive approach into the cavity of the ventricles. The aim of our study was the development of a noninvasive and 3-D mapping system based upon echocardiography.

METHODS

In a porcine model, animals underwent ablation of the atrioventricular node (AV-node). 3-D electrophysiological cardiac mapping was performed using the ENSITE™ electro-anatomical system (St. Jude Medical, Minneapolis, MN, USA). Simultaneously, transesophageal echocardiography (TEE) including pulse wave (Pw) tissue Doppler was performed, and time to peak early diastolic velocity (PEDV) was measured. Both ENSITE-mapping and tissue Pw-Doppler were compared as to their ability to pinpoint the origin of ventricular ectopic focus.

RESULTS

PEDV corresponded well with the results as determined by noncontact mapping with ENSITE.

CONCLUSIONS

Tissue Doppler is a reliable method to deliver information about the topography of first onset of myocardial excitation. Further development of this method with a higher regional resolution and integration of color Doppler as well as 3-D echocardiography may eventually lead to the development of a completely noninvasive and echo-based electromechanical mapping system.

Echocardiography, dyssynchrony, and the response to cardiac resynchronization therapy

Biventricular pacing or cardiac resynchronization therapy (CRT) has been a considerable advance in the therapy of chronic heart failure. However, it is clear that not all patients benefit either in terms of symptoms or cardiac function, and some may be worsened by CRT. In this review, we consider the arguments, both clinical and economical, in favour of improved selection of patients for CRT other than those in current guidelines. It also seems clear that the fundamental mechanism of CRT is correction of dyssynchrony, and we review the various methodologies available to detect dyssynchrony. Other factors are probably also important in determining outcomes such as lead position, the extent and form of myocardial damage, optimizing pacemaker performance, and clinical expertise. The potential costs of inappropriate CRT implantation are high to our patients and to the health economy, and it behooves the cardiology community to develop better selection criteria. The current guidelines can and should be improved.

Left ventricular systolic and diastolic dyssynchrony in asymptomatic hypertensive patients

BACKGROUND

Diastolic and systolic dyssynchrony are common in patients with heart failure. However, the presence of dyssynchrony in asymptomatic patients with hypertension who are susceptible to the development of heart failure is not well understood. The aims of this study were (1) to evaluate the prevalence of systolic and diastolic dyssynchrony and (2) to identify the main determinants of left ventricular (LV) dyssynchrony in asymptomatic patients with hypertension.

METHODS

One hundred ten patients with hypertension consecutively enrolled were compared with 55 age-matched and gender-matched normal control subjects. Comprehensive echocardiography was performed, including conventional and Doppler tissue imaging parameters. LV end-systolic wall stress was calculated using a hemodynamic and echocardiographic M-mode data set. For the assessment of LV dyssynchrony, both the standard deviation of the time from QRS onset to peak systolic velocity and the maximal difference of the time from QRS onset to peak systolic velocity from 6 basal segments at the apical views were used and were compared between the two groups.

RESULTS

Both systolic and diastolic dyssynchrony indexes were significantly higher in patients with hypertension than in the normal controls (P < .001), with no significant correlation between the systolic and diastolic dyssynchrony indexes. The proportions of patients with hypertension who had LV systolic and diastolic dyssynchrony were 24% and 21%, respectively. Multivariate analysis showed that the E/E' ratio (P < .001) was independently associated with LV systolic dyssynchrony, whereas LV mass index (P = .001) and E/E' (P < .001) were major determinants of LV diastolic dyssynchrony.

CONCLUSIONS

LV systolic and diastolic dyssynchrony are not uncommon in asymptomatic patients with hypertension and are significantly associated with LV filling pressure. The determinants of LV systolic dyssynchrony are not the same as those of diastolic dyssynchrony, implying that different mechanisms are involved in the development of LV systolic and diastolic dyssynchrony in asymptomatic patients with hypertension.

Assessment of regional atrial function in patients with hypertrophic cardiomyopathies using tissue Doppler imaging

BACKGROUND

This study applied tissue Doppler imaging and color tissue Doppler imaging to study atrial function changes in patients with hypertrophic cardiomyopathy (HCM). The profile of the segmental atrial velocities and the strain rate were determined and compared with those of normal matched control subjects.

METHODS

This study investigated 20 patients with HCM and 20 age-matched healthy control subjects. In a four-chamber apical view, tissue Doppler imaging was used to measure the lateral left and right atrial (LA and RA) and interatrial septal (IAS) wall systolic, early, and late diastolic velocities. Similarly, the atrial strain rate during ventricular systole (SR(S)) and the early (SR(E)) and late (SR(A)) diastolic phases in patients and control subjects were measured. The interventricular septal tissue Doppler-derived isovolumic relaxation time was calculated.

RESULTS

Only the IAS annular and middle segments showed a significant reduction in the early diastolic velocity (mean, 4.01 +/- 2.2 vs 8.7 +/- 1.1, p = 0.001; 3.23 +/- 2 vs 6.01 +/- 1.9, p = 0.001, respectively) for the patients with HCM in comparison with the control subjects. Generally, the atrial strain rate was clearly reduced. The systolic strain rate (SR(S)) was significantly reduced in the LA wall in the annular (p = 0.007) and middle (p = 0.001) segments and in the IAS middle segment (p = 0.007). Similarly, there was a reduction of the early diastolic strain rate (SR(E)) in the LA annular (p = 0.001) and middle (p = 0.01) segments and in the IAS annular (p = 0.05) and middle (p = 0.001) segments, as well as in the RA annular segment (p = 0.02). The RA middle segments showed insignificant changes.

CONCLUSION

Atrial function may be affected by HCM due to impairment of myocardial diastolic function. Strain rate imaging is reproducible, yields readily obtained parameters that provide unique data about global and longitudinal segmental atrial contraction, and can quantify the atrial dysfunction in patients with HCM.

The Mitral Annular Middiastolic Velocity Curve: Functional Correlates and Clinical Significance in Patients with Left Ventricular Hypertrophy

BACKGROUND

Little is known regarding the tissue Doppler characteristics and clinical significance of mitral annular motion during diastasis (L' wave).

METHODS

In consecutive patients with left ventricular hypertrophy and normal ejection fraction, standard Doppler and Doppler tissue imaging were performed. Patients were followed up for heart failure (HF) hospitalization.

RESULTS

Of 177 patients, 53 (30%) had an L', detected most frequently at the lateral mitral annulus, whereas 35 (20%) had middiastolic transmitral flow (L wave), which almost invariably coexisted with the L'. The L' predicted increased left ventricular filling pressure with 74% sensitivity and 82% specificity, and increased risk of future HF (hazard ratio 3.9 [P = .030]), even after adjusting for baseline clinical differences (hazard ratio 6.5 [P = .024]). When associated with an L wave, HF risk increased further.

CONCLUSIONS

Middiastolic annular motion, detectable in almost a third of patients with left ventricular hypertrophy, may be an early marker of diastolic dysfunction and a prognostic marker for HF.

Improvement of Atrial Function and Atrial Reverse Remodeling After Cardiac Resynchronization Therapy for Heart Failure

OBJECTIVES

We sought to examine whether cardiac resynchronization therapy (CRT) improves atrial function and induces atrial reverse remodeling.

BACKGROUND

Cardiac resynchronization therapy is an established therapy for advanced heart failure with prolonged QRS duration, which improves left ventricle (LV) function and is associated with LV reverse remodeling.

METHODS

A total of 107 heart failure patients (66 +/- 11 years) who received CRT and were followed up for 3 months were studied. Atrial function was assessed by M-mode, 2-dimensional echocardiography, transmitral Doppler, tissue Doppler velocity, and strain (epsilon) imaging. Left atrial (LA) emptying fraction based on the change in areas (LAA-EF) and volumes (LAV-EF) were calculated. The LV reverse remodeling was defined by a reduction of LV end-systolic volume >10%.

RESULTS

In the responders of LV reverse remodeling (n = 62), LAA-EF and LAV-EF were significantly increased (p < 0.001). Responders also had significant decrease in LA size area and volumetric measurements, both before (p < 0.05) and after atrial systole (p < 0.001). However, these parameters were unchanged in the nonresponders (n = 45, p = NS). In the responders, tissue Doppler velocity analysis showed improvement of contraction velocity in both left (p = 0.005) and right atria (p = 0.018), whereas epsilon in both atria were increased in all the phases of cardiac cycle, namely ventricular end-systole (p < 0.001), early diastole (p < 0.001), and late diastole (p = 0.007).

CONCLUSIONS

Cardiac resynchronization therapy improves both left and right atrial pump function. The increase in atrial epsilon throughout the cardiac cycle is likely reflecting the improvement of atrial compliance. These changes lead to LA reverse remodeling with reduction of LA size before and after atrial systole.

Non-invasive radial pulse wave assessment for the evaluation of left ventricular systolic performance in heart failure

INTRODUCTION

Left ventricular (LV) developed pressure (dP/dt) is a classical index of myocardial contractility related to prognosis during heart failure. We sought to assess the reproducibility and feasibility of use of the maximal first derivative of the radial pulse, Rad dP/dt, as a peripheral criterion of ventricular contractility in patients with heart failure.

METHODS

We assessed 50 consecutive, patients with heart failure using aplanation tonometry to record the radial pulse wave and calculate Rad dP/dt. Echocardiography, Doppler flow and tissue Doppler imaging were used to record classical parameters of LV function: LV ejection fraction (LVEF), Tei index, dP/dt on mitral regurgitation (MR dP/dt) and peak systolic velocity (S'). Total systemic vascular resistance (TSVR) was calculated by use of the Doppler calculated cardiac output. Preload was assessed by the E/Ea ratio. Feasibility was tested in an ongoing prospective mortality study (n=310).

RESULTS

The Bland and Altman representation of repeated measurements of the Rad dP/dt showed good agreement. Feasibility was greater than 99% for a successful assessment on the right arm during the first attempt. The Rad dP/dt correlated with the LVEF, S' or Tei index as usual parameters of impaired contractility but not preload (E/Ea) or afterload (TSVR) parameters. MR dP/dt and Rad dP/dt were closely related (r=0.75, p<0.001). The ability of the arterial dP/dt to characterize LVEF was not modified by adjustment for arterial viscoelastic properties.

CONCLUSION

The maximal dP/dt of the radial pulse appears to be a valuable and reproducible peripheral criterion of LV systolic performance.

Positive Isovolumic Relaxation Velocity Detected by a Spectral Tissue Doppler Mapping Technique as an Indicator of Coronary Artery Disease: A Prospective Study

BACKGROUND

A positive myocardial velocity during isovolumic relaxation phase (V(IR)) detected by spectral tissue Doppler imaging has been shown to indicate ischemic myocardium. We sought to examine the diagnostic value of positive V(IR) for detecting coronary artery disease (CAD) in patients with chest pain and apparently normal left ventricular contraction.

METHODS

A total of 138 patients (74 men, age 69 +/- 8 years) underwent spectral Doppler tissue imaging measurements at the annular and mid left ventricular levels in the apical 4- and 2-chamber views (8 points/patient) at rest in addition to standard echocardiography. Subsequently, patients underwent thallium-201 myocardial perfusion single photon emission computed tomography (n = 98) and/or coronary angiography (n = 60). The duration of positive V(IR) was also assessed. CAD was diagnosed by having more than 75% diameter stenosis in coronary angiography.

RESULTS

CAD was present in 41 patients (30%). The duration of positive V(IR) was distributed from 0 to 280 milliseconds with the median value of 100 milliseconds. Presence of positive V(IR) predicted CAD with sensitivity of 80% and specificity of 61%.

CONCLUSIONS

Positive V(IR) detected by spectral tissue Doppler imaging is a useful indicator of CAD in patients with apparently normal left ventricular contraction and chest pain.

Role of Diastolic Dyssynchrony in the Delayed Relaxation Pattern of Left Ventricular Filling

We investigated the extent to which diastolic dyssynchrony contributes to the delayed relaxation pattern of left ventricular filling and limitation in exercise capacity. In 100 patients with diabetes, preserved left ventricular systolic function, normal filling pressure, and no coronary disease, we measured magnitude of early diastolic tissue lengthening (tissue velocity and strain rate) and diastolic dyssynchrony (SD in QRS to peak early diastolic tissue velocity interval across 4 basal myocardial segments). From transmitral flow patients were divided into those with normal filling (50 patients) and delayed relaxation (50 patients). Myocardial lengthening was reduced and SD in interval from QRS onset to peak early diastolic tissue velocity across all segments was higher in patients with delayed relaxation compared with control patients. Myocardial lengthening was the only predictor of delayed relaxation and correlation with exercise capacity was better for lengthening indices than SD in interval from QRS onset to peak early diastolic tissue velocity across all segments. Therefore, in this group a reduced rate of myocardial lengthening plays a more important role in delayed relaxation than diastolic dyssynchrony.

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

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Left ventricular circumferential function in patients with essential hypertension

The aim of the study was to investigate left ventricular (LV) systolic and diastolic circumferential myocardial function using tissue Doppler imaging in patients with essential hypertension. One hundred and two patients and 33 healthy age-matched controls were studied. Each patient underwent echocardiographic study with analysis of tissue velocity curves, which included mean peak systolic (Sm), early (Em) and late diastolic velocity (Am) and isovolumic relaxation time (IRTm). These parameters were expressed as means from the six basal segments of left ventricle reflecting its longitudinal function (L). The same indices estimated in mid-anteroseptal (C-AS) and mid-posterior (C-P) segments in parasternal short-axis view served as a measure of LV circumferential function. Higher value of C-AS-Sm and a similar trend in C-P-Sm suggest increased LV circumferential systolic function in hypertensive patients, whereas lower values of C-AS-Em, C-P-Em, C-AS-Em/Am and C-P-Em/Am indicate impaired LV circumferential diastolic function. Decreased L-Sm as well as decreased L-Em and L-Em/Am reflects LV longitudinal systolic and diastolic dysfunction, respectively. By univariate analysis, positive correlations were demonstrated between C-AS-Sm and LV mass index (LVMI) (r=0.61, P<0.001), interventricular septum thickness (IVS) (r=0.55, P<0.001) and LV posterior wall thickness (PW) (r=0.43, P<0.01) and negative ones between L-Sm and LVMI (r=-0.51, P<0.001) and PW (r=-0.36, P<0.04). By stepwise multivariate regression analysis, LVMI, IVS and age independently predicted C-AS-Sm and LVMI predicted L-Sm. Our study demonstrated in hypertensive patients increased LV circumferential systolic and decreased diastolic function. The former may be a compensatory response to the impairment in LV longitudinal systolic performance.

Effect of Age and Heart Rate on Atrial Mechanical Function Assessed by Doppler Tissue Imaging in Healthy Individuals

BACKGROUND

The potential usefulness of Doppler tissue imaging (DTI) to assess atrial mechanical function in cardiac disease has been demonstrated. However, there are few reports on normal values of atrial function by DTI analysis.

METHODS

Echocardiography with color-coded DTI was performed in 131 healthy control subjects. The peak atrial contraction velocity (V(A)) and the timing of mechanical events were assessed offline at the left atrial (LA) and right atrial (RA) free wall and interatrial septum.

RESULTS

V(A) was higher in the RA (9.0 +/- 2.6 cm/s) than the LA (7.5 +/- 2.4 cm/s, P < .001), and both sites were higher than the interatrial septum (5.6 +/- 1.3 cm/s, both P < .001). The interatrial delay was 24 +/- 21 milliseconds. V(A) at the LA was higher in the participants aged 60 years or older than those who were younger than 60 years (8.1 +/- 2.7 vs 6.7 +/- 1.4 cm/s, P < .001), as was the velocity at the RA (9.6 +/- 2.8 vs 8.0 +/- 2.1 cm/s, P < .01). V(A) at the LA was higher in the participants with heart rate of 60/min or higher than those with lower heart rate (7.9 +/- 2.5 vs 6.8 +/- 1.8 cm/s, P < .05). Sex difference had no effect on V(A) and timings of atrial events.

CONCLUSIONS

Assessment of atrial mechanical function by DTI is feasible in healthy individuals. The V(A) is the highest at the RA, followed by LA, and the lowest at the interatrial septum. Older age and faster heart rate seems to augment V(A) in the atrial walls.

Longitudinal Isovolumic Displacement of the Left Ventricular Myocardium Assessed by Tissue Velocity Echocardiography in Healthy Individuals

Rapid myocardial isovolumic motions are reportedly involved in the left ventricular reshaping process and may contribute to total systolic myocardial shortening. In this study, the qualitative and quantitative analysis of longitudinal myocardial isovolumic displacement was performed in 49 healthy individuals (23 men and 26 women) in age groups 21 to 49 and 50 to 76 years using tissue velocity echocardiography. The obtained isovolumic contraction and relaxation displacement curves were biphasic and displayed a significant regional heterogeneity most probably reflecting active presystolic and postsystolic reshaping of left ventricular cavity. Besides some sex difference in younger individuals, there was an age-dependent lengthening of the isovolumic relaxation time and their motion components. Even if being of short duration, the longitudinal myocardial isovolumic displacement may accounted for as much as 14% of the total longitudinal myocardial shortening, a fact which should be taken into consideration when assessing left ventricular systolic function.

Aortic wall mechanics in the Marfan syndrome assessed by transesophageal tissue Doppler echocardiography

The aim of this study was to investigate the value of tissue Doppler imaging (TDI) using transesophageal echocardiography (TEE) in assessing the elastic properties of the thoracic aorta in patients with Marfan's syndrome. Aortic distensibility, stiffness index, and pulse-wave velocity were calculated using M-mode data in a TEE short-axis view in 31 patients with Marfan's syndrome and 22 normal controls. Acceleration time, maximum wall expansion velocity (Vmax), and wall strain were determined from TDI tracings. Indexes derived from TDI differed at a greater level of significance than M-mode-derived indexes in patients with dilated and normal aortas. Significant predictors of aortic dilation were systolic blood pressure, aortic stiffness index, Vmax, and strain. Decreased aortic strain and Vmax and increased stiffness index were predictive of aortic dissection (odds ratios 4.5, 3.3, and 2.2). In conclusion, the TDI assessment of aortic wall mechanics is complementary to standard M-mode measurements in discriminating normal subjects from patients with Marfan's syndrome and is accurate in predicting aortic dilation and dissection.

Usefulness of tissue Doppler imaging for demonstrating altered septal contraction sequence during dual-chamber pacing in obstructive hypertrophic cardiomyopathy

Dual-chamber pacing reduces left ventricular (LV) outflow obstruction in patients with obstructive hypertrophic cardiomyopathy (HC), the mechanism of which lies in pacing-induced paradoxic septal motion. This study was conducted to test the hypothesis that tissue Doppler imaging (TDI) could demonstrate changes in the septal contraction sequence during dual-chamber pacing in patients with HC. TDI was performed in 16 patients (5 women; mean age 63+/-11 years) who underwent dual-chamber pacing for 7.6+/-2.1 year. With and without pacing, the time to peak systolic myocardial velocity was measured from the basal, mid, and distal segments in the 4 different LV walls. Without pacing, there was almost no longitudinal segmental asynchrony. During pacing, however, marked longitudinal segmental asynchrony appeared, especially in the anteroseptal wall (from p=NS to p<0.01 by analysis of variance) and the ventricular septum (from p<0.05 to p<0.01), with the time to peak velocity extremely prolonged at the distal segments. This was associated with a modest but significant decrease in the LV pressure gradient (from 20+/-8 to 14+/-7 mm Hg, p<0.01). In patients with obstructive HC, altered septal contraction sequence accounts for the reduced LV outflow obstruction during dual-chamber pacing, which was clearly demonstrated by TDI.