C.M. Yu

High prevalence of left ventricular systolic and diastolic asynchrony in patients with congestive heart failure and normal QRS duration

Objective: To study the possible occurrence of left ventricular (LV) systolic and diastolic asynchrony in patients with systolic heart failure (HF) and narrow QRS complexes. Design: Prospective study. Setting: University teaching hospital. Patients: 200 subjects were studied by echocardiography. 67 patients had HF and narrow QRS complexes (≤ 120 ms), 45 patients had HF and wide QRS complexes (> 120 ms), and 88 served as normal controls. Interventions: Echocardiography with tissue Doppler imaging was performed using a six basal, six mid-segmental model. Main outcome measures: Severity and prevalence of systolic and diastolic asynchrony, as assessed by the maximal difference in time to peak myocardial systolic contraction (TS) and early diastolic relaxation (TE), and the standard deviation of TS (TS-SD) and of TE (TE-SD) of the 12 LV segments. Results: The mean (SD) maximal difference in TS (controls 53 (23) ms v narrow QRS 107 (54) ms v wide QRS 130 (51) ms, both p < 0.001 v controls) and in TS-SD (controls 17.0 (7.8) ms v narrow QRS 33.8 (16.9) ms v wide QRS 42.0 (16.5) ms, both p < 0.001 v controls) was prolonged in the narrow QRS group compared with normal controls. Similarly, the maximal difference in TE (controls 59 (19) ms v narrow QRS 104 (71) ms v wide QRS 148 (87) ms, both p < 0.001 v controls) and in TE-SD (controls 18.5 (5.8) ms v narrow QRS 33.3 (27.7) ms v wide QRS 48.6 (30.2) ms, both p < 0.001 v controls) was prolonged in the narrow QRS group. The prevalence of systolic and diastolic asynchrony was 51% and 46%, respectively, in the narrow QRS group, and 73% and 69%, respectively, in the wide QRS group. Stepwise multiple regression analysis showed that a low mean myocardial systolic velocity from the six basal LV segments and a large LV end systolic diameter were independent predictors of systolic asynchrony, while a low mean myocardial early diastolic velocity and QRS complex duration were independent predictors of diastolic asynchrony. Conclusions: LV systolic and diastolic mechanical asynchrony is common in patients with HF with narrow QRS complexes. As QRS complex duration is not a determinant of systolic asynchrony, it implies that assessment of intraventricular synchronicity is probably more important than QRS duration in considering cardiac resynchronisation treatment.

Assessing right ventricular function: the role of echocardiography and complementary technologies

The physiological importance of the right ventricle (RV) has been underestimated; the RV was considered mainly as a conduit whereas its contractile performance was thought to be haemodynamically unimportant.1 However, its essential contribution to normal cardiac pump function is well established with the primary RV functions being: RV function may be impaired either by primary right sided heart disease, or secondary to left sided cardiomyopathy or valvar heart disease.2 In addition, it should be considered that RV dysfunction may affect left ventricular (LV) function, not only by limiting LV preload, but also by adverse systolic and diastolic interaction via the intraventricular septum and the pericardium (ventricular interdependence). Moreover, RV function has been shown to be a major determinant of clinical outcome3–9 and consequently should be considered during clinical management and treatment.10 Thus, the need for diagnosis of RV dysfunction is evident. In practice, clinicians largely rely on non-invasive imaging methods for assessment of RV function. Two dimensional echocardiography is the mainstay for analysis of RV function, but recently alternative techniques have been proposed, including tissue Doppler imaging (TDI) techniques,11 three dimensional echocardiography,12 magnetic resonance imaging (MRI), and even invasive assessment of pressure–volume loops.13–17 An overview of these imaging modalities for assessment of RV function is provided in the current manuscript. Due to its widespread availability, echocardiography is used as the first line imaging modality for assessment of RV size and RV function. The quantitative assessment of RV size and function is often difficult, because of the complex anatomy. Nevertheless, when used …

Variable left ventricular activation pattern in patients with heart failure and left bundle branch block

Objective: To determine the left ventricular (LV) activation pattern in patients with chronic heart failure and left bundle branch block (LBBB) on ECG. Design: Prospective study. Setting: Tertiary cardiology referral centre in Hong Kong. Patients: Seven patients with LV ejection fraction < 35% and typical LBBB on ECG with QRS duration ⩾ 130 ms were recruited. Five of them had non-ischaemic dilated cardiomyopathy. Methods: Non-contact mapping was used to investigate the LV global activation sequences. Tissue Doppler imaging was performed with the LV mapping and correlated with the activation sequences. Results: Three patients had preserved left bundle activation despite LBBB on ECG. Conduction block was detected in four patients during LV activation and the other three had homogeneous depolarisation propagation within the left ventricle. The latest segment of activation was located in either the lateral or the posterior region. Tissue Doppler imaging correlated well with non-contact mapping to locate the conduction block and the latest segment of activation. Conclusions: LV endocardial activation sequences in patients with chronic heart failure and LBBB are variable. This may have implications for patient selection for treatment with cardiac resynchronisation.

Improvement of left ventricular myocardial short-axis, but not long-axis function or torsion after cardiac resynchronisation therapy: an assessment by two-dimensional speckle tracking

Aims: To evaluate whether short-axis function plays a part in determining left ventricular (LV) geometric and functional improvement after cardiac resynchronisation therapy (CRT). Methods and results: 39 patients who received CRT were enrolled. 2D speckle tracking echocardiography was performed at baseline and three months after CRT to assess mean systolic circumferential (ϵ-circum), radial (ϵ-radial) and longitudinal (ϵ-long) strain and torsion. Responders of reverse remodelling (n = 21) had higher baseline mean ϵ-circum than non-responders (p<0.05), who also had improvement in mean ϵ-circum and mean ϵ-radial (both p<0.05) after CRT. Also, the increase in mean ϵ-circum correlated with increase in ejection fraction (r = 0.57, p<0.001) and decrease in mid-cavity width (r = −0.52, p = 0.001). A baseline mean ϵ-circum of ⩾6.5% predicted a gain in ejection fraction ⩾5%, with a sensitivity of 73% and a specificity of 71%. The baseline ϵ-long was not different between the two groups, and remained unchanged after CRT. The torsion did not improve in responders, but was worsened in non-responders (p<0.05). Conclusions: The improvement of LV short-axis function but not long-axis function or torsion contributes to the improvement in LV global function and geometry at three-month follow up. A relatively preserved mean ϵ-circum of ⩾6.5% might be useful to predict favourable responses after CRT.

Echocardiographic evaluation of cardiac dyssynchrony for predicting a favourable response to cardiac resynchronisation therapy

Cardiac resynchronisation therapy (CRT) is an established therapy for patients with heart failure with wide QRS duration. Recent studies observed that assessment of systolic dyssynchrony is an important diagnostic tool as the treatment involves the re-coordination of regional wall contraction within the left ventricle. Therefore, the effectiveness of CRT depends heavily on whether systolic dyssynchrony is present before the treatment. Echocardiography is a useful tool for quantitative measurement of the severity of dyssynchrony in these patients before and after CRT. A number of echocardiographic tools have been developed during the past three years for such purpose, include M mode measurement of septal-to-posterior wall delay, tissue Doppler imaging for septal-to-lateral wall delay, the measurement of standard deviation of peak contraction time over 12 left ventricular segments, delayed longitudinal contraction, and potentially three dimensional echocardiography. This review discusses the potential role of various echocardiographic techniques in the assessment of systolic dyssynchrony and their clinical applications.

Tissue Doppler imaging for predicting outcome in patients with cardiovascular disease

Purpose of review Tissue Doppler imaging is being increasingly used for assessing global ventricular function in systole and diastole, and for quantifying regional wall motion abnormalities both in systolic heart failure with mechanical dyssynchrony and ischemic heart disease. Its use as a predictive tool is recent and the authors review publications relating to this aspect. Recent findings Peak early diastolic mitral annular velocity is a powerful predictor of outcome in a variety of cardiovascular conditions and adds incremental value to clinical parameters and standard mitral Doppler inflow velocities. Tissue Doppler imaging can also predict the development of hypertrophic cardiomyopathy in asymptomatic individuals carrying the genetic mutation even before the onset of overt left ventricular hypertrophy. In addition, the standard deviation of the time to peak systolic velocity is a good marker of mechanical asynchrony and can predict reverse remodeling. It may also be useful in identifying individuals with ischemic heart disease and regional wall motion abnormalities who have an adverse outcome. Summary Tissue Doppler imaging is a powerful new echocardiographic tool that is now becoming the standard for assessing ventricular function in a variety of situations and diseases.

Increased arterial stiffness correlated with disease activity in systemic lupus erythematosus

To evaluate the relationships between arterial stiffness, disease activity and end-organ damage in systemic lupus erythematosus (SLE), non-invasive vascular assessments were made on 32 female SLE patients and 32 female normal controls. The patients had significantly increased brachial-ankle pulse wave velocity (PWV) (13.06 ± 1.79 vs. 11.50 ± 1.00 m/s; P < 0.001), heart-ankle PWV (8.98 ± 1.16 vs. 7.88 ± 0.73 m/s; P < 0.001), carotid augmentation index (AI) (21.6 ± 17.2% vs. 5.4 ± 14.0%; P = 0.001) and carotid intima-medial thickness (IMT) (0.753 ± 0.132 vs. 0.644 ± 0.092 mm; P = 0.002) when compared with controls. The disease activity and organ damage were evaluated by SLE disease activity index (SLEDAI) and systemic lupus international collaborating clinics (SLICC) damage index. Patients with active disease (SLEDAI ≥ 3) had significantly higher carotid AI (34.4 ± 9.7% vs. 17.8 ± 17.3%, P < 0.05) than stable ones (SLEDAI < 3) and those with organ damage (SLICC ≥ 1) had significantly higher heart-ankle PWV (9.69 ± 1.13 vs. 8.61 ± 1.02 m/s, P < 0.05) than those with SLICC = 0. After making adjustments for age, body mass index (BMI) and blood pressure, carotid AI was found to show correlation with SLEDAI and haPWV with SLICC. A carotid AI value of 33.3% identified SLEDAI ≥ 3 with a sensitivity of 83% and a specificity of 80%, whereas a heart-ankle PWV value of 9.0 m/s identified SLICC ≥ 1 with a sensitivity of 91% and a specificity of 67%. In conclusion, SLE was an independent risk factor of sub-clinical atherosclerosis and arterial stiffness may identify the presence of active disease.

Effects of cardiac resynchronisation therapy in patients with heart failure having a narrow QRS Complex enrolled in PROSPECT

Introduction Current guidelines recommend cardiac resynchronisation therapy (CRT) in patients with severe symptomatic heart failure, depressed left ventricular (LV) systolic function and a wide QRS complex (≥120 ms). However, patients with heart failure having a narrow QRS complex might also benefit from CRT. Design setting patients interventions During the Predictors of Response to Cardiac Resynchronisation Therapy (PROSPECT) trial, 41 patients were enrolled in a ‘narrow’ QRS sub-study. These patients had a QRS complex <130 ms, but documented evidence of mechanical dyssynchrony by any of seven pre-defined echocardiographic measures. Results After 6 months of CRT, 26 (63.4%) patients showed improvement according to the Clinical Composite Score, 4 (9.8%) remained unchanged and 11 (26.8%) worsened. In patients with paired data, the 6-min walking distance increased from 334±118 m to 382±128 m, (p=0.003) and quality-of-life score improved from 44.2±19.7 to 26.8±20.2 (p<0.0001). Furthermore, there was a significant decrease in LV end-systolic diameter (from 59±9 to 55±12 mm, p=0.002) and in LV end-diastolic diameter (from 67±9 to 63±11 mm, p=0.007). Conclusion The results suggest that CRT may have a beneficial effect in heart failure patients with a narrow QRS complex and mechanical dyssynchrony as assessed by echocardiography. The majority of patients improved on clinical symptoms, and there was an evident reduction in LV diameters. Larger studies are needed to clearly define selection criteria for CRT in patients with a narrow QRS complex.

Triplane tissue Doppler imaging: a novel three-dimensional imaging modality that predicts reverse left ventricular remodelling after cardiac resynchronisation therapy

Background: Several two-dimensional (2-D) tissue Doppler imaging (TDI) echocardiographic techniques have proved useful to identify responders to cardiac resynchronisation therapy (CRT). Recently a 3-D probe allowing simultaneous acquisition of TDI data in three imaging planes became available. Objective: To evaluate the value of triplane TDI to predict reverse left ventricular (LV) remodelling after CRT. Methods: Sixty patients with heart failure, scheduled for CRT, underwent triplane echocardiography with simultaneous TDI acquisition before and 6 months after implantation. From the triplane dataset a 3-D LV volume was generated and LV volumes and ejection fraction were calculated. Intraventricular dyssynchrony was quantitatively analysed by evaluating time from onset of the QRS complex to peak myocardial systolic velocity in 12 LV segments from the triplane dataset and calculation of the standard deviation (Ts-SD-12). Clinical response was defined as an improvement of at least one New York Heart Association class. Reverse LV remodelling was defined as ⩾15% decrease of LV end-systolic volume at 6 months’ follow-up. Results: Responders to CRT had significantly more LV dyssynchrony at baseline than non-responders (mean (SD) Ts-SD-12: 42 (14) vs 22 (12), p<0.001). A cut-off value of 33 ms for baseline Ts-SD-12, acquired from the triplane TDI dataset, yielded a sensitivity of 89% with a specificity of 82% to predict clinical response to CRT; sensitivity and specificity to predict reverse LV remodelling were 90% and 83%, respectively. Conclusion: Triplane TDI echocardiography predicts clinical response and reverse LV remodelling 6 months after CRT implantation.

Difference in long-term clinical outcome after cardiac resynchronisation therapy between ischaemic and non-ischaemic aetiologies of heart failure.

Objective: To examine the impact of heart failure (HF) aetiology on long-term outcome after cardiac resynchronisation therapy (CRT). Design: Prospective cohort study. Setting: University hospital. Patients: 119 patients (44% with ischaemic and 56% non-ischaemic aetiology) who underwent CRT. Interventions: Clinical follow-up for 39 (24) months. Main outcome measures: Cardiovascular mortality, HF and cardiovascular hospitalisation were compared by Kaplan-Meier curves between the two groups, followed by Cox regression analysis for prognostic predictor(s). Results: 41 (34%) patients died, in whom cardiovascular causes were identified in 32 (27%) patients. The ischaemic group had a higher cardiovascular mortality (log-rank χ2 = 4.293, p = 0.038) and cardiovascular hospitalisation (log-rank χ2 = 5.123, p = 0.024) when compared with the non-ischaemic group, though no difference was found in HF hospitalisation (log-rank χ2 = 0.019, p = 0.892). At three months, left ventricular reverse remodelling occurred in 52% of the ischaemic group and 55% of the non-ischaemic group (χ2 = 0.128, p = 0.720). By Cox regression analysis, ischaemic aetiology and absence of reverse remodelling at three months were independent predictors of cardiovascular mortality (HR = 2.698, p = 0.032; HR = 3.541, p = 0.030) and cardiovascular hospitalisation (HR = 1.905, p = 0.015; HR = 2.361, p = 0.004). Furthermore, these two factors had an incremental value in predicting cardiovascular mortality when compared with either alone (left ventricular reverse remodelling, log-rank χ2 = 10.275 vs 6.311, p = 0.05; Ischaemic aetiology, log-rank χ2 = 10.275 vs 4.293, p<0.05). Conclusion: Ischaemic aetiology of HF is an independent predictor of higher cardiovascular mortality and hospitalisation after CRT. This may implicate the progressive nature of coronary heart disease leading to a worse outcome despite similar short-term benefits of CRT.