Gabriel Wk Yip

Tissue Doppler imaging provides incremental prognostic value in patients with systemic hypertension and left ventricular hypertrophy.

Objectives We sought to determine the prognostic value of left ventricular (LV) mitral annular velocities measured by tissue Doppler imaging (TDI) in hypertensive patients with echocardiographic evidence of LV hypertrophy. Background Echo LV hypertrophy and LV geometry provide additional predictive value of all-cause mortality beyond traditional cardiovascular risk factors. Limited data exist regarding the predictive value of TDI velocities for cardiovascular risk stratification in treated hypertensive patients. Methods Two-dimensional and Doppler echocardiograms were obtained in 252 consecutive subjects, including 174 subjects with systemic hypertension and 78 age-matched normal subjects. The end point was cardiac death in subsequent median follow-up of 19 months. Results Nineteen patients (7.54%) died of cardiac causes. The TDI mitral annulus systolic velocity and the early diastolic mitral annular velocity (Em) were significantly lower in the non-survivors (all P < 0.001). The pseudonormal (PN) or restrictive filling pattern (RFP) was associated with cardiac mortality. The other parameters associated with cardiac mortality were LV ejection fraction, LV mass index, inter-ventricular septal wall thickness in diastole and the ratio of early mitral inflow to early myocardial velocity. In multivariate analysis, Em, inter-ventricular septal wall thickness in diastole and either PN or RFP were the strongest predictors. The addition of Em < 3.5 cm/s significantly improved the outcome of a model that contained clinical risk factors, inter-ventricular septal wall thickness in diastole > 1.4 cm and either PN or RFP (P = 0.043). Conclusions Early diastolic mitral annulus velocity measured by TDI provides prognostic information, incremental to clinical data and standard echocardiographic variables, for risk stratification of hypertensive patients under treatment.

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.

Tissue Doppler velocity is superior to displacement and strain mapping in predicting left ventricular reverse remodelling response after cardiac resynchronisation therapy

Objective: To compare the values of three different forms of tissue Doppler imaging (TDI) processing in predicting left ventricular (LV) reverse remodelling—namely, tissue velocity, displacement and strain mapping. Design: Standard echocardiography with TDI was performed before and 3 months after cardiac resynchronisation therapy (CRT). Setting: University teaching hospital. Patients: 55 patients with heart failure who received CRT and were followed up for at least 3 months were recruited. Interventions: During off-line analysis, the time to peak systolic velocity in the ejection phase, time to peak positive displacement and time to peak negative strain were measured in the six basal, six mid-segmental model. Parameters of systolic asynchrony derived by velocity, displacement and strain mapping were correlated with percentage reduction in LV end systolic volume (LVESV) and absolute gain in ejection fraction (EF). Results: Among the three TDI processing technologies, all parameters of tissue velocity correlated with LV reverse remodelling (r  = −0.49 to r  =  −0.76, all p < 0.001), but the predictive value was strongest in models with 12 LV segments. For displacement mapping, only the two parameters that included 12 LV segments correlated modestly with reduction in LVESV (r  =  −0.36, p < 0.05) and gain in EF. However, none of the strain mapping parameters predicted a favourable echocardiographic response. The receiver operating characteristic (ROC) curve areas were higher for parameters of tissue velocity based on 12 LV segments (ROC areas 0.88 and 0.94) than the corresponding areas derived from displacement mapping (ROC areas 0.72 and 0.71). Conclusion: Tissue velocity parameters of systolic asynchrony are superior to those of displacement and strain mapping in predicting LV reverse remodelling response after CRT.

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.

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.

Disease chronicity and activity predict subclinical left ventricular systolic dysfunction in patients with systemic lupus erythematosus

Objective: This study investigates parameters that could predict subclinical cardiac dysfunction in systemic lupus erythematosus (SLE) in the absence of valvular, clinical coronary artery and pericardial disease. Design: A case-control trial. Setting: Rheumatology clinic, a university teaching hospital. Patients: Eighty-two female SLE patients (49 (SD 9) years) and 82 female normal subjects (49 (13) years) matched for age, body mass index, blood pressure and heart rate. Interventions: All underwent standard echocardiography and tissue Doppler imaging. Main outcome measures: Twenty-two (27%) patients had evidence of impaired left ventricular (LV) long-axis function with mean myocardial peak systolic velocity (Sm) of basal six segments <4.4 cm/s and also subnormal stress-corrected midwall fractional shortening. Thirty-four (42%) patients demonstrated impaired right ventricular (RV) long-axis function. These occurred in the presence of comparable normal LV ejection fraction, cardiac index, and RV fractional area change to the control group. Patients with subnormal mean Sm were older (49 (8) vs 44 (9); p = 0.043) and had a higher prevalence of hypertension (46% vs 22%; p = 0.034), longer disease duration >10 years (82% vs 50%, p = 0.01), higher disease activity score (73% vs 48% for Systemic Lupus Erythematosus Disease Activity Index (SLEDAI)⩾1, p = 0.049) and end-organ damage index (64% vs 47% with Systemic Lupus International Collaborating Clinics Damage Index (SLICC)⩾1, p = 0.049) than those with normal values. Disease duration >10 years, disease activity index and increased arterial stiffness provided additional incremental predictive value of LV long-axis function. Conclusion: SLE patients have subclinical long and short-axis dysfunctions. Regular monitoring of cardiac function by tissue Doppler echocardiography may be indicated for patients who had SLE for >10 years, frequent flare or when arterial stiffening is demonstrated.