Evaluation of left ventricular dyssynchrony using combined pulsed wave and tissue Doppler imaging

Left atrial mechanical functions in chronic primary mitral regurgitation patients: a velocity vector imaging-based study

INTRODUCTION

Assessment of the left atrium (LA) mechanical function provides further information on the level of cardiac compensation. We aimed to evaluate LA function using a strain imaging method: velocity vector imaging (VVI) in chronic primary mitral regurgitation (MR).

MATERIAL AND METHODS

We recruited 48 patients with chronic, isolated, moderate to severe MR (54.70 ±15.35 years and 56% male) and 30 age- and sex-matched healthy controls (56.52 ±15.95 years and 56% male). The LA volumes during reservoir (RV), conduit (CV) and contractile phases (AV) were measured. Global strain (S), systolic strain rate (SRs), early diastolic (ESRd) and late diastolic strain rate (LSRd) were calculated.

RESULTS

LA RV (50 ±18.7 to 37.9 ±5.9; p = 0.0001), CV (43.1 ±29 to 21 ±2.56; p = 0.0001), and AV (17.9 ±13.5 to 10.9 ±1.9; p = 0.006) were increased in MR patients. The LA reservoir phase strain was 16.2 ±8.1% in the MR group and 51.1 ±5.7% in the control group (p = 0.0001). The LA SRs (1.01 ±0.52 s(-1) for MR and 2.1 ±0.22 s(-1) for controls; p = 0.0001), LA ESRd (0.83 ±0.34 s(-1) for MR and 2.26 ±0.17 s(-1) for controls; p = 0.0001) and LA LSRd (0.76 ±0.24 s(-1) for MR and 2.2 ±0.26 s(-1) for controls; p = 0.0001) were impaired in MR patients.

CONCLUSIONS

The LA deformation indices may be used as adjunctive parameters to determine LA dysfunction in chronic primary MR.

Baseline tissue Doppler imaging-derived echocardiographic parameters and left ventricle reverse remodelling following cardiac resynchronization therapy introduction

INTRODUCTION

The aim of the study was to assess the relation of baseline mechanical dyssynchrony with the left ventricular end-systolic volume (LVESV) decrease following cardiac resynchronization (CRT) therapy introduction.

MATERIAL AND METHODS

Sixty consecutive patients (aged 66.3 ± 8.7 years; 57 men) with chronic heart failure (71.7% of ischaemic and 28.3% of non-ischaemic origin) and current indications for CRT were assessed before and 3 months after biventricular heart stimulator implantation. Longitudinal movements of twelve segments of the left ventricle (LV) (6 basal and 6 midlevel) and two segments of the right ventricle (RV) were analysed using tissue Doppler imaging (TDI) techniques with time from onset of Q wave in ECG to peak systolic velocity in colour-coded TDI (T(TDI)), time to peak strain (T(strain)) and time to peak strain rate (T(strain) (rate)). Minimal and maximal time differences within LV and between LV and RV walls were calculated.

RESULTS

In the study group LVEF and 6-min walk test distance increased, while NYHA class, NT-proBNP level, left ventricular end-diastolic volume and LVESV decreased. Significant correlations between the magnitude of LVESV reduction with maximal time differences between T(strain) of 12 LV segments (r=0.34, p = 0.017) and time differences between T(TDI) basal LV-RV segments (r = -0.29, p=0.041) were found.

CONCLUSIONS

Only a few TDI-derived parameters such as maximal time differences between T(strain) of 12 LV segments and T(TDI) difference of LV-RV basal segments can be useful to predict the magnitude of left ventricle reverse remodelling after CRT introduction.

Right atrial appendage pacing in cardiac resynchronization therapy - haemodynamic consequences of interatrial conduction delay

The present case report describes a patient with an artificial mitral valve and dual chamber pacemaker implanted due to perioperative complete atrio-ventricular block. One year later an upgrade to cardiac resynchronization therapy (CRT) combined with ICD function was performed due to significant progression of heart failure symptoms. Beneficial effects of CRT are demonstrated, but unfavourable haemodynamic consequences of right atrial appendage pacing are also underlined. Important interatrial conduction delay during atrial paced rhythm resulted in a significant time difference between optimal sensed and paced atrio-ventricular delay (AVD). This report provides a practical outline how to determine the interatrial delay and the sensed-paced AVD offset under echocardiography in patients treated with CRT.

A new baseline scoring system may help to predict response to cardiac resynchronization therapy

INTRODUCTION

The PROSPECT trial reported no single echocardiographic measurement of dyssynchrony is recommended to improve patient selection for cardiac resynchronization therapy (CRT).

MATERIAL AND METHODS

In 100 consecutive patients who received CRT, we analyzed 27 ECG and echocardiographic variables to predict a positive response to CRT defined as a left ventricular (LV) end systolic volume decrease of ≥ 15% after CRT.

RESULTS

Right ventricular (RV) pacing-induced left bundle branch block (LBBB), time difference between LV ejection measured by tissue Doppler and pulsed wave Doppler (T(TDI-PW)), and wall motion score index (WMSI) were significantly associated with positive CRT response by multivariate regression. We assigned 1 point for RV pacing-induced LBBB, 1 point for WMSI ≤ 1.59, and 2 points for T(TDI-PW) > 50 ms. Overall mean response score was 1.79 ±1.39. Cutoff point for response score to predict positive response to CRT was > 2 by receiver operating characteristic (ROC) analysis. Area under ROC curve was 0.97 (p = 0.0001). Cardiac resynchronization therapy responders in patients with response score > 2 and ≤ 2 were 36/38 (95%) and 7/62 (11%, p < 0.001), respectively. After age and gender adjustment, the response score was related to CRT response (OR = 45.4, p < 0.0001).

CONCLUSIONS

A response score generated from clinical, ECG and echocardiographic variables may be a useful predictor for CRT response. However, this needs to be validated.