Speckle tracking echocardiography analyses of myocardial contraction efficiency predict response for cardiac resynchronization therapy

Global longitudinal strain and the risk of major adverse cardiac events in post-myocardial infarction patients: A retrospective cohort study

BACKGROUND

This study evaluates the relationship between global longitudinal strain (GLS) and late major adverse cardiovascular events (MACEs) in patients after acute myocardial infarction (AMI).

METHODS

Data of newly diagnosed AMI patients between March 2010 and July 2014 were retrospectively evaluated. The patients underwent serial echocardiography at admission and at third and sixth months post-admission. We calculated GLS by averaging the strain from all myocardial segments using speckle-tracking echocardiography (STE). We used multivariate Cox regression analysis and receiver operating characteristic (ROC) curve analyses to assess the relationship between GLS at admission and late MACEs.

RESULTS

Eighty-nine newly diagnosed AMI patients were enrolled. The average age at diagnosis was 61 ± 12.5 years, and approximately 89.9% of the patients were men. The average level of GLS was -17.5 ± 3.9%. The overall prevalence of MACEs was 23.6% (21/89), compared with 44% (11/25) in the group with GLS≥-15% and 17.9% (5/28) in the group with GLS<-20%. GLS was positively linked with MACEs in the fully adjusted Cox proportional hazard model (hazard ratio [HR], 1.19; 95% confidence interval [CI], 1.04-1.37; P=0.014) after adjusting potential confounders. The ROC curve analysis for one year MACEs between GLS at admission, with the most significant area under the curve(AUC) 78.1% (95% CI, 63.8% - 92.6%).

CONCLUSIONS

Myocardial dysfunction, characterized by impaired GLS, is often observed in AMI patients, and a decrease in GLS levels at admission were associated with an increased risk of long-term MACEs in post-myocardial infarction patients.

A predictive model of super response to cardiac resynchronization therapy in short-term period

BACKGROUND

The left bundle branch block, nonischemic heart failure (HF) and female gender are the most powerful predictors of a super response to cardiac resynchronization therapy (CRT). It is important to identify super responders who can derive most benefits from CRT. We aimed to establish a predicting model that could be used for prognosis of a super response to CRT in short-term period.

METHODS

Patients with QRS ≥ 130 ms, New York Heart Association (NYHA) II-III class of HF, left ventricle ejection fraction (LVEF) ≤ 35% and indications for CRT were included in the study. Before and 6 month after CRT the electrocardiography, echocardiography and cardiac scintigraphy were performed. The study's primary endpoint was the NYHA class improvement ≥ 1 and left ventricle end systolic volume decrease > 30% or LVEF improvement > 15% after 6 month CRT. Based on collected data, we developed a predictive model regarding a super response to CRT.

RESULTS

Of 49 (100.0%) patients, 32 (65.3%) had a super response to CRT. Patients with a super response were likelier to have a lower cardiac index (p = 0.007), higher rates of interventricular delay (IVD) (p = 0.003), phase standard deviation of left ventricle anterior wall (PSD LVAW) (p = 0.009) and ∆QRS (p = 0.02). Only IVD and PSD LVAW were independently associated with a super response to CRT in univariate and multivariate logistic regression. We created a logistic equation and calculated a cut-off value. The resulting ROC curve revealed a discriminative ability with AUC of 0.812 (sensitivity 90.62%; specificity 70.59%).

CONCLUSION

Our predictive model is able to distinguish patients with a super response to CRT.

The Value of Left Ventricular Mechanical Dyssynchrony and Scar Burden in the Combined Assessment of Factors Associated with Cardiac Resynchronization Therapy Response in Patients with CRT-D

Background: Cardiac resynchronization therapy (CRT) improves the outcome in patients with heart failure (HF). However, approximately 30% of patients are nonresponsive to CRT. The aim of this study was to determine the role of the left ventricular (LV) mechanical dyssynchrony (MD) and scar burden as predictors of CRT response. Methods: In this study, we included 56 patients with HF and the left bundle-branch block with QRS duration ≥ 150 ms who underwent CRT-D implantation. In addition to a full examination, myocardial perfusion imaging and gated blood-pool single-photon emission computed tomography were performed. Patients were grouped based on the response to CRT assessed via echocardiography (decrease in LV end-systolic volume ≥15% or/and improvement in the LV ejection fraction ≥5%). Results: In total, 45 patients (80.3%) were responders and 11 (19.7%) were nonresponders to CRT. In multivariate logistic regression, LV anterior-wall standard deviation (adjusted odds ratio (OR) 1.5275; 95% confidence interval (CI) 1.1472–2.0340; p = 0.0037), summed rest score (OR 0.7299; 95% CI 0.5627–0.9469; p = 0.0178), and HF nonischemic etiology (OR 20.1425; 95% CI 1.2719–318.9961; p = 0.0331) were the independent predictors of CRT response. Conclusion: Scar burden and MD assessed using cardiac scintigraphy are associated with response to CRT.

Role of Strauss ECG criteria as predictor of response in patients undergoing cardiac resynchronization therapy

Background

Cardiac resynchronization therapy (CRT) is a standard treatment in patients with heart failure; however, approximately 20–40% of recipients of (CRT) do not respond to it based on the current patients’ selection criteria. The purpose of this study was to identify the baseline parameters that predict the CRT response and how the ECG morphology can affect the outcome. The study aimed to evaluate the Strauss ECG criteria as a predictor of response in patients undergoing cardiac resynchronization therapy.

Results

Out of 70 patients, 3 patients missed the 6-month follow-up after CRT implantation, so the study enrolled 67 patients that have been classified according to ECG morphology of LBBB to 37 patients with non-Strauss ECG criteria—one of whom died after 4 months—and 30 patients with Strauss ECG criteria. The number of responders in the study was 50 patients with percentage 75.8%; 52% of CRT responder (26 patients) had non-Strauss ECG criteria, while 48% of CRT responders (24 patients) had Strauss ECG criteria with P value = 0.463. While there was no statistical significance of overall CRT response nor 6-month hospitalization and mortality between patients of Strauss and non-Strauss ECG criteria, there was a significant improvement in NYHA class, EF assessed by biplane Simpson’s, end-systolic volume, global longitudinal strain and global circumferential strain by speckle tracking echocardiography in patients with Strauss ECG criteria of LBBB.

Conclusions

There is no statistical significance in overall CRT response nor the 6-month hospitalization and mortality after 6 months of follow-up between patients with Strauss and non-Strauss ECG criteria of LBBB; however, patients with Strauss ECG criteria have better improvement in NYHA class, echocardiographic parameters such as EF and ESV and speckle tracking parameters (GLS and GCS).

Improved risk-stratification in heart failure patients with mid-range to severe abnormalities of QRS duration and systolic function using mechanical dyssynchrony assessed by myocardial perfusion-gated SPECT

BACKGROUND

The use of left ventricular mechanical dyssynchrony (LVMD), which has been reported to be responsible for unfavorable outcomes, might improve conventional risk-stratification by clinical indices including QRS duration (QRSd) and systolic dysfunction in patients with heart failure (HF).

METHODS AND RESULTS

Following measurements of 12-lead QRSd and left ventricular ejection fraction (LVEF), three-dimensional (3-D) LVMD was evaluated as a standard deviation (phase SD) of regional mechanical systolic phase angles by gated myocardial perfusion imaging in 829 HF patients. Patients were followed up for a mean period of 37 months with a primary endpoint of lethal cardiac events (CEs). In an overall multivariate Cox proportional hazards model, phase SDs were identified as significant prognostic determinants independently. The patients were divided into 4 groups by combining with the cut-off values of LVEF (35% and 50%) and QRSd (130 ms and 150 ms). The groups with lower LVEF and prolonged QRSd more frequently had CEs than did the other groups. Patient groups with LVEF < 35% and with 35% ≦ LVEF < 50% were differentiated into low-risk and high-risk categories by using an optimal phase SD cut-off value of both QRSd thresholds.

CONCLUSIONS

3-D LVMD can risk-stratify HF patients with mid-range as well as severe abnormalities of QRSd and systolic dysfunction.

Vectorcardiography-derived index allows a robust quantification of ventricular electrical synchrony

Alteration of muscle activation sequence is a key mechanism in heart failure with reduced ejection fraction. Successful cardiac resynchronization therapy (CRT), which has become standard therapy in these patients, is limited by the lack of precise dyssynchrony quantification. We implemented a computational pipeline that allows assessment of ventricular dyssynchrony by vectorcardiogram reconstruction from the patient’s electrocardiogram. We defined a ventricular dyssynchrony index as the distance between the voltage and speed time integrals of an individual observation and the linear fit of these variables obtained from a healthy population. The pipeline was tested in a 1914-patient population. The dyssynchrony index showed minimum values in heathy controls and maximum values in patients with left bundle branch block (LBBB) or with a pacemaker (PM). We established a critical dyssynchrony index value that discriminates electrical dyssynchronous patterns (LBBB and PM) from ventricular synchrony. In 10 patients with PM or CRT devices, dyssynchrony indexes above the critical value were associated with high time to peak strain standard deviation, an echocardiographic measure of mechanical dyssynchrony. Our index proves to be a promising tool to evaluate ventricular activation dyssynchrony, potentially enhancing the selection of candidates for CRT, device configuration during implantation, and post-implant optimization.

Synergistic prognostication of left ventricular hypertrophy and three-dimensional mechanical dyssynchrony in heart failure

AIMS

In this study, we investigated the prognostic interplay of left ventricular hypertrophy and mechanical dyssynchrony (LVMD), both of which can be measured three-dimensionally by gated myocardial perfusion imaging (MPI), in patients with chronic systolic heart failure (HF).

METHODS AND RESULTS

In 829 consecutive HF patients with reduced left ventricular ejection fraction less than 50%, LVMD was evaluated as a standard deviation (phase SD) of regional onset of mechanical contraction phase angles. A phase histogram was created by Fourier phase analysis applied to regional time-activity curves obtained by gated MPI. Left ventricular mass index (LVMI) was measured by Corridor 4DM version 6.0. Patients were followed up with a primary endpoint of lethal cardiac events (CE) for a mean interval of 34 months. CE were documented in 223 (27%) of the HF patients. The CE group had a greater phase SD and a greater LVMI than those in the non-CE group. Patients in the CE group had a more advanced age, greater New York Heart Association (NYHA) functional class, left ventricular cavity size, and left atrial diameter or septal E/e' and lower kidney or cardiac function than did patients in the non-CE group. Phase SD > 37 and LVMI > 122.7 g/m2 were identified as optimal cut-off values by receiver operating characteristic analyses for discrimination of the most increased risk HF subgroup from others (P < 0.0001). When classified into four patient subgroups using both cut-off values, HF patients with phase SD > 37 (LVMD) and LVMI > 122.7g/m2 had the highest CE rate among the subgroups (P < 0.0001). Univariate analysis and subsequent multivariate analysis with a Cox proportional hazards model showed that phase SD and LVMI were significant independent predictors of CE with hazard ratios of 1.038 (confidence interval [CI], 1.024-1.051, P < 0.0001) and 1.005 (CI, 1.001-1.008, P = 0.0073), respectively, as well as conventional clinical parameters such as age, NYHA class, estimated glomerular filtration rate (eGFR), and BNP concentration. Patients with increased phase SD and LVMI had incrementally improved prognostic values of clinical parameters including age, NYHA functional class, eGFR, and BNP with increases in the global χ2 value: 5.9 for age; 139.5 for age and NYHA; 157.9 for age, NYHA, and eGFR; 163.9 for age, NYHA, eGFR, and BNP; 183.4 for age, NYHA, eGFR, BNP, and phase SD; and 192.5 for age, NYHA, eGFR, BNP, phase SD, and LVMI.

CONCLUSIONS

Three-dimensionally assessed LVMD has independent prognostic values and can improve the risk stratification of chronic HF patients synergistically in combination with conventional clinical parameters.

[123 I-MIBG scintigraphy in the assessment of heart failure prognosis and effectiveness of cardiac resynchronization therapy]

Cardiac resynchronization therapy (CRT) is one of the methods of treating patients with chronic heart failure, which can reduce the mortality rate of this group. Scintigraphic assessment of sympathetic myocardial innervation allows us to evaluate the heart failure prognosis and the effectiveness of interventional treatment. The method is based on use of the radiopharmaceutical 123 I-methiodiobenzylguanidine (123 I-MIBG), which is a structural analogue of norepinephrine and is able to selectively accumulate in the sympathetic nerve endings. This review includes a brief description of norepinephrine metabolism and pharmacokinetics of 123 I-MIBG in the sympathetic nerve ending, a brief description of the study methodology and the clinical significance of this method in patients with heart failure. Particular attention is paid to the possibilities of using this method in patients with severe chronic heart failure before and after CRT.