Right ventricular remodelling after transcatheter pulmonary valve implantation.

OBJECTIVES: To define the optimal timing for percutaneous pulmonary valve implantation (PPVI) in patients with severe pulmonary regurgitation (PR) after Fallot's Tetralogy (ToF) correction. BACKGROUND: PPVI among the aforementioned patients is mainly driven by symptoms or by severe right ventricular (RV) dilatation/dysfunction. The optimal timing for PPVI is still disputed. METHODS: Twenty patients [age 13.9 ± 9.2 years, (range 4.3-44.9), male 70%] with severe PR (≥3 grade) secondary to previous correction of ToF, underwent Melody valve (Medtronic, Minneapolis, MN) implantation, after a pre-stent placement. Full echocardiographic assessment (traditional and deformation analysis) and cardiovascular magnetic resonance evaluation were performed before and at 3 months after the intervention. 'Favorable remodelling' was considered the upper quartile of RV size decrease (>20% in 3 months). RESULTS: After PPVI, indexed RV effective stroke volume increased from 38.4 ± 9.5 to 51.4 ± 10.7 mL/m2 , (P = 0.005), while RV end-diastolic volume and strain indices decreased (123.1 ± 24.1-101.5 ± 18.3 mL/m2 , P = 0.005 and -23.5 ± 2.5 to -21 ± 2.5%, P = 0.002, respectively). After inserting pre-PPVI clinical, RV volumetric and deformation parameters in a multiple regression model, only time after last surgical correction causing PR remained as significant regressor of RV remodelling [R2 = 0.60, beta = 0.387, 95%CI(0.07-0.7), P = 0.019]. Volume reduction and functional improvement were more pronounced in patients treated with PPVI earlier than 7 years after last RV outflow tract (RVOT) correction, reaching close-to-normal values. CONCLUSIONS: Early PPVI (<7 years after last RVOT operation) is associated with a more favorable RV reverse remodelling toward normal range and should be considered, before symptoms or RV damage become apparent. © 2017 Wiley Periodicals, Inc.

Tissue Doppler, strain and strain rate in ischemic heart disease "how I do it".

Echocardiography is the standard method for assessing myocardial function in patients with ischemic heart disease. The acquisition and interpretation of echocardiographic images, however, remains a highly specialized task which often relies entirely on the subjective visual assessment of the reader and requires therefore, particular training and expertise. Myocardial deformation imaging allows quantifying myocardial function far beyond what can be done with sole visual assessment. It can improve the interpretation of regional dysfunction and offers sensitive markers of induced ischemia which can be used for stress tests. In the following, we recapitulate shortly the pathophysiological and technical basics and explain in a practical manner how we use this technique in investigating patients with ischemic heart disease.

Sheep can be used as animal model of regional myocardial remodeling and controllable work.

BACKGROUND: Pacing the right heart has been shown to induce reversible conduction delay and subse-quent asymmetric remodeling of the left ventricle (LV) in dogs and pigs. Both species have disadvantages in animal experiments. Therefore the aim of this study was to develop a more feasible and easy-to-use animal model in sheep. METHODS: Dual-chamber (DDD) pacemakers with epicardial leads on the right atrium and right ven-tricular free wall were implanted in 13 sheep. All animals underwent 8 weeks of chronic rapid pacing at 180 bpm. Reported observations were made at 110 bpm. RESULTS: DDD pacing acutely induced a left bundle branch block (LBBB) - like pattern with almost doubling in QRS width and the appearance of a septal flash, indicating mechanical dyssynchrony. Atrial pacing (AAI) resulted in normal ventricular conduction and function. During 8 weeks of rapid DDD pacing, animals developed LV remodeling (confirmed with histology) with septal wall thinning (-30%, p < 0.05), lateral wall thickening (+22%, p < 0.05), LV volume increase (+32%, p < 0.05), decrease of LV ejection fraction (-31%, p < 0.05), and functional mitral regurgitation. After 8 weeks, segmental pressure-strain-loops, representing regional myocardial work, were recorded. Switching from AAI to DDD pacing decreased immediately work in the septum and increased it in the lateral wall (-69 and +41%, respectively, p < 0.05). Global LV stroke work and dP/dtmax decreased (-27% and -25%, respectively, p < 0.05). CONCLUSIONS: This study presents the development a new sheep model with an asymmetrically remod-eled LV. Simple pacemaker programing allows direct modulation of regional myocardial function and work. This animal model provides a new and valuable alternative for canine or porcine models and has the potential to become instrumental for investigating regional function and loading conditions on regional LV remodeling.

"A ball in a cage".

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New Automatic Tools to Identify Responders to Cardiac Resynchronization Therapy.

BACKGROUND: New echocardiographic parameters (apical rocking [AR], septal flash [SF]) are intended to detect patterns specific to responders to cardiac resynchronization therapy (CRT). The patterns are visually recognized and qualitatively described, requiring experience and training. Speckle-tracking echocardiography can reflect SF and AR by using newly developed, dedicated parameters, such as start systolic index (SSI) and peak longitudinal displacement (PLD). The aim of this study was to investigate whether SSI and PLD can identify potential CRT responders. METHODS: In 125 patients, echocardiograms from before and 9 ± 3 months after CRT were retrospectively analyzed with dedicated EchoPAC prerelease software. From speckle-tracking baseline images, color-coded bull's-eye displays of SSI and PLD were generated. Cutoff values for both parameters were derived from 25 randomly selected patients and applied to the remaining 100 patients to identify CRT response, defined as a decrease in end-systolic volume of ≥15% during follow-up. The performance of SSI and PLD was compared with the visual assessment of AR and SF by expert and novice readers. RESULTS: Expert readers detected 77 patients with AR, identifying CRT responders with sensitivity and specificity of 85 ± 2% and 82 ± 2%, respectively. Novice readers reached 74 ± 7% sensitivity and 55 ± 11% specificity, while the sensitivity and specificity of the quantitative analysis were 72 ± 3% and 84 ± 4% for SSI and 80 ± 1% and 75 ± 2% for PLD, respectively. CONCLUSIONS: New speckle-tracking-based quantitative assessment of mechanical dyssynchrony by SSI and PLD performs comparably in identifying CRT responders as visual analysis by expert readers and performs significantly better than novice readers.

How to define end-diastole and end-systole?: Impact of timing on strain measurements.

OBJECTIVES: This study aimed to investigate to what extent timing definitions influence strain measurements and which surrogates are reliable and feasible to define end-diastole (ED) and end-systole (ES) during speckle-tracking (STI) analysis. BACKGROUND: Current STI-based strain measurements are highly automated. It remains unclear when a particular analysis software defines the zero baseline and the systolic strain measurement position. METHODS: A total of 60 subjects (20 healthy volunteers, 20 patients with coronary artery disease, and 20 patients with typical left bundle-branch block) underwent a complete echocardiographic examination. In one-half of them, a real M-mode through the mitral valve was acquired for each electrocardiographic (ECG) lead of the echo machine. Timing of peak R and automatic ECG trigger were compared with mitral valve closure for every electrode. Mitral and aortic valve closure, as observed in the apical 3-chamber view, served as reference for ED and ES. With the use of these references, end-systolic global longitudinal strain (ES-GLS) and end-systolic segmental longitudinal strain (ES-SLS) longitudinal end-systolic strain were measured at baseline and after changing the definition of either ED or ES by ±4 frames. Furthermore, strain and volume curves derived from the same tracking, as well as the Doppler interrogation of the valves, were compared with the references. RESULTS: Depending on the selected lead, timing of the ECG-derived time markers changed considerably compared with mitral valve closure. Changing the definition of ED and ES resulted in significantly different ES-GLS and ES-SLS values in all subjects. ES-SLS in dyssynchronous hearts showed the highest sensitivity to timing definition. From all methods, spectral Doppler was the most reliable time marker in all subjects (p > 0.05). CONCLUSIONS: Exact temporal definition of ED and ES has a major impact on the accuracy of strain measurements. After direct observation of the valves, Doppler evaluation is the best means for characterizing ED and ES for STI analysis.