Echocardiographic evaluation of cardiac resynchronization therapy: ready for routine clinical use?
A critical appraisal
Jeroen J. Bax, MD, PhD*,*,
Gerardo Ansalone, MD ,
Ole A. Breithardt, MD ,
Genevieve Derumeaux, MD ,
Christophe Leclercq, MD||,
Martin J. Schalij, MD, PhD*,
Peter Sogaard, MD¶,
Martin St. John Sutton, MD# and
Petros Nihoyannopoulos, MD, FRCP, FACC**
* Leiden University Medical Center, Leiden, the Netherlands
San Filippo Neri Hospital Rome, Rome, Italy
University Hospital Aachen, Aachen, Germany
Rouen University, Rouen, France
|| Hopital Pontchaillou, Rennes, France
¶ Skejby Hospital, Aarhus, Denmark
# University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
** Imperial College, NHLI, Hammersmith Hospital, London, United Kingdom
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Figure 1 Measurement of the interventricular mechanical delay (IVMD) by Doppler echocardiography: the right ventricular and left ventricular (LV) preejection intervals are measured from the onset of the QRS on the electrocardiogram (ECG) to the onset of pulmonary (Pulm) (RV-PEI) and aortic (Ao) (LV-PEI) outflow; IVMD is calculated by subtracting the RV-PEI from the LV-PEI.
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Figure 2 Parasternal M-mode recording in a heart failure patient with left bundle branch block. The left ventricular cavity is dilated and shows severely reduced systolic function. A clear delay between peak systolic septal and posterior wall inward motion is observed (skewed white line).
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Figure 3 (A) End-diastolic still frame image in the apical four-chamber view with a semiautomatically drawn left ventricular endocardial contour tracing. (B) Left ventricular wall motion displacement (between end-diastole and end-systole) for 100 endocardial segments determined with the centerline method. (C) Averaged septal (dashed line) and lateral (solid line) wall motion from 40 adjacent septal and lateral segments and three to seven cardiac cycles displayed as displacement (mm) over time (s). The "shift" between the curves indicates the degree of regional dyssynchrony and can be expressed quantitatively by the regional phase angle difference (based on reference 24).
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Figure 4 Quantification of regional wall motion from real-time three-dimensional echocardiographic data. After semiautomatic segmentation of the left ventricular chamber (upper left), the extent and timing of regional wall motion is analyzed in a 16-segment model (lower left) and in this example expressed as regional ejection fraction over time. There is clear regional dyssynchrony between the inferoseptal and the anterolateral segments during left bundle branch block (LBBB) (lower middle), which improves immediately after initiation of cardiac resynchronization therapy (CRT) (lower right). (Courtesy of A. Franke, University Hospital Aachen, Germany.)
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Figure 5 (A) The typical tissue Doppler imaging tracings (peak systolic velocity [PSV], diastolic velocities [E' and A']) obtained in the septum of a normal individual. (B) Illustration of assessment of timing from onset of QRS to peak systolic velocity. (C) Evaluation of intraventricular (dys)synchrony by placing sample volumes on the septum (yellow curve) and lateral wall (green curve). Data from a normal individual showing complete intraventricular synchrony. (D) Severe intraventricular dyssynchrony between the septum (yellow curve) and lateral wall (green curve).
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Figure 6 Myocardial deformation as assessed by strain rate imaging. Negative strain indicates shortening and is expressed as the percentage from its initial end-diastolic length (%). Strain curves obtained from six segments show synchronous onset of shortening and peak shortening in a normal individual (left panel). In contrast, a delay in the onset and the peak of lateral wall shortening (yellow curve) is observed in a patient with heart failure and left bundle branch block (right panel). Postsystolic shortening is present in the late activated lateral wall, as indicated by the late negative peak (arrow).
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Figure 7 Tissue tracking (TT) in a patient with heart failure and left bundle branch block. An irregular distribution of color-bands is seen during systole (left panel), indicating poor systolic performance of the lateral wall. Systolic apical displacement occurs only in the basal part of the lateral wall, whereas the remaining parts of the lateral wall show no net apical displacement during systole (gray color). After adjusting the TT time interval to left ventricular diastole (identified by aortic valve closure and mitral valve closure), the delayed longitudinal shortening of the lateral wall can be visualized by the apical displacement during diastole (right panel).
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Figure 8 Relationship between the septal-lateral phase angle ( LS) at baseline and the best achievable hemodynamic improvement, measured as the percent increase in left ventricular (LV) peak positive dP/dt. Type I: near synchronous wall motion; Type II: delayed lateral wall movement; Type III: biphasic septal motion (based on reference 24).
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