Improvement of left ventricular mechanical dyssynchrony associated with restoration of left ventricular function in a patient with fulminant myocarditis and complete left bundle branch block

Long-term imaging analysis of a myocarditis case: Utilizing strain with echocardiography and cardiovascular magnetic resonance findings

Herein, we report a case of myocarditis in a 27-year-old male with long-term follow-up using longitudinal peak systolic strain (LPSS) measurements with transthoracic echocardiography (TTE) and late gadolinium enhancement (LGE) in cardiovascular magnetic resonance imaging (CMR). On admission, a predominant decrease was observed in the LPSS in the posterolateral segments of the TTE. After a period of two weeks, the values of the LPSS observed in the posterolateral segments were still slightly reduced, which is consistent with the LGE results in CMR. After a duration of 16 months, an improvement was noted in the LPSS and LGE results in all the segments. Moreover, a time-phase discrepancy was observed in the segmental longitudinal strain curve for a period of two weeks from the onset of myocarditis. However, an improvement in the discrepancy was detected after 16 months.

Learning objective

Longitudinal peak systolic strain (LPSS) on transthoracic echocardiography (TTE) has predominantly focused on diagnosing the acute phase of myocarditis. Herein, LPSS was evaluated not only in the acute phase but also in the chronic phase. Furthermore, the relationship between the results of segmental LPSS and late gadolinium enhancement was documented. We would like to emphasize the usefulness of LPSS on TTE both for identifying myocarditis and as a tool for the long-term follow-up of patients.

How to approach the great mimic? Improving techniques for the diagnosis of myocarditis

Myocarditis is characterized by inflammation of the myocardium, assessed by histological, immunological and immunohistochemical criteria, due to exogenous or endogenous causes. Abnormal QRS, increased troponin T and left ventricular regional or global dysfunction may be detected. Strain Doppler echocardiography can detect longitudinal segmental dysfunction of the myocardium, due to edema, which is in agreement with cardiac magnetic resonance imaging. Nuclear imaging shows a good sensitivity, but carries serious limitations. Somatostatin receptor positron emission tomography/computed tomography seems promising. Cardiac magnetic resonance imaging, using T2-weighted, early T1-weighted, delayed enhanced images and recently T2 and T1 mapping, has the best diagnostic capability. Endomyocardial biopsy has further contributed to the etiologic diagnosis of myocarditis. To conclude, cardiac magnetic resonance and endomyocardial biopsy have both significantly increased our diagnostic performance. However, further assessment by multicenter studies is needed to establish a clinically useful algorithm.

Assessment of mechanical dyssynchrony in fulminant myocarditis

It is often difficult to assess ventricular synchrony in patients with fulminant myocarditis. We report a pediatric case of fulminant myocarditis where clinical course and changes in dyssynchrony were followed with speckle tracking echocardiography. Dyssynchrony of the left ventricle changed day by day. It was useful to assess the progression of ventricular damage and its recovery.

Phase space analysis of myocardial coordination related to left ventricular ejection fraction by echocardiographic speckle-tracking radial strain

Phase space reconstruction, which is performed by converting echocardiogram-derived strain data from different ventricular regions into phase space trajectories, is applied in this study to describe nonlinear behaviour of myocardial coordination. A new method was developed to quantify patterns of phase space trajectories. Echocardiograms of 31 healthy individuals and 63 patients with left bundle branch block (LBBB) and different left ventricular ejection fractions (LVEFs) were used to evaluate this method. The LBBB patients were separated into two groups: LBBB with a LVEF≥50% and LBBB with a LVEF<50%. LVEF is used to represent levels of systolic function and disease severity. A classifying map was constructed to separate the reconstructed phase space into three zones and to acquire the parameters Pz1, Pz2 and Pz3 as percentiles of phase points related to the zones. The criteria used to define the zones were cross-tested. Based on these parameters, significant group-related differences in myocardial coordination were observed. Significantly smaller Pz1 and significantly larger Pz2 values were observed in the healthy group, as compared to the patient group, and similar, significant results were obtained for the patients with LVEF≥50%, as compared to the patients with LVEF<50% (p<.05). A significantly larger Pz3 was observed in patients with LVEF<50%, as compared to the other patients (p<.05). In addition, different inter-regional relationships among strain pairs (all, near-side, middle-side and opposite-wall) were examined to create phase space trajectories. Consistent group-related differences were observed when different inter-regional relationships were applied. Expanding the use of the proposed method to assess various pathological factors and therapeutic impacts is promising.

Assessment of myocardial mechanics using speckle tracking echocardiography: fundamentals and clinical applications

The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle. STE holds promise to reduce interobserver and intraobserver variability in assessing regional LV function and to improve patient care while reducing health care costs through the early identification of subclinical disease. Following a brief overview of the approach, the authors pool the initial observations from clinical studies on the development, validation, merits, and limitations of STE.

Isolated left bundle branch block mimicking outflow ventricular septal defect in a fetus

Bundle branch block (BBB) is impossible to diagnose in a fetus with conventional fetal echocardiography. Isolated left BBB is rare in the neonatal period. Asymmetric left ventricular remodeling in isolated left BBB is secondary to chronic dyschronous activation and relaxation, resulting in thinning of the interventricular septum (IVS). This report describes a case of possible ventricular septal defect diagnosed at 34 weeks of gestation due to significant dropout in the outflow portion of the IVS seen in multiple views secondary to undiagnosed isolated left BBB in a fetus, with postnatal follow-up evaluation.

Speckle tracking in the evaluation of left ventricular dyssynchrony

A number of echocardiographic techniques have been introduced to determine left ventricular dyssynchrony (LVD) and to improve selection of patients for CRT. During the last years tissue Doppler imaging (TDI) has been used as the most preferred technique to quantify LVD, but results with nonresponder rates below 30% have been shown only in small studies based on high experience. Angle of incidence dependency, noise, artifacts, and tethering motion of adjacent segments are the main limitations of TDI influencing selection of patients for CRT. Although strain TDI is not affected by translation or tethering, accurate measurement of regional strain is also limited. Two-dimensional (2D) strain imaging based on novel speckle tracking echocardiography (STE) is a relatively new tool to define regional myocardial strain and to quantify dyssynchrony based on a more robust technique and avoiding angle of incidence. Current studies are promising to use strain or vector velocity imaging derived from STE for qualitative and quantitative assessment of LVD and follow-up studies as well. If one compare different types of strain components at present, radial strain imaging seems to be the most promising technique to determine LVD and to predict positive response to CRT. Furthermore, STE offers an insight into rotational mechanics of the dyssynchronous ventricle. Although clinical studies using 2D strain have analyzed LVD related to various conditions, measures are based on a 2D data set. Three-dimensional strain imaging, based on speckle tracking will probably open a new door to assess patients with heart failure and LVD.