The study population consisted of 13 patients with ILVNC from the Cardiology Center of the University of Szeged, Hungary, and 23 age- and gender-matched healthy volunteers, who served as normal controls. All patients and controls were in sinus rhythm and all were examined by two-dimensional Doppler echocardiography and 3DSTE. The echocardiographic diagnostic criteria for ILVNC of Jenni et al.1 were used:

• (1)

  Segmental and excessive thickening of the LV wall with a two-layered structure, consisting of a thin, compacted epicardial layer and a thicker, noncompacted layer. The latter has a characteristic appearance with numerous prominent trabeculations (meshwork) and deep intertrabecular recesses. LV thickening is predominant in the apical, mid-lateral, and mid-inferior walls.

• (2)

  A noncompacted/compacted myocardial thickness ratio >2 measured at maximal thickness in end-systole in parasternal short-axis view.

• (3)

  Evidence of deeply perfused intertrabecular recesses communicating with the LV cavity by color Doppler echocardiography.

• (4)

  Coexisting cardiac anomalies are absent.

The present work is part of the Motion Analysis of the heart and Great vessels bY three-dimensionAl speckle-tRacking echocardiography in Pathological cases (MAGYAR-Path) Study (‘Magyar’ means ‘Hungarian’ in the Hungarian language), which aims to examine the diagnostic and prognostic significance of 3DSTE-derived parameters in specific disorders. The study protocol was approved by the institutional review board on biomedical research, and all patients and healthy subjects gave informed consent consistent with the protocol.

A Toshiba Artida™ ultrasound system (Toshiba Medical Systems, Tokyo, Japan) with a PST-30SBP (1-5 MHz) phased-array transducer was used for standard Doppler echocardiographic examinations. All echocardiographic studies were digitally recorded and evaluated by experts (AK, DP). Simpson's method was used to calculate LV ejection fraction, while LV and LA internal dimensions were measured by M-mode echocardiography. Tricuspid annular plane systolic excursion (TAPSE) and right ventricular fractional area change (RVFAC) were calculated to characterize RV function. Color Doppler echocardiography was used to visually quantify the degree of tricuspid and mitral regurgitation.

A special matrix phased-array transducer (2.5 MHz PST-25SX; Toshiba Medical Systems, Tokyo, Japan) was used for the acquisition of 3D echocardiographic datasets in apical view.6,7 Six R-wave-triggered subvolumes were acquired during six consecutive cardiac cycles and one breath-hold to form the pyramid-shaped 3D full volume including the RA. 3D Wall Motion Tracking software version 2.7 (Toshiba Medical Systems, Tokyo, Japan) was used for RA quantifications. Firstly, apical two-chamber (AP2CH) and four-chamber (AP4CH) views and three short-axis views at different levels of the RA at end-diastole were automatically selected from the full volume 3D dataset by the software. After finding optimal non-foreshortened views by optimizing long-axis views, the reader set markers on orthogonal AP2CH and AP4CH views. Firstly, the edge of the lateral wall-tricuspid annulus was traced, then markers were set in a counterclockwise rotation around the RA to the edge of the septum-tricuspid annulus. The RA appendage, caval veins and coronary sinus were excluded from the RA cavity during evaluations. Finally, the 3D endocardial surface of the RA was automatically reconstructed and tracked in 3D space throughout the entire cardiac cycle. The user could correct the shape of the RA if needed (Figure 1). The same 3DSTE-derived methodology for detailed assessment of atrial function including volumetric and strain measurements applied initially for the LA was used during evaluations.8

Figure 1.

Images from the three-dimensional speckle-tracking echocardiography-derived full-volume dataset. Apical 4-chamber (A) and 2-chamber (B) views and parasternal short-axis views at basal (C3), mid-atrial (C5) and superior (C7) right atrial level are displayed. Right atrial volumetric data and three-dimensional right atrial cast together with time-global volume (dashed line) and segmental time-longitudinal strain (colored lines) curves are also demonstrated. The method presented allows automatic measurement of peak strains (white arrow) and strains at atrial contraction (dashed arrow). EDV: end-diastolic volume; ESV: end-systolic volume; EF: ejection fraction; RA: right atrium; RV: right ventricle.

(0.11MB).

The following RA volumetric data were calculated: end-systolic maximum RA volume (Vmax, before tricuspid valve opening); early diastolic RA volume before atrial contraction (VpreA, at the time of the P wave on the ECG); and end-diastolic minimum RA volume (Vmin, before tricuspid valve closure). From RA cyclic volumetric data several parameters featuring all phases of LA function (reservoir, conduit and active contraction) were calculated (Table 1).10

Using the same 3D dataset, similarly to other studies, several one-directional (longitudinal, LS; radial, RS; circumferential, CS) and complex (area strain: AS; 3D strain: 3DS) strain parameters were measured in each case.10 Peak strains were calculated for the RA reservoir phase, while strains at atrial contraction were calculated for the RA booster pump phase. Global, mean segmental and regional strains were measured.

Results are expressed as mean ± standard deviation. Data were compared with the two-tailed Student's t test, chi-square analysis, and Fisher's exact test. Statistical significance was a p value <0.05. All calculations were performed with MedCalc software (MedCalc, Inc., Mariakerke, Belgium).

Clinical and two-dimensional echocardiographic features of ILVNC patients and of controls are presented in Table 2. Significant (grade >2) mitral and tricuspid regurgitation was detected in four (31%) and two (15%) patients with ILVNC, respectively, but in none of the controls. LV dimensions were significantly increased in ILVNC, while LV ejection fraction was significantly reduced (Table 2). The TAPSE and RVFAC values of ILVNC patients were 14.8±4.3 mm and 35.5±3.2%, respectively. Five ILVNC patients had reduced RVFAC (mean 31.8±0.84%), while eight ILVNC patients had normal RVFAC (mean 37.8±1.0%).

The mean volume rate was 27±3 Hz. Increased Vmax, VpreA and Vmin were detected in ILVNC patients (Table 3). Only total (TASV) and passive (PASV) RA stroke volumes, representing features of the RA reservoir and conduit phases, were found to be increased in ILVNC; active RA stroke volume (AASV) and all emptying fractions did not differ between ILVNC patients and matched controls. Global, mean segmental and mean regional peak strains and strains at atrial contraction did not show significant differences between ILVNC patients and controls (Tables 4–7). Increased Vmax (59.0±16.9 ml vs. 58.1±12.6 ml, p=0.92), Vmin (38.7±16.0 ml vs. 43.2±14.8 ml, p=0.62), VpreA (45.0±18.4 ml vs. 51.0±12.9 ml, p=0.54), TASV (20.3±9.5 ml vs. 14.9±5.4 ml, p=0.28) and PASV (14.9±15.4 ml vs. 7.1±3.5 ml, p=0.28) were observed in ILVNC patients regardless of the presence or absence of RV dysfunction demonstrated by RVFAC.

The study has several limitations:

• -

  The RA appendage, coronary sinus and caval veins were excluded from assessments, as in other 3DSTE studies assessing the RA.22,23 This should be taken into consideration when interpreting the results.

• -

  Although there was the opportunity to assess the LV, RV and LA by 3DSTE, this was beyond the scope of this study.

• -

  Only a small number of ILVNC patients from a single tertiary center were examined. However, it should be borne in mind that ILVNC is a relatively rare disorder. Therefore, further multicenter 3DSTE studies with larger patient populations are warranted to confirm our findings.

• -

  There were important technical limitations, including low spatial and temporal resolution.7–9 It is known that 3DSTE is currently subject to these technical limitations, and significant improvements in image resolution are required.

• -

  Finally, there is disagreement as to whether the atrial septum is a part of the LA or the RA. In the present study the septum was considered as a part of the virtual 3D cast of the RA.

The authors declare that the procedures followed were in accordance with the regulations of the relevant clinical research ethics committee and with those of the Code of Ethics of the World Medical Association (Declaration of Helsinki).

The authors declare that they have followed the protocols of their work center on the publication of patient data.

The authors have obtained the written informed consent of the patients or subjects mentioned in the article. The corresponding author is in possession of this document.