Racial Differences in Age-Related Changes in Left Ventricular Structural and Functional Echocardiographic Measurements Among Healthy Japanese and American Participants　- A Subanalysis of the World Alliance Society of Echocardiography Normal Values Study.

BACKGROUND: Age-related changes in left ventricular (LV) structure and function lower the threshold for the onset of heart failure with preserved ejection fraction (HFpEF). LV parameters change also with race; however, the racial differences in age-related changes in LV parameters with and without adjustment for body mass index (BMI), heart rate (HR), and blood pressure (BP) remain unclear.Methods and Results: We performed a subanalysis of the World Alliance Society of Echocardiography Normal Values Study, an international cross-sectional study that examined normal echocardiographic values in 15 countries. The age-related changes in 2-dimensional echocardiographic derived parameters including LV size, systolic function, and mass, were compared between healthy Japanese (n=227) and healthy White (n=98) and Black (n=69) American participants. In men, age-related changes in all parameters did not differ significantly among races. However, compared with Japanese women, White American women had a smaller body surface area (BSA)-indexed LV volume, BSA-indexed LV internal dimension at end-systole, BSA-indexed LV stroke volume, and LV mass index to BSA, and a larger LV ejection fraction with age, even after adjusting for BMI, HR, and BP. CONCLUSIONS: Age-related changes in LV structure and function, which are important for the pathophysiology of HFpEF, may differ by race. Therefore, future studies examining echocardiographic reference values for each age group in each race are needed.

Sex-Specific Left Ventricular and Aorta Size Cut-Off Values for Hemodynamically Significant Chronic Aortic Regurgitation　- Implications for Treatment in Asian Populations.

BACKGROUND: There are no sex-specific guidelines for chronic aortic regurgitation (AR). This retrospective study examined sex-specific differences and propose treatment criteria from an Asian AR cohort.Methods and Results: Consecutive 1,305 patients with moderate-severe AR or greater at 3 tertiary centers in Taiwan and Japan (2008-2022) were identified. Study endpoints were aortic valve surgery (AVS), all-cause death (ACD), and cardiovascular death (CVD). The median follow up was 3.9 years (interquartile range 1.3-7.1 years). Compared with men (n=968), women (n=337) were older, had more advanced symptoms, more comorbidities, larger indexed aorta size (iAortamax) and indexed left ventricular (LV) end-systolic dimension (LVESDi; P<0.001 for all). Symptomatic status was poorly correlated with the degree of LV remodeling in women (P≥0.18). Women received fewer AVS (P≤0.001) and men had better overall 10-year survival (P<0.01). Ten-year post-AVS survival (P=0.9) and the progression of LV remodeling were similar between sexes (P≥0.16). Multivariable determinants of ACD and CVD were age, advanced symptoms, iAortamax, LV ejection fraction (LVEF), LVESDi, LV end-systolic volume index (LVESVi), and Taiwanese ethnicity (all P<0.05), but not female sex (P≥0.05). AVS was associated with better survival (P<0.01). Adjusted LVEF, LVESDi, LVESVi, and iAortamaxcut-off values for ACD were 53%, 24.8 mm/m2, 44 mL/m2, and 25.5 mm/m2, respectively, in women and 52%, 23.4 mm/m2, 52 mL/m2, and 23.2 mm/m2, respectively, in men. CONCLUSIONS: Early detection and intervention using sex-specific cut-off values may improve survival in women with AR.

Prognostic Value of Apical Sparing of Longitudinal Strain in Patients with Symptomatic Aortic Stenosis.

Background: Older patients with aortic stenosis (AS) have a higher incidence of wild-type transthyretin cardiac amyloidosis (ATTR-CA). This study aimed to determine whether apical sparing of longitudinal strain (LS) could help diagnose ATTR-CA and provide useful prognostic information in symptomatic AS. Methods: We performed vendor-independent two-dimensional speckle-tracking analysis of regional and global left ventricular LS in 16 patients with ATTR-CA and 31 patients with non-obstructive hypertrophic cardiomyopathy to determine the best cutoff value of the apical sparing ratio (APSR) for diagnosing ATTR-CA. We then determined the prevalence in patients who had an APSR higher than the best cutoff value and investigated its prognostic value in 230 patients with symptomatic AS. To determine the natural history of symptomatic AS, patients who had aortic valve replacement were censored at the time of surgery. Results: The best cutoff value of APSR was 0.76. APSR ≥ 0.76 was observed in 108 patients with symptomatic AS (48%). The prevalence was not different among the four AS subgroups. During a median follow-up period of 5.7 months, 47 patients had cardiac events. Cox proportional hazards analysis revealed that neither APSR nor APSR ≥ 0.76 was significantly associated with future cardiac events. Conclusions: Apical sparing was frequently observed in patients with symptomatic AS, and it was not a useful predictor of future adverse outcomes. Our results suggest that the underlying cause of apical sparing in AS may not be related to the presence of ATTR-CA.

A review of current trends in three-dimensional analysis of left ventricular myocardial strain.

Three-dimensional (3D) left ventricular (LV) myocardial strain measurements using transthoracic 3D echocardiography speckle tracking analysis have several advantages over two-dimensional (2D) LV strain measurements, because 3D strain values are derived from the entire LV myocardium, yielding more accurate estimates of global and regional LV function. In this review article, we summarize the current status of 3D LV myocardial strain. Specifically, we describe how 3D LV strain analysis is performed. Next, we compare characteristics of 2D and 3D strain, and we explain validation of 3D strain measurements, feasibility and measurement differences between 2D and 3D strain, reference values of 3D strain, and its applications in several clinical scenarios. In some parts of this review, we used a meta-analysis to draw reliable conclusions. We also describe the added value of 3D over 2D strain in several specific pathologies and prognoses. Finally, we discuss novel techniques using 3D strain and suggest its future directions.

Estimation of B-type Natriuretic Peptide Values from N-Terminal proBNP Levels.

Both brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are established biomarkers that are necessary in the diagnosis and management of heart failure (HF). However, it is difficult to infer BNP concentration from NT-proBNP concentration for a clinician who is familiar with BNP. We investigated whether estimated BNP concentration from NT-proBNP has an equivalent prognostic strength compared with the actual BNP concentration in the prediction of future outcomes. We created a formula for estimating BNP concentration using multivariate analysis in a derivation cohort with known or suspected HF (n = 374). We determined whether the estimated BNP level had a similar prognostic power compared with the actual BNP and NT-proBNP levels in a validation cohort (n = 375). There was a strong correlation between log-transformed BNP and log-transformed NT-proBNP (r = 0.90) in the derivation cohort. We created two types of equation from the derivation cohort. During a median of 1 year of follow up, 49 major adverse cardiac events developed in the validation cohort. Cox proportional analysis revealed that the actual and estimated BNP levels represented equivalent and significant predictors of the future cardiovascular outcome. The estimated BNP levels calculated by our new formula showed a prognostic power similar to the actual BNP levels. This equation will be useful, especially for a physician who is not familiar with NT-proBNP testing.

Insights into the mechanism of paradoxical low-flow, low-pressure gradient severe aortic stenosis: association with reduced O2 consumption by the whole body.

The mechanism of reduced stroke volume index (SVi) in paradoxical low-flow, low-pressure gradient (PLFLPG) aortic stenosis (AS) remains unclarified. Guyton et al. ( 21 ) demonstrated that SVi is determined by whole body O2 consumption (V̇o2) in many subjects, including patients with heart disease. We hypothesized that reduced SVi in PLFLPG AS is associated with reduced V̇o2 by the whole body. This study investigated the relationship between V̇o2, SVi, and AS severity in patients with AS to examine the association between reduced V̇o2 and PLFLPG AS. In 59 patients (24 men and 35 women, mean age: 78 ± 7 yr old) with severe AS, SVi, AS severity, and type were evaluated by echocardiography, and V̇o2 was measured by the fraction of O2 in expired gases. SVi and V̇o2 were significantly decreased in 20 patients with PLFLPG AS compared with 39 patients with non-PLFLPG AS (30 ± 4 vs. 41 ± 7 ml/m2 and 2.4 ± 0.5 vs. 3.0 ± 0.5 ml·min-1·kg-1, respectively, P < 0.01). The SVi-to-V̇o2 ratio was not different between the two groups (13.1 ± 2.6 vs. 13.6 ± 2.1, not significant). SVi was independently correlated with V̇o2 ( r = 0.74, P < 0.01) but not with the aortic valve area index. Categorized PLFLPG AS was also significantly associated with reduced V̇o2 ( P < 0.001). PLFLPG AS is associated with reduced V̇o2 by the whole body, which may offer insights into the mechanism of PLFLPG AS. NEW & NOTEWORTHY Paradoxical low-flow, low-pressure gradient severe aortic stenosis (PLFLPG AS) is an important and problematic subtype, and its central pathophysiology with reduced stroke volume is yet to be clarified. We hypothesized and subsequently clarified that reduced stroke volume in PLFLPG AS is associated with reduced O2 consumption by the whole body. This study suggests important insights into the mechanism of PLFLPG AS and may further promote studies to investigate further mechanisms and novel treatment.

Possible mechanism of late systolic mitral valve prolapse: systolic superior shift of leaflets secondary to annular dilatation that causes papillary muscle traction.

Progressive superior shift of the mitral valve (MV) during systole is associated with abnormal papillary muscle (PM) superior shift in late systolic MV prolapse (MVP). The causal relation of these superior shifts remains unclarified. We hypothesized that the MV superior shift is related to augmented MV superiorly pushing force by systolic left ventricular pressure due to MV annular dilatation, which can be corrected by surgical MV plasty, leading to postoperative disappearance of these superior shifts. In 35 controls, 28 patients with holosystolic MVP, and 28 patients with late systolic MVP, the MV coaptation depth from the MV annulus was measured at early and late systole by two-dimensional echocardiography. The PM tip superior shift was monitored by echocardiographic speckle tracking. MV superiorly pushing force was obtained as MV annular area × (systolic blood pressure - 10). Measurements were repeated after MV plasty in 14 patients with late systolic MVP. Compared with controls and patients with holosystolic MVP, MV and PM superior shifts and MV superiorly pushing force were greater in patients with late systolic MVP [1.3 (0.5) vs. 0.9 (0.6) vs. 3.9 (1.0) mm/m2, 1.3 (0.5) vs. 1.2 (1.0) vs. 3.3 (1.3) mm/m2, and 487 (90) vs. 606 (167) vs. 742 (177) mmHg·cm2·m-2, respectively, means (SD), P < 0.001]. MV superior shift was correlated with PM superior shift ( P < 0.001), which was further related to augmented MV superiorly pushing force ( P < 0.001). MV and PM superior shift disappeared after surgical MV plasty for late systolic MVP. These data suggest that MV annulus dilatation augmenting MV superiorly pushing force may promote secondary superior shift of the MV (equal to late systolic MVP) that causes subvalvular PM traction in patients with late systolic MVP. NEW & NOTEWORTHY Late systolic mitral valve prolapse (MVP) is associated with mitral valve (MV) and papillary muscle (PM) abnormal superior shifts during systole, but the causal relation remains unclarified. MV and PM superior shifts were correlated with augmented MV superiorly pushing force by annular dilatation and disappeared after surgical MV plasty with annulus size and MV superiorly pushing force reduction. This suggests that MV annulus dilatation may promote secondary superior shifts of the MV (late systolic MVP) that cause subvalvular PM traction.

Impact of a training program incorporating cardiac magnetic resonance imaging on the accuracy and reproducibility of two-dimensional echocardiographic measurements of left ventricular volumes and ejection fraction.

BACKGROUND: Left ventricular (LV) ejection fraction (LVEF) assessed by two-dimensional echocardiography (2DE) is the most widely used parameter for clinical decision-making, but reproducibility and accuracy problems remain. We evaluated the usefulness of a novel training program based on cardiac magnetic resonance (CMR) imaging to obtain more reliable values of 2DE-derived LVEF and LV volumes. METHODS: Fifty-four sonographers from five hospitals independently measured LV volumes and LVEF using the same 2DE images from 15 patients who underwent CMR and 2DE. After receiving a lecture from an expert on how to properly trace the LV endocardium, each sonographer voluntary performed the measurements using the same datasets, and was invited to perform the same analysis for additional patients. The effect of the training intervention was evaluated using the coefficient of variation (CV) and coverage probability (CP). RESULTS: Before the intervention, the LV volumes were significantly underestimated and the LVEF was significantly overestimated compared to the CMR results; however, these differences were reduced after the intervention. In particular, the CP (0.52 vs. 0.76, p < 0.001) for the LVEF showed significant improvement. However, the degree of improvement differed among institutions, and the CV actually became worse in two hospitals after the intervention. Level of experience and self-practice was associated with the reproducibility after the intervention. CONCLUSIONS: A training program using CMR as a reference improved the accuracy of 2DE-determined LV measurements. Since the degree of improvements differed among hospitals, individualization of training programs and periodical objective evaluation may be required to reduce inter-institutional variability.

Usefulness of Cibenzoline Stress Echocardiography to Determine Severity of Aortic Stenosis in a Patient with Combined Left Ventricular Outflow Tract Obstruction and Aortic Stenosis.

Left ventricular outflow tract obstruction (LVOTO) is sometimes accompanied by aortic stenosis (AS). Reliable estimation of the true severity of AS is often difficult because it cannot be discriminated from dual stenosis. A 75-year-old woman was referred to our hospital due to traumatic hemopneumothorax with exertional dyspnea. Echocardiography revealed AS and LVOTO by chance. A continuous Doppler echocardiography revealed a late-systolic peaking dagger-shaped profile with a 6.0 m/s of peak jet velocity across the LVOT and aortic valve, but it was difficult to discriminate between the coexisting peak flows. For an accurate evaluation of AS, we performed landiolol (short acting beta-blocker) and cibenzoline (Na+ channel-blocking agent) stress echocardiography with simultaneous recordings of both left ventricular and aortic pressure by catheter examination. Cibenzoline successfully eliminated the LVOTO, but landiolol did not. Cibenzoline stress echocardiography enabled us to evaluate the AS severity as less than moderate, resulting in proper decision-making. The findings in this case clearly showed that cibenzoline stress echocardiography has a potential utility for determining AS severity in a patient with coexistent dynamic LVOTO.

Application of left ventricular strain to patients with coronary artery disease.

PURPOSE OF REVIEW: Myocardial strain imaging has gained popularity during the last decade in various clinical scenarios. The objective of this article was to review the potential application of two-dimensional (2D) and three-dimensional (3D) strains in patients with coronary artery disease. RECENT FINDINGS: Reports on the diagnostic accuracy of myocardial deformation analysis using 2D and 3D speckle-tracking analyses to detect significant coronary stenosis at rest or during stress and to evaluate myocardial viability are limited. A newer 2D strain approach that uses layer-specific strain analysis might be sensitive in the detection of subtle regional myocardial dysfunction induced by myocardial ischemia. However, its potential accuracy is controversial. The regional assessment of wall motion by 2D/3D strain is not recommended because of measurement variabilities. SUMMARY: Further studies are required for the adoption of this technology in patients with coronary artery disease.

[A Case of Cecal Cancer with Liver and Lung Metastases That Maintained Long Stable Disease by TFTD and Bevacizumab Chemotherapy].

The patient was a 69-year-old female diagnosed with cecum cancer, pMP, pN1, sH1, sP0, cM0, fStage IV. A laparoscopic cecal resection with D3 dissection was performed against the primary cecal cancer in January 2015. The histological diagnosis was moderately differentiated adenocarcinoma>mucinous adenocarcinoma, ly1, v0, RAS wild type(not known to start chemotherapy for primary treatment). Liver metastasis is very likely to invade the inferior vena cava, so the liver metastasis was judged unresectable, and mFOLFOX6 and bevacizumab(Bmab)chemotherapy was performed. After 4 courses of chemotherapy, the patient exhibited progressive disease(PD)and was transitioned to a secondary treatment with FOLFIRI plus panitumumab(Pmab)therapy. Lung metastases was observed(PD)upon computed tomography after 16 courses. Therefore, salvage line chemotherapy with TFTD and Bmab was performed. Long stable disease(SD)was obtained by the salvage line chemotherapy with TFTD and Bmab. We suspect that the effects of TFID increased in combination with Bmab. Moreover, the TFTD and Bmab chemotherapy was performed relatively safely.

Ventricular-Arterial Coupling and Exercise-Induced Pulmonary Hypertension During Low-Level Exercise in Heart Failure With Preserved or Reduced Ejection Fraction.

BACKGROUND: Exercise-induced pulmonary hypertension (EIPH) may develop even at low workloads in heart failure (HF) patients. Ventricular-arterial stiffening plays an important role in the pathophysiology of HF with preserved ejection fraction (HFpEF). This study aimed to compare the response of ventricular-arterial coupling and PH during low-level exercise between HFpEF and HF with reduced EF (HFrEF). METHODS AND RESULTS: Echocardiography was performed at rest and during 10 W of bicycle exercise in HFpEF (n = 37) and HFrEF (n = 43). Load-independent contractility (end-systolic elastance [Ees], preload recruitable stroke work [PRSW], and peak power index [PWRI]), arterial afterload (arterial elastance [Ea]), and ventricular-arterial interaction (Ea/Ees) were measured with the use of a noninvasive single-beat technique. EIPH was defined as an estimated pulmonary arterial systolic pressure (PASP) of ≥50 mm Hg at 10 W of exercise. PASP was significantly increased during 10 W of exercise in both HF types, and ~50% of HFpEF patients developed EIPH. Arterial afterload was increased significantly during exercise in both groups. HFrEF and HFpEF patients showed a significant increase in LV contractility assessed by Ees, PRSW, and PWRI during exercise. Although Ea/Ees ratio decreased significantly in HFrEF, reduction in Ea/Ees was attenuated because of blunted Ees increases in patients with HFpEF compared with HFrEF. CONCLUSIONS: Even at low-level exercise, ~50% of HFpEF patients developed EIPH. Reduction in Ea/Ees was attenuated owing to less Ees increase in HFpEF compared with HFrEF. Further studies are needed to elucidate the association between ventricular-arterial coupling and EIPH in HFpEF.

Prognostic value of biventricular mechanical parameters assessed using cardiac magnetic resonance feature-tracking analysis to predict future cardiac events.

PURPOSE: To study and compare the prognostic value of cardiac magnetic resonance feature tracking (MR-FT) of biventricular strain parameters with a conventional method. MATERIALS AND METHODS: We retrospectively enrolled 364 patients undergoing clinically indicated cardiac MR examinations (1.5 or 3T scanner). Standard steady-state free precession (SSFP) images were used for analysis. Left ventricular (LV) and right ventricular (RV) ejection fraction (EF) were measured using conventional disk-area summation methods. Biventricular strain parameters were measured using MR-FT. All patients were followed to record major adverse cardiac events (MACEs). RESULTS: The correlations between LV volumes and LVEF using both methods were excellent (r = 0.87-0.98). RV strain parameters were modestly correlated with RVEF (r = 0.44-0.63). During a median follow-up of 15 months, 36 patients developed MACEs. All MR-FT-derived parameters except for RV global longitudinal strain were significantly associated with future MACEs (P < 0.05) in univariate analysis. In stepwise Cox proportional hazard models, RV global radial strain (RVGRS) provided incremental prognostic value in models adjusted for age, gender, conventional LVEF (hazard ratio 0.93; P = 0.029) or RVEF (hazard ratio 0.93; P = 0.038). LV global transverse strain (LVGTS) also offered additional value over age, gender, conventional LVEF (hazard ratio 0.94; P = 0.041), or RVEF (hazard ratio 0.94; P = 0.004). Kaplan-Meier analysis showed significant survival differences in subgroups stratified by the median value of LVGTS, RVGRS, and LVEF using MR-FT (all log-rank P < 0.05). CONCLUSION: Deformation analysis of both ventricles using MR-FT provided significant prognostic power similar to parameters obtained using conventional methods. MR-FT is a promising alternative both for ventricular chamber quantification and for providing information of future cardiac events. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:1034-1045.

Three-Dimensional Echocardiography: Current Status and Real-Life Applications.

The use of cardiac ultrasound is fundamental to the understanding of normal heart function and crucial to pathophysiological diagnosis. The growing availability of 3D echocardiography (3DE) over the last decade has allowed its applications to expand from establishing reference values for chamber size and elucidating ventricular mechanics, to assessing valvular disease severity and playing pivotal roles in interventional procedures. Several important advantages of 3DE include eliminating geometric assumptions, quantifying complex geometric shape volumes, viewing structures from any perspective, assessing lesion in simultaneous multiplanes or multislice mode, all of which are not possible with traditional 2D echocardiography (2DE). Real-time 3DE has been shown to be simple, accurate, reproducible, and versatile, and generally has superior outcome prognosis compared to the 2DE.

Coronary Artery Imaging with Transthoracic Doppler Echocardiography.

Coronary artery imaging with transthoracic Doppler echocardiography is a simple and useful technique to diagnose significant coronary artery stenosis. The visualization of mosaic flow in the proximal left coronary artery provides a direct indication of the presence of significant stenosis at the corresponding site during routine echocardiography. Coronary flow velocity reserve (CFVR) has a high diagnostic accuracy and feasibility in detecting the presence of functionally significant coronary stenosis in the left anterior descending coronary artery (LAD) and in the right coronary artery. The measurement of CFVR in the LAD also provides prognostic information in patients with intermediate coronary stenosis. This review summarizes the utility of transthoracic coronary artery imaging.

Risk Factors for Progression of Degenerative Aortic Valve Disease in the Japanese- The Japanese Aortic Stenosis Study (JASS) Prospective Analysis.

BACKGROUND: Because of ethnic difference in the risk of degenerative aortic valve disease (DAVD), risk factors should be clarified in each race to establish prophylactic strategies for severe aortic valve stenosis (AS). METHODS AND RESULTS: This study prospectively followed 359 Japanese subjects with DAVD and age ≥50 years for 3 years. As both patients with peak aortic transvalvular flow velocity ≥2 m/s and <2 m/s were enrolled, subgroup analysis was also conducted. Most patients were under treatment for their comorbidities. The use of warfarin, but none of the traditional risk factors for atherosclerosis, was related to greater reduction in aortic valve area indexed to body surface area (iAVA). In patients with peak aortic transvalvular flow velocity <2 m/s, the use of an angiotensin-receptor blocker (ARB) was associated with less decrease in iAVA. In patients with peak velocity ≥2 m/s, changes in iAVA were not related to any baseline characteristics, but peak velocity was less increased under treatment with an angiotensin-converting enzyme inhibitor (ACEI). CONCLUSIONS: In Japanese, the use of warfarin may exacerbate DAVD, and augmented management of atherosclerotic risk factors beyond the recommendations in the current guidelines is unlikely to exert additional benefit. The prescription of ARB for DAVD patients before the development of AS or ACEI after the development of AS may be useful.

Prognostic Implication of Three-Dimensional Mitral Valve Tenting Geometry in Dilated Cardiomyopathy.

BACKGROUND AND AIM OF THE STUDY: Functional mitral regurgitation (FMR) is a clinically important complication of left ventricular (LV) dysfunction, occurring as a result of geometric deformity in the mitral valve (MV) complex. The study aim was to determine whether tenting parameters derived from real-time three-dimensional echocardiography (RT3DE) can predict the long-term prognosis for patients with dilated cardiomyopathy (DCM). METHODS: Mitral valve tenting morphology, LV volume and function, and papillary muscle positions were monitored using transthoracic RT3DE in 75 subjects (66 with DCM, nine controls). The maximum tenting sites of the leaflet (maxTS) were also mapped from the reconstructed 3D images, to determine if the 3D tenting parameters correlated to long-term outcome. RESULTS: Follow up information was collected from 62 patients with DCM over a mean period of 42 +/- 31 months. Cardiovascular events occurred in 30 patients (48%), including 13 cardiac deaths (21%). The patients were allocated to an Event group (n = 30) or a Non-event group (n = 32). The LV volumes were significantly larger and LV ejection fraction was lower in the Event group compared to the Non-event group. The 3D tenting volumes were significantly larger in the Event group than the Non- event group (p = 0.05). The maxTS were positioned mostly in the middle portion of the anterior mitral leaflet in the Non-event group (maxTS-mid AML), but in the Event group they were mostly found in the MV coaptation region of the leaflet (maxTS-coapt) (p <0.001). Patients with maxTS-coapt had a worse prognosis compared to those with maxTS-mid AML. On multivariate Cox regression analysis, maxTS was the strongest predictor of event-free survival. CONCLUSION: The 3D tenting pattern, assessed with RT3DE, would be an important clinical parameter in predicting long-term prognosis in patients with DCM.

Assessment of the developmental change in the left atrial volume using real time three-dimensional echocardiography.

AIMS: Real time 3D echocardiography (RT3DE) has been applied for the assessment of left atrial (LA) function in patients with adult heart disease; however, LA function is not well known in children. We aimed at determining the normal range of LA volume (LAV) using RT3DE and the feasibility and reproducibility of this method in healthy subjects and at elucidating the developmental changes in the LAV with aging. METHODS AND RESULTS: In this study, 359 healthy people (mean age, 23.9 ± 21.3; range, 0.1-76.4 years) were enrolled. We performed transthoracic RT3DE and measured the maximum and minimum LAV. Simultaneously, we measured the LAV using the 2D biplane Simpson's method. Inter-observer and intra-observer variability and the agreement of LAV measurements between RT3DE and 2DE were assessed in a subset of subjects. The RT3DE feasibility for LAV measurement was 93%. Both maximum and minimum LAVs exponentially increased with age and linearly increased with increasing of body surface area (BSA). The LA distensibility, which demonstrates LA reservoir function, decreased with age and BSA. The LAVs measured by RT3DE were significantly smaller than those measured by the 2D biplane Simpson's method. The 3D volumetric method had favorable intra-observer and inter-observer agreement. CONCLUSION: The reference values of LAV from early infancy to adulthood were obtained using RT3DE, which could be useful for future studies in children with congenital heart disease. RT3DE is a reproducible method and a feasible tool for evaluating the LAV in children. LA reservoir function is likely to decrease with age and increasing of body size.

Atrial pacing site and atrioventricular conduction in patients paced for sinus node disease.

BACKGROUND: Unnecessary ventricular pacing in sinus node disease (SND) must be avoided. To test the hypothesis that in SND, with or without 1st degree atrioventricular (AV) block, cumulative percent ventricular pacing (cum%VP) can be limited by low right atrial septal (LRAS) instead of right atrial appendage (RAA) pacing. METHODS: We studied 102 dual-chamber pacemaker recipients with SND. The PQ interval on 12-lead electrocardiogram and the atrial paced to ventricular sensed interval (Ap-Vs) during LRAS and RAA pacing were measured and compared at implantation, 3 months and 1 year of follow-up. Group 1 included 62 patients with baseline PQ interval <200 milliseconds during LRAS (n = 28) versus RAA (n = 34) pacing. Group 2 included 40 patients with baseline PQ ≥200 milliseconds during LRAS (n = 20) versus RAA (n = 20) pacing. cum%VP were measured at 3 months and 1 year. RESULTS: The characteristics and AV conduction properties were similar and the Ap-Vs interval was significantly shorter in the LRAS than in the RAA pacing group up to 1 year (193 ± 32 milliseconds vs. 220 ± 27 milliseconds in Group 1; P = 0.003, 222 ± 41 milliseconds vs. 281 ± 30 milliseconds in Group 2; P < 0.001). While cumulative percent atrial pacing was consistently similar, cum%VP was significantly smaller during LRAS than RAA pacing (1 ± 1% vs. 8 ± 18% in Group 1; P = 0.03, 7 ± 10% vs. 48 ± 38% in Group 2; P < 0.001). Similar observations were made with or without left atrial (LA) enlargement. CONCLUSION: Compared with RAA, LRAS pacing showed shorter AV interval in SND patients with or without 1st degree AV block and LA enlargement. This beneficial effect persisted through 1-year follow-up, and decreased cum%VP significantly.