Organization and Activity of Italian Echocardiographic Laboratories: A Survey of the Italian Society of Echocardiography and Cardiovascular Imaging.

Background: The Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI) conducted a national survey to understand better how different echocardiographic modalities are used and accessed in Italy. Methods: We analyzed echocardiography laboratory activities over a month (November 2022). Data were retrieved via an electronic survey based on a structured questionnaire, uploaded on the SIECVI website. Results: Data were obtained from 228 echocardiographic laboratories: 112 centers (49%) in the northern, 43 centers (19%) in the central, and 73 (32%) in the southern regions. During the month of observation, we collected 101,050 transthoracic echocardiography (TTE) examinations performed in all centers. As concern other modalities there were performed 5497 transesophageal echocardiography (TEE) examinations in 161/228 centers (71%); 4057 stress echocardiography (SE) examinations in 179/228 centers (79%); and examinations with ultrasound contrast agents (UCAs) in 151/228 centers (66%). We did not find significant regional variations between the different modalities. The usage of picture archiving and communication system (PACS) was significantly higher in the northern (84%) versus central (49%) and southern (45%) centers (P < 0.001). Lung ultrasound (LUS) was performed in 154 centers (66%), without difference between cardiology and noncardiology centers. The evaluation of left ventricular (LV) ejection fraction was evaluated mainly using the qualitative method in 223 centers (94%), occasionally with the Simpson method in 193 centers (85%), and with selective use of the three-dimensional (3D) method in only 23 centers (10%). 3D TTE was present in 137 centers (70%), and 3D TEE in all centers where TEE was done (71%). The assessment of LV diastolic function was done routinely in 80% of the centers. Right ventricular function was evaluated using tricuspid annular plane systolic excursion in all centers, using tricuspid valve annular systolic velocity by tissue Doppler imaging in 53% of the centers, and using fractional area change in 33% of the centers. When we divided into cardiology (179, 78%) and noncardiology (49, 22%) centers, we found significant differences in the SE (93% vs. 26%, P < 0.001), TEE (85% vs. 18%), UCA (67% vs. 43%, P < 0001), and STE (87% vs. 20%, P < 0.001). The incidence of LUS evaluation was similar between the cardiology and noncardiology centers (69% vs. 61%, P = NS). Conclusions: This nationwide survey demonstrated that digital infrastructures and advanced echocardiography modalities, such as 3D and STE, are widely available in Italy with a notable diffuse uptake of LUS in the core TTE examination, a suboptimal diffusion of PACS recording, and conservative use of UCA, 3D, and strain. There are significant differences between northern and central-southern regions and echocardiographic laboratories that pertain to the cardiac unit. This inhomogeneous distribution of technology represents one of the main issues that must be solved to standardize the practice of echocardiography.

Stress Echocardiography in Italian Echocardiographic Laboratories: A Survey of the Italian Society of Echocardiography and Cardiovascular Imaging.

Background: The Italian Society of Echography and Cardiovascular Imaging (SIECVI) conducted a national survey to understand the volumes of activity, modalities and stressors used during stress echocardiography (SE) in Italy. Methods: We analyzed echocardiography laboratory activities over a month (November 2022). Data were retrieved through an electronic survey based on a structured questionnaire, uploaded on the SIECVI website. Results: Data were obtained from 228 echocardiographic laboratories, and SE examinations were performed in 179 centers (80.6%): 87 centers (47.5%) were in the northern regions of Italy, 33 centers (18.4%) were in the central regions, and 61 (34.1%) in the southern regions. We annotated a total of 4057 SE. We divided the SE centers into three groups, according to the numbers of SE performed: <10 SE (low-volume activity, 40 centers), between 10 and 39 SE (moderate volume activity, 102 centers) and ≥40 SE (high volume activity, 37 centers). Dipyridamole was used in 139 centers (77.6%); exercise in 120 centers (67.0%); dobutamine in 153 centers (85.4%); pacing in 37 centers (21.1%); and adenosine in 7 centers (4.0%). We found a significant difference between the stressors used and volume of activity of the centers, with a progressive increase in the prevalence of number of stressors from low to high volume activity (P = 0.033). The traditional evaluation of regional wall motion of the left ventricle was performed in all centers, with combined assessment of coronary flow velocity reserve (CFVR) in 90 centers (50.3%): there was a significant difference in the centers with different volume of SE activity: the incidence of analysis of CFVR was significantly higher in high volume centers compared to low - moderate - volume (32.5%, 41.0% and 73.0%, respectively, P < 0.001). The lung ultrasound (LUS) was assessed in 67 centers (37.4%). Furthermore for LUS, we found a significant difference in the centers with different volume of SE activity: significantly higher in high volume centers compared to low - moderate - volume (25.0%, 35.3% and 56.8%, respectively, P < 0.001). Conclusions: This nationwide survey demonstrated that SE was significantly widespread and practiced throughout Italy. In addition to the traditional indication to coronary artery disease based on regional wall motion analysis, other indications are emerging with an increase in the use of LUS and CFVR, especially in high-volume centers.

Reshaping of Italian Echocardiographic Laboratories Activities during the Second Wave of COVID-19 Pandemic and Expectations for the Post-Pandemic Era.

BACKGROUND: Cardiology divisions reshaped their activities during the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to analyze the organization of echocardiographic laboratories and echocardiography practice during the second wave of the COVID-19 pandemic in Italy, and the expectations for the post-COVID era. METHODS: We analyzed two different time periods: the month of November during the second wave of the COVID-19 pandemic (2020) and the identical month during 2019 (November 2019). RESULTS: During the second wave of the COVID-19 pandemic, the hospital activity was partially reduced in 42 (60%) and wholly interrupted in 3 (4%) echocardiographic laboratories, whereas outpatient echocardiographic activity was partially reduced in 41 (59%) and completely interrupted in 7 (10%) laboratories. We observed an important change in the organization of activities in the echocardiography laboratory which reduced the operator-risk and improved self-protection of operators by using appropriate personal protection equipment. Operators wore FFP2 in 58 centers (83%) during trans-thoracic echocardiography (TTE), in 65 centers (93%) during transesophageal echocardiography (TEE) and 63 centers (90%) during stress echocardiography. The second wave caused a significant reduction in number of echocardiographic exams, compared to November 2019 (from 513 ± 539 to 341 ± 299 exams per center, -34%, p < 0.001). On average, there was a significant increase in the outpatient waiting list for elective echocardiographic exams (from 32.0 ± 28.1 to 45.5 ± 44.9 days, +41%, p < 0.001), with a reduction of in-hospital waiting list (2.9 ± 2.4 to 2.4 ± 2.0 days, -17%, p < 0.001). We observed a large diffusion of point-of-care cardiac ultrasound (88%), with a significant increase of lung ultrasound usage in 30 centers (43%) during 2019, extended to all centers in 2020. Carbon dioxide production by examination is an indicator of the environmental impact of technology (100-fold less with echocardiography compared to other cardiac imaging techniques). It was ignored in 2019 by 100% of centers, and currently it is considered potentially crucial for decision-making in cardiac imaging by 65 centers (93%). CONCLUSIONS: In one year, major changes occurred in echocardiography practice and culture. The examination structure changed with extensive usage of point-of-care cardiac ultrasound and with lung ultrasound embedded by default in the TTE examination, as well as the COVID-19 testing.

Echocardiographic reference ranges for normal left ventricular layer-specific strain: results from the EACVI NORRE study.

AIMS: To obtain the normal range for 2D echocardiographic (2DE) measurements of left ventricular (LV) layer-specific strain from a large group of healthy volunteers of both genders over a wide range of ages. METHODS AND RESULTS: A total of 287 (109 men, mean age: 46 ± 14 years) healthy subjects were enrolled at 22 collaborating institutions of the EACVI Normal Reference Ranges for Echocardiography (NORRE) study. Layer-specific strain was analysed from the apical two-, three-, and four-chamber views using 2DE software. The lowest values of layer-specific strain calculated as ±1.96 standard deviations from the mean were -15.0% in men and -15.6% in women for epicardial strain, -16.8% and -17.7% for mid-myocardial strain, and -18.7% and -19.9% for endocardial strain, respectively. Basal-epicardial and mid-myocardial strain decreased with age in women (epicardial; P = 0.008, mid-myocardial; P = 0.003) and correlated with age (epicardial; r = -0.20, P = 0.007, mid-myocardial; r = -0.21, P = 0.006, endocardial; r = -0.23, P = 0.002), whereas apical-epicardial, mid-myocardial strain increased with the age in women (epicardial; P = 0.006, mid-myocardial; P = 0.03) and correlated with age (epicardial; r = 0.16, P = 0.04). End/Epi ratio at the apex was higher than at the middle and basal levels of LV in men (apex; 1.6 ± 0.2, middle; 1.2 ± 0.1, base 1.1 ± 0.1) and women (apex; 1.6 ± 0.1, middle; 1.1 ± 0.1, base 1.2 ± 0.1). CONCLUSION: The NORRE study provides useful 2DE reference ranges for novel indices of layer-specific strain.

Correlation between non-invasive myocardial work indices and main parameters of systolic and diastolic function: results from the EACVI NORRE study.

AIMS: The present study sought to evaluate the correlation between indices of non-invasive myocardial work (MW) and left ventricle (LV) size, traditional and advanced parameters of LV systolic and diastolic function by 2D echocardiography (2DE). METHODS AND RESULTS: A total of 226 (85 men, mean age: 45 ± 13 years) healthy subjects were enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. Global work index (GWI), global constructive work (GCW), global work waste (GWW), and global work efficiency (GWE) were estimated from LV pressure-strain loops using custom software. Peak LV pressure was estimated non-invasively from brachial artery cuff pressure. LV size, parameters of systolic and diastolic function and ventricular-arterial coupling were measured by echocardiography. As advanced indices of myocardial performance, global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were obtained. On multivariable analysis, GWI was significantly correlated with GLS (standardized beta-coefficient = -0.23, P < 0.001), ejection fraction (EF) (standardized beta-coefficient = 0.15, P = 0.02), systolic blood pressure (SBP) (standardized beta-coefficient = 0.56, P < 0.001) and GRS (standardized beta-coefficient = 0.19, P = 0.004), while GCW was correlated with GLS (standardized beta-coefficient = -0.55, P < 0.001), SBP (standardized beta-coefficient = 0.71, P < 0.001), GRS (standardized beta-coefficient = 0.11, P = 0.02), and GCS (standardized beta-coefficient = -0.10, P = 0.01). GWE was directly correlated with EF and inversely correlated with Tei index (standardized beta-coefficient = 0.18, P = 0.009 and standardized beta-coefficient = -0.20, P = 0.004, respectively), the opposite occurred for GWW (standardized beta-coefficient =--0.14, P = 0.03 and standardized beta-coefficient = 0.17, P = 0.01, respectively). CONCLUSION: The non-invasive MW indices show a good correlation with traditional 2DE parameters of myocardial systolic function and myocardial strain.

Echocardiographic reference ranges for normal non-invasive myocardial work indices: results from the EACVI NORRE study.

AIMS: To obtain the normal ranges for 2D echocardiographic (2DE) indices of myocardial work (MW) from a large group of healthy volunteers over a wide range of ages and gender. METHODS AND RESULTS: A total of 226 (85 men, mean age: 45 ± 13 years) healthy subjects were enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. Global work index (GWI), global constructive work (GCW), global work waste (GWW), and global work efficiency (GWE) were estimated from left ventricle (LV) pressure-strain loops. Peak LV systolic pressure was non-invasively derived from brachial artery cuff pressure. The lowest values of MW indices in men and women were 1270 mmHg% and 1310 mmHg% for GWI, 1650 mmHg% and 1544 mmHg% for GCW, and 90% and 91% for GWE, respectively. The highest value for GWW was 238 mmHg% in men and 239 mmHg% in women. Men had significant lower values of GWE and higher values of GWW. GWI and GCW significantly increased with age in women. CONCLUSION: The NORRE study provides useful 2DE reference ranges for novel indices of non-invasive MW.

Left ventricular longitudinal systolic dysfunction is an independent marker of cardiovascular risk in patients with hypertension.

BACKGROUND: To explore the prognostic value of left ventricular (LV) longitudinal systolic dysfunction in patients with hypertension. METHODS: In 156 hypertensive subjects, LV longitudinal systolic function was assessed by echocardiographic measurement of M-mode left atrioventricular plane displacement (AVPD) and Tissue Doppler (TD)-derived mitral annulus peak systolic velocity (Sm). Patients were followed for development of the following cardiovascular events: congestive heart failure requiring hospitalization, new-onset angina, nonfatal myocardial infarction, coronary revascularization procedures, transient ischemic attack, nonfatal stroke, and cardiovascular death. RESULTS: Over a follow-up of 23.3 +/- 5.4 months, 24 patients had 29 events. Both longitudinal systolic indices were predictive of outcome (hazard ratios: AVPD, 0.24, P < 0.001; Sm, 0.22; P < 0.001). AVPD < or = 11.4 mm (75.0% sensitivity and 53.8% specificity) and Sm < or = 8.9 cm/s (79.2% sensitivity and 61.4% specificity) were identified as the best cutoffs for the prediction of cardiovascular events (area under curve: AVPD, 0.66, P < 0.01; Sm, 0.71; P < 0.0001). Compared to conventional indices of circumferential systolic function, AVPD and Sm showed similar overall diagnostic performance, but higher sensitivity and lower specificity. Coexistence of longitudinal and circumferential systolic dysfunction was associated with the worst prognosis (P < 0.0001). Multivariate analysis confirmed an independent association of longitudinal indices with clinical outcome, incremental to circumferential systolic impairment, and other confounding variables. CONCLUSIONS: Longitudinal systolic dysfunction is an independent marker of cardiovascular risk in hypertensive patients. Despite similarity in predictive accuracy, longitudinal indices are more sensitive but less specific than circumferential indices for the prediction of cardiovascular events in these subjects.

Echocardiographic reference ranges for normal left atrial function parameters: results from the EACVI NORRE study.

Aims: To obtain the normal ranges for echocardiographic measurements of left atrial (LA) function from a large group of healthy volunteers accounting for age and gender. Methods and results: A total of 371 (median age 45 years) healthy subjects were enrolled at 22 collaborating institutions collaborating in the Normal Reference Ranges for Echocardiography (NORRE) study of the European Association of Cardiovascular Imaging (EACVI). Left atrial data sets were analysed with a vendor-independent software (VIS) package allowing homogeneous measurements irrespective of the echocardiographic equipment used to acquire data sets. The lowest expected values of LA function were 26.1%, 48.7%, and 41.4% for left atrial strain (LAS), 2D left atrial emptying fraction (LAEF), and 3D LAEF (reservoir function); 7.7%, 24.2%, and -0.53/s for LAS-active, LAEF-active, and LA strain rate during LA contraction (SRa) (pump function) and 12.0% and 21.6% for LAS-passive and LAEF-passive (conduit function). Left atrial reservoir and conduit function were decreased with age while pump function was increased. All indices of reservoir function and all LA strains had no difference in both gender and vendor. However, inter-vendor differences were observed in LA SRa despite the use of VIS. Conclusion: The NORRE study provides contemporary, applicable echocardiographic reference ranges for LA function. Our data highlight the importance of age-specific reference values for LA functions.

Two-dimensional transthoracic echocardiographic normal reference ranges for proximal aorta dimensions: results from the EACVI NORRE study.

AIMS: To report normal reference ranges for echocardiographic dimensions of the proximal aorta obtained in a large group of healthy volunteers recruited using state-of-the-art cardiac ultrasound equipment, considering different measurement conventions, and taking into account gender, age, and body size of individuals. METHODS AND RESULTS: A total of 704 (mean age: 46.0 ± 13.5 years) healthy volunteers (310 men and 394 women) were prospectively recruited from the collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. A comprehensive echocardiographic examination was obtained in all subjects following pre-defined protocols. Aortic dimensions were obtained in systole and diastole, following both the leading-edge to leading-edge and the inner-edge to inner-edge conventions. Diameters were measured at four levels: ventricular-arterial junction, sinuses of Valsalva, sino-tubular junction, and proximal tubular ascending aorta. Measures of aortic root in the short-axis view following the orientation of each of the three sinuses were also performed. Men had significantly larger body sizes when compared with women, and showed larger aortic dimensions independently of the measurement method used. Dimensions indexed by height and body surface area are provided, and stratification by age ranges is also displayed. In multivariable analysis, the independent predictors of aortic dimensions were age, gender, and height or body surface area. CONCLUSION: The NORRE study provides normal values of proximal aorta dimensions as assessed by echocardiography. Reference ranges for different anatomical levels using different (i) measurement conventions and (ii) at different times of the cardiac cycle (i.e. mid-systole and end-diastole) are provided. Age, gender, and body size were significant determinants of aortic dimensions.

Echocardiographic reference ranges for normal left ventricular 2D strain: results from the EACVI NORRE study.

AIMS: To obtain the normal ranges for 2D echocardiographic (2DE) measurements of left ventricular (LV) strain from a large group of healthy volunteers accounting for age and gender. METHODS AND RESULTS: A total of 549 (mean age: 45.6 ± 13.3 years) healthy subjects were enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. 2DE data sets have been analysed with a vendor-independent software package allowing homogeneous measurements irrespective of the echocardiographic equipment used to acquire the data sets. The lowest expected values of LV strains and twist calculated as ± 1.96 standard deviations from the mean were -16.7% in men and -17.8% in women for longitudinal strain, -22.3% and -23.6% for circumferential strain, 20.6% and 21.5% for radial strain, and 2.2 degrees and 1.9 degrees for twist, respectively. In multivariable analysis, longitudinal strain decreased with age whereas the opposite occurred with circumferential and radial strain. Male gender was associated with lower strain for longitudinal, circumferential, and radial strain. Inter-vendor differences were observed for circumferential and radial strain despite the use of vendor-independent software. Importantly, no intervendor differences were noted in longitudinal strain. CONCLUSION: The NORRE study provides contemporary, applicable 2D echocardiographic reference ranges for LV longitudinal, radial, and circumferential strain. Our data highlight the importance of age- and gender-specific reference values for LV strain.

3D echocardiographic reference ranges for normal left ventricular volumes and strain: results from the EACVI NORRE study.

AIM: To obtain the normal ranges for 3D echocardiography (3DE) measurement of left ventricular (LV) volumes, function, and strain from a large group of healthy volunteers. METHODS AND RESULTS: A total of 440 (mean age: 45 ± 13 years) out of the 734 healthy subjects enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study had good-quality 3DE data sets that have been analysed with a vendor-independent software package allowing homogeneous measurements regardless of the echocardiographic machine used to acquire the data sets. Upper limits of LV end-diastolic and end-systolic volumes were larger in men (97 and 42 mL/m2) than in women (82 and 35 mL/m2; P < 0.0001). Conversely, lower limits of LV ejection fraction were higher in women than in men (51% vs. 50%; P < 0.01). Similarly, all strain components were higher in women than in men. Lower range was -18.6% in men and -19.5% in women for 3D longitudinal strain, -27.0% and -27.6% for 3D circumferential strain, -33.2% and -34.4% for 3D tangential strain and 38.8% and 40.7% for 3D radial strain, respectively. LV volumes decreased with age in both genders (P < 0.0001), whereas LV ejection fraction increased with age only in men. Among 3DE LV strain components, the only one, which did not change with age was longitudinal strain. CONCLUSION: The NORRE study provides applicable 3D echocardiographic reference ranges for LV function assessment. Our data highlight the importance of age- and gender-specific reference values for both LV volumes and strain.

Echocardiographic reference ranges for normal cardiac Doppler data: results from the NORRE Study.

AIMS: Reference values for Doppler parameters according to age and gender are recommended for the assessment of heart physiology, specifically for left ventricular (LV) diastolic function. In this study, we report normal reference ranges for Doppler parameters obtained in a large group of healthy volunteers. Echocardiographic data were acquired using state-of-the-art cardiac ultrasound equipment following Doppler acquisition and measurement protocols approved by the European Association of Cardiovascular Imaging. METHODS AND RESULTS: A total of 449 (mean age: 45.8 ± 13.7 years) healthy volunteers (198 men and 251 women) were enrolled at the collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. A comprehensive echocardiographic examination was obtained from all subjects following predefined protocols. The majority of the Doppler diastolic parameters (e', E/e') as well as right ventricle systolic s' wave velocity were similar in men and women. Left ventricle s' wave velocity was higher in men than in women. E wave and e' were higher in younger subjects and decreased progressively in the older ones. E/e' ratio increased with ageing. Septal e' <8 cm/s was present in 19.7% of the subjects in the 40-60 year group and in 55% of those in the ≥60 year group. However, the cut-off value of average E/e' or lateral E/e' remained <15 or 13, respectively, in the majority of patients. CONCLUSION: The NORRE study provides the reference values for the most useful Doppler parameters in the evaluation of heart physiology. These data highlight the need of using age-specific reference values especially for the diagnosis of LV systolic and diastolic dysfunction and for the estimation of LV filling pressures.

[Therapeutic angiogenesis of critical lower limb ischemia. Review of the literature and prospects of research on stem cells]. / Angiogenesi terapeutica nell'ischemia critica degli arti inferiori. Revisione della letteratura e prospettive della ricerca sulle cellule staminali.

Chronic peripheral arterial disease affects up to 15% of adults over the age of 55 years; critical limb ischemia represents the most dramatic clinical outcome. Patients with chronic critical limb ischemia who are not candidate for surgical or percutaneous revascularization have impending limb loss; those who benefit from successful revascularization suffer from high rate of recurrent symptoms or revision surgery or progressive amputations. In these patients no medical treatment is considered effective for rest pain or ulcer healing. Therapeutic angiogenesis, which has the goal to achieve the process of new blood vessel formation via the administration of growth factors, has become a new promising hope. The discovery of the possibility of inducing sprouting of new vessels from preexisting vasa (angiogenesis) or the in situ differentiation of endothelial cells from stem cell precursors (vasculogenesis) have open new lease on life. However, a careful analysis of experimental results achieved in animal models is required before proposing for clinical setting. Although a major concern is that most of the experimental work has been done on animal models that do not represent the clinical process, benefit from growth factor administration or stem cell therapy has been proven in clinical trials, suggesting the importance of this new research frontier. This literature review is aimed to examine potential applications of therapeutic angiogenesis to treat critical limb ischemia with particular attention to angiogenesis obtained with stem cells.

Echocardiographic reference ranges for normal cardiac chamber size: results from the NORRE study.

AIMS: Availability of normative reference values for cardiac chamber quantitation is a prerequisite for accurate clinical application of echocardiography. In this study, we report normal reference ranges for cardiac chambers size obtained in a large group of healthy volunteers accounting for gender and age. Echocardiographic data were acquired using state-of-the-art cardiac ultrasound equipment following chamber quantitation protocols approved by the European Association of Cardiovascular Imaging. METHODS: A total of 734 (mean age: 45.8 ± 13.3 years) healthy volunteers (320 men and 414 women) were enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. A comprehensive echocardiographic examination was performed on all subjects following pre-defined protocols. There were no gender differences in age or cholesterol levels. Compared with men, women had significantly smaller body surface areas, and lower blood pressure. Quality of echocardiographic data sets was good to excellent in the majority of patients. Upper and lower reference limits were higher in men than in women. The reference values varied with age. These age-related changes persisted for most parameters after normalization for the body surface area. CONCLUSION: The NORRE study provides useful two-dimensional echocardiographic reference ranges for cardiac chamber quantification. These data highlight the need for body size normalization that should be performed together with age-and gender-specific assessment for the most echocardiographic parameters.

Normal Reference Ranges for Echocardiography: rationale, study design, and methodology (NORRE Study).

BACKGROUND: Availability of normative reference values for cardiac chamber dimensions, volumes, mass, and function is a prerequisite for the accurate application of echocardiography for both clinical and research purposes. However, due to the lack of consistency in current echocardiographic 'reference values', their use for clinical decision-making remains questionable. AIMS: The aim of the 'Normal Reference Ranges for Echocardiography Study (NORRE Study)' is to obtain a set of 'normal values' for cardiac chamber geometry and function in a large cohort of healthy Caucasian individuals aged over a wide range of ages (25-75 years) using both conventional and advanced echocardiographic techniques. METHODS: The NORRE Study is a large prospective, observational multicentre study in which transthoracic echocardiographic studies will be acquired in 22 laboratories accredited by the European Association of Cardiovascular Imaging and in one laboratory in the USA accredited by ICAEL. The final sample size has been estimated in 1100 normal subjects in whom M-mode, 2D, and 3D imaging, colour Doppler, pulsed-wave Doppler, pulsed-wave tissue Doppler, and colour tissue Doppler imaging data will be obtained. All studies will be sent to a central echocardiographic core laboratory for quantitative analysis. Multiple studies will be performed for reproducibility analysis. CONCLUSION: After completion of the NORRE Study, uniform reference limits according to age, gender, and anthropometric parameters will be available to standardize the quantitative interpretation of echocardiography.