Magnetic resonance investigations in Brugada syndrome reveal unexpectedly high rate of structural abnormalities.

AIMS: Recent data suggest that sub-clinical structural abnormalities may be part of the Brugada syndrome (BrS) phenotype, a disease traditionally thought to occur in the structurally normal heart. In this study, we carried out detailed assessment of cardiac morphology and function using cardiac magnetic resonance imaging (CMRI). METHODS AND RESULTS: Thirty consecutive patients with BrS were compared with 30 sex- (26/4 male/female), body surface area- (+/-0.2 m(2)), and age-matched (+/-5 years) normal volunteers. CMRI exam included long- and short-axis ECG-gated breath-hold morphological T1-TSE sequences for fatty infiltration and cine-SSFP sequences for kinetic assessment. Fatty infiltration was not found in any subject. Patients with BrS compared with normal subjects showed higher incidence of mild right ventricle (RV) wall-motion abnormalities [15 (50%) vs. 5 (17%) subjects (P = 0.006) with reduced radial fractional shortening in more than two segments], reduction of outflow tract ejection fraction (49 +/- 11% vs. 55 +/- 10%; P = 0.032), enlargement of the inflow tract diameter (46 +/- 4 vs. 41 +/- 5 mm, P < 0.001 in short-axis; 46 +/- 4 vs. 42 +/- 5 mm, P = 0.001 in four-chamber long-axis view) and area (22 +/- 2 vs. 20 +/- 3 cm(2); P = 0.050), and of global RV end-systolic volume (34 +/- 10 vs. 30 +/- 6 mL/m(2); P = 0.031) but comparable outflow tract dimensions, global RV end-diastolic volume, left ventricle parameters, and atria areas. CONCLUSION: CMRI detects a high prevalence of mild structural changes of the RV, and suggests further pathophysiological complexity in BrS. Prospective studies to assess the long-term evolution of such abnormalities are warranted.

Intra-observer and interobserver reproducibility of right ventricle volumes, function and mass by cardiac magnetic resonance.

OBJECTIVES: Cardiac magnetic resonance (CMR) allows quick and non-invasive evaluation both of right ventricle (RV) volume and function, which are important in many heart diseases. We have evaluated CMR intra- and interobserver reproducibility in different conditions of RV dimension and function. METHODS: We have analysed CMR exams of 45 subjects, randomly selected from our database according to RV end-diastolic volume (EDV; 15-subject groups with EDV < 25th, 25-75th and > 75th percentiles of a normal control population). Selected subjects were of both sexes (male/female 33/12) and of variable age (8-83 years) and body surface (0.9-2.3 m). RV end-diastolic and end-systolic volumes (ESV), ejection fraction (EF) and mass were blindly evaluated by two operators. Bland-Altman bias and coefficient of variability (CoV) were used to assess intra- and interobserver reproducibility. RESULTS: A wide range of EDV (range = 46-239 ml), ESV (20-129 ml) and EF (6-64%) was observed. The intra-observer bias was -5 ml for EDV, -2 ml for ESV, -1% for EF and 5 g for mass, with a CoV of 7-12%. The interobserver bias was 5 ml for EDV, 2 ml for ESV, 2% for EF and 6 g for mass, with a CoV of 8-13%. Analysis by tertiles showed EF assessment variability to be higher in the lower tertiles at intra-observer (P < 0.036) and, above all, at interobserver (P < 0.000) analysis. Mass assessment variability was higher in the upper tertile (P < 0.004) at intra-observer analysis. CONCLUSIONS: Intra- and interobserver reproducibility of RV parameters assessed by CMR are adequate in a wide range of RV dimensions and function. However, caution is required with respect to the significance of small changes of EF and mass in the case of poor function and hypertrophy of the RV, respectively.

Improved reproducibility of right ventricular volumes and function estimation from cardiac magnetic resonance images using level-set models.

This study aims to assess whether an alternative method, that is based on volumetric surface detection (VoSD) without tracing and is totally free of geometric assumptions, can improve the reproducibility of right ventricular (RV) volume quantification from cardiac magnetic resonance (CMR) images, in comparison with a conventional disk-area technique. In a sample of 23 patients, with wide variability of RV end-diastolic volume (EDV: 47-131 ml), end-systolic volume (ESV: 20-76 ml), and ejection fraction (EF: 29-73%), using the standard method (Argus, Siemens) as the reference, the VoSD method showed good agreement for EDV, ESV, and EF estimations (correlation coefficient: 0.91, 0.94, and 0.94; Bland-Altman biases: 1 ml, 1 ml, and 0%; limits of agreement: +/-16 ml, +/-11 ml, and +/-11%, respectively). An analysis of the reproducibility of the two methods showed lower intraobserver variability for the VoSD method than for the conventional method, as evidenced by the coefficient of variability (CoV) values (2-6% vs. 8-15%; P < 0.05). In addition, the VoSD method showed improved interobserver reproducibility (7-10% vs. 8-15%), but the difference was statistically significant only for EF estimation variability (8 vs. 15%, P < 0.05). In conclusion, the newly developed VoSD technique allows accurate measurements of RV volumes and function, and appears to be more reproducible than the conventional methodology.