Background-The question of whether training-induced left ventricular hypertrophy in athletes is a physiological rather than a pathophysiological phenomenon remains unresolved. The purpose of the present study was to detect any abnormalities in cardiac function in hypertrophic hearts of elite cyclists and to examine the response of myocardial high-energy phosphate metabolism to high workloads induced by atropine-dobutamine stress. Methods and Results-We studied 21 elite cyclists and 12 healthy control subjects. Left ventricular mass, volume, and function were determined by cine MRI. Myocardial high-energy phosphates were examined by 31 P magnetic resonance spectroscopy. There were no significant differences between cyclists and control subjects for left ventricular ejection fraction (59Ϯ5% versus 61Ϯ4%), left ventricular cardiac index (3.4Ϯ0.4 versus 3.4Ϯ0.4 L ⅐ min Ϫ1 ⅐ m Ϫ2 ), peak early filling rate (562Ϯ93 versus 535Ϯ81 mL/s), peak atrial filling rate (315Ϯ93 versus 333Ϯ65 mL/s), ratio of early and atrial filling volumes (3.0Ϯ1.0 versus 2.6Ϯ0.6), mean acceleration gradient of early filling (5.2Ϯ1.4 versus 5.8Ϯ1.9 L/s 2 ), mean deceleration gradient of early filling(Ϫ3.1Ϯ0.9 versus Ϫ3.2Ϯ0.7 L/s

Arrhythmogenic right ventricular dysplasia (ARVD) is a myocardial disorder of primarily the right ventricle, with unknown cause and prevalence and with a frequent familial occurrence. The typical clinical manifestation consists of ventricular arrhythmias with a left bundle branch block (LBBB) pattern that occur predominantly in young adults. ARVD may result in sudden death. Other manifestations are electrocardiographic repolarization and depolarization changes, structural abnormalities that range from subtle wall aneurysms within the so-called "triangle of dysplasia" to biventricular regional or global dysfunction, and localized or widespread fibrofatty infiltration of the right ventricular myocardium. The diagnosis of ARVD is based on the presence of major and minor criteria encompassing genetic, electrocardiographic, pathophysiologic, and histopathologic factors. The imaging modalities used to evaluate right ventricular abnormalities include conventional angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance (MR) imaging. Among these techniques, MR imaging allows the clearest visualization of the heart. Because MR imaging depicts both functional and structural abnormalities, positive MR imaging findings should be used as important additional criteria in the clinical diagnosis of ARVD. MR imaging appears to be the optimal technique for detection and follow-up of clinically suspected ARVD.

In 21 patients, the authors compared results with quantitative gated single photon emission computed tomography (SPECT) to results with magnetic resonance imaging in the assessment of left ventricular (LV) end-diastolic volume (LVEDV), end-systolic volume (LVESV), and ejection fraction (LVEF). Between the two methods, correlations were good for LVEF (r = 0.85), LVEDV (r = 0.94), and LVESV (r = 0.95). Quantitative gated SPECT can help determine LVEF, LVEDV, and LVESV.

Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder of unknown cause that is characterized pathologically by fibrofatty replacement of the right ventricular myocardium. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation with ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD and they are distributed in the so-called "triangle of dysplasia", i.e., right ventricular outflow tract, apex, and infundibulum. Ventricular aneurysms at these sites can be considered pathognomonic of ARVD. Another typical hallmark of ARVD is fibrofatty infiltration of the right ventricular free wall. These functional and morphologic characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance imaging (MRI). Among these techniques, MRI allows the clearest visualization of the heart, in particular because the right ventricle is involved, which is usually more difficult to explore with the other imaging modalities. Furthermore, MRI offers the specific advantage of visualizing adipose infiltration as a bright signal of the right ventricular myocardium. MRI provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD within one single study. As a result, MRI appears to be the optimal imaging technique for detecting and following patients with clinical suspicion of ARVD.

We evaluated the effect of through-plane motion on tricuspid flow measurements performed with MR velocity mapping in nine normal subjects and 15 patients with possible right ventricular (RV) disease. Eight parameters of RV diastolic function were derived from the tricuspid flow measurements, both before and after a correction for through-plane motion. Measurements of E-peak, A-peak, and time-to-peak filling rate changed significantly after correction for through-plane motion (P < .05). Tricuspid flow as a marker of RV diastolic function should be corrected for the effect of through-plane motion to improve functional evaluation of the RV.

The authors compared an automated observer-independent acquisition planning method for short-axis multisection multiphase cardiac magnetic resonance imaging studies with conventional manual image planning. Systematic and random differences and reproducibility of left ventricular function measurements and image geometry were evaluated in five healthy adult volunteers and 20 patient studies. Results with the automated planning method were as accurate and reproducible as those with the manual planning method.

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