Utility of Cardiac Magnetic Resonance Imaging in the Management of Adult Congenital Heart Disease.

The increasing number of patients with adult congenital heart disease (ACHD) calls for the development of noninvasive imaging techniques that allow a long-term evaluation of native and postsurgical anatomy and function. Echocardiography remains the imaging modality of choice for congenital heart disease, but it is affected by limited acoustic windows and poor tissue characterization. Cardiac computed tomography and cardiac catheter angiography are 2 valid alternatives for the anatomic and functional assessment of ACHD; however, both use ionizing radiation, and cardiac catheter angiography requires an invasive approach. Cardiac magnetic resonance (CMR), noninvasively and in the absence of ionizing radiation, has the ability to evaluate the biventricular function, quantify flows, characterize tissue, and provide information on cardiac anatomy. Despite the long acquisition time and lower spatial resolution compared with cardiac computed tomography, CMR represents the ideal technique for long-term follow-up of ACHD. CMR is now widely utilized and is well described in the literature with regard to diagnosis, identification of complications, timing of surgery, and postoperative prognosis in ACHD. CMR represents a fundamental technique for the evaluation of patients with ACHD.

Quantification of total and free carnitine in human plasma by hydrophilic interaction liquid chromatography tandem mass spectrometry.

Carnitine is an endogenous quaternary amine whose primary function is to shuttle long chain fatty acids to the mitochondrial matrix, where they subsequently undergo beta oxidation. Accurate quantification of total and free carnitine is essential for the accurate diagnosis of a number of inborn errors of metabolism, including disorders of fatty acid oxidation as well as various organic acidurias. Early methods for carnitine measurement were enzyme based. Recently, liquid chromatography tandem mass spectrometry has become the method of choice for carnitine measurement. Typically, carnitine is derivitized to from a butyl ester, thus improving its ionization and retention characteristics. A potential problem with this approach is that the acidic conditions used to carry out the reaction may hydrolyze other acyl esters, resulting in ex-vivo artifacts. Consequently, we developed a hydrophobic interaction chromatography (HILIC) tandem mass spectrometry method for the quantification of carnitine. The use of HILIC allows for the derivitization step to be circumvented, while still allowing for favorable chromatographic performance. The method was shown to be accurate, precise, and robust.