RESUMO
The chordae tendineae, described as fibro-collagenous structures, support the leaflets of the atrioventricular valves of the heart in various ways. The chordae tendineae are composed of collagen and elastic fibers. They connect to the ventricular side of the valve leaflets' free border and hinder the leaflets from swinging back into the atrial cavity during systole. Mitral valve chordae tendineae have been classified using a variety of classification systems. To our knowledge, we report a variant chordae tendinea that has yet to be described in the literature. The variant, present only on the mitral anterior papillary muscle, did not show the characteristic appearance of the chorda tendineae. Muscular fibers were observed extending from a larger than usual mitral anterior papillary muscle, inserting into the rough zone of the anterior leaflet. Several tendinous primary and secondary true leaflet chordae emerge from the apical portion of the anterior papillary muscle, inserting into the anterior leaflet's free edge and rough zone. Contraction of this muscular chorda during systole could disrupt the mechanics of valvular closure and result in possible regurgitation across the mitral valve. Additionally, this structure may be subject to rupture during myocardial infarction, leading to valvular dysfunction. The developmental connection between the chordae and papillary muscles could explain the anomalous muscularization of the chordae tendineae observed in this case.
Assuntos
Cordas Tendinosas , Valva Mitral , Músculos Papilares , Humanos , Músculos Papilares/anormalidades , Músculos Papilares/anatomia & histologia , Cordas Tendinosas/anormalidades , Cordas Tendinosas/anatomia & histologia , Valva Mitral/anormalidades , Masculino , Variação Anatômica , Feminino , Cadáver , IdosoRESUMO
Medical education programs in the United States or Canada comply with the Liaison Committee on medical education standards to ensure their graduates provide proficient medical care. One standard includes student development as a lifelong learner. The competency of lifelong learning is developed through self-directed activities such as students evaluating their learning objectives and resources without external help.Quick response (QR) codes were the technological tools introduced in a traditional medical institution to enhance students' self-directed initiative to tap resources. Relevant lecture objectives and other information such as supplemental discipline content, reading assignments and web-based link resources were embedded into codes and 'pasted' onto all pages of their course PDF handouts. It was anticipated that most students had access to smart phones to conveniently scan the codes and retrieve the information.However, an in-class survey conducted showed that only 30% of the students found the QR codes useful. Further questioning revealed that some students just didn't know how to use the codes or didn't think the information embedded was worth the effort to decrypt. Although students were tech-savvy in the social and entertainment realms, they were not adept in the use of technology for educational purposes.QR codes presented several theoretical, pedagogical advantages to enhance experiential and self-directed learning. However, implementation among students, in a traditional classroom, required prior instructions on usage. Student feedback was also imperative when introducing novel, innovative tools like QR codes.