[Mutations of the mitochondrial genome and its clinical expression in cardiology]. / Mutaciones del genoma mitocondrial y su expresión clínica en cardiología.

One of the great challenges in molecular biology is to understand the mechanisms by which a particular genetic defect gives origin to a specific disease. Mitochondrial DNA is more susceptible than nuclear DNA to mutations. Mitochondrial mutations have been associated with a wide spectrum of disorders characterized by a complex phenotype and actually named mitochondrial cytopathies or oxidative phosphorylation diseases. The objective of this paper is to review the relevant genetic, clinical, and morphologic features of cardiac involvement in this heterogeneous but exciting group of diseases. The clinical features of cardiac involvement in mitochondrial cytopathies vary in the different subgroups of these disorders and in particular, mitochondrial mutations can causes characteristic cardiac abnormalities.

[Malfunction of a permanent pacemaker]. / Disfunción de marcapaso definitivo.

Forty years have gone by since the first pacemaker implant; this fact had strong impact in the life of thousands of persons. The objective of this work is to report the case of definitive pacemaker malfunction with epicardiac lead and review the literature concerning the important aspects of the causes and diagnosis of pacemaker malfunction. We consider that physicians dealing with patients implanted these devices must be prepared to diagnose and treat them adequately.

[The heart and blood in the Mexican cosmos vision]. / El corazón y la sangre en la cosmovisión mexica.

The heart and blood have inspired the interest of many cultures'. Even before the heart became a subject of scientific study it was considered as a host to deities and feelings. Prehispanic peoples who inhabited Mesoamerica were not the exception. The heart and blood became the core of the life force and the link to a religious doctrine. It is very clear that these people knew the anatomy of the heart for their human sacrifices to their gods, to maintain the steady course of the planets through out the universe, which consisted of skillfully removing this vital organ as well as the blood for their offerings. Works of art such as paintings, sculptures, carvings, ceramics and even poetry portray the importance of the heart and blood in culture and religion. The aim of this review is to study from the historical and medical point of view, the heart and blood, and their importance to the early Mexicans, to enable them to face and understand the world around them.

[The other genome: the clinical concept of mitochondrial cytopathies or disorders of pxidative phosphorylation]. / El otro genoma: el concepto clínico de las citopatías mitocondriales o enfermedades de la fosforilación oxidativa.

The investigations of mitochondrial DNA abnormalities and its relationship with derangements of oxidative phosphorylation and electron transport system, has yielded description a myriad of syndromes called mitochondrial diseases or cytopathies. The objective of this paper is to review the clinical relevant features of this heterogeneous group of diseases, to understand the board spectrum of signs and symptoms and suggest an algorithm for the diagnosis.

Kearns-Sayre syndromes an absolute indication for prophylactic implantation of definitive pacemaker?

Kearns-Sayre syndrome is a mitochondrial cytopathy characterized by chronic progressive external ophthalmoplegia, retinitis pigmentosa and heart block, the last of which determines the survival of these patients. The case of a 23 year old man with Kearns-Sayre syndrome, conduction disturbances and mitral valve prolapse is presented. The characteristics of this syndrome are described and the criteria for prophylactic installation of a pacemaker discussed.