1926 - 2003 Biography 
Mauricio B. Rosenbaum was born August 26, 1926 in Carlos Casares, province of Buenos Aires, Argentina, to Russian immigrant parents. He graduated from the Faculty of Medicine in 1946 and received a doctorate in 1951 from the Universidad de Cordoba after which he was a post-doctoral fellow in medicine at the Cordoba Hospital Nacional de Clinicas where he studied with professor Jorge Orgaz and later cardiology with professor Blas Moia at Ramos Mejia Hospital in Buenos Aires where, in 1963, he became Chief of Cardiology, remaining until retirement in 1988. During 1954 he was a research associate with Drs. Eugene Lepeschkin and Wilhelm Raab at the University of Vermont and during 1968-69 a visiting professor at the University of Kentucky in Lexington.
By 1955, he had published two classic papers, "Bilateral bundle branch block" and "The effect of ventricular systole on auricular rhythm in auriculo-ventricular block". From 1952 to 1960 he undertook clinical and epidemiological studies on the parasite caused Chagas disease, one of the most important public health problems in Latin America. These studies persuaded the Argentine government to begin its first national Chagas prevention and control program.
Rosenbaum's international recognition was the result of his description in 1967 of the trifascicular nature of intraventricular cardiac conduction. His concept of hemiblocks, published that year was immediately and widely accepted as a major contribution to cardiac electrophysiology and supplanted the previous understanding that intraventricular conduction was bifascicular, acknowledging only right and left bundle branch blocks. His newly introduced interpretation allowed the diagnosis of left anterior and posterior hemiblock, either in isolation or combined with right bundle branch block, divisional left bundle branch block and bi- or trifascicular A-V block. His concepts were promulgated at almost the same time as the initial recording of the human His bundle potential and the introduction of the artificial pacemaker, resulting in substantial progress in the diagnosis and treatment of intraventricular and auriculo-ventricular conduction defects.
In the 1970s, Rosenbaum began evaluation of amiodarone, an antianginal drug developed in Europe, as an antiarrhythmic agent for the control of supraventricular and ventricular arrhythmias, with promising results. That work resulted in US clinical electrophysiologists using amiodarone to treat selected patients with severe ventricular arrhythmias, ultimately winning FDA approval for that purpose in 1986. Simultaneously he led investigations that established the concept of phase 3 and phase 4 blocks, and clarified the relationship between automaticity and conduction in cardiac electrophysiology.
In 1981, Rosenbaum convened a workshop in Buenos Aires involving the world's most distinguished electrocardiologists and electrophysiologists for discussion of the most important contemporary topics. The landmark volume, "Frontiers of Cardiac Electrophysiology" resulted from that meeting.
In 1982 he published his observations on cardiac memory which, as the rest of his scientific work, was accomplished without economic support and with scant resources. Rosenbaum's numerous scientific contributions illustrate his creativity, intellectual talent and observational skills. His unusual approach combined clinical and experimental research conducted by the same team, allowing translation of experimental data into clinically useful interpretations and finding, in the laboratory, answers to questions posed by everyday clinical work.
Rosenbaum was a member of the Editorial Boards of Circulation, the American Heart Journal, the American Journal of Cardiology and the European Journal of Cardiology. He was Chairman of the Scientific Committee of the VII World Congress of Cardiology, received special distinctions in Argentina and was named an honorary member of American and European cardiology societies. The American College of Cardiology elected him to Honorary Membership and presented a Presidential Citation, in 1975.
His engaging intellect, creativity, keen sense of humor and kindness to co-workers generated admiration in those who had the privilege of working with him. He died May 4, 2003.
- Julio Lazzari MD
