Gerbezius' Pulsus Mira Inconstantia and the First Descriptions of the Atrioventricular Block

This article reconstructs the steps leading to the identification of the atrioventricular block, from its first descriptions to current studies, highlighting the roles of Arthur Keith (1866-1955) and Martin Flack (1882-1931), who contributed to establish the theoretic basis for electrocardiography.

James Herrick (1861-1954): Consultant physician and cardiologist

In 1910, James Bryan Herrick published the first clinical and laboratory description of sickle cell anemia. Two years later, he published a case report on coronary thrombosis. Together, these case reports solidified his reputation as one of the premier diagnosticians of his generation. Now regarded as a central figure in the history of American medicine, Herrick played an integral role in the clinical adoption of the electrocardiograph and the professionalization of cardiology in the United States. Although a full decade passed before the medical profession recognized his clinical description of coronary thrombosis and myocardial infarction, it has had profound implications for cardiovascular medicine and prevention over the past hundred years. As a consultant physician, Herrick advocated in favor of incorporating chemistry and laboratory evaluation into clinical practice.

The History of Home Cardiorespiratory Monitoring

Home cardiorespiratory monitoring has changed significantly since it was first introduced in the 1970s. It has improved from a simple alarm system to a sophisticated piece of equipment capable of monitoring the patient's electrocardiogram, respiratory effort, and oxygen saturations. In addition, the indications for using a monitor have also changed. The home monitor was initially used to reduce the incidence of sudden infant death syndrome (SIDS). Although there were several studies demonstrating the reduction of SIDS rates in communities where apnea programs existed, none was a prospective, double-blinded study or had adequate numbers to be clinically significant. Therefore, the American Academy of Pediatrics took the stance that monitors were not an effective way to reduce SIDS. However, when used appropriately, as part of a complete program (ie, the monitor is just one of many clinically based modalities), by a clinician with expertise in interpreting download tracings, home cardiorespiratory monitoring can be a useful, lifesaving, and economical tool to observe infants who are at increased risk of sudden death or increased morbidity secondary to intermittent hypoxia. [Pediatr Ann. 2017;46(8):e303-e308.].

The rise of cardiovascular medicine

Modern cardiology was born at the turn of the nineteenth to twentieth centuries with three great discoveries: the X ray, the sphygmomanometer, and the electrocardiograph. This was followed by cardiac catheterization, which led to coronary angiography and to percutaneous coronary intervention. The coronary care units and early reperfusion reduced the early mortality owing to acute myocardial infarction, and the discovery of coronary risk factors led to the development of Preventive Cardiology. Other major advances include several cardiac imaging techniques, the birth and development of cardiac surgery, and the control of cardiac arrhythmias. The treatment of heart failure, although greatly improved, remains a challenge. Current cardiology practice is evidence-based and global in scope. Research and practice are increasingly conducted in cardiovascular centres and institutes. It is likely that in the future, a greater emphasis will be placed on prevention, which will be enhanced by genetic information.

[Disputes and history of fetal heart monitoring]

The concept of fetal heart monitoring to determine the fetal wellbeing state has been employed for almost 300 years, but in the last 50 years it has observed drastic changes due to the incorporation of the electronic devices that has started controversy since the moment of its description and point of start. The purpose of this article is to mention the key points and controversial moments in the history of the cardiotocography

[Historical sketches on classical physiology of the heart: the initial phase of systole]

Crucial physiological advances in the phase analysis of cardiac performance with respect to their historical and biographical aspects are elucidated. The described period started from the early measurement of blood pressure (1733) and the first graphical representation of cardiac performance (1861), continued by the progress in recording of cardiac electrical activity and a detailed study of the consecutive events throughout the cardiac cycle (1921) and, finally, reached the recording of changes in the left ventricular dimensions and shape during the phase which precedes the start of blood ejection (1955-2005).

[Seeing sounds? The visualization of acoustic phenomena in heart diagnostics]

During the nineteenth century physiologists and clinicians developed several graphical recording systems for the mechanical registration of heart sounds. However, none of these replaced traditional methods of auscultation. The paper describes criticism of the aural sense as one of the driving forces behind the development of phonocardiography and analyses its variants from a technological and clinical perspective. Against the background of the physiological “method of curves,” the parameters that prevented the implementation of phonocardiography against overwhelming odds are highlighted. Contemporaries denied specific evidence beyond auscultation. Many clinicians also feared that the art of auscultation was being undermined by the new, reproducible mechanical methods. The paper argues that phonocardiography was on the one hand regarded as impractical in clinical settings; on the other hand—and even more important—implicit practices, tacit knowledge and cultural models fostered skepticism against the new method. The argument of “self-evidence”—often connected to medical images, curves, graphs or tables—was not valid for the visualization of cardiac sounds in the opinion of the promoters of acoustic heart sound registration and its individual interpretation. Rather, the acts of subjective hearing and objectively reporting what was heard seemed “self-evident” for pathophysiological characteristics and the development of a diagnosis. Therefore, auscultation and phonocardiography coexisted with different emphases. While auscultation remained the method of choice for a bedside diagnosis, phonocardiography played its role in differential diagnostics or research settings.

Concealed accessory pathways: Historical notes

Concealment of an accessory pathway is caused by its ability to conduct retrogradely only. This variant of accessory pathway conduction could not be confirmed until invasive electrophysiology was introduced in the 1970s. As a rule, it is reported that concealed accessory pathways were predicted from animal experiments in 1971. However, even earlier studies suggested an accessory pathway or mechanisms comparable to those of the Wolff-Parkinson-White syndrome to be the cause of supraventricular tachycardias even though preexcitation during sinus rhythm had been lacking. Such interpretations were derived from clinical considerations, from patients having lost their ventricular preexcitation spontaneously, and from the disappearance of the delta wave after drug administration. Some authors postulated but did not provide the correct interpretation. Even a few contributions published before the paper of Wolff, Parkinson, and White in 1930 are worth considering in this context.

[Incursion into bioelectromagnetism]

The term of bioelectromagnetism include electromagnetosenzitive processes at the fundamental interaction of energetical fields with the matter. The alive matter has a dynamical, chemical and energetics structure, but above all, an intense informational activity. The bioelectromagnetism was gradually discovered and understood throughout history of humanity. J. Bernstein defined the cell's bioelectricity, Wagner calculated electrical conductivity and permeability of cells, starting from the Maxwell's field equations, others discovered "mitogenetic radiation" or "dark luminescence" or "ultraweak bioluminescence" and F. A. Popp founded the biophotons theory. On the other hand, Hirata and Nakatani finded points with different electrical conductivity on the surface of the skin and Voll invented the system of electro dermal testing. The practical applications of the bioelectromagnetism are the medical devices based on bioresonance, useful in diagnosis and treatment, as shown in the 17 studies (902 patients) published in 1999-2006.

Derivation of the correct waveform of the human electrocardiogram by Willem Einthoven, 1890-1895

In the period 1890 to 1895, Willem Einthoven greatly improved the quality of tracings that could be directly obtained with the capillary electrometer. He then introduced an ingenious correction for the poor frequency response of these instruments, using differential equations. This method allowed him to predict the correct form of the human electrocardiogram, as subsequently revealed by the new string galvanometer that he introduced in 1902. For Einthoven, who won the Nobel Prize for the development of the electrocardiogram in 1924, one of the most rewarding aspects of the high fidelity recording of the human electrocardiogram was its validation of his earlier theoretical predictions regarding the electrical activity of the heart.

[The cardiological perspective: Francisco Laranja and research on Chagas' disease. Interview by Rose Goldschmidt, Jaime Benchimol, Marcos Chor Maio]

Francisco Laranja began working in cardiology when this was yet a fledgling specialty in Brazilian medicine. An expert in electrocardiography, he has gained national and international renown for his research conducted in Bambuí in the 1940s, which led to the clinical characterization of the cardiac profile of chronic cases of Chagas' disease. In this interview, Laranja talks about the development of the field of cardiology and electrocardiography in Brazil, his work at the Institute of Retirement and Pensions for Industrial Workers, his research in Bambuí, and his term as director of the Oswaldo Cruz Institute.

WH Craib: a critical account of his work - with reference to : a study of the electrical field surrounding skeletal muscle, W.H. Craib

One hundred years after its introduction, the ECG remains the most commonly used cardiovascular laboratory procedure. It fulfils all the requirements of a diagnostic test: it is non-invasive, simple to record, highly reproducible and can be applied serially. It is the first laboratory test to be performed in a patient with chest pain, syncope or cardiac arrhythmias. It is also a prognostic tool that aids in risk stratification and clinical management. Among the many South Africans who have made remarkable contributions in the field of electrocardiography, Don Craib was the first to investigate the changing patterns of the ECG action potential in isolated skeletal muscle strips under varying conditions. It was during his stay at Johns Hopkins Hospital in Baltimore and Sir Thomas Lewis laboratory in London that Craib made singular observations about the fundamental origins of electrical signals in the skeletal muscle, and from these developed his hypothesis on the generation of the action potential in the electrocardiogram. His proposals went contrary to scientific opinion at the time and he was rebuffed by the scientific community. Frank Wilson subsequently went on to develop Craib's doublet hypothesis into the dipole theory, acknowledging Craib's work. Today the dipole theory is fundamental to the understanding of the spread of electrical activation in the myocardium and the genesis of the action potential.

Historical perspectives of cardiac electrophysiology

The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From earliest times, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favored these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequently arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts: it may also provide the observer with a chronological vantage point from which to view the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories.

Leo Schamroth: his contributions to clinical electrocardiography - with reference to : incomplete left bundle-branch block

Leo Schamroth (1924-1988) was one of the best-known South Africans in the international medical community. His book, An Introduction to Electrocardiography, first published in 1957, was my introduction to the mysteries of the ECG. The first edition was only 90 pages and was a model of clarity and simplicity, with remarkable insight into the needs of a student new to the subject. It has been translated into Spanish, Italian, Greek, Turkish and Japanese, and is said to be the book most often stolen from medical libraries worldwide. Schamroth was a superb teacher, not only of the ECG, and will be remembered by generations of students who passed through his hands during his tenure at the Chris Hani-Baragwanath Hospital from 1956 to 1987, occupying the Chair of Medicine there from 1972. As a lecturer who combined unrivalled clarity with showmanship, he held his audiences, at home and all over the world, spellbound. However, it was his ability to wring insights from the most ordinary-appearing ECG, by painstaking analysis, that is his enduring legacy.

Resuscitation great. Karel Wenckebach: the story behind the block

The first documentation of a human atrioventricular (AV) block dates back to 1873, when A.L. Galabin reported a 34-year-old patient using an apexcardiogram. This was followed the same year by Luciani, recording 2nd degree AV blocks while studying frogs. In 1899, Karel F. Wenckebach provided the cardiology field with the criteria of what he called "Luciani periods", what we now know as Wenckebach Periodicity or Mobitz I AV block. The classic electrocardiographic presentation of Mobitz I/Wenckebach periodicity is characterized by progressive prolongation of the PR interval on the electrocardiogram (EKG) on consecutive beats followed by a blocked P wave. This clinical entity is the first and most common of two types of 2nd degree AV block. This manuscript reviews the life of Karel F. Wenckebach and the events that led this great Dutch physician to make one of the most important contributions to the field of cardiology.

Past and future aspects of clinical electrophysiology

The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From the earliest time, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favoured these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequent arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts; it may also assist the observer in a chronological vantage point of the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories.

Einthoven's string galvanometer: the first electrocardiograph

Willem Einthoven (1860--1927), known as the creator of the electrocardiograph, won a Nobel Prize in 1924 for his contributions to the field of electrocardiography. He was dedicated to research and learning. In developing the electrocardiograph, Einthoven built on the work of earlier physiologists who had studied the electrical mechanisms of the heart. Each earlier invention proved important by contributing concepts and knowledge that would shape Einthoven's device. Herein, we review the history of the electrocardiograph, with a focus on Willem Einthoven's quest to make the device a practical clinical instrument in the diagnosis of cardiac abnormalities.

The early history of paediatric cardiology in the United Kingdom, with specific reference to KD Wilkinson

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