Directional Doppler in Cardiology: A 50-Year Journey.

In 1968, while cardiologists were focused on cardiac structures imaged by ultrasound, Daniel Kalmanson in Paris, France, devised a new ultrasonic modality, directional continuous-wave Doppler, enabling him to record instantaneous cardiovascular blood flow velocities with recognition of their direction (relative to the transducer) in vessels. An innovative presentation of Doppler data also made velocity traces physiologically understandable. Following the noninvasive study of the arterial and venous beds, flow velocity in the right (1969) and left (1970) cardiac chambers was studied by means of a directional Doppler catheter. The curtain was then raised for the renewal of our pathophysiologic understanding of cardiac dynamics and the adoption of a new methodology. Technological evolution paved the way for clever researchers to pioneer important advances, diversifying the technique. Guided by the early principles, which are still valid in 2018, directional Doppler finally gained acceptance from the entire scientific community.

The Integration of Doppler Ultrasound With Two-Dimensional Echocardiography and the Noninvasive Cardiac Hemodynamic Revolution of the 1980s.

In the 1970s, as cardiac imaging matured from M-mode to two-dimensional echocardiography, investigators in Norway showed that continuous-wave Doppler ultrasonography could be used to accurately measure the mean gradient and pressure half-time for stenotic mitral valves. In the 1980s, continuous-wave Doppler was validated for measurement of the pressure gradient across stenotic aortic valves, and pulsed-wave Doppler combined with two-dimensional echocardiographic imaging was validated for noninvasive measurement of stroke volume and cardiac output. The combination of stroke volume measurement and measurement of the time-velocity integral of flow through the aortic valve was then validated as a means to accurately calculate valve area for patients with stenotic aortic valves or aortic prostheses. This integration of cardiac Doppler ultrasonography with two-dimensional echocardiographic cardiac imaging led to a revolution in noninvasive hemodynamic evaluations, which have replaced invasive hemodynamic evaluations in surgical decision making for most patients with native or prosthetic valvular stenosis.

[A history of the clinical research in cardiology]. / Une histoire de la recherche clinique en cardiologie.

On January 21 1968, nearly an half-century ago, a small Parisian group of cardiologists presented a directional Doppler prototype making possible the detection of forward and backward flows in the arteries. This princeps report, rapidly followed by the Directional Doppler recording of intracardiac flows, has upset the traditional approach to cardiovascular pathophysiology and launched a new examination method that will spread upon the whole word. Single CNRS researcher among this group of clinical cardiologists, Dr Colette Veyrat recalls this early period….

The Remarkable 50 Years of Imaging in HCM and How it Has Changed Diagnosis and Management: From M-Mode Echocardiography to CMR.

The almost 50-year odyssey of cardiac imaging in hypertrophic cardiomyopathy (HCM), revisited and described here, has been remarkable, particularly when viewed in the timeline of advances that occurred during a single generation of investigators. At each step along the way, from M-mode to 2-dimensional echocardiography to Doppler imaging, and finally over the last 10 years with the emergence of high-resolution tomographic cardiac magnetic resonance (CMR), evolution of the images generated by each new technology constituted a paradigm change over what was previously available. Together, these advances have transformed the noninvasive diagnosis and management of HCM in a number of important clinical respects. These changes include a more complete definition of the phenotype, resulting in more reliable clinical identification of patients and family members, defining mechanisms (and magnitude) of left ventricular outflow obstruction, and novel myocardial tissue characterization (including in vivo detection of fibrosis/scarring); notably, these advances afford more precise recognition of at-risk patients who are potential candidates for life-saving primary prevention defibrillator therapy. This evolution in imaging as applied to HCM has indelibly changed cardiovascular practice for this morphologically and clinically complex genetic disease.

Shigeo Satomura: 60 years of Doppler ultrasound in medicine.

This year we celebrate 60 years since Shigeo Satomura published the first measurements of the Doppler shift of ultrasonic signals from a beating heart. He demonstrated that Doppler signals can be retrieved from heart movements when insonated with 3 MHz ultrasonic waves. Later, togheter with Ziro Kaneko, he constructed the first Doppler flowmeter to measure the blood flow velocities in peripheral and extracranial brain-supplying vessels using ultrasounds. They proved that ultrasonic Doppler signals from arteries and veins can be recorded from the surface of the skin and pioneered transcutaneous flow analysis in systole and diastole in both normal and diseased blood vessels. These were the first medical applications of Doppler sonography and impressive technologic innovations have been continuing ever since. Over time, Doppler techniques became a key player in diagnostic ultrasound for hemodynamic assessment, replacing cardiac catheterization in many clinical settings.

The glorious years leading Doppler flow to the heart, the odyssey of the pioneers!

This review pays tribute to those pioneers in Doppler flow during an early and exciting period ranging from the end of the 1960s to the 1990s. Three major 'approaches' contributed to what is nowadays built into every patient's investigation. The source was Daniel Kalmanson, who developed flow directionality, assigning a physiological meaning to the recordings. This was the first time Doppler flow was used on the heart, providing new insights in cardiac pathophysiology. The second approach relied on the Norwegian group who applied the laws of physics to fluid dynamics. Simplification of the formula provided a new non-invasive approach enabling quantification of valvular lesions and haemodynamic measurements. This new tool pushed back previous routine catheterisation. To crown it all, the introduction of colour Doppler flow, mainly relying on the Japanese groups, overcame the long-lasting scepticism of the scientific community: cardiologists started to "believe" in the Doppler technique. Other innovative pioneers around the world joined the three groups to develop this new field of cardiology. At the turning of the new millennium, the Doppler technique is mature, through a strong methodology. Convergence of the three original approaches for mutual benefit, constant update of examination modalities according to improved technology, and new insights into cardiac dynamics, are the three cornerstones supporting this methodology. They should contribute to keep it alive and efficient, independently of the imaging modality of the future.

Valvular heart disease: a century of progress.

The 20th century witnessed amazing advances in the diagnosis and treatment of valvular heart disease. The advances and our hopes for future progress are described.

History of echocardiography and its future applications in medicine.

This review concisely presents the chronology of events that shaped the development of echocardiography. The concept of "seeing" structures using "sound" dates back to the 1920s, when ultrasound produced by piezoelectric crystals was used to detect flaws in metals. In the early 1950s, Hertz and Edler described the use of ultrasound for assessing mitral-valve disease. Subsequently, Harvey Feigenbaum in the 1960s standardized the clinical use of M-mode echocardiography for quantitative assessment of left-ventricular dimensions. The advent of 2-dimensional echocardiography (1970s), pulsed Doppler (1970s), and color Doppler (1980s) introduced new methods for routine assessment of cardiac anatomy and hemodynamics at bedside. Flexible scopes and superior transducers further paved the way to the application of transesophageal echocardiography. Tissue Doppler and contrast echocardiography recently have emerged as important tools for evaluation of regional myocardial function and blood flow. Miniaturization and the ability to pack thousands of crystals in an electronic array have transformed the application of 3-dimensional echocardiography into a bedside tomographic tool. At the current pace of development, echocardiography will be able to provide complete assessment of the heart in terms of its anatomy, coronary flow, and physiology. Training people and making it available at every bedside may be the only remaining challenges.

[A historical perspective of tissue Doppler--when the starlight illuminates the myocardial function].

In 1842, an Austrian professor of mathematics and practical geometry, Christian Doppler, presented results of his investigations in the field of astronomy, without any clue that they would become important principles of modern ultrasound diagnostics. Almost a century later, at the University of Osaka, Japan, S. Satomura first applied these principles to measure the blood flow velocities in peripheral and extracranial brain-supplying vessels. The father of tissue Doppler imaging is Karl Isaaz, a French scientist, who was the first to realize the importance of clinical and diagnostic potentials of tissue Doppler imaging. Today, this noninvasive echocardiographic method is widely used in evaluation of myocardial function, especially in diagnosing of diastolic heart failure and early diagnosis of coronary artery disease, but also in diffrential diagnosis of restrictive cardiomyopathy and constrictive pericarditis and aberrant myocardial conduction. It is also an antecedent of "stain rate", a new sensitive method for diagnosing myocardial diseases.

Daniel Kalmanson, pioneer of intracardiac Doppler exploration in 1969: Emphasis on the first mitral and tricuspid flow velocity recordings.

Intracardiac Doppler flow patterns remained unexplored until 1969, when Daniel Kalmanson could specify the features and physiological interpretation of intracardiac traces by mounting the new directional continuous-wave Doppler device on a catheter-tip. Within a year of time, he defined the continuum of changes from a three-waved venous inlet pattern (two positive S and D, one negative A) to a single systolic wave S at the arterial outlet. Moreover, the first descriptions of mitral and tricuspid Doppler flow traces were reported on man from 1969 (right heart) to 1972 (left heart). Pathophysiologic significance of their fundamental changes in pattern was specified in patients. Major clinical advances resulted from the integration of flow phenomena into physician's medical reasoning.

The history of echocardiography.

Following a brief review of the development of medical ultrasonics from the mid-1930s to the mid-1950s, the collaboration between Edler and Hertz that began in Lund in 1953 is described. Using an industrial ultrasonic flaw detector, they obtained time-varying echoes transcutaneously from within the heart. The first clinical applications of M-mode echocardiography were concerned with the assessment of the mitral valve from the shapes of the corresponding waveforms. Subsequently, the various M-mode recordings were related to their anatomical origins. The method then became established as a diagnostic tool and was taken up by investigators outside Lund, initially in China, Germany, Japan and the USA and, subsequently, world-wide. The diffusion of echocardiography into clinical practice depended on the timely commercial availability of suitable equipment. The discovery of contrast echocardiography in the late 1960s further validated the technique and extended the range of applications. Two-dimensional echocardiography was first demonstrated in the late 1950s, with real-time mechanical systems and, in the early 1960s, with intracardiac probes. Transesophageal echocardiography followed, in the late 1960s. Stop-action two-dimensional echocardiography enjoyed a brief vogue in the early 1970s. It was, however, the demonstration by Bom in Rotterdam of real-time two-dimensional echocardiography using a linear transducer array that revolutionized and popularized the subject. Then, the phased array sector scanner, which had been demonstrated in the late 1960s by Somer in Utrecht, was applied to cardiac studies from the mid-1970s onwards. Satomura had demonstrated the use of the ultrasonic Doppler effect to detect tissue motion in Osaka in the mid-1950s and the technique was soon afterwards applied in the heart, often in combination with M-mode recording. The development of the pulsed Doppler method in the late 1960s opened up new opportunities for clinical innovation. The review ends with a mention of color Doppler echocardiography. (E-mail:

Cardiovascular applications of the Doppler technique: A long way from birth to scientific acceptance.

Analysis of the early developments of cardiac Doppler illustrates a gap, frequently encountered in science, between initial concepts and final acceptance. Acceptance may only emerge as a result of multidisciplinary collaboration and fruitful dialogue between physicians, physiologists, physicists, and engineers. By 1980, after a good deal of trial and error and a long period of incremental improvement, the majority of the theoretic and scientific issues had been defined. The explosive development of Doppler techniques can now intervene to sweep aside the medical community's scepticism.