History of Echocardiography

Early Developments in Echocardiography

• Floyd Firestone: An American engineer who adapted flaw detection techniques using reflected sound waves for medical applications.
  • Previously developed a method for detecting flaws in metals using reflected sound waves.
  • This method was adapted for medical applications.
• 1953: Firestone obtained a commercial ultrasonoscope (originally used for nondestructive testing).
• Dr. Inge Edler: A cardiologist in Lund, Sweden who collaborated with Firestone.
  • Repurposed ultrasonoscope technology to examine the heart.
  • This marked the beginning of clinical echocardiography.

Technological Foundations

• Piezoelectricity: Discovered in 1880, essential for creating ultrasonic waves.
• Sonar: Used during World War I, contributing to ultrasound technology.
• Edler's Significance: Later known as the "Father of Echocardiography."
  • Pioneering efforts in cardiac imaging.
  • Laid the foundation for modern techniques like Doppler and transesophageal echocardiography.

Historical Perspectives on Diagnostic Ultrasound

• Histories of diagnostic ultrasound and cardiac ultrasound are written from various perspectives.
• Vitruvius: A Roman architect who first coined the word "echo".
• Marin Mersenne (1588–1648): Franciscan friar, often called the “father of acoustics”.
  • First measured the velocity of sound.
• Robert Boyle (1627–1691): Early physicist who recognized the necessity of a medium for sound propagation.
• Abbe Lazzaro Spallanzani (1727–1799): Frequently referred to as the “father of ultrasound”.
  • Demonstrated that bats navigate using echo reflection of inaudible sound.

Doppler Effect and Piezoelectricity

• Christian Johann Doppler (1803–1853):
  • In 1842, noted that the pitch of a sound wave varies if the source is moving (Doppler effect).
  • Developed the mathematical relationship between pitch and relative motion of source and observer.
• Curie and Curie (1880): Discovered piezoelectricity.
  • Observed that certain crystalline materials produce an electric charge when compressed.
  • Noted the reverse effect: applying an electrical potential to a crystal causes compression and decompression, producing high-frequency sound.

Early Applications of Echo Techniques

• 1912: L. F. Richardson: British engineer suggested using echo techniques to detect underwater objects.
• World War I: Paul Langevin: Developed sonar to detect enemy submarines.
• 1929: Sokolov: Described using reflected sound to detect metal flaws.
• 1942: Floyd Firestone: American engineer, applied Sokolov's technique and received a patent for flaw detection, which was later used in medicine.

Post-War Medical Applications

• Karl Dussik (1941): Austrian, likely the first to apply ultrasound for medical diagnosis.
  • Attempted to outline brain ventricles using transmission ultrasound (rather than reflected).
• Post-World War II: Technologies developed during the war (including sonar) were applied for peaceful and medical uses.
• 1950: W. D. Keidel: German investigator, used ultrasound to examine the heart.
  • Transmitted ultrasonic waves through the heart and recorded the effect on the other side of the chest.
  • Aimed to determine cardiac volumes.

Development of Pulse-Reflected Ultrasound

• Dr. Helmut Hertz: From Sweden, familiar with Firestone’s flaw detection techniques.
• 1953: Hertz obtained a commercial ultrasonoscope for nondestructive testing and collaborated with Dr. Inge Edler.
• This collaboration is considered the beginning of clinical echocardiography.

Early Echocardiographic Instruments and Findings

• Original Instrument: Quite insensitive; initially, only echoes from the back wall of the heart could be recorded (likely from the posterior left ventricular wall).
• Mitral Valve Echo: After modifications, they recorded an echo from the anterior leaflet of the mitral valve but initially misattributed it to the anterior left atrial wall.
• Autopsy Investigations: Helped identify the true origin of the mitral valve echo.
• Edler’s Studies: Performed numerous ultrasonic studies of the heart and described many cardiac echoes still used today.

Clinical Application and Further Research

• Mitral Stenosis Detection: Principal clinical application of echocardiography developed by Edler.
  • Observed differences in the motion pattern of the anterior mitral leaflet in patients with and without mitral stenosis.
  • Early studies (mid-1950s, early 1960s) primarily focused on detecting mitral stenosis.
• Sven Effert (Germany): Duplicated Edler’s work, publishing similar findings in the late 1950s.
• Effert and Domanig: Detected left atrial masses.
• Schmidt and Braun (Germany): Began ultrasound cardiography in 1958, replicating Edler and Effert's work.

Key Publications and Presentations

• 1960: Edler et al.: Developed a scientific film shown at the Third European Congress of Cardiology in Rome.
• 1961: Edler et al.: Wrote a comprehensive review of cardiac ultrasound as a supplement to Acta Medica Scandinavica.
  • It remained the most comprehensive review of the field for over 10 years.
  • Described techniques for detecting mitral stenosis, left atrial tumors, aortic stenosis, and anterior pericardial effusion.