Kazuo Yamada, MD, PhD　― 1924–2019 ―

Kazuo Yamada MD, PhD, Professor Emeritus of Nagoya University Graduate School of Medicine, Japan, passed away on June 10, 2019, at 95 years old.

He was engaged in basic and clinical research on the relationship between electrocardiography and the electromotive force generated by myocardial electrogensis and its impulse conduction through the heart.

Dr. Yamada was born on March 14, 1924 at Shikatsu-Cho (now Kitanagoya City) in Aichi Prefecture. He graduated Nagoya University School of Medicine in 1947. After completion of the residency program, he started basic research on inverse solution of electromotive forces generated by excitation of ventricles at Cardiopulmonary Department, the Research Institute of Environmental Medicine, Nagoya University, and got his PhD from Nagoya University Graduate School of Medicine.

After 1 year of study at the Department of Medicine, University of California, Dr. Yamada conducted research on impulse transmission from the sinus node to the atrioventricular (AV) node and then to the ventricles, using a glass microelectrode technique. He revealed the existence of 3 or 4 preferential pathways in the sinus to AV node transmission, and proposed that the genesis of “absolute arrhythmia” in atrial fibrillation was attributable to inhomogeneous conduction of AV node cells.^1,2 He also provided new insights into the contribution of the His-Purkinje network to ventricular excitation.³

Dr. Yamada devised a multichannel recorder to get electrocardiographic (ECG) data from 87 lead points on the body surface, simultaneously. He investigated theoretical number of lead points on the body surface needed to acquire complete ECG data⁴ and proposed that an inter-electrode distance of 2.5 cm maximum was essential for its data acquisition.⁵ Then, he initiated the clinical application of this device to record precise bioelectric signals by applying body surface and epicedial mapping system.^6,7

His glorious academic achievements in basic and clinical medicine is inclusive of his ability to instruct and lead researchers of electronics and basic medicine and those of cardiology, with his extensive knowledge and broad-minded attitude. He trained valuable human resources in each field and groomed them to become academic leaders.

He devoted himself to the promotion of excellence in Japanese cardiac science as the chairperson of the 44^th Scientific Meeting of the Japanese Circulation Society (JCS), the president of JCS (1985–1987), and vice-president of the Japan Heart Foundation (1993–1999).

He granted a total of ¥1,570,000,000 (US$14,300,000) to 1,250 young investigators as the Board Chairman of the Suzuken Memorial Foundation (1995–2014). He was awarded the Order of the Rising Sun Gold Rays with Neck Ribbon (Kyokujitsu-sho) in 1988 and the Medal of Honor with Purple Ribbon (Shiju-hosho) in 1993.

Dr. Kazuo Yamada’s contributions, teaching and all memories will be remembered and treasured forever.

References

• 1.   Yamada K, Horiba M, Sakaida Y, Okajima M, Horibe H, Kobayashi T, et al. Origination and transmission of impulse in right auricle. Jpn Heart J 1965; 6: 71–97.
• 2.   Yamada K, Okajima M, Hori K, Fujino T, Muraki H, Hisida H, et al. On the genesis of the absolute ventricular arrhythmia associated with atrial fibrillation. Circ Res 1968; 22: 707–715.
• 3.   Okajima M, Fujino T, Kobayashi T, Yamada K. Computer simulation of the propagation process in excitation of the ventricles. Circ Res 1968; 23: 203–211.
• 4.   Toyama J, Ohta T, Yamada K. Newly developed body surface mapping system for clinical use. In: Yamada K, Harumi K, Musha K, editors. Advances in body surface potential mapping. The University of Nagoya Press, 1983; 125–134.
• 5.   Toyama J, Tabata O. Recognition of the epicardial breakthrough on the body surface isopotential maps: Influence of the inter-electrode distance on the patterns reflecting the epicardial breakthrough. Jpn Circ J 1981; 45: 1172–1178.
• 6.   Yamada K, Toyama J, Wada M, Sugiyama S, Sugenoya J, Toyoshima H, et al. Body surface isopotential mapping in Wolf-Parkinson-White syndrome: Noninvasive method to determine the location of the accessory atrioventricular pathway. Am Heart J 1975; 90: 721–734.
• 7.   Sugenoya J, Sugiyama S, Wada M, Niimi N, Oguri H, Toyama J, et al. Body surface distribution following the production of right bundle branch block in dogs: Effect of breakthrough and right ventricular excitation on the body surface potentials. Circulation 1977; 55: 49–54.