Silvio Weidmann: laying the foundations for unravelling the mechanism of heart rhythm

Figures

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  Figure 1.. Silvio Weidmann at the farewell dinner of the 1986 Silvio Weidmann Symposium in Bern. Courtesy Ernst Niggli.

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  Figure 2.. Oscilloscope recordings of membrane resistance changes in a Purkinje fibre during the cardiac cycle. Repetitive square pulses of current were injected through one microelectrode while the membrane potential and its repetitive displacements were recorded with the second microelectrode. Horizontal lines are 10 mV apart, while the time marks are at 100 ms intervals [4].

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  Figure 3.. The nonlinear responses to larger current pulses. (a) Pulses of various magnitudes applied during the pacemaker depolarization showing a threshold for excitation of an action potential. (b) Pulses of various amplitudes applied during the action potential plateau showing a threshold for depolarization [4].

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  Figure 4.. Denis Noble's copy of Elektrophysiologie der Herzmuskelfaser (1956) [5] signed by Silvio Weidmann. (Online version in colour.)

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  Figure 5.. First recording of activity in a Purkinje fibre, from Coraboeuf & Weidmann (1949) [1]. Note that the action potential does not show a normal spike-like overshoot, as noted by the authors: ‘Il n'a pas été possible jusqu'à présent d'observer d'«overshoots» du potentiel d'action au-dessus du potentiel zéro plus importants que celui de la figure 1’. It is possible that the input to the amplifier had too low resistance. All the later recordings in Weidmann's papers clearly showed an overshoot.

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  Figure 6.. From the programme of the International Union of Physiological Sciences (IUPS) 1962 Congress in Leiden, Holland.

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  Figure 7.. Back of a photograph of D.D. taken and autographed by Silvio Weidmann on 13 January 1976. The last sentence reads: 'Auguriamo successo per il voltage clamp'.

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  Figure 8.. Abstract of the communication ‘Electrical activity of rabbit sino-atrial node as studied by a double sucrose gap method' delivered by Hiroshi Irisawa at a symposium in Brussels in 1972 [14]. Silvio Weidmann gave it to D.D. during his visit to Bern in January 1976.