Rudolp von Kölliker (1817-1905) and Johannes Müller demonstrated that the heart also produced electricity. In 1847, Ludwig was the first to outline sinus arrhythmia by recording pulse wave and respiratory patterns simultaneously. Heinrich Bidder (1810-1894) described them at the auriculo-ventricular junction in 1852, and Carl Ludwig (1816-1895) found the same ganglion cells in the interatrial septum. Around this time, Robert Remak (1815-1865, a pupil of Johannes Müller ) found that frog heart ganglion cells were present in the sinus venosus. Although a large part of the ‘world’ joined Haller’s theory around 1830, the discussion persisted, especially in France where adherence to the neurogenic theory continued, promoted by Julien Legallois (1775-1814). Albrecht von Haller (1708-1777) argued, based on animal experiments, that the heart beats spontaneously. Thomas Willis (1621-1657) stated that the heart was stimulated to contract by a “nervous liquor” that was carried by nerves from the cerebellum to the heart walls. In the 17th century the neurogenic theory became in vogue. 384-322 BC) theory that blood inside the heart triggers contraction: the myogenic theory. Centuries later, the English physician William Harvey (1578-1657) was still not able to explain this in his De motu cordis (1628). 129-c.216 CE, state physician to Marcus Aurelius) wrote that the excised hearts of animals continued to beat for some time, but he did not provide an explanation. Physicians and philosophers debated for centuries on the origin of the heartbeat. Origin of heartbeat: myogenic versus neurogenic theory It became increasingly possible to do research not only in animals, but also in humans. In the 19th century, anatomy and physiology expanded when more instruments were invented and made available. Some decades later, Giovanni Morgagni (1682-1771, a pupil of Antonio Valsalva) described the course of a patient with AV block in De sedibus et causis morborum per anatomen indagatis. This observation was published after his death. In 1717, Marcus Gerbezius (1658-1718) performed a very accurate pulse analysis and described symptoms of bradycardia, probably induced by a complete AV block. Many centuries later in Europe, Sanctorius Sanctorius (1561-1636) developed techniques for clinical measurements such as pulse rate. The ancient Egyptians described the pulse in the ‘Eber-papers’. It all started much earlier: in the Chinese and Arab world, pulse measurement had already been practiced for centuries: Wang Chu Ho was said to have authored ten books alone on the pulse by 280 BC and Pien Ts’lo is said to have been the first to have recognised the pulse as a diagnostic toom in the fifth century. Centuries of discourse on anatomy and physiology passed before recording ECGs became feasible. Although electrophysiology may sound like a new field, bioelectricity (in animals) was discovered in 1791 by Luigi Galvani (1737-1798). Today we take our smartphone and use two fingers to register an ECG. The patient had to put two hands and one foot in a bucket with electrolyte solution to obtain a 3-lead electrocardiogram (ECG). Willem Einthoven (1860-1927) needed a 600-pound machine and five operators to capture the first PQRST complex in a human in 1901.
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