Karl-Friedrich Wenckebach (1864–1940)
The cinchona bark of Peru and its active chemical quinine are most commonly associated with malaria. However, eighteenth-century reports described how quinine also corrected heart problems in malaria sufferers who experienced abnormal heart rhythms. In 1912, a Dutch merchant who sought assistance in ridding himself of atrial fibrillation visited the eminent Dutch cardiologist Karl-Friedrich Wenckebach. In this condition, the upper heart chambers (the atria) are beating too fast and causing palpitations. Wenckebach professed an inability to help. The patient returned the following morning with a regular heartbeat, explaining that he took quinine, which benefited him on business trips to countries in which malaria was common.
Wenckebach tried quinine in some patients, with disappointing results, and shared these findings in his 1914 book on arrhythmias. Wenckebach’s account inspired the German physician Walter Frey to compare the effects of quinine and quinidine, another naturally occurring alkaloid in cinchona bark, on his patients with atrial fibrillation. Frey’s 1918 report showed the superiority of quinidine, leading to its widespread use for a variety of heart rhythm disorders.
Quinidine continues to be used for the treatment of a wide range of arrhythmias and has been joined by almost twenty other antiarrhythmic drugs over the years. Based on their rather complex mechanisms of action, these drugs have been categorized into four major classes, several subclasses, and a fifth “miscellaneous” class.
While most arrhythmias neither interfere with the heart’s ability to pump blood nor present a health risk, some can be life threatening. “Pharmacophiles” note that the use of antiarrhythmic drugs is declining; they can worsen existing arrhythmias and even cause new ones. Moreover, new nondrug approaches, such as artificial pacemakers, defibrillators, and surgical procedures, are more effective and are now the preferred treatments. In short, drugs are not always the first and best means of treating medical disorders.
SEE ALSO Cinchona Bark (1639), Alkaloids (1806), Quinine (1820), Xylocaine (1948), Propranolol (1964).
The electrocardiogram (ECG) is used to measure heart rhythm disorders and monitor the effectiveness of quinidine and other antiarrhythmic drugs. This compact, portable monitoring device has evolved from Einthoven’s very cumbersome laboratory apparatus first used in 1903.