Ventricular tachycardia historical perspective
Early Clinical and Experimental Observations
The first electrocardiographic description and evidence of Ventricular Tachycardia (VT) was given by Thomas Lewis in 1909. He described a patient with shortness of breath, precordial pain, and dropsy in whom he observed from three to eleven "successive extrasystoles".[1] He deduced from the electrocardiogram, venous pulse recording, and clinical evidence that the rhythm was of ventricular origin. In 1906, Einthoven had recorded ventricular premature beats and ventricular bigeminy using his string galvanometer.[2] In 1906 Gallavardin did landmark work in France in which he found the reason of instability of VT and its ability to convert in Ventricular Fibrillation.3 He challenged the fact that ventricular tachycardia was no more than a succession of extrasystoles suggesting that although the two phenomena were intimately related, the same mechanism might not be responsible for both.[3][4] Lewis and Smith did experimentation with dogs by simulating VT by ligating coronary arteries and was able to find characteristics of VT as we have described in the other sections.5,6
Electrocardiographic Features
Robinson and Herrmann, in 1921, suggested that coronary occlusion was a frequent cause of ventricular tachycardia and the prognosis in these cases appeared to be poor.7 They also suggested the most initial criteria for VT classification. That was modified later by Rosenberg as well as Dressler and Roesler who pointed out the occasional occurrence of fusion beats in tracings showing the arrhythmia.8,9 Since then we have come a long way in making of the diagnostic criteria better with advent of Esophageal10,11 & Venous leads and Invasive Electrophylogic Studies.12
Physical Examination
Initially Phlebography was very popular amongst scientists for features of VT. Prinzmetal and Kellogg in 1934 concluded that slower, independent A waves might be encountered in two-thirds of cases of VT.13 Schrire and Vogelpoel discovered that the so-called "cannon" A is encountered in presence of atrioventricular dissociation, but could occur in regular fashion at the same rate in nodal tachycardias.14 The AV dissociation and its reflection was demonstrated by Wilson et al. in 1964. 15 Levine was the first who noted slight irregularity in cycle length in patients with ventricular tachycardia which was audible with the stethoscope.16 In 1927, he mentioned variation in intensity of the first heart sound, due to atrioventricular dissociation, and extended these observations in conjunction with Harvey in 1948.17,18 Harvey and Corrado demonstrated multiple low-frequency sounds audible in ventricular tachycardia as a differential point.19
References
- ↑ Lewis T(1909). Single and successive extrasystoles. Lancet 1:382. 1909
- ↑ Einthoven W(1906). Le telecardiogramme. Arch Int Physiol 4:132.
- ↑ Gallavardin L(1922). Extrasystolie ventriculaire a paroxysmes tachycardiques prolonges. Arch Mal Coeur 15:298.
- ↑ Gallavardin, L(1926). Tachycardie ventriculaire terminale: complexes alternants ou multiformes: ses rapports avec une forme severe d'extra-systolie ventriculaire. Arch Mal Coeur 19:153.