Q. Explain Reproducibility of Venricular Ectopy ?

Experimentally it has been shown that PVCs are frequently seen at the inception of acute ischaemia. Thus, exercise induced PVCs or VT may be an ischaemic equivalent, and good reproducibility would be expected. Approximately 50 per cent reproducibility has been shown in clinically normal subjects, after a 3-year interval. Sheps and associates repeated the exercise test after 45 minutes and found that the second test resulted in significant decrease in irritability. Others have reported a reproducibility of 30 per cent of PVCs and 50 per cent for VT. Thus, when using a stress test to evaluate the efficiency of an antiarrhythmic agent the degree of unreliability must be kept in mind. An even lower rate of reproducibility in Holter monitoring (10 per cent) has been reported.