[The exercise stress test in patients with intraventricular conduction troubles (author's transl)]. / Il test ergometrico nelle anomalie della conduzione intraventricolare.

The results of exercise stress test in 86 patients with intraventricular conduction troubles (BBBand or Emiblock) are discussed in order to asses the meaning of exercise induced ECG alterations and possibly of an etiopathogenetic interpretation. The AA. examined the following parameters during stress test and recovery: max heart rate, percent of teoric max heart rate, max BP, max heart rate x BP product, AQRS at rest and during recovery immediately after exercise test, QRS duration, ST depression, T amplitude. The majority (91,67%) of isolated RBBB patients had negative test; 30,43% of RBBB + LAEmiblock patients had ECG signs and clinical symptoms of myocardial ischemia. In LBBB patients the test was considered positive only if present ST depression and precordial pain. The AQRS tends during exercise to the right; in the 60% of RBBB + LAEmiblock patients it can be seen a tendency to left axis deviation; the amplitude of T-wave is increasing in more than 50% in LBBB. The conclusions are that in patients with intraventricular conduction troubles the interpretation of results is always difficult; the presence of clinical symptoms like precordial pain may give an aide when associated to the ECG variations.