:
We present a case of 75-year-old lady with effort intolerance and baseline ECG showing 2:1 atrio-ventricular block, in whom it was unclear as to requirement of permanent pacing, even after long term ECG monitoring. She underwent a tread mill test during which her QRS became wide and developed complete heart block within 2 minutes of the test. Thus, a simple exercise test helped in confirming level of block to be infra nodal without need for invasive study. In patients with exertional symptoms, even in elderly, and in those where ECG masquerades as a benign entity, exercise testing is useful to differentiate benign cases of atrio-ventricular block from the more serious cases that mandate a pacemaker implantation.
