Differences in Treadmill Exercise Tolerance Parameters Between Patients With Partial and Advanced Interatrial Depolarization Abnormality

Abstract

Advanced interatrial block (aIAB) is considerably much less common than partial interatrial block (pIAB), occuring in <2% of the elderly hospitalized population. Less is, therefore, known of the true clinical burden of aIAB, particularly in relation to graded exercise. Therefore, 12 patients with aIAB and 30 patients with pIAB who performed a baseline exercise tolerance test and had a repeat test performed > or = 2 years later were included in the study. Exercise tolerance, echocardiographic findings, and major adverse cardiovascular events were compared. Left atrial size progressed at a significantly faster rate in those with aIAB. In addition, Duke Prognostic Treadmill scores were significantly lower on follow-up in those patients with aIAB. Overall, patients with aIAB had significantly greater left atrial size (48.3 +/- 9 vs 42.8 +/- 4 mm, p < 0.01) and significantly lower Duke Prognostic Treadmill scores than those with pIAB (-0.2 +/- 5 vs 4.1 +/- 4, p < 0.05). There were, however, no significant differences in the occurence of major adverse cardiovascular events. In conclusion, left atrial size progressed at a significantly faster rate but Duke Prognostic Treadmill scores were significantly lower in those with aIAB compared with patients with pIAB after > or = 2 years of follow-up. Further study is required to determine whether patients with aIAB require follow-up echocardiography and/or exercise tolerance tests for optimal risk stratification.