Introduction: Exercise-induced pulmonary hypertension (ePH) must be a crucial finding for diagnosing etiology of exertional dyspnea on exercise stress echocardiography. Although it is indispensable to measure maximal tricuspid regurgitation pressure gradient (TRPG) which is recorded at peak exercise, it is difficult to measure maximal TRPG during treadmill walking exercise test.
Hypothesis: If elevated TRPG due to ePH continues for a certain time during recovery after exercise termination, it would be a practical diagnostic clue.
Methods and Results: Fifty-five patients (66±11 years, 16 men) underwent symptom-limited exercise echocardiography by using supine bicycle ergometry in our institution. Twenty-two patients (40%) who underwent mitral valve repair and 21 patients (38%) with connective tissue disease were included in our study cohort. PH was defined as maximal TRPG >50 mmHg. All subjects did not have significant PH at rest. We consecutively measured TRPG during exercise and immediately after exercise termination through five minutes after exercise. Twenty-six patients (47%) were diagnosed as having ePH, i.e., their median value of maximal TRPG was 57 mmHg [interquartile range: 52 - 61 mmHg] at 37 watts work load [interquartile range: 34 - 65 watts]. TRPG in patients with ePH was higher than 40 mmHg until two minutes after and still higher than 30 mmHg through five minutes after exercise. The differences of TRPG were statistically significant from baseline through five minutes after exercise termination (all p <0.05) between patients with ePH and those without (Figure).
Conclusions: At least until five minutes after exercise, elevated TRPG could continue in patients with ePH, which must be a clue for its diagnosis on exercise stress echocardiography.