American journal of physiology. Heart and circulatory physiology
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Am. J. Physiol. Heart Circ. Physiol. · Oct 2018
Exercise cardiac MRI unmasks right ventricular dysfunction in acute hypoxia and chronic pulmonary arterial hypertension.
Coupling of right ventricular (RV) contractility to afterload is maintained at rest in the early stages of pulmonary arterial hypertension (PAH), but exercise may unmask depleted contractile reserves. We assessed whether elevated afterload reduces RV contractile reserve despite compensated resting function using noninvasive exercise imaging. Fourteen patients with PAH (mean age: 39.1 yr, 10 women and 4 men) and 34 healthy control subjects (mean ageL 35.6 yr, 17 women and 17 men) completed real-time cardiac magnetic resonance imaging during submaximal exercise breathing room air. ⋯ In conclusion, noninvasive cardiac imaging during exercise unmasks depleted RV contractile reserves in healthy adults under hypoxic conditions and patients with PAH under normoxic conditions despite preserved ejection fraction at rest. NEW & NOTEWORTHY Right ventricular (RV) reserve was assessed using real-time cardiac magnetic resonance imaging in patients with pulmonary arterial hypertension and in healthy control subjects under normobaric hypoxia, which has been previously associated with acute pulmonary hypertension. Hypoxia caused a mild reduction in RV reserve, whereas chronic pulmonary arterial hypertension was associated with a marked reduction in RV reserve.