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Abstract Background Interventricular mechanical dyssynchrony is a characteristic of pulmonary hypertension. We studied the role of right ventricular (RV) wall stress in the recovery of interventricular dyssynchrony, after pulmonary endarterectomy (PEA) in chronic thromboembolic pulmonary hypertension (CTEPH). Methods In 13 consecutive patients with CTEPH, before and 6 months after pulmonary endarterectomy, cardiovascular magnetic resonance myocardial tagging was applied. For the left ventricular (LV) and RV free walls, the time to peak (Tpeak) of circumferential shortening (strain) was calculated. Pulmonary Artery Pressure (PAP) was measured by right heart catheterization within 48 hours of PEA. Then the RV free wall systolic wall stress was calculated by the Laplace law. Results After PEA, the left to right free wall delay (L-R delay) in Tpeak strain decreased from 97 ± 49 ms to -4 ± 51 ms (P < 0.001), which was not different from normal reference values of -35 ± 10 ms (P = 0.18). The RV wall stress decreased significantly from 15.2 ± 6.4 kPa to 5.7 ± 3.4 kPa (P < 0.001), which was not different from normal reference values of 5.3 ± 1.39 kPa (P = 0.78). The reduction of L-R delay in Tpeak was more strongly associated with the reduction in RV wall stress (r = 0.69,P = 0.007) than with the reduction in systolic PAP (r = 0.53, P = 0.07). The reduction of L-R delay in Tpeak was not associated with estimates of the reduction in RV radius (r = 0.37,P = 0.21) or increase in RV systolic wall thickness (r = 0.19,P = 0.53). Conclusion After PEA for CTEPH, the RV and LV peak strains are resynchronized. The reduction in systolic RV wall stress plays a key role in this resynchronization.

Objectives: We sought to study whether patients with right ventricular failure (RVF) secondary to chronic thromboembolic pulmonary hypertension (CTEPH) have reduced left ventricular (LV) mass, and whether LV mass reduction is caused by atrophy., Background: The LV in patients with CTEPH is underfilled (unloaded). LV unloading may cause atrophic remodeling that is associated with diastolic and systolic dysfunction., Methods: We studied LV mass using cardiac magnetic resonance imaging (MRI) in 36 consecutive CTEPH patients (before/after pulmonary endarterectomy [PEA]) and 11 healthy volunteers selected to match age and sex of patients. We studied whether LV atrophy is present in monocrotaline (MCT)-injected rats with RVF or controls by measuring myocyte dimensions and performing in situ hybridization., Results: At baseline, CTEPH patients with RVF had significantly lower LV free wall mass indexes than patients without RVF (35 ± 6 g/m(2) vs. 44 ± 7 g/m(2), p = 0.007) or volunteers (42 ± 6 g/m(2), p = 0.006). After PEA, LV free wall mass index increased (from 38 ± 6 g/m(2) to 44 ± 9 g/m(2), p = 0.001), as right ventricular (RV) ejection fraction improved (from 31 ± 8% to 56 ± 12%, p < 0.001). Compared with controls, rats with RVF had reduced LV free wall mass and smaller LV free wall myocytes. Expression of atrial natriuretic peptide was higher, whereas that of α-myosin heavy chain and sarcoplasmic reticulum calcium ATPase-2 were lower in RVF than in controls, both in RV and LV., Conclusions: RVF in patients with CTEPH is associated with reversible reduction in LV free wall mass. In a rat model of RVF, myocyte shrinkage due to atrophic remodeling contributed to reduction in LV free wall mass., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Chronic thrombo-embolic pulmonary hypertension (CTEPH) was diagnosed in two patients, a man aged 55 years and a woman aged 54 years, who had both suffered an episode of pulmonary embolism. CTEPH is a rare but serious late complication of pulmonary embolism. If left untreated, it is a progressive disease with a poor prognosis. Pulmonary endarterectomy is the treatment of choice for CTEPH; both patients were treated successfully with this operation. In clinical practice patients are often initially misdiagnosed, due to unawareness of the condition, and are therefore subjected to a long delay before treatment. In the first patient the condition had not been recognised on CT scans. The second patient had initially been treated with psychotherapy for a suspected burn-out. All physicians involved in taking care of patients with pulmonary embolism, must be aware of this serious complication. Diagnosis and treatment of CTEPH require a high level of expertise.