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Left ventricular dysfunction induced by nonsevere idiopathic pulmonary arterial hypertension: a pressure-volume relationship study.
RATIONALESevere increase in right ventricular pressure can compromise left ventricular (LV) function because of impaired interventricular interaction and aggravate the symptoms.
OBJECTIVESTo elucidate how nonsevere idiopathic pulmonary arterial hypertension (IPAH) influences LV function because of impaired interventricular interaction.
METHODSInvasive pressure-volume (PV) loop analysis obtained by conductance catheterization was performed at rest and during atrial pacing in patients with mild IPAH (n = 10) compared with patients with isolated LV diastolic dysfunction (DD) (n = 10) and control subjects without heart failure symptoms (n = 9).
MEASUREMENTS AND MAIN RESULTSPatients with nonsevere IPAH (pulmonary artery pressure mean 29 ± 5 mm Hg) and patients with DD showed preserved systolic (ejection fraction 63 ± 12% and 62 ± 9%) and impaired LV diastolic function at rest (LV stiffness 0.027 ± 0.012 ml(-1) and 0.029 ± 0.014 ml(-1)). During pacing at 120 per minute patients with IPAH and DD decreased their stroke volume (-25% and -30%; P < 0.05) and failed to increase cardiac output significantly. Opposite to patients with DD and control subjects, temporary preload reduction during inferior vena cava occlusion initially induced an expansion of LV end-diastolic volume in IPAH (+7%; P < 0.05), whereas end-diastolic pressure continuously dropped. This resulted in an initial downward shift to the right of the PV loop indicating better LV filling, which was associated with a temporary improvement of cardiac output (+11%; P < 0.05) in the patients with IPAH, but not in patients with DD and control subjects.
CONCLUSIONSMild idiopathic pulmonary arterial pressure impairs LV diastolic compliance even in the absence of the intrinsic LV disease and contributes to the reduced cardiac performance at stress.
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American journal of respiratory and critical care medicine 186:2 2012 Jul 15 pg 181-9
Ventricular Dysfunction, Left
Pub Type(s)Journal Article
Research Support, Non-U.S. Gov't