This Article Full Text Free Full Text (PDF) Free All Versions of this Article: chest.06-2690v1 132/1/37    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Karamanoglu, M. Articles by Bennett, T. D. Search for Related Content PubMed PubMed Citation Articles by Karamanoglu, M. Articles by Bennett, T. D.

Right Ventricular Pressure Waveform and Wave Reflection Analysis in Patients With Pulmonary Arterial Hypertension^*

^* From NT&D Research, Medtronic Inc. (Drs. Karamanoglu and Bennett, and Ms. Kjellström), Minneapolis, MN; Division of Cardiovascular Diseases (Drs. McGoon and Frantz), Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN; Department of Medicine (Drs. Benza and Bourge), University of Alabama at Birmingham, Birmingham, AL; and Department of Pediatrics (Dr. Barst), Columbia University College of Physicians and Surgeons, New York, NY.

Correspondence to: Mustafa Karamanoglu, PhD, NT & D Research, Medtronic Inc, 7000 Central Ave NE, CW320, Fridley, MN 55432; e-mail: mustafa.karamanoglu{at}Medtronic.com

Abstract

Background: Cardiac index is an important determinant of outcome in patients with idiopathic pulmonary artery hypertension (IPAH). An implantable hemodynamic monitor (IHM) [Chronicle; Medtronic; Minneapolis, MN; a system limited to investigational use only] that records right ventricular (RV) pressure waveforms continuously may increase our understanding of IPAH and improve therapeutic selections and outcomes. The aim of this study was to investigate whether the RV pressure waveform utilizing an IHM can be used to estimate the magnitude of pressure wave reflection and cardiac index in patients with IPAH in acute settings.

Methods: In eight patients with pulmonary arterial hypertension, RV pressure waveforms were recorded utilizing the IHM, and breath-by-breath cardiac index was recorded during acute IV epoprostenol infusion at 3, 6 and 9 ng/kg/min. Late systolic pressure augmentation and cardiac index were estimated using the RV pressure waveforms and correlated with direct measurement of cardiac index.

Results: At baseline, the cardiac index was 2.1 ± 0.2 L/min/m², total pulmonary resistance index was 38 ± 2 Wood U/m², and RV systolic pressure was 92 ± 4 mm Hg. Wave reflection accounted for 29 ± 1 mm Hg of the RV systolic pressure. During epoprostenol infusion, total pulmonary resistance index and wave reflection decreased (– 15 ± 4 Wood U/m², p < 0.001, and – 5 ± 2 mm Hg, p < 0.05, respectively). The breath-by-breath cardiac index correlated with the RV pressure waveform cardiac index estimates (r² = 0.95).

Conclusions: RV pressure waveform analysis provides continuous hemodynamic assessments including cardiac index in acute settings. Once confirmed in long-term settings, this information may prove useful in optimizing a treatment regimen in patients with IPAH.

Key Words: cardiac output • epoprostenol • pulmonary arterial hypertension • right ventricular pressure • wave reflection