RV dysfunction and failure PATHOPHYSIOLOGY. Adam Torbicki MD, Dept Chest Medicine Institute of Tuberculosis and Lung Diseases Warszawa, Poland

Transcription

1 RV dysfunction and failure PATHOPHYSIOLOGY Adam Torbicki MD, Dept Chest Medicine Institute of Tuberculosis and Lung Diseases Warszawa, Poland

2 Normal Right Ventricle (RV) Thinner wall Weaker myocytes Differences in potassium channels Different action potential s shape (repolarization) Less calcium available for contraction Smaller force developed after stimulation of isolated harvested RV compared to LV myocytes Wayne R. Giles, University of Calgary ATS at 2007

3 We do not need RV...? Severe damage of RV free wall (of the dog) had no apparent effect on hemodynamics... from Starr I et al. Am Heart J, 1943,26,291 5 mm Hg pressure difference is sufficient to provide adequate pulmonary flow...

4 RV-RA gradient 16mmHg Patient WR, 60 yrs old, 5 years post RV infarction

5 RV ejection pattern Pulsed wave Doppler Right ventricular outflow tract Diastolic forward flow!! Aorta Pulmonary artery

6 Z x Input impedance is... an indication of hydraulic energy associated with blood flow, expressing the opposition of the vessels to pulsatile flow... William R. Milnor Hemodynamics, 1989

7 Z o Characteristic impedance Z x Input impedance

8 pulmonary impedance spectrum and profile William R. Milnor Hemodynamics, 1989

9 Pressure Pressure-volume loop, basic concepts Contractility Ees=Pes/Ves Ees Ea Afterload Ea=Pes/SV Volume Preload=EDV Sagawa et al. Cardiac contraction and the PV relationship, Oxford University Press, 1988.

10 1 Pressure/volume curve End systole End ejection Stroke volume Moughan and Oikawa, 1998

11 end-systolic pressure-volume relation right ventricle (dog) Ees = Endsystolic elastance Moughan et al. 1979

12 end-systolic pressure-volume relation, pig baseline Experimental Acute PE Ea = Arterial elastance Morimont P. 2008

13 Effect of PGI2 in PH on Ees and Ea control PGI2 Naeije et al. AJPCCMApril 2007

14 Effect of PGI2 in PH on RV stroke volume Naeije et al. AJPCCMApril 2007

15 Pressure Pressure-volume loop, basic concepts Contractility Ees=Pes/Ves Ees Ea Afterload Ea=Pes/SV Volume Preload=EDV Sagawa et al. Cardiac contraction and the PV relationship, Oxford University Press, 1988.

16 Pressure Anrep effect increase in contractility in the face of increased afterload (denervated heart) Maintained Stroke Volume! Ees Ea Volume

17 Pressure Ees Ea Volume

18 Pressure Decreased Stroke Volume! Ees Ea Preload=EDV Volume

19 Pressure Starling effect increase in stroke volume induced by increased preload (EDV) Maintained Stroke Volume! Ees Ea Increased Preload Volume

20 Pressure Decreased Stroke Volume! Ees Ea Volume

21 Pressure Lower Ees/Ea = RV-PA uncoupling Ees Ea Volume

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23 RV Failure due to progressively increasing afterload MRI courtesy of Dr. Heiko Mahrholdt Chicago/Stuttgart

24 Leeuwenburgh BPJ et al, J Thoracic Cardiovasc Surg 2003

25 Effect of aortic pressure on RV performance Klima UP et al. J Thoracic Cardiovasc Surg 2002

26 PAH control RCA LCA

27 Vicious vortex in severe PH Increased afterload Adrenergic activity RV dilation Decreased RV coronary gradient/perfusion Low SBP RV failure Increased wall stress Increased O2 demand Low cardiac output RV ischemia

28 What protects Patients with Eisenmenger Syndrome? Preconditioned Right Ventricle - hypertrophy - fetal fenotype of myocytes - relatively more coronary arteries Dilated central PA? lower input impedance - inverted shunt - Better left heart filling and aortic pressure (coronary perfusion)

29 IPAH Eisenmenger

30 How to help the RV? Reverse/stop/slow rise of RV afterload characteristic impedance + reflected wave Keep aortic pressure high for the sake of RV coronary perfusion Control excessive sympathetic activity to decrease oxygen demand and hypertrophy Keep LV busy to support RV through IV septal interaction

31 Before and after PEA CETPH

32 RV DYSFUNCTION - resolution post embolectomy courtesy Prof. Andrzej Biederman Institute of Cardiology, Warszawa