RV dysfunction and failure PATHOPHYSIOLOGY Adam Torbicki MD, Dept Chest Medicine Institute of Tuberculosis and Lung Diseases Warszawa, Poland
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
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...
RV-RA gradient 16mmHg Patient WR, 60 yrs old, 5 years post RV infarction
RV ejection pattern Pulsed wave Doppler Right ventricular outflow tract Diastolic forward flow!! Aorta Pulmonary artery
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
Z o Characteristic impedance Z x Input impedance
pulmonary impedance spectrum and profile William R. Milnor Hemodynamics, 1989
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.
1 Pressure/volume curve End systole End ejection Stroke volume Moughan and Oikawa, 1998
end-systolic pressure-volume relation right ventricle (dog) Ees = Endsystolic elastance Moughan et al. 1979
end-systolic pressure-volume relation, pig baseline Experimental Acute PE Ea = Arterial elastance Morimont P. 2008
Effect of PGI2 in PH on Ees and Ea control PGI2 Naeije et al. AJPCCMApril 2007
Effect of PGI2 in PH on RV stroke volume Naeije et al. AJPCCMApril 2007
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.
Pressure Anrep effect increase in contractility in the face of increased afterload (denervated heart) Maintained Stroke Volume! Ees Ea Volume
Pressure Ees Ea Volume
Pressure Decreased Stroke Volume! Ees Ea Preload=EDV Volume
Pressure Starling effect increase in stroke volume induced by increased preload (EDV) Maintained Stroke Volume! Ees Ea Increased Preload Volume
Pressure Decreased Stroke Volume! Ees Ea Volume
Pressure Lower Ees/Ea = RV-PA uncoupling Ees Ea Volume
RV Failure due to progressively increasing afterload MRI courtesy of Dr. Heiko Mahrholdt Chicago/Stuttgart
Leeuwenburgh BPJ et al, J Thoracic Cardiovasc Surg 2003
Effect of aortic pressure on RV performance Klima UP et al. J Thoracic Cardiovasc Surg 2002
PAH control RCA LCA
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
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)
IPAH Eisenmenger
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
Before and after PEA CETPH
RV DYSFUNCTION - resolution post embolectomy courtesy Prof. Andrzej Biederman Institute of Cardiology, Warszawa