Hemodynamic Rounds

5/13/11

Hemodynamics

• Equalization of diastolic pressures (RA, RV, LV, Wedge) and pericardial pressure

• Total intracardiac volume fixed, so flow into heart occurs mainly during systole;X-descent is the dominant wave

• Loss of Y-descent: No overall change in intracardiac volume in diastole

Zipes. Braunwald’s Heart Disease, 7th ed. Ch. 64.

Paradoxical Pulse and Interdependence

• Hallmark of tamponade• Inspiration causes increased venous return

with fixed intracardiac volume• RV size increases, septum shifts, LV size

decreases (180 degrees out of phase)

Zipes. Braunwald’s Heart Disease, 7th ed. Ch. 64.

Tamponade• Critical point where effusion reduces volume of

cardiac chambers – “Last Drop Phenomenon”

• Decreases stroke volume in both left and right heart

• Primarily affects the right heart due to lower pressures

• Fixed total cardiac volume accentuates interdependence

Zipes. Braunwald’s Heart Disease, 7th ed. Ch. 64.

Hemodynamic Findings• High RA, RVEDP, LVEDP and intrapericardial

pressure prior to tap• Cardiac output reduced• Low RA transmural pressure• Post-tap, intrapericardial pressure dropped, RA

transmural pressure increased, RA and RVEDP dropped slightly and LVEDP was unchanged

• CO increased slightly• Y-descent returned• Dip-plateau visible

Sagrista-Sauleda. NEJM 350: 2004.

Constriction Hemodynamics• Chief characteristic: Failure of transmission of

intrathoracic pressure changes of respiration to the cardiac chambers

• Interdependence: Pressure changes continue to transmit to the pulmonary circulation, so inspiration decreases pulmonary venous pressure– Drops the PV-LA gradient, with reduced LA inflow and

reduced transmitral flow– Underfilled LV permits septal shift to left and

increased RV filling

Hemodynamics

• Equilibration of RA, RV diastolic, Wedge and LV diastolic pressures (less than 3-5mmHg difference)

• Atrial wave: Preserved X-descent, prominent Y-descent (“M” or “W” configuration)

Zipes. Braunwald’s Heart Disease, 7th ed. Ch. 64.

Hemodynamics

• RV and LV show “dip and plateau” or “square root” sign

• Reflects lack of mid-to-late diastolic filling

Zipes. Braunwald’s Heart Disease, 7th ed. Ch. 64.

Constriction vs. Tamponade

• Both restrict cardiac filling and raise systemic and pulmonary venous pressures

• Venous pressure waveforms differ

Zipes. Braunwald’s Heart Disease, 7th ed. Ch. 64.

Vs. Restriction: DissociationVs. Restriction: Dissociation of Intrathoracic and Intracardiac

Pressures

Hatle LK, et. al.Circ. 1989;79357-370

Ventricular Interdependence

Insp Expir

Hatle LK, et. al.Circ. 1989;79357-370

Ventricular PressuresAre DISCORDANT

Little. Circulation 2006, 113: 1629.

Kussmaul’s Sign• Pericardial constriction• Restrictive cardiomyopathy• Congestive Heart Failure:RV

failure– Right ventricular infarction

• Acute pulmonary embolism• COPD