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Updated: Jun 23, 2026
Cardiac Pressure-Volume Loop Analysis Using Conductance Catheters in Mice
Published on: September 17, 2015
Hemodynamic effects of long-term cardiac resynchronization therapy: analysis by pressure-volume loops
Paul Steendijk1, Sven A Tulner, Jeroen J Bax
1Department of Cardiology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands. p.steendijk@lumc.nl
Insights
Cardiac resynchronization therapy (CRT) offers long-term hemodynamic benefits, improving heart function and patient exercise tolerance. This study confirms sustained improvements in ventricular-arterial coupling and mechanical efficiency after 6 months of CRT.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Medical Devices
Background:
- Limited invasive data exist on long-term hemodynamic effects of cardiac resynchronization therapy (CRT).
- Previous studies focused primarily on acute hemodynamic responses to CRT.
Purpose of the Study:
- To investigate the chronic hemodynamic consequences of CRT in patients with heart failure.
- To assess long-term changes in left ventricular (LV) function, remodeling, and efficiency following CRT implantation.
Main Methods:
- Invasive hemodynamic assessment using pressure-volume loops via conductance catheters in 22 patients before and after 6 months of CRT.
- Evaluated responses during atrial and biventricular pacing at varying heart rates.
- Measured New York Heart Association class, quality of life, and 6-minute hall-walk distance.
Main Results:
- CRT significantly improved clinical status (NYHA class, QoL, 6MWT), LV ejection fraction, and reduced LV end-diastolic pressure.
- Sustained improvements in LV contractility (dP/dtmax, -dP/dtmin) and stroke work were observed.
- Enhanced ventricular-arterial coupling and mechanical efficiency, with improved chronotropic responses.
Conclusions:
- Long-term CRT maintains acute hemodynamic benefits and improves ventricular-arterial coupling and mechanical efficiency.
- These chronic improvements contribute to enhanced functional status and exercise capacity in CRT patients.
- Findings support the long-term efficacy of CRT in managing heart failure with improved hemodynamic performance.
Background:
Acute hemodynamic effects of cardiac resynchronization therapy (CRT) were reported previously, but detailed invasive studies showing hemodynamic consequences of long-term CRT are not available.
Methods And Results:
We studied 22 patients scheduled for implantation of a CRT device based on conventional criteria (New York Heart Association class III or IV, left ventricular [LV] ejection fraction <35%, left bundle-branch block, and QRS duration >120 ms). During diagnostic catheterization before CRT, we acquired pressure-volume loops using conductance catheters during atrial pacing at 80, 100, 120, and 140 bpm. Studies were repeated during biventricular pacing at the same heart rates after 6 months of CRT. Our data show a significant clinical benefit of CRT (New York Heart Association class change from 3.1+/-0.5 to 2.1+/-0.8; quality-of-life score change from 44+/-12 to 31+/-16; and 6-minute hall-walk distance increased from 260+/-149 to 396+/-129 m; all P<0.001), improved LV ejection fraction (from 29+/-10% to 40+/-13%, P<0.01), decreased end-diastolic pressure (from 18+/-8 to 13+/-6 mm Hg, P<0.05), and reverse remodeling (end-diastolic volume decreased from 257+/-67 to 205+/-54 mL, P<0.01). Previously reported acute improvements in LV function remained present at 6 months: dP/dtmax increased 18%, -dP/dtmin increased 13%, and stroke work increased 34% (all P<0.01). Effects of increased heart rate were improved toward more physiological responses for LV ejection fraction, cardiac output, and dP/dtmax. Moreover, our study showed improved ventricular-arterial coupling (69% increase, P<0.01) and improved mechanical efficiency (44% increase, P<0.01).
Conclusions:
Hemodynamic improvements with CRT, previously shown in acute invasive studies, are maintained chronically. In addition, ventricular-arterial coupling, mechanical efficiency, and chronotropic responses are improved after 6 months of CRT. These findings may help to explain the improved functional status and exercise tolerance in patients treated with CRT.
