Hemodynamic Optimization in Cardiac Resynchronization Therapy: Should We Aim for dP/dtmax or Stroke Work?
Alwin Zweerink1, Odette A E Salden2, Wouter M van Everdingen2
1Department of Cardiology, and Amsterdam Cardiovascular Sciences (ACS), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, the Netherlands.
Insights
Stroke work (SW)-guided optimization during cardiac resynchronization therapy (CRT) significantly improves patient outcomes. Acute SW changes predict long-term CRT response better than dP/dtmax, enhancing ventricular-arterial coupling.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) aims to improve cardiac function in heart failure patients.
- Hemodynamic optimization is crucial for maximizing CRT benefits.
- Maximal left ventricular pressure rise (dP/dtmax) and stroke work (SW) are key hemodynamic parameters.
Purpose of the Study:
- To evaluate the acute effects of dP/dtmax-guided versus SW-guided CRT optimization.
- To assess the relationship between acute hemodynamic changes and long-term CRT response.
Main Methods:
- Forty-one patients received CRT with invasive pressure-volume loop measurements.
- 16 left ventricular (LV) pacing configurations were tested with varying atrioventricular (AV) delays.
- Conventional CRT involved distal electrode pacing with a 120 ms AV delay.
Main Results:
- Both dP/dtmax and SW optimization significantly increased their respective parameters compared to conventional CRT.
- SW optimization enhanced ventricular-arterial (VA) coupling (45% vs. 32%), while dP/dtmax favored LV contractility (8% vs. 5%).
- Acute changes in SW were predictive of long-term CRT response (AUC=0.78), unlike dP/dtmax changes (AUC=0.65).
Conclusions:
- PV-guided hemodynamic optimization in CRT significantly improves SW through enhanced VA coupling.
- dP/dtmax optimization primarily enhances LV contractility.
- Acute SW changes are a stronger predictor of long-term CRT response than dP/dtmax changes.
Objectives:
This study evaluated the acute effect of dP/dtmax- versus stroke work (SW)-guided cardiac resynchronization therapy (CRT) optimization and the related acute hemodynamic changes to long-term CRT response.
Background:
Hemodynamic optimization may increase benefit from CRT. Typically, maximal left ventricular (LV) pressure rise dP/dtmax is used as an index of ventricular performance. Alternatively, SW can be derived from pressure-volume (PV) loops.
Methods:
Forty-one patients underwent CRT implantation followed by invasive PV loop measurements. The stimulation protocol included 16 LV pacing configurations using each individual electrode of the quadripolar lead with 4 atrioventricular (AV) delays. Conventional CRT was defined as pacing from the distal electrode with an AV delay of approximately 120 ms.
Results:
Compared with conventional CRT, dP/dtmax-guided optimization resulted in a one-third additional dP/dtmax increase (17 ± 11% vs. 12 ± 9%; p < 0.001). Similarly, SW-guided optimization resulted in a one-third additional SW increase (80 ± 55% vs. 53 ± 48%; p < 0.001). Comparing both optimization strategies, dP/dtmax favored contractility (8 ± 12% vs. 5 ± 10%; p = 0.015), whereas SW optimization improved ventricular-arterial (VA) coupling (45% vs. 32%; p < 0.001). After 6 months, mean LV ejection fraction (LVEF) change was 10 ± 9% with 23 (56%) patients becoming super-responders to CRT (≥10% LVEF improvement). Although acute changes in SW were predictive for long-term CRT response (area under the curve: 0.78; p = 0.002), changes in dP/dtmax were not (area under the curve: 0.65; p = 0.112).
Conclusions:
PV-guided hemodynamic optimization in CRT results in approximately one-third SW improvement on top of conventional CRT, caused by a mechanism of enhanced VA coupling. In contrast, dP/dtmax optimization favored LV contractility. Ultimately, acute changes in SW showed larger predictive value for long-term CRT response compared with dP/dtmax.
More Related Videos
Related Concept Videos
01:22Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
01:11Cardiac Output and Stroke Volume
In an average resting adult male, the typical cardiac...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart...
01:27Regulation of Stroke Volume
Preload refers to the degree of stretch on the heart before it contracts. It's analogous to the stretching of a rubber band; the more it's stretched, the more forcefully it snaps back. This concept is encapsulated in the Frank-Starling law of the...
01:30Cardiomyopathy II: Dilated Cardiomyopathy
01:26Imbalances in Cardiac Output
CHF can occur due to the failure of either side of the heart. Left-side failure leads to pulmonary congestion—the right side continues to send...