Energy Dissipation in Resynchronization Therapy: Impact of Atrioventricular Delay - 04/06/19
, José Luis Moya Mur, MD, PhD, Javier Moreno, MD, PhD, Covadonga Fernández-Golfín, MD, Eduardo Franco, MD, PhD, Juan Manuel Monteagudo, MD, Roberto Matía, MD, PhD, Antonio Hernández-Madrid, MD, PhD, José Luis Zamorano, MD, PhDAbstract |
Background |
Optimal atrioventricular delay (AVD) achieves maximum cardiac output in patients undergoing cardiac resynchronization therapy (CRT). Nonoptimal AVD decreases left ventricular (LV) end-diastolic volume and causes loss of flow momentum prior to LV ejection.
Objective |
We investigated the potential role of energy dissipation (ED) in these changes in cardiac output through the study of intraventricular flow. We hypothesized that short and long AVD increases ED when compared with optimal AVD by altering the physiologic flow mechanics that preserve kinetic energy in the LV.
Methods |
Forty-four patients under CRT underwent echocardiographic LV flow analysis under optimal, short, and long AVD. LV ED and vortical flow in the inflow-outflow tract were studied during the end-diastolic and early systolic period, and paired comparisons were obtained between optimal and nonoptimal values.
Results |
ED in the left ventricle was minimal in optimal AVD and significantly increased with nonoptimal values (79.1 ± 27.5 J/m·sec in optimal AVD vs 96.5 ± 34.7 J/m·sec in short AVD; n = 18, P = .006; 123.3 ± 67.6 J/m·sec in optimal AVD vs 292.4 ± 202.5 J/m·sec in long AVD; P < .001). Increase in ED occurred due to inadequate flow redirection toward the outflow tract in short AVD and due to both turbulence and prolonged ineffective flow rotation in long AVD.
Conclusions |
Optimal AVD in resynchronization therapy favors physiological vortex flow patterns in the left ventricle during the end-diastolic and early systolic period. These patterns are altered when nonoptimal values are programmed, increasing ED.
Le texte complet de cet article est disponible en PDF.Highlights |
• | Optimal atrioventricular delay (AVD) is associated with maximal cardiac output. |
• | We studied intraventricular flow patterns in cardiac resynchronization therapy patients. |
• | Energy dissipation in the left ventricle was minimal in optimal AVD. |
• | We describe the physiologic mechanisms involving energy dissipation. |
• | We provide a basis for the contribution of energy dissipation to cardiac performance. |
Keywords : Atrioventricular delay, Resynchronization therapy, Energy dissipation
Abbreviations : AV, AVD, CRT, ED, ICC, LV, LVEDV, MR, PW, VFM, VTI
Plan
| All authors have significantly contributed to and approved the content of this manuscript. All authors report no conflicts of interest. |
Vol 32 - N° 6
P. 744 - juin 2019 Retour au numéro
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