Cardiac dyssynchrony analysis using circumferential versus longitudinal strain : Implications for assessing cardiac resynchronization

• Published in: Circulation (New York, N.Y.) Vol. 111; no. 21; pp. 2760 - 2767
• Main Authors: HELM, Robert H, LECLERCQ, Christophe, FARIS, Owen P, OZTURK, Cengizhan, MCVEIGH, Elliot, LARDO, Albert C, KASS, David A
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 31.05.2005
• Subjects: Animals; Biological and medical sciences; Blood and lymphatic vessels; Bundle-Branch Block - diagnosis; Cardiac Pacing, Artificial; Cardiology. Vascular system; Cardiovascular system; Disease Models, Animal; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Dogs; Echocardiography, Doppler; Heart; Heart Conduction System - physiopathology; Heart Failure; Heart failure, cardiogenic pulmonary edema, cardiac enlargement; Medical sciences; Pharmacology. Drug treatments; Systole; Vascular wall; Ventricular Dysfunction, Left - diagnosis; Heart failure; resynchronization therapy; bundle-branch block; Treatment; Arrhythmia; pacing; Heart block; Heart disease; Cardiovascular disease; Bundle branch block; Conduction disorder; Comparative study
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/CIRCULATIONAHA.104.508457

QRS duration is commonly used to select heart failure patients for cardiac resynchronization therapy (CRT). However, not all patients respond to CRT, and recent data suggest that direct assessments of mechanical dyssynchrony may better predict chronic response. Echo-Doppler methods are being used increasingly, but these principally rely on longitudinal motion (epsilonll). It is unknown whether this analysis yields qualitative and/or quantitative results similar to those based on motion in the predominant muscle-fiber orientation (circumferential; epsiloncc). Both epsilonll and epsiloncc strains were calculated throughout the left ventricle from 3D MR-tagged images for the full cardiac cycle in dogs with cardiac failure and a left bundle conduction delay. Dyssynchrony was assessed from both temporal and regional strain variance analysis. CRT implemented by either biventricular (BiV) or left ventricular-only (LV) pacing enhanced systolic function similarly and correlated with improved dyssynchrony based on epsiloncc-based metrics. In contrast, longitudinal-based analyses revealed significant resynchronization with BiV but not LV for the overall cycle and correlated poorly with global functional benefit. Furthermore, unlike circumferential analysis, epsilonll-based indexes indicated resynchronization in diastole but much less in systole and had a lower dynamic range and higher intrasubject variance. Dyssynchrony assessed by longitudinal motion is less sensitive to dyssynchrony, follows different time courses than those from circumferential motion, and may manifest CRT benefit during specific cardiac phases depending on pacing mode. These results highlight potential limitations to epsilonll-based analyses and support further efforts to develop noninvasive synchrony measures based on circumferential deformation.