Key result
Acute cardiac resynchronization therapy significantly increased left ventricular torsion in responders (from 0.32 to 0.41 °/cm) but decreased it in non-responders (from 0.54 to 0.28 °/cm, interaction P=0.02).
Why the study?
CRT improves LV function, but the exact mechanisms regarding its acute effect on LV torsional mechanics and subsequent short-term remodeling were not completely depicted.
Does biventricular stimulation (CRT-on) improve acute left ventricular torsional mechanics compared to CRT-off in heart failure patients?
Cohort (n=48)
Randomized order for acute testing (CRT-on vs CRT-off)
No
Does biventricular stimulation (CRT-on) improve acute left ventricular torsional mechanics compared to CRT-off in heart failure patients?
Acute improvement in left ventricular apical torsion during CRT is associated with positive short-term reverse remodeling in heart failure patients.
Answers are grounded in this paper and cite their sources.
CRT effects on LV torsion by 3DSTE are hypothesis-generating; leaves open link to short-term remodeling.
BACKGROUND: Left ventricular (LV) torsion is an important aspect of cardiac mechanics and is altered in heart failure patients. Cardiac resynchronization therapy (CRT) has a positive effect on LV function, but the exact mechanisms through which it works are not completely depicted. Our aim was to investigate (1) the acute CRT effect on LV torsional mechanics in heart failure patients using 3D speckle tracking echocardiography (3DSTE) and (2) its effect on short-term LV remodeling. METHODS AND RESULTS: We considered 48 patients (age 72±11 years, 35 men) who received CRT. They underwent 3DSTE during CRT-on (biventricular stimulation) vs. CRT-off (intrinsic conduction/right atrial/ventricular stimulation alone), in a random fashion. Patients were classified as CRT responders based on LV systolic volume reduction ≥15% at 6 months (final population: 31 responders, 17 non-responders). Acute CRT positively affected responders in terms of LV torsion (from 0.32±0.06°/cm CRT-off to 0.41±0.06°/cm CRT-on), but adversely affected non-responders (from 0.54±0.08°/cm CRT-off to 0.28±0.08°/cm CRT-on, interaction P=0.02). A similar trend was confirmed for apical (interaction P<0.04), but not for basal torsion (interaction P=0.351). CONCLUSIONS: CRT has a positive role in acute recovery of LV torsion (particularly in its apical component) in responders, likely modulating the improvement in LV remodeling at early follow-up.
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Sartori et al. (2018) conducted a cohort in Heart failure (n=48). Cardiac resynchronization therapy (CRT-on) vs. CRT-off (intrinsic conduction or right atrial/ventricular stimulation alone) was evaluated on Acute change in left ventricular torsion (CRT-on vs CRT-off) in responders vs non-responders (p=0.02). Acute cardiac resynchronization therapy significantly increased left ventricular torsion in responders (from 0.32 to 0.41 °/cm) but decreased it in non-responders (from 0.54 to 0.28 °/cm, interaction P=0.02).
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