In:
Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 113, No. 10 ( 2006-03-14), p. 1295-1304
Abstract:
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/dt max increased 18%, −dP/dt min 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/dt max . 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.
Type of Medium:
Online Resource
ISSN:
0009-7322
,
1524-4539
DOI:
10.1161/CIRCULATIONAHA.105.540435
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2006
detail.hit.zdb_id:
1466401-X
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