Key result
An intrathoracic impedance index exceeding 60 ohms after CRT-D implantation was associated with a lack of reverse left ventricular remodeling and a 29% rate of heart failure rehospitalization, compared to 0% in those not exceeding 60 ohms.
Why the study?
Does intrathoracic impedance change reflect reverse left ventricular remodeling in response to CRT in patients with CHF?
Observational (n=29)
Single-blind
No
Does intrathoracic impedance change reflect reverse left ventricular remodeling in response to CRT in patients with CHF?
Answers are grounded in this paper and cite their sources.
Continuous intrathoracic impedance monitoring via CRT-D devices can predict reverse left ventricular remodeling and identify CRT responders in patients with chronic heart failure.
Intrathoracic impedance monitoring has been reported to be useful for prediction of worsening chronic heart failure (CHF). However, it has not revealed the relation between changes in intrathoracic impedance and improvement of cardiac function in CHF patients with cardiac resynchronization therapy (CRT) implantation. Therefore, we investigated whether intrathoracic impedance change reflects reverse left ventricular (LV) remodeling in response to CRT in patients with CHF. The study subjects consisted of 29 CHF patients (23 males, mean age 64 ± 12 years) with CRT-defibrillator (CRT-D) implantation. The patients were divided into two groups based on whether the Opti-vol Fluid Index® reached over 60 ohms (group A, n = 7) or not (group B, n = 22) within 6 months of observation after CRT-D implantation. Levels of plasma B-type natriuretic peptide (BNP) were measured, and LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were evaluated before and 6 months after CRT-D implantation. In group B, BNP (556 ± 88 pg/mL versus 330 ± 70 pg/mL, P < 0.05), LVEDV (177 ± 18 mL versus 149 ± 14 mL, P < 0.01), and LVESV (128 ± 14 mL versus 100 ± 12 mL, P < 0.01) were significantly decreased 6 months after CRT-D implantation. LVEF (28 ± 2% versus 35 ± 2%, P < 0.01) was significantly increased after CRT-D implantation. On the other hand, no significant changes were detected in any parameters in group A. These data showed intrathoracic impedance changes reflected reverse LV remodeling in response to CRT in patients with CHF. Therefore, the monitoring of changes in intrathoracic impedance is useful for predicting CRT responders in patients with CHF.
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Kaneshiro et al. (2012) conducted an observational in Chronic heart failure (n=29). Opti-vol Fluid Index > 60 ohms vs. Opti-vol Fluid Index ≤ 60 ohms was evaluated on Hospitalization due to CHF worsening (p=<0.05). An intrathoracic impedance index exceeding 60 ohms after CRT-D implantation was associated with a lack of reverse left ventricular remodeling and a 29% rate of heart failure rehospitalization, compared to 0% in those not exceeding 60 ohms.
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