Left ventricular resynchronization is a widely diffused therapeutic approach in patients with heart failure (HF) who show an increased delay between the septal and posterior wall electrical activation of the left ventricle. This increased delay, which in some cases may produce a QRS duration higher than 120 ms, is associated with a mechanical dissinchrony which impairs the just limited ventricular function, with a very negative effect on the emodynamic parameters. To compensate this negative evolution, few years ago the producers of cardiac electric stimulators developed special devices for anticipating the electrical stimulation of the left ventricular postero-lateral wall by an electrode lead inserted through the coronary venous system . Nowadays this approach is widely used and the results are quite satisfactory, depending on the optimization of the stimulation delay between the septal and the posterior wall, which must be optimized on a single patient, depending on the ventricular shape and volume. The standard optimization approach is the measurement of the stroke volume (SV) by Doppler Ultrasound at different stimulation delays, which requires repetitive measurements ending in a very time consuming procedure. Recently the procedure developed by Kubicek in the seventies to monitor the SV by transthoracic electrical impedance, has been revised and optimized by some companies, and this approach is now proposed for the optimization of the left ventricular resynchronization as an efficient time saving approach. In order to verify the possibility to substitute the standard echographyc method with the alternative thoracic impedance method, we applied in parallel the two procedures on 9 HF patients with implanted resynchronization devices. On a single patient we measured the stroke volume at 15 different stimulation delays and the comparison was made on 135 pair results. The result of the comparison was quite surprising: a) the correlation coefficients between the SV obtained with the two methods on a single patient were very low (0.06 < R< 0.42 ) ; b) the changes of SV at different stimulation delays were limited, probably lower than the measurement error of the procedure. These results suggest a deeper evaluation of the procedures for optimization of ventricular resynchronization, both for the methods and for the observed physiological parameter (is SV the right parameter to observe?).
M. Graziano, C. Valzania, D. Bianchini, I. Corazza, G. Loreti, M.L. Bacchi Reggiani, et al. (2008). Left ventricular resynchronization in HF: comparison of alternative optmization methods. BOLOGNA : Tecnoprint SNC.
Left ventricular resynchronization in HF: comparison of alternative optmization methods
VALZANIA, CINZIA;BIANCHINI, DAVID;CORAZZA, IVAN;BACCHI REGGIANI, MARIA LETIZIA;ZANNOLI, ROMANO
2008
Abstract
Left ventricular resynchronization is a widely diffused therapeutic approach in patients with heart failure (HF) who show an increased delay between the septal and posterior wall electrical activation of the left ventricle. This increased delay, which in some cases may produce a QRS duration higher than 120 ms, is associated with a mechanical dissinchrony which impairs the just limited ventricular function, with a very negative effect on the emodynamic parameters. To compensate this negative evolution, few years ago the producers of cardiac electric stimulators developed special devices for anticipating the electrical stimulation of the left ventricular postero-lateral wall by an electrode lead inserted through the coronary venous system . Nowadays this approach is widely used and the results are quite satisfactory, depending on the optimization of the stimulation delay between the septal and the posterior wall, which must be optimized on a single patient, depending on the ventricular shape and volume. The standard optimization approach is the measurement of the stroke volume (SV) by Doppler Ultrasound at different stimulation delays, which requires repetitive measurements ending in a very time consuming procedure. Recently the procedure developed by Kubicek in the seventies to monitor the SV by transthoracic electrical impedance, has been revised and optimized by some companies, and this approach is now proposed for the optimization of the left ventricular resynchronization as an efficient time saving approach. In order to verify the possibility to substitute the standard echographyc method with the alternative thoracic impedance method, we applied in parallel the two procedures on 9 HF patients with implanted resynchronization devices. On a single patient we measured the stroke volume at 15 different stimulation delays and the comparison was made on 135 pair results. The result of the comparison was quite surprising: a) the correlation coefficients between the SV obtained with the two methods on a single patient were very low (0.06 < R< 0.42 ) ; b) the changes of SV at different stimulation delays were limited, probably lower than the measurement error of the procedure. These results suggest a deeper evaluation of the procedures for optimization of ventricular resynchronization, both for the methods and for the observed physiological parameter (is SV the right parameter to observe?).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
