Efficacy of the Phase Images in Fourier Analysis Using Gated Cardiac POOL-SPECT for Determining the Indication for Cardiac Resynchronization Therapy

Abstract

ntraventricular conduction delay is clearly found in some patients with heart failure and these conduction abnormalities might be related to a delay in the onset of right or left ventricular (LV) contraction. Inefficient cardiac contraction caused by such mechanical asynchrony may be partly responsible for further impairment of LV function. Cardiac resynchronization therapy (CRT) restores optimum synchrony of ventricular contraction. A metaanalysis of 4 randomized controlled trials showed that the morbidity of progressive heart failure decreased by 51% after CRT, and the admission rate was decreased by 29%. [1][2][3] The aim of the present study was to evaluate ventricular asynchrony by the phase images obtained by Fourier analysis using gated cardiac pool emission computed tomography, and to evaluate whether these images can be used to determine the indication for CRT. Methods Study PatientsInitially, we examined the efficacy of phase image from pool single photon emission computed tomography (POOL-SPECT) for evaluating heart failure in 19 patients with idiopathic dilated cardiomyopathy (DCM; 16 men, 3 women; Circulation Journal Vol.69, December 2005 age 50±17 years; LV ejection fraction (LVEF): 22±9%). Of these, 3 patients were New York Heart Association (NYHA) functional class I, 7 were class II, and 9 were class III. Our definition of wide QRS was >120 ms in duration and 7 patients fitted the definition (Table 1). This study was performed consecutively and continuously between November 2001 and December 2004. All patients were treated with angiotensin-converting enzyme inhibitors, diuretics and -blockers during follow-up. In the next stage of the study, to evaluate the efficacy of the phase images for CRT setting, the 7 patients with advanced heart failure and wide QRS complex who underwent CRT were studied (5 men, 2 women; age 63±16 years; DCM 6, ischemic cardiomyopathy 1; 6 NYHA III, 1 class IIM). Phase imaging using POOL-SPECT was performed before and within 11 months (3.8±3.6 month) after CRT between October 2002 and October 2004. POOL-SPECTPOOL-SPECT was performed using technetium-99m ( 99m Tc) red blood cells with an in vivo labeling method. 99m Tc pertechnetate (740 MBq) was injected intravenously. POOL-SPECT imaging used a Prism 3000XP with a 3-headed single photon emission computed tomography (SPECT) system that had low-energy, high resolution, parallel-hole collimators. A total of 72 projection images obtained over 360 degrees every 5 degrees of rotation were acquired in 64×64 matrices on a magnetic disk with 16 frames/cardiac cycle. The data acquisition time was 40 s for each projection. Reconstructed images were made Background Although cardiac resynchronization therapy (CRT) improves quality of life and survival for patients with heart failure, exact methods to estimate the effect of cardiac asynchrony have not yet been defined. Methods and ResultsInitially, to examine whether the phase analysis images in the Fourier analysis using gated cardiac pool single photon emission computed tomography...

Normal limits of gated blood pool SPECT count-based regional cardiac function parameters

“…Also computed were ''z-scores,'' defined conventionally as the difference between a measurement for an individual versus the mean for a normal population, and normalized to the standard deviation for a normal population, for which values [2.0 indicate a probability [95% for the measured parameter to fall outside the normal range [15]. RV-LV apical phase differences also were computed [9].…”

“…GBPS has been used to quantify regional function as well as global function [6,8]. GBPS measurements have shown that clinical improvement of patients with dilated cardiomyopathy following successful CRT is accompanied by improved intra-and inter-ventricular synchrony [9].…”

“…While GBPS normal limits of global function have been reported [11], the current study was conducted to establish reproducibility and normal limits of regional function, and to determine whether regional normal values are different for males versus females, or for the RV versus LV. Because of the potential for dyssynchrony studies [9], we also sought to establish normal limits of regional intra-and inter-ventricular contraction patterns.…”

Identification of the Right Ventricular Pacing Site for Cardiac Resynchronization Therapy (CRT) Guided by Electroanatomical Mapping (CARTO)

“…11 As for the latter, several recent reports have suggested that selection based on the direct assessment of mechanical dyssynchrony by tissue-Doppler echocardiography is a potentially useful tool to increase response rate for CRT. [12][13][14][15][16][17] As for the optimal LV pacing site, the PATH-CHF II study has demonstrated that pacing at LV free wall sites consistently produces better short-term hemodynamic responses than does pacing at LV anterior sites. 4,5 Furthermore, Auricchio et al demonstrated that the functional block line of LV, as determined by CARTO and non-contact mapping, varied among individual patients with left bundle branch block (LBBB) (ie, anterior, lateral, or inferior aspects), and suggested that the site of delay above the functional block line was the optimal pacing site.…”

Sincronia ventricular em portadores de miocardiopatia dilatada e indivíduos normais: avaliação através da ventriculografia radioisotópica

“…Studies with computed tomography by single photon emission are being developed, which can improve the performance of this technique in evaluating dyssynchrony and help to determine the implantation site of the electrode in LV 34 . On the other hand, determination of normal values for specific groups, e.g.…”