Quantitative gated SPECT-derived phase analysis on gated myocardial perfusion SPECT detects left ventricular dyssynchrony and predicts response to cardiac resynchronization therapy.

UNLABELLED: The significance of left ventricular (LV) dyssynchrony for the prediction of response to cardiac resynchronization therapy (CRT) has been demonstrated. Parameters reflecting LV dyssynchrony (phase SD, histogram bandwidth) can be derived from gated myocardial perfusion SPECT (GMPS) using phase analysis. The feasibility of LV dyssynchrony assessment with phase analysis on GMPS using Quantitative Gated SPECT (QGS) software has not been demonstrated in patients undergoing CRT. The aim of the present study was to validate the QGS algorithm for phase analysis on GMPS in a direct comparison with echocardiography using tissue Doppler imaging (TDI) for LV dyssynchrony assessment. Also, prediction of response to CRT using GMPS and phase analysis was evaluated. METHODS: Patients (n = 40) with severe heart failure (New York Heart Association class III-IV), an LV ejection fraction of no more than 35%, and a QRS complex greater than or equal to 120 ms were evaluated for LV dyssynchrony using GMPS and echocardiography with TDI. At baseline and after 6 mo of CRT, clinical status, LV volumes, and LV ejection fraction were evaluated. Patients with functional improvement were classified as CRT responders. RESULTS: Both histogram bandwidth (r = 0.69, r(2) = 0.48, SEE = 25.4, P < 0.01) and phase SD (r = 0.65, r(2) = 0.42, SEE = 26.8, P < 0.01) derived from GMPS correlated significantly with TDI for assessment of LV dyssynchrony. At baseline, CRT responders showed a significantly larger histogram bandwidth (94 degrees +/- 23 degrees vs. 68 degrees +/- 21 degrees , P < 0.01) and a larger phase SD (26 degrees +/- 6 degrees vs. 18 degrees +/- 5 degrees , P < 0.01) than did nonresponders. Receiver-operating-characteristic curve analysis identified an optimal cutoff value of 72.5 degrees for histogram bandwidth to predict CRT response, yielding a sensitivity of 83% and a specificity of 81%. For phase SD, sensitivity and specificity similar to those for histogram bandwidth were obtained at a cutoff value of 19.6 degrees . CONCLUSION: QGS phase analysis on GMPS correlated significantly with TDI for the assessment of LV dyssynchrony. Moreover, a high accuracy for prediction of response to CRT was obtained using either histogram bandwidth or phase SD.

Multi-slice computed tomography coronary angiography for ruling out suspected coronary artery disease: what is the prevalence of a normal study in a general clinical population?

AIMS: To assess the prevalence of a normal multi-slice computed tomography (MSCT) in patients with suspected coronary artery disease (CAD) and to relate these observations to clinical presentation and pre-test likelihood of CAD. METHODS AND RESULTS: In total, 340 consecutive patients (182 men, 55 +/- 12 years) without a history of CAD who were referred for MSCT angiography were included in the study. Based on patient characteristics and the referral reason for MSCT angiography, patients were classified as having a low, intermediate, or high pre-test likelihood of CAD. Patients were evaluated for the presence of coronary artery calcium as well as the presence of atherosclerosis. Overall, 157 (46%) patients did not have coronary artery calcium and 133 (40%) patients had a completely normal MSCT angiogram. In 58% of the patients with low pre-test likelihood, no coronary atherosclerosis was observed when compared with 33 and 17% of the patients with intermediate and high pre-test likelihood, respectively. CONCLUSION: MSCT ruled out coronary atherosclerosis in 40-46% of patients without known CAD who were referred for MSCT. Accordingly, in patients with low-to-intermediate pre-test likelihood, MSCT may be an attractive modality to exclude coronary atherosclerosis and may prevent unnecessary additional functional testing or invasive angiography.

Comparison of multislice computed tomography to gated single-photon emission computed tomography for imaging of healed myocardial infarcts.

The aim of the study was to evaluate the performance of multislice computed tomography (MSCT) for the detection and semiquantitative analysis of healed myocardial infarct in comparison to single-photon emission computed tomography (SPECT). Recently, MSCT was shown to allow detection of myocardial infarct by the presence of hypoenhanced areas. However, direct comparisons to other imaging modalities for infarct imaging were scarce. In 69 patients with healed myocardial infarct (>3 months), the presence of myocardial infarct and infarct score was assessed using SPECT and MSCT. In addition, regional and global left ventricular function was assessed using MSCT. In 62 of 69 patients (90%), a perfusion defect was detected using gated SPECT at rest. Using MSCT in these 62 patients (100%), hypoenhanced areas reflecting infarct were shown. In 3 of 7 patients (43%) without perfusion defects who underwent gated SPECT, MSCT identified regions of infarct. The infarct score on MSCT related well to the SPECT infarct score (12 +/- 10% vs 16 +/- 13%; r = 0.93, p <0.0001). In addition, good (inverse) correlations were shown for infarct score using MSCT and parameters of left ventricular function. In conclusion, healed myocardial infarct can be detected accurately using MSCT, with good correlation with SPECT.

Myocardial collagen metabolism in failing hearts before and during cardiac resynchronization therapy.

BACKGROUND: In patients with heart failure cardiac resynchronization therapy (CRT) leads to reverse ventricular remodelling. AIM: To evaluate whether myocardial collagen metabolism in patients with heart failure is implicated in adverse ventricular remodelling and response to CRT. METHODS: Collagen synthesis and degradation were assessed from the concentrations of aminoterminal propeptides of type I and type III collagen (PINP and PIIINP) and carboxyterminal telopeptide of type I collagen (ICTP), respectively, in serum of 64 patients with heart failure before and after 6 months of CRT. Forty-six patients (72%) showed a > 10% reduction in LV end-systolic volume at follow-up and were classified as responders to CRT, the other 18 patients (28%) were classified as non-responders. RESULTS: Responders demonstrated a mean (+/-SEM) increase of serum PINP and PIIINP during follow-up, from 32.9+/-2.2 to 46.7+/-4.0 microg/L (p < 0.001) and from 4.59+/-0.24 to 5.13+/-0.36 microg/L (p < 0.05), respectively. In non-responders, serum PINP and PIIINP remained unchanged during follow-up. At baseline, responders had significantly lower serum PINP than non-responders (32.9+/-2.2 vs. 41.8+/-4.3 microg/L; p < 0.05). ICTP levels of responders at baseline tended to be higher than in non-responders (3.54+/-0.56 vs. 2.08+/-0.37 microg/L, p = ns), and in both groups ICTP levels did not change upon CRT. CONCLUSION: Reverse LV remodelling following CRT is associated with increased collagen synthesis rate in the first 6 months of follow-up.

Left ventricular dyssynchrony assessed by two three-dimensional imaging modalities: phase analysis of gated myocardial perfusion SPECT and tri-plane tissue Doppler imaging.

PURPOSE: To compare left ventricular (LV) dyssynchrony assessment by phase analysis from gated myocardial perfusion SPECT (GMPS) with LV dyssynchrony assessment by tri-plane tissue Doppler imaging (TDI). Baseline LV dyssynchrony assessed with standard deviation (SD) of time-to-peak systolic velocity of 12 LV segments (Ts-SD) with TDI has proven to be a powerful predictor of response to CRT. Information on LV dyssynchrony can also be provided by GMPS with phase analysis of regional LV maximal count changes throughout the cardiac cycle. METHODS: Forty heart failure patients, referred for evaluation of potential eligibility for CRT, underwent both 3D echocardiography, with tri-plane TDI, and resting GMPS. From tri-plane TDI, Ts-SD was used as a validated parameter of LV dyssynchrony and compared with different indices (histogram bandwidth, phase SD, histogram skewness and kurtosis) derived from phase analysis of GMPS. RESULTS: Histogram bandwidth and phase SD showed good correlation with Ts-SD (r=0.77 and r=0.74, p<0.0001, respectively). Patients with substantial LV dyssynchrony assessed with tri-plane TDI (Ts-SD >or=33 ms) had also significantly higher values of histogram bandwidth and phase SD. CONCLUSIONS: The results of this study support the use of phase analysis by GMPS to evaluate LV dyssynchrony. Histogram bandwidth and phase SD showed the best correlation with Ts-SD assessed with tri-plane TDI and appeared the most optimal variables for assessment of LV dyssynchrony with GMPS.

Assessment of left ventricular mechanical dyssynchrony by phase analysis of ECG-gated SPECT myocardial perfusion imaging.

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have shown that the presence of LV dyssynchrony is an important predictor of response to CRT. Phase analysis has been developed to allow assessment of LV dyssynchrony by gated single photon emission computed tomography myocardial perfusion imaging. This technique uses Fourier harmonic functions to approximate regional wall thickness changes over the cardiac cycle and to calculate the regional onset-of-mechanical contraction phase. Once the onset-of-mechanical contraction phases are obtained 3-dimensionally over the left ventricle, a phase distribution map is formed that represents the degree of LV dyssynchrony. This technique has been compared with other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review the phase analysis methodology is described, and its up-to-date validations are summarized.

Is nuclear imaging a viable alternative technique to assess dyssynchrony?

Cardiac resynchronization therapy (CRT) has shown benefits in patients with end-stage heart failure (HF) (NYHA class III or IV), depressed left ventricular (LV) ejection fraction, and prolonged QRS duration (>120 ms). However, at least 30% of the patients who meet the above criteria show no response to CRT. It has shown with echocardiography that the presence of LV mechanical dyssynchrony is an important predictor for response to CRT. However, echocardiography requires expertise to produce reproducible and reliable results. The recent report from the Predictors of Response to Cardiac Resynchronization Therapy trial showed that under 'real-world' conditions the current available echocardiographic techniques including tissue Doppler imaging (TDI) and myocardial strain-rate imaging are not ready for routine clinical practice to assess LV dyssynchrony. It suggested that there is a need for better standardization and refinements of the echocardiographic screening tools currently used for the evaluation of LV dyssynchrony. This article reviews a technique such as phase analysis that allows measuring LV dyssynchrony from conventional electrocardiogram-gated single-photon emission computed tomography myocardial perfusion imaging with no additional procedure. Its advantages over TDI are its automation, repeatability, and reproducibility that are very promising in improving prediction of CRT response in HF patients.

Noninvasive imaging in cardiac resynchronization therapy--part 1: selection of patients.

Cardiac resynchronization therapy (CRT) is an established therapy for patients with advanced heart failure, depressed left ventricular function, and wide QRS complex. However, individual response varies, and a substantial amount of patients do not respond to CRT. Recent studies observed that assessment of inter- and particularly intraventricular dyssynchrony may allow identification of potential responders to CRT. In addition, presence of scar tissue and venous anatomy may play a role in the selection of candidates. In this review, an extensive overview of the available dyssynchrony measurements is provided using echocardiography as well as magnetic resonance imaging (MRI) and nuclear imaging. Furthermore, other information derived from MRI, nuclear imaging, and computed tomography useful for the selection of potential candidates for CRT will be discussed.

Noninvasive imaging in cardiac resynchronization therapy--Part 2: Follow-up and optimization of settings.

Cardiac resynchronization therapy (CRT) has become a therapeutic option for drug-refractory heart failure. Several noninvasive imaging techniques play an increasingly important role before and after device implantation. This review highlights the acute and long-term CRT benefits after implantation as assessed with echocardiography and nuclear imaging. Furthermore, optimization of CRT settings, in particular atrioventricular and interventricular delay, will be discussed using echocardiography and other (device-based) techniques.

Left ventricular mechanical dyssynchrony as assessed by phase analysis of ECG-gated SPECT myocardial perfusion imaging.

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. The traditional criteria to select patients for CRT (NYHA class III or IV, depressed left ventricular (LV) ejection fraction, and prolonged QRS duration) result in at least 30% of the selected patients with no response to CRT. Recent studies with tissue Doppler imaging (TDI) have shown that the presence of LV dyssynchrony is an important predictor for response to CRT. Phase analysis has been developed to assess LV dyssynchrony from electrocardiography-gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). This technique uses Fourier harmonic functions to approximate regional wall thickening over the cardiac cycle and to calculate phases of regional onset of mechanical contraction (OMC). These OMC phases are obtained three-dimensionally over the left ventricle to generate an OMC phase distribution. Quantitative indices are calculated from the phase distribution to assess degree of LV dyssynchrony. This technique has been compared to other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review, the phase analysis methodology is described and its up-to-date validations are summarized.

Nuclear imaging in cardiac resynchronization therapy.

Recently, cardiac resynchronization therapy (CRT) has become implemented in the treatment of patients with severe heart failure. Although the improvement in systolic function after CRT implantation can be considerable, 20%-30% of patients do not respond to CRT. Evidence is accumulating that the presence of left ventricular (LV) dyssynchrony is mandatory for a response to CRT. Since the early 1980s attempts have been made to assess cardiac dyssynchrony with nuclear imaging, and it has been reported recently that information on LV dyssynchrony can be obtained from gated myocardial perfusion SPECT with phase analysis. Other studies with SPECT have shown that extensive scar tissue will limit the response to CRT; similarly, it has been demonstrated that viable tissue (assessed with SPECT) in the target zone for the LV pacing lead (usually the lateral wall) is needed for a response to CRT. Moreover, studies with PET have provided insight into the changes in myocardial perfusion, metabolism, and efficiency after CRT. In the current review, a comprehensive summary is provided on the potential role of nuclear imaging in the selection of heart failure patients for CRT. The value of other imaging techniques is also addressed.

Can LV dyssynchrony as assessed with phase analysis on gated myocardial perfusion SPECT predict response to CRT?

UNLABELLED: Cardiac resynchronization therapy (CRT) is now a well-recognized therapeutic option for patients with end-stage heart failure. However, not all patients respond to CRT, and, therefore, preimplantation identification of responders is desirable. The aim of the present study was to investigate whether the degree of left ventricular (LV) dyssynchrony, as assessed with phase analysis from gated myocardial perfusion SPECT (GMPS), can predict which patients will respond to CRT. METHODS: Forty-two patients with severe heart failure, depressed LV ejection fraction, and wide QRS complex were prospectively included for implantation of a CRT device and underwent GMPS and 2-dimensional echocardiography as part of the clinical protocol. Clinical status was evaluated using the New York Heart Association (NYHA) classification, 6-min walk test, and quality-of-life score. The histogram bandwidth and phase SD (parameters indicating LV dyssynchrony) were assessed from GMPS, and the clinical status and echocardiographic variables were reassessed at 6-mo follow-up. RESULTS: Responders (71%) and nonresponders (29%) had comparable baseline characteristics, except for histogram bandwidth (175 degrees +/- 63 degrees vs. 117 degrees +/- 51 degrees [P < 0.01]) and phase SD (56.3 degrees +/- 19.9 degrees vs. 37 degrees .1 +/- 14.4 degrees [P < 0.01]), which were significantly larger in responders compared with nonresponders. Moreover, receiver-operating-characteristic curve analysis demonstrated an optimal cutoff value of 135 degrees for histogram bandwidth (sensitivity and specificity of 70%) and of 43 degrees for phase SD (sensitivity and specificity of 74%) for the prediction of response to CRT. CONCLUSION: Response to CRT is related to the presence of LV dyssynchrony assessed by phase analysis with GMPS. A cutoff value of 135 degrees for histogram bandwidth and of 43 degrees for phase SD could be used to predict response to CRT. Larger prospective studies are warranted to confirm the present findings.

Reverse ventricular remodelling after cardiac resynchronization therapy is associated with a reduction in serum tenascin-C and plasma matrix metalloproteinase-9 levels.

BACKGROUND: In heart failure patients, cardiac resynchronization therapy (CRT) leads to reverse ventricular remodelling. AIM: The aim of this study was to evaluate whether changes in levels of circulating biomarkers of extracellular matrix metabolism correlate with the response to CRT. METHODS AND RESULTS: Clinical parameters, left ventricular (LV) volumes, and circulating levels of tenascin-C (TNC), matrix metalloproteinase-2 (MMP-2), MMP-9, and amino-terminal propeptide of brain natriuretic peptide (NT-proBNP) were assessed in 64 patients at baseline and 6 months follow-up. The majority of patients (72%) showed a >10% reduction in LV end-systolic volume at follow-up, and were classified as responders to CRT. The remaining patients were classified as non-responders. In responders, a significant decrease in circulating levels of TNC (from 60+/-40 ng/mL to 47+/-30 ng/mL, p<0.01), MMP-9 (from 55+/-30 AU to 44+/-27 AU, p<0.01), and NT-proBNP (from 2106+/-1805 pg/mL to 1132+/-1289 pg/mL, p<0.001) were observed at follow-up; MMP-2 levels were unchanged. In non-responders TNC, NT-proBNP, MMP-9 and MMP-2 levels remained unchanged. CONCLUSION: At 6 months follow-up, CRT was associated with reverse LV remodelling, and a significant decrease in TNC, MMP-9, and NT-proBNP levels. This suggests an important role of ECM modulation in the process of reverse ventricular remodelling in patients responding to CRT.

Global and regional left ventricular function: a comparison between gated SPECT, 2D echocardiography and multi-slice computed tomography.

PURPOSE: Global and regional left ventricular (LV) function are important indicators of the cardiac status in patients with coronary artery disease (CAD). Therapy and prognosis are to a large extent dependent on LV function. Multi-slice computed tomography (MSCT) has already earned its place as an imaging modality for non-invasive assessment of the coronary arteries, but since retrospective gating to the patient's ECG is performed, information on LV function can be derived. METHODS: In 49 patients with known or suspected CAD, coronary angiography with MSCT imaging was performed, in addition to gated SPECT and 2D echocardiography. LV end-diastolic and LV end-systolic volumes and LV ejection fraction were analysed with dedicated software (CMR Analytical Software System, Medis, Leiden, The Netherlands for MSCT; gated SPECT by QGS, Cedars-Sinai Medical Center, Los Angeles, CA, USA), and by the biplane Simpson's rule for 2D echocardiography. Regional wall motion was evaluated according to a 17-segment model and a three-point score system. RESULTS: Correlations were fairly good between gated SPECT and MSCT (LVEDV: r=0.65; LVESV: r=0.63; LVEF: r=0.60), and excellent between 2D echocardiography and MSCT (LVEDV: r=0.92; LVESV: r=0.93; LVEF: r=0.80). Agreement for regional wall motion was 95% (kappa=0.66) between gated SPECT and MSCT, and 96% (kappa=0.73) between 2D echocardiography and MSCT. CONCLUSION: Global and regional LV function and LV volumes can be adequately assessed with MSCT. Correlations with 2D echocardiography are stronger than with gated SPECT.

Assessment of global and regional left ventricular function and volumes with 64-slice MSCT: a comparison with 2D echocardiography.

BACKGROUND: In patients with coronary artery disease (CAD), LV function and volumes are important parameters for long-term prognosis. Multislice computed tomography (MSCT) allows noninvasive assessment of the coronary arteries, but the accuracy of 64-slice MSCT for the assessment of left ventricular (LV) volumes and function is unknown. METHODS AND RESULTS: A head-to-head comparison between 64-slice MSCT and 2-dimensional (2D) echocardiography was performed in 40 patients with known or suspected CAD. The LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV) were determined and the LV ejection fraction (LVEF) was derived. Regional wall motion was assessed visually using a 17-segment model. A 3-point scoring system was used to assign to each segment a wall motion score: 1 = normokinesia, 2 = hypokinesia, 3 = akinesia or dyskinesia. Two-dimensional echocardiography served as the gold standard. MSCT agreed well with 2D echocardiography for assessment of LVEDV (r = 0.97; p < .0001) and LVESV (r = 0.98; p < .0001). An excellent correlation between MSCT and 2D echocardiography was shown for the evaluation of LVEF (r = 0.91; p < .0001). Agreement for the assessment of regional wall motion was excellent (96%, kappa = 0.82). CONCLUSIONS: An accurate assessment of global and regional LV function and volumes is feasible with 64-slice MSCT.

Cardiac sympathetic denervation assessed with 123-iodine metaiodobenzylguanidine imaging predicts ventricular arrhythmias in implantable cardioverter-defibrillator patients.

OBJECTIVES: The purpose of this study was to evaluate whether 123-iodine metaiodobenzylguanidine (123-I MIBG) imaging predicts ventricular arrhythmias causing appropriate implantable cardioverter-defibrillator (ICD) therapy (primary end point) and the composite of appropriate ICD therapy or cardiac death (secondary end point). BACKGROUND: Although cardiac sympathetic denervation is associated with ventricular arrhythmias, limited data are available on the predictive value of sympathetic nerve imaging with 123-I MIBG on the occurrence of arrhythmias. METHODS: Before ICD implantation, patients underwent 123-I MIBG and myocardial perfusion imaging. Early and late 123-I MIBG (planar and single-photon emission computed tomography [SPECT]) imaging was performed to assess cardiac innervation (heart-to-mediastinum ratio, cardiac washout rate, and 123-I MIBG SPECT defect score). Stress-rest myocardial perfusion imaging was performed to assess myocardial infarction and perfusion abnormalities (perfusion defect scores). During follow-up, appropriate ICD therapy and cardiac death were documented. RESULTS: One-hundred sixteen heart failure patients referred for ICD therapy were enrolled. During a mean follow-up of 23 +/- 15 months, appropriate ICD therapy (primary end point) was documented in 24 (21%) patients and appropriate ICD therapy or cardiac death (secondary end point) in 32 (28%) patients. Late 123-I MIBG SPECT defect score was an independent predictor for both end points. Patients with a large late 123-I MIBG SPECT defect (summed score >26) showed significantly more appropriate ICD therapy (52% vs. 5%, p < 0.01) and appropriate ICD therapy or cardiac death (57% vs. 10%, p < 0.01) than patients with a small defect (summed score

Noninvasive evaluation with multislice computed tomography in suspected acute coronary syndrome: plaque morphology on multislice computed tomography versus coronary calcium score.

OBJECTIVES: Our aim was to evaluate the atherosclerotic plaque burden and morphology as determined by 64-slice multislice computed tomography (MSCT) coronary angiography in relation to the calcium score in patients presenting with suspected acute coronary syndrome (ACS). BACKGROUND: The absence of coronary calcium during coronary calcium scoring has been proposed to rule out significant coronary artery disease (CAD). However, data in patients presenting with suspected ACS are scarce. METHODS: In 40 patients (age 57 +/- 11 years, 26 men) presenting with suspected ACS, MSCT coronary angiography in combination with coronary calcium scoring was performed before conventional coronary angiography. MSCT angiograms were evaluated for the presence or absence of coronary atherosclerotic plaque and the presence or absence of obstructive (> or =50% luminal narrowing) CAD. In addition, plaque type was determined, and findings were related to the calcium score. RESULTS: Coronary artery disease was observed in 38 patients, of whom 10 patients had nonobstructive and 28 patients had obstructive CAD, confirmed by conventional coronary angiography in all patients. In patients with CAD, plaques were distributed as follows: 39% noncalcified plaques, 47% mixed plaques, and 14% calcified plaques. Coronary calcium was detected in 27 patients, of whom 10 had a score >400. In 13 (33%) patients, no coronary calcium was observed, but in 11 (85%), atherosclerotic plaques were detected on MSCT angiography. CONCLUSIONS: In patients presenting with suspected ACS, noncalcified plaques are highly prevalent and the absence of coronary calcium does not reliably exclude the presence of (significant) atherosclerosis. This information may be of value to improve our understanding of the potential role of MSCT in this patient population.

Real-time three-dimensional echocardiography as a novel approach to quantify left ventricular dyssynchrony: a comparison study with phase analysis of gated myocardial perfusion single photon emission computed tomography.

BACKGROUND: Different imaging modalities have been explored for assessment of left ventricular (LV) dyssynchrony. Gated myocardial perfusion single photon emission computed tomography (GMPS) with phase analysis is a reliable technique to quantify LV dyssynchrony and predict response to cardiac resynchronization therapy. OBJECTIVE: Real-time 3-dimensional echocardiography (RT3DE) is a novel imaging technique that provides a LV systolic dyssynchrony index, based on regional volumetric changes as a function of time and calculated as the SD of time to minimum systolic volume of 16 standard myocardial segments expressed in percentage of cardiac cycle. The aim of this study was to compare LV dyssynchrony evaluated with GMPS with LV dyssynchrony assessed with RT3DE. METHODS: The study population consisted of 40 patients with heart failure who underwent both GMPS and RT3DE. RESULTS: Good correlations between LV dyssynchrony assessed with RT3DE and GMPS were demonstrated (r = 0.76 for histogram bandwidth, r = 0.80 for phase SD, P < .0001). Patients with substantial LV dyssynchrony on GMPS (defined as > or = 135 degrees for histogram bandwidth and > or = 43 degrees for phase SD) had significantly higher LV systolic dyssynchrony index than patients without substantial LV dyssynchrony. CONCLUSIONS: The good correlations between LV dyssynchrony assessed with GMPS and with RT3DE provide further support for the use of RT3DE for reliable assessment of LV dyssynchrony.

Phase analysis of gated myocardial perfusion single-photon emission computed tomography compared with tissue Doppler imaging for the assessment of left ventricular dyssynchrony.

OBJECTIVES: The purpose of this study was to compare left ventricular (LV) dyssynchrony assessment by gated myocardial perfusion single-photon emission computed tomography (SPECT) (GMPS) and tissue Doppler imaging (TDI). BACKGROUND: Recently, it has been suggested that LV dyssynchrony is an important predictor of response to cardiac resynchronization therapy (CRT); dyssynchrony is predominantly assessed by TDI with echocardiography. Information on LV dyssynchrony can also be provided by GMPS with phase analysis of regional LV maximal count changes throughout the cardiac cycle, which tracks the onset of LV thickening. METHODS: In 75 patients with heart failure, depressed LV function, and wide QRS complex, GMPS and 2-dimensional echocardiography, including TDI, were performed as part of clinical screening for eligibility for CRT. Clinical status was evaluated with New York Heart Association functional classification, 6-min walk distance, and quality-of-life score. Different parameters (histogram bandwidth, phase SD, histogram skewness, and histogram kurtosis) of LV dyssynchrony were assessed from GMPS and compared with LV dyssynchrony on TDI with Pearson's correlation analyses. RESULTS: Histogram bandwidth and phase SD correlated well with LV dyssynchrony assessed with TDI (r = 0.89, p < 0.0001 and r = 0.80, p < 0.0001, respectively). Histogram skewness and kurtosis correlated less well with LV dyssynchrony on TDI (r = -0.52, p < 0.0001 and r = -0.45, p < 0.0001, respectively). CONCLUSIONS: The LV dyssynchrony assessed from GMPS correlated well with dyssynchrony assessed by TDI; histogram bandwidth and phase SD showed the best correlation with LV dyssynchrony on TDI. These parameters seem most optimal for assessment of LV dyssynchrony with gated SPECT. Outcome studies after CRT are needed to further validate the use of GMPS for assessment of LV dyssynchrony.