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Phase analysis is expected to improve the accuracy of myocardial ischemia diagnosis in conjunction with myocardial perfusion and wall motion imaging and quantification. Although previous studies have reported perfusion image disagreements in relation to radionuclides, a few reports have examined the influences of radionuclides on phase analysis. We evaluated the influences of different radionuclides on stress-induced left ventricular mechanical dyssynchrony by phase analysis using electrocardiogram (ECG)-gated myocardial perfusion single photon emission computed tomography (SPECT) (MPS) imaging in patients with ischemic heart disease (IHD). A total of 202 patients with suspected or known IHD were investigated retrospectively. All the patients underwent coronary arteriography and were subsequently classified into the following groups: 43 patients without any coronary lesion (0VD), 71 patients with single-vessel disease (1VD), 59 patients with two-vessel disease (2VD), and 29 patients with three-vessel disease (3VD). Both stress and rest gated-MPS were performed using 99mTc-methoxyisobutylisonitrile (MIBI)/tetrofosmin (TF) in 118 patients and with 201TlCl in 84 patients. Phase analysis was performed to obtain the peak phase, phase standard deviation (SD), and bandwidth. Finally, we investigated potential differences between the phase analysis indices and the respective radionuclides used. The peak phase did not exhibit any significant differences in the numbers of affected branches in either 99mTc-MPS or 201Tl-MPS during stress or rest MPS. Furthermore, both the phase SD and bandwidth demonstrated a tendency to increase in patients with increased numbers of affected branches. A significant difference was observed in the stress MPS when 99mTc-MIBI/TF was used (p

A low appropriate therapy rate indicates that a minority of patients will benefit from their implantable cardioverter defibrillator (ICD). Quantitative measurements from 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) may predict ventricular arrhythmia (VA) occurrence after ICD placement. We performed a prospective observational study and recruited patients who required ICD placement. Pre-procedure image scans were performed. Patients were followed up for VA occurrence. Associations between image results and VA were analyzed. In 51 patients (33 males, 53.9 ± 17.2 years) analyzed, 17 (33.3%) developed VA. Compared with patients without VA, patients with VA had significantly larger values in scar area (17.7 ± 12.4% vs. 7.0 ± 7.9%), phase standard deviation (51.4° ± 14.0° vs. 34.0° ± 15.0°), bandwidth (172.9° ± 39.8° vs. 128.7° ± 49.9°), sum thickening score (STS, 29.5 ± 11.1 vs. 17.8 ± 13.2), and sum motion score (42.9 ± 11.5 vs. 33.0 ± 19.0). Cox regression analysis and receiver operating characteristic curve analysis showed that scar size, dyssynchrony, and STS were associated with VA occurrence (HR, 4.956, 95% CI 1.70-14.46). Larger left ventricular scar burden, increased dyssynchrony, and higher STS quantified by 18F-FDG PET may indicate a higher VA incidence after ICD placement.

Background: Super-responders (SRs) to cardiac resynchronization therapy (CRT) regain near-normal or normal cardiac function. The extent of cardiac synchrony of SRs and whether continuous biventricular (BIV) pacing is needed remain unknown. The aim of this study was to evaluate the cardiac electrical and mechanical synchrony of SRs. Methods: We retrospectively analyzed CRT recipients between 2008 and 2016 in 2 centers to identify SRs, whose left ventricular (LV) ejection fraction was increased to ≥50% at follow-up. Cardiac synchrony was evaluated in intrinsic and BIV-paced rhythms. Electrical synchrony was estimated by QRS duration and LV mechanical synchrony by single-photon emission computed tomography myocardial perfusion imaging. Results: Seventeen SRs were included with LV ejection fraction increased from 33.0 ± 4.6% to 59.3 ± 6.3%. The intrinsic QRS duration after super-response was 148.8 ± 30.0 ms, significantly shorter than baseline (174.8 ± 11.9 ms, P = 0.004, t = -3.379) but longer than BIV-paced level (135.5 ± 16.7 ms, P = 0.042, t = 2.211). Intrinsic LV mechanical synchrony significantly improved after super-response (phase standard deviation [PSD], 51.1 ± 16.5° vs. 19.8 ± 8.1°, P < 0.001, t= 5.726; phase histogram bandwidth (PHB), 171.7 ± 64.2° vs. 60.5 ± 22.9°, P < 0.001, t= 5.376) but was inferior to BIV-paced synchrony (PSD, 19.8 ± 8.1° vs. 15.2 ± 6.4°, P = 0.005, t = 3.414; PHB, 60.5 ± 22.9° vs. 46.0 ± 16.3°, P = 0.009, t = 3.136). Conclusions: SRs had significant improvements in cardiac electrical and LV mechanical synchrony. Since intrinsic synchrony of SRs was still inferior to BIV-paced rhythm, continued BIV pacing is needed to maintain longstanding and synchronized contraction. Key words: Cardiac resynchronization; Super-responders; Electrical synchrony; Mechanical synchrony

Gated myocardial perfusion SPECT (GMPS) provides a one-stop-shop evaluation for cardiac resynchronization therapy (CRT). However, conflicting results have been observed regarding whether the baseline left-ventricular (LV) mechanical dyssynchrony as assessed by phase analysis on GMPS was predictive of therapeutic response to CRT. Since dyssynchrony parameters by phase analysis spuriously increased by scarred myocardium, the purpose of this study was to explore the value of dyssynchrony after stripping off the scar region in correlation to mechanical response to CRT. Forty-seven patients following standard indications for CRT received GMPS with phase analysis as pre-CRT evaluation. A decrease of end-systolic volume (ESV) > 15% on follow-up echocardiography after CRT was considered as a mechanical response to CRT. Myocardial regions with less than 50% of maximal activity on GMPS were considered as a scar. The phase standard deviation (PSD) and histogram bandwidth (BW) without or with stripping off scar were assessed by phase analysis of GMPS and were used for evaluation of LV dyssynchrony of all myocardium or only the viable myocardium, respectively. No significant difference was noted between mechanical responders (31 of 47 patients, 66%) and nonresponders ( 16 of 47 patients, 34%) for PSD (48.6° ± 19.4° vs 43.9° ± 20.7°, p = 0.46) and BW (225° ± 91.1° vs 163.5° ± 94.6°, p = 0.38) of the entire myocardium. However, responders had significantly larger PSD (40.5° ± 15.7° vs 30.5° ± 13.2°, p = 0.03) and borderlinely larger BW (215° ± 91.2° vs. 139.5° ± 78.2°, p = 0.05) than non-responders after stripping off scar. Logistic regression analysis showed that scar area and PSD after stripping off scar were independent predictors of mechanical response. Our result showed that LV dyssynchrony of the entire myocardium did not predict response to CRT. However, LV dyssynchrony only in the viable myocardium was a significant predictor of CRT mechanical response.

To test whether phase analysis indices from SPECT-MPI for left ventricular mechanical dyssynchrony (LVMD) are predictors of major adverse cardiac events (MACEs) in long-standing diabetes mellitus (DM). A total of 136 DM patients with normal perfusion and left ventricular systolic functions were followed up for about two years and divided into two groups according to the presence and the absence of MACEs. Thirteen (9.5%) patients experienced MACEs during follow-up. Patients experiencing MACEs showed significantly higher phase standard deviation (PSD) and wider phase bandwidth (PBW) than those who did not. Moreover, both PSD and PBW showed significant correlations (r = 0.25 and 0.27; P

The association between left ventricular (LV) dyssynchrony parameters, given by phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), and acquisition orbits is unclear. The aim of this study was to assess the dependence of LV dyssynchrony parameters on acquisition orbits. Ninety-nine patients who underwent 201Tl-gated SPECT MPI were categorized into minor hypoperfusion or major hypoperfusion groups. Forty-four patients who underwent 99mTc-tetrofosmin-gated SPECT MPI were categorized into minor hypoperfusion or major hypoperfusion groups. The major hypoperfusion group with 201Tl was divided into inferior or non-inferior wall hypoperfusion subgroups, and anteroseptal or non-anteroseptal wall hypoperfusion subgroups. Gated SPECT MPI data over a 360° acquisition orbit (360° images) and a 180° acquisition orbit (180° images) were reconstructed, and histogram bandwidth (HBW) and phase standard deviation (PSD) were compared. Between 360° and 180° images with 201Tl, there were significant differences in HBW and PSD both globally (HBW 34.8 ± 16.6 vs. 29.1 ± 10.2; PSD 8.8 ± 4.9 vs. 7.0 ± 2.3, p

An interaction between coronary anatomy, myocardial perfusion, and left ventricular (LV) functional parameters in the development of mechanical LV dyssynchrony (LVD) has been suggested. This study examined the correlates of LVD in a large sample size of patients with known or suspected coronary artery disease (CAD) using cadmium-zinc-telluride camera. Six-hundred and fifty-seven consecutive patients who underwent myocardial perfusion imaging (MPI) and coronary angiography were included. Coronary stenosis >70% was considered significant. LV perfusion and functional parameters were computed from MPI images. The presence of significant LVD was evaluated by phase standard deviation and histogram bandwidth. 415/657 (63%) patients had significant CAD. LVD was present in 247 (38%) patients and was associated with the presence of a higher CAD burden (P

Background . Left ventricular (LV) pacing has been suggested to complement other forms of therapy in patients with heart failure. Methods and Results . We investigated 17 patients (15 men, 2 women, aged 68 ± 6 years, 10 ischemic and 7 primary dilated cardiomyopathy) with heart failure (13 were in New York Heart Association class IV and 4 in class III). One month after LV pacer implantation, 12 patients reported clinical improvement (mean class 3.7 before pacing vs 2.6 with LV pacing; P = .001). We report the results of 3 equilibrium-gated blood pool studies performed in each patient, 1 before pacing and 2 after pacer implantation (1 with pacing on, and 1 after turning off the pacer). LV pacing did not modify LV ejection fraction. Phase analysis demonstrated a significant decrease of the interventricular phase shift (Δπ) with LV pacing (no pacing, Δπ = 8.99° ± 19.05°; Δπ= −0.97° ± 27.85° with LV pacing). Clinical improvement was observed in patients with an initial positive Δπ that decreased with pacing and/or an initial LV phase standard deviation >50° that decreased with pacing. Conclusion . LV pacing induces interventricular and intraventricular synchronization. A decrease of the interventricular phase shift seems to be the most important predictor of functional recovery for paced patients with heart failure.

Purpose of the Study: Normal values of cardiac mechanical synchrony parameters in gated myocardial perfusion single-photon emission computed tomography (GMPS) are well established in literature from the Western population. The aim of the study is to establish normal values of mechanical synchrony with GMPS in Indian population and to find out whether it differs significantly from established values. Procedure: We retrospectively analyzed 1 day low-dose stress/high-dose rest GMPS studies of 120 patients (sixty males, 52 ± 11.7 years) with low pretest likelihood of coronary artery disease and having normal GMPS study. In GMPS, first-harmonic fast Fourier transform was used to extract a phase array using commercially available software. Phase standard deviation (PSD) and phase histogram bandwidth (PHB) were used to quantify cardiac mechanical dyssynchrony. Results: The values obtained were as follows, PSD: In men, 14.3 ± 4.7 (stress) and 8.9 ± 2.9 (rest), in women 11 ± 4 (stress) and 7.7 ± 2.7 (rest), and PHB: In men, 40.1 ± 11.9 (stress) and 30.6 ± 7.6 (rest), in women, 34.7 ± 12.6 (stress) and 25.3 ± 8.6 (rest). The value of PSD and PHB was significantly less in Indian population as compared with established values in literature. We also observed that synchrony indices derived from the low-dose stress studies are higher than high-dose rest studies. Conclusions: The value of synchrony parameters differs significantly according to population and methodology suggesting that specific population and methodology-based normal database for assessment of cardiac mechanical dyssynchrony should be established.

The development of agriculture in the Near East was the result of innovative methods of plant and animal husbandry. The adoption of these new methods led to the domestication of plants and animals, that is to say the development of plants and animals that are dependent on humans for survival and reproduction. While these innovative methods of utilization were adopted deliberately, not all of the consequences of these changes could be foreseen; the domestication of plants and animals affected productivity in surprising ways and entailed a reorganization of subsistence activities. This reorganization had wide-spread ramifications in the social organization of these early farmers; it is this entire suite of changes that is presently understood as the Neolithic Revolution.

1817 Objectives The prevalence of left ventricular mechanical dyssynchrony (LVMD) in stable angina pectoris (AP) has not been fully clarified. The aim of this study was to assess the presence and severity of LVMD in stable AP. Methods A total of 201 patients (age 69 ± 11, 137 males) with suspected ischemic heart disease underwent stress/rest gated myocardial perfusion SPECT (GMPS). For the evaluation of LVMD, histogram bandwidth (HBW) and phase standard deviation (PSD) were determined by GMPS using phase analysis. LVMD at stress and rest were compared among three groups: 103 normal patients (NG) [summed stress score (SSS) 50 %], 54 patients with ischemia (IG) [SSS > 3, summed difference score (SDS) > 1, and summed rest score (SRS) 3 and SDS Results The measured LVMD parameters (HBW and PSD) in NG, IG, and pMIG are summarized in the figure. At stress, both HBW and PSD in IG were significantly greater than those in NG (p Conclusions In patients with stable AP, LVMD was demonstrated to be enhancement at stress, and was found to be detectable equally well with prior MI

Left ventricular (LV) phase dyssynchrony parameters based on gated myocardial perfusion imaging varied among software programs. The aim of this study was to determine normal ranges and factors affecting phase parameters. Normal databases were derived from the Japanese Society of Nuclear Medicine working group (n = 69). The programs were Emory Cardiac Toolbox with SyncTool (ECTb), Quantitative Gated SPECT (QGS), Heart Function View (HFV), and cardioREPO (cREPO); parameters of phase standard deviation (PSD), 95% bandwidth, and entropy were compared with parameters with ECTb as a reference. PSD (degree) was 5.3 ± 3.3 for QGS (P

The amplitude spectra of the auditory brainstem potentials evoked by free-field stimuli revealed significant differences from the corresponding spectra of pre-stimulus records. This was most marked for low order harmonics and in response to high intensity stimuli. In general, however, the shape of the amplitude spectrum for pre-stimulus and post-stimulus epochs was similar and the magnitude of the differences between corresponding harmonics became progressively smaller as stimulus intensity was reduced. Given that the spectrum of each coherent grand average is a function of the amplitude and phase spectra of the response ensemble, these were separately examined. Ensemble mean amplitude of individual harmonics diminished with stimulus intensity while their phases became progressively less aggregated. Phase standard deviation, used as a parameter of this aggregation, was found to change more systemically with stimulus intensity than ensemble mean amplitude. Phase standard deviation values for threshold responses were generally significantly smaller than corresponding harmonics obtained from sub-threshold responses. By contrast the amplitude differences between populations of threshold and sub-threshold responses were generally non-significant. These findings suggested that fully objective methods of threshold determination might more successfully be based on ensemble phase measures rather than amplitude measures.