ABSTRACT
BACKGROUND: Positron emission tomography using (18)F-Fluorodeoxyglucose (FDG) is an emerging modality for diagnosis of cardiac sarcoidosis (CS). We compared the location and degree of FDG uptake in CS patients presenting with either advanced atrioventricular block (AVB) or ventricular tachycardia (VT). METHODS AND RESULTS: We included consecutive patients who presented with either AVB or VT with a diagnosis of CS. A cohort of patients with clinically silent CS was included as controls. FDG activity was quantified as standardized uptake values (SUV) and both the overall mean left ventricular (LV) SUV as well as the Maximum Mean Segmental SUV was recorded for each patient. Receiver operator characteristic (ROC) analysis was performed to identify cutoff SUV values that best identified patients with VT. A total of 27 patients with CS were included (13 females; mean age, 56 ± 8 years; 8 VT, 12 AVB, and 7 controls). Both mean LV SUV and Max SUV in CS patients presenting with VT were significantly higher compared with those with AVB (mean SUV: VT median 5.33, range 4.7-9.35 versus AVB median 2.48, range 0.86-8.59, P=0.016; max SUV: VT median 11.07, range 9.24-14.4 versus AVB median 5.63, range 3.42-15.71, P=0.005) and compared with controls. There was no significant difference in SUV values between AVB patients and controls. ROC analysis for identification of patients with VT showed AUCs of 0.93 and 0.895 for a mean LV SUV of >3.42 and a max SUV >8.56, respectively (P<0.001). CONCLUSIONS: CS patients with VT displayed significantly higher FDG uptake when compared with those with AVB and asymptomatic controls. Further prospective studies are required to evaluate this finding.
Subject(s)
Cardiomyopathies/diagnostic imaging , Fluorodeoxyglucose F18 , Multimodal Imaging , Positron-Emission Tomography , Radiopharmaceuticals , Sarcoidosis/diagnostic imaging , Tomography, X-Ray Computed , Adult , Aged , Area Under Curve , Atrioventricular Block/diagnostic imaging , Atrioventricular Block/etiology , Cardiomyopathies/complications , Cardiomyopathies/physiopathology , Case-Control Studies , Female , Humans , Male , Middle Aged , Multidetector Computed Tomography , Perfusion Imaging , Predictive Value of Tests , ROC Curve , Registries , Sarcoidosis/complications , Sarcoidosis/physiopathology , Stroke Volume , Tachycardia, Ventricular/diagnostic imaging , Tachycardia, Ventricular/etiology , Ventricular Function, LeftABSTRACT
BACKGROUND: Up to 50% of patients do not respond to Cardiac Resynchronization Therapy (CRT). Recent work has focused on quantifying mechanical dyssynchrony and left ventricular scar. Septal reverse-mismatch (R-MM) (reduced FDG uptake vs perfusion) has been observed in patients with cardiomyopathy and prolonged QRS duration. We hypothesized that a greater quantity of septal R-MM would indicate a greater potential for reversibility of the cardiomyopathy, when the dyssynchrony is improved with CRT. Therefore, this study's objective was to assess whether greater septal R-MM pattern predicts response to CRT. METHODS AND RESULTS: Forty-nine patients had pre-implant Rubidium-82 and Fluorine-18-fluorodeoxyglucose PET scanning. Total and regional left ventricular scar size and extent of R-MM were calculated. Response to CRT was defined as ≥10% improvement in left ventricular end-systolic volume or ≥5% absolute ejection fraction improvement. In the non-ischemic cardiomyopathy subset non-responders had significantly less septal R-MM than responders (13.1% compared to 27.1%, P = .012). There were correlations between the extent of septal R-MM and the increase in ejection fraction (r = 0.692, P = .0004) and reduction in left ventricular end-systolic volume (r = -0.579, P = .004). For each 5% absolute increase in extent of septal R-MM the odds ratio of being a responder was 2.17 (95% CI 1.15, 4.11, P = .017). Extent of septal R-MM displayed high sensitivity and specificity (area under curve = 0.855, P = .017) to predict response. CONCLUSIONS: In patients with non-ischemic cardiomyopathy, greater extent of septal glucose metabolic R-MM pattern, predicted response to CRT. This parameter may be useful for identifying patients who benefit from CRT.
Subject(s)
Cardiomyopathies/metabolism , Cardiomyopathies/prevention & control , Fluorodeoxyglucose F18/pharmacokinetics , Heart Septum/diagnostic imaging , Heart Septum/metabolism , Aged , Cardiac Resynchronization Therapy , Cardiomyopathies/diagnostic imaging , Female , Humans , Male , Patient Selection , Prognosis , Radionuclide Imaging , Radiopharmaceuticals/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Treatment OutcomeABSTRACT
The objective of this study was to determine whether sending an information pamphlet to patients scheduled for a PET test two weeks prior to the appointment date significantly reduced patient anxiety and increased patient knowledge about the test. This study was conducted as a randomized controlled trial in which patients were randomly allocated to receive a mailed information pamphlet (intervention) or no mailed pamphlet two weeks prior to the appointment (usual care). The results of this study suggested that sending information pamphlets to patients scheduled for PET scans did not decrease pre-test levels of patient anxiety or result in increased patient knowledge about test preparation and procedures.
