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Background In patients with heart failure and reduced left ventricular ejection fraction (LVEF), the effect of upgrading from right ventricular (RV) apical to biventricular pacing on RV and left ventricular (LV) volumes and ejection fraction (EF) is unknown. Also, the relationship of symptom improvement after biventricular upgrade to RV and LV volumes and EF has not been clarified.

BACKGROUND Electrosurgery used during dermatologic surgical procedures can cause malfunction of pacemakers and implantable cardiac defibrillators (ICDs), producing problems with rhythm detection, proper function, or alteration of the device. Well-documented safety data on electrosurgery in patients with cardiac devices are limited. At Mayo Clinic in Rochester, Minnesota, the Pacemaker Clinic manages all patients with pacemakers and ICDs undergoing dermatologic surgery. The preoperative and postoperative evaluations provide a unique opportunity to evaluate the safety of dermatologic surgery with electrosurgery in such patients. OBJECTIVES The objective was to review the evaluation and management, by an experienced cardiology team, of patients with cardiac devices undergoing dermatologic surgery and to characterize perioperative complications. METHODS A retrospective chart review of all patients identified with pacemakers or ICDs undergoing Mohs micrographic or dermatologic excisional surgery with electrosurgery at Mayo Clinic 2001 through 2004 were identified. Data were abstracted to identify any possible complications. RESULTS The 173 patients with pacemakers and 13 with ICDs undergoing dermatologic surgery had no documented complications from electrosurgery. CONCLUSION The lack of complications associated with pacemakers and ICDs with electrosurgery is reassuring. The authors support published recommendations about techniques and precautions to optimize safety during electrosurgery in patients with cardiac devices. The care of patients with ICDs in particular requires special consideration.

Careful, systematic inspection of planar projection and tomographic images is essential as extracardiac findings and non-perfusion abnormalities may be present and on occasion account for the patient's symptoms. Two case histories and the corresponding images are presented below in which a stress myocardial perfusion single photon emission computed tomography (SPECT) study was performed and the diagnosis of a pericardial effusion was made. Although pericardial effusions are typically diagnosed by other imaging modalities (echocardiography and computed tomography) they can also be identified by radionuclide imaging techniques. Findings on planar projection and gated SPECT include the appearance of a "halo" of reduced tracer concentration surrounding the heart on both the rest and stress planar projection and tomographic images, and a "rocking" motion of the heart on gated images.

INTRODUCTION Cardiac resynchronization therapy (CRT) can improve left ventricular (LV) hemodynamics and function. Recent data suggest the energy cost of such improvement is favorable. The effects of sequential CRT on myocardial oxidative metabolism (MVO(2)) and efficiency have not been previously assessed. METHODS AND RESULTS Eight patients with NYHA class III heart failure were studied 196 +/- 180 days after CRT implant. Dynamic [(11)C]acetate positron emission tomography (PET) and echocardiography were performed after 1 hour of: 1) AAI pacing, 2) simultaneous CRT, and 3) sequential CRT. MVO(2) was calculated using the monoexponential clearance rate of [(11)C]acetate (k(mono)). Myocardial efficiency was expressed in terms of the work metabolic index (WMI). P values represent overall significance from repeated measures analysis. Global LV and right ventricular (RV) MVO(2) were not significantly different between pacing modes, but the septal/lateral MVO(2) ratio differed significantly with the change in pacing mode (AAI pacing = 0.696 +/- 0.094 min(-1), simultaneous CRT = 0.975 +/- 0.143 min(-1), and sequential CRT = 0.938 +/- 0.189 min(-1); overall P = 0.001). Stroke volume index (SVI) (AAI pacing = 26.7 +/- 10.4 mL/m(2), simultaneous CRT = 30.6 +/- 11.2 mL/m(2), sequential CRT = 33.5 +/- 12.2 mL/m(2); overall P < 0.001) and WMI (AAI pacing = 3.29 +/- 1.34 mmHg*mL/m(2)*10(6), simultaneous CRT = 4.29 +/- 1.72 mmHg*mL/m(2)*10(6), sequential CRT = 4.79 +/- 1.92 mmHg*mL/m(2)*10(6); overall P = 0.002) also differed between pacing modes. Compared with simultaneous CRT, additional changes in septal/lateral MVO(2), SVI, and WMI with sequential CRT were not statistically significant on post hoc analysis. CONCLUSION In this small selected population, CRT increases LV SVI without increasing MVO(2), resulting in improved myocardial efficiency. Additional improvements in LV work, oxidative metabolism, and efficiency from simultaneous to sequential CRT were not significant.

PET absolute myocardial blood flow (MBF) with H(2)15O and 13NH3 are widely used in clinical and research settings. However, their reproducibility with a 16-myocardial segment model has not been examined in chronic coronary artery disease (CAD). We examined the short-term reproducibility of PET H(2)15O MBF and PET 13NH3 MBF in an animal model of chronic CAD.Twelve swine (mean weight +/- SD, 38 +/- 5 kg) underwent percutaneous placement of a copper stent in the mid circumflex coronary artery, resulting in an intense inflammatory fibrotic reaction with luminal stenosis at 4 wk. Each animal underwent repeated resting MBF measurements by PET H(2)15O and PET 13NH3. Attenuation-corrected images were analyzed using commercial software to yield absolute MBF (mL/min/g) in 16 myocardial segments. MBF was also normalized to the rate.pressure product (RPP).By Bland-Altman reproducibility plots, the mean difference was 0.01 +/- 0.18 mL/min/g and 0.01 +/- 0.11 mL/min/g, with confidence limits of +/-0.36 and +/-0.22 mL/min/g for uncorrected regional PET H(2)15O MBF and for uncorrected regional PET 13NH3 MBF, respectively. The repeatability coefficient ranged from 0.09 to 0.43 mL/min/g for H(2)15O and from 0.09 to 0.18 mL/min/g for 13NH3 regional MBF. RPP correction did not improve reproducibility for either PET H(2)15O or PET 13NH3 MBF. The mean difference in PET H(2)15O MBF was 0.03 +/- 0.14 mL/min/g and 0.02 +/- 0.19 mL/min/g for infarcted and remote regions, respectively, and in PET 13NH3 MBF was 0.03 +/- 0.11 mL/min/g and 0.00 +/- 0.09 mL/min/g for infarcted and remote regions, respectively.PET H(2)15O and PET 13NH3 resting MBF showed excellent reproducibility in a closed-chest animal model of chronic CAD. Resting PET 13NH3 MBF was more reproducible than resting PET H(2)15O MBF. A high level of reproducibility was maintained in areas of lower flow with infarction for both isotopes.

Background and Purpose —Gene transfer to cerebral blood vessels has been accomplished in rats and dogs by injection of replication-deficient adenovirus into cerebrospinal fluid. In this study we examined transgene expression after injection of adenovirus into the cerebrospinal fluid of mice. Responses were observed in ICR mice and C57BL/6 mice, which are outbred and inbred strains, respectively. Methods —We injected replication-deficient recombinant adenovirus expressing nuclear targeted β-galactosidase, driven by either the Rous sarcoma virus promoter (AdRSV-βGal) or the cytomegalovirus promoter (AdCMV-βGal), into the cisterna magna of anesthetized ICR and C57BL/6 strains of mice. The brains were examined from 1 to 21 days after injection by chemiluminescent enzyme activity assay or histochemical staining. Results —After injection of AdRSV-βGal, expression of β-galactosidase in ICR mice peaked on day 7 and returned to basal by day 14. Expression of β-galactosidase in C57BL/6 mice was maximal on days 7 to 14 and was minimal by day 21 after injection of AdRSV-βGal. After injection of AdCMV-βGal in C57BL/6 mice, peak expression of transgene occurred on day 1 and was greatly diminished by day 3. Transgene expression was observed primarily on the ventral surface of the brain, with preferential expression in leptomeninges and adventitia along the major cerebral arteries of that region. Conclusions —Injection of recombinant adenovirus in the cisterna magna resulted in transgene expression in leptomeninges and perivascular tissue of cerebral blood vessels in two strains of mice. The CMV promoter elicited rapid but short-lived expression of the transgene, while the RSV promoter elicited slower, more sustained transgene expression. Expression of AdRSV transgene was prolonged in C57BL/6 mice compared with ICR mice. This approach for gene transfer may be useful to study cerebral vascular biology in genetically altered strains of mice.

Background: Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) can be utilized to assess myocardial viability. The objective of this study was to assess FDG PET image quality during the hyperinsulinemic euglycemic clamp (HE clamp) in patients with and without diabetes referred for myocardial viability assessment. Methods: Consecutive FDG PET viability scans at Mayo Clinic from June 2000Nov 2003 were reviewed retrospectively. Scans were performed using static acquisition. Image quality was visually assessed at the time of reading by two experienced observers. Image quality was also assessed by calculating the myocardium to blood pool (M/B) activity ratio (mean activity from regions of interest over normal myocardium and the LV cavity, averaged over three midventricular slices). Results: 81 of 82 FDG PET scans utilized the HE clamp; 39 Type 2 diabetics (DM2), 2 Type 1 diabetics, and 40 non-diabetics (Non-DM). By visual assessment, images were inadequate in 1 DM2 (M/B=1.6) and 1 Non-DM (M/B=1.8). All other patients (97%) had adequate images (M/B range 2.2–30.0). DM2 Non-DM P-Value Age, yrs 67.4 ± 10.3 64.8 ± 13.0 NS BM, kg/m 2 2 30.9 ± 5.9 27.7 ± 5.4 0.02 LVEF, % 27.3 ± 9.5 29.8 ± 11.0 NS Blood glucose before clamp, mg/dL 141.1 ± 34.6 101.7 ± 13.3 0.0001 Clamp start to FDG injection, min 155.7 ± 71.8 104.7 ± 35.1 0.0001 FDG injection to scan, min 39.8 ± 10.9 39.8 ± 16.1 NS Blood glucose during scan, mg/dL 91.6 ± 10.5 85.4 ± 13.3 0.03 Dextrose infusion during scan, mg/kg/min 3.1 ± 1.6 3.9 ± 1.6 0.02 M/B ratio 6.5 ± 4.6 8.1 ± 4.6 0.06 Conclusions: HE clamp yielded adequate image quality in >97% of both diabetic and non-diabetic patients referred for FDG PET myocardial viability assessment. HE clamp time was longer in diabetics, primarily due to higher baseline glucose and longer time until FDG injection.