Stergios Theodoropoulos

Myocardial Sympathetic Innervation and Long-Term Left Ventricular Mechanical Unloading

OBJECTIVES The purpose of this study was to analyze the effects of left ventricular assist devices (LVADs) on myocardial sympathetic innervation of the failing heart. BACKGROUND Ventricular unloading by LVADs seems to cause reverse remodeling of the failing heart, but little is known about the sympathetic nerve activity during long-term mechanical unloading. METHODS We studied the effects of LVADs on myocardial sympathetic innervation, by iodine 123-meta-iodobenzylguanidine (123I-mIBG) scintigraphy performed before and 3 months after LVAD implantation in 12 end-stage heart failure patients. We calculated the: 1) heart-to-mediastinum (H/M) uptake ratio on early and delayed images, indicating myocardial accumulation of 123I-mIBG; and 2) rate of 123I-mIBG washout after initial accumulation. Similar 123I-mIBG imaging and functional and hemodynamic measurements were made 3 months apart in 6 other heart failure patients not treated with an LVAD. RESULTS After 3 months of LVAD support, the mean left ventricular ejection fraction had increased from 19+/-6% to 29 +/- 9% (p=0.006), peak oxygen consumption increased from 9+/-4 ml/kg/min to 13+/-3 ml/kg/min (p=0.058), serum sodium increased from 135+/-4 mEq/l to 140+/-2 mEq/l (p=0.014), whereas the left ventricular end-diastolic diameter decreased from 72+/-7 mm to 56+/-3 mm (p=0.002), pulmonary capillary wedge pressure decreased from 30+/-6 mm Hg to 5+/-3 mm Hg (p=0.012), serum creatinine decreased from 1.5+/-0.6 mg/dl to 1.0+/-0.4 mg/dl (p=0.011), and B-type natriuretic peptide decreased from 2,279+/-1,900 pg/ml to 102+/-5 pg/ml (p=0.003). After 3 months of LVAD, the H/M ratio increased on delayed images from 1.25+/-0.18 to 1.43+/-0.13 (p=0.01) and on early images from 1.35+/-0.19 to 1.44+/-0.11 (p=0.028), and the washout rate decreased from 51.0+/-23.2% to 30.6+/-8.7%, (p=0.015). There was a significant correlation between the late H/M mIBG ratio and B-type natriuretic peptide (R=0.77, p=0.01) and systolic pulmonary pressure (R=0.7, p=0.05). No significant scintigraphic, functional or hemodynamic change was observed between the 2 evaluations in the 6 patients not treated with an LVAD. CONCLUSIONS Ventricular unloading caused clinical, functional, and hemodynamic improvements accompanied by improvements in sympathetic innervation in the failing heart.

In Vivo Aortic Valve Thermal Heterogeneity in Patients With Nonrheumatic Aortic Valve Stenosis: The First In Vivo Experience in Humans

OBJECTIVES We investigated in vivo in aortic valve stenosis (AVS) whether there is: 1) thermal heterogeneity within the valve leaflets; 2) temperature difference between the leaflets and the ascending aortic wall; and 3) a possible correlation between heat production, inflammation, and neoangiogenesis. BACKGROUND Histological studies have demonstrated a potential role of inflammation and neoangiogenesis in AVS. METHODS We examined 96 leaflets scheduled for aortic valve replacement. Twenty-five patients had AVS, and 7 had aortic valve insufficiency (AVI). Temperature measurements were performed right before hypothermic cardioplegia. Temperature difference (DeltaT) was assigned as the mean temperature of each leaflet minus the temperature of the aortic wall. Histological, immunohistological analysis, and vascular endothelial growth factor (VEGF) immunoreactivity was performed. RESULTS Significant thermal heterogeneity was recorded within the leaflets of AVS, compared with AVI (1.52 +/- 1.35 degrees C vs. 0.13 +/- 0.11 degrees C, p < 0.01). In AVS DeltaT was greater in all leaflets compared with the AVI group (p < 0.01). Leaflets of AVS had increased inflammatory cell infiltration, calcium deposit, and anti-VEGF expression compared with AVI (p < 0.01). CONCLUSIONS Thermal heterogeneity is increased in AVS and correlates with inflammatory mononuclear cell infiltration, expression of pro-inflammatory cytokines and neoangiogenic factors.

Reverse electrophysiologic remodeling after cardiac mechanical unloading for end-stage nonischemic cardiomyopathy

BACKGROUND Left ventricular assist devices (LVAD)-induced unloading appear to cause reverse cardiac remodeling. However, its effect on arrhythmogenicity is a controversial issue, and prospective data are lacking. We sought to investigate the impact of LVAD-induced unloading on the electrical properties of the failing heart. METHODS We prospectively studied the effects of LVAD therapy on QRS, QT, and QTc durations and ventricular arrhythmias from electrocardiograms and 24-hour ambulatory electrocardiograms recorded before and during 6 months of mechanical support in 12 LVAD patients and 7 other patients with advanced nonischemic cardiomyopathy untreated with LVAD. RESULTS After 1 week of LVAD support, QTc duration had decreased from 479 ± 79 ms to 411 ± 57 ms (p = 0.037), and QRS duration from 150 ± 46 ms to 134 ± 32 ms (p = 0.029). At 6 months, QTc was found to be 372 ± 56 ms (p = 0.046 versus baseline, 15% shortening) and QRS 118 ± 25 ms (p = 0.028 versus baseline, 11% shortening). A strong correlation was found between QTc shortening and increase in left ventricular ejection fraction and decrease in left ventricular filling pressures. After 2 months of LVAD support, premature ventricular contractions had decreased from 3,507 ± 4,252 to 483 ± 417 in 24 hours (p = 0.043), ventricular couplets from 82 ± 99 to 29 ± 25 in 24 hours (p = 0.05), and ventricular runs from 9 ± 8 to 10 ± 9 (not significant). No patient died suddenly or suffered a symptomatic arrhythmic event during follow-up. No significant electrocardiographic, functional, or hemodynamic change was observed in the 7 patients untreated with LVAD. CONCLUSIONS The LVAD support caused progressive shortening of QTc and QRS intervals, consistent with reverse remodeling of the failing hearts electrical properties, accompanied by a decrease in frequency of ventricular arrhythmias.

Influence of beta blockade on exercise capacity and heart rate response after human orthotopic and heterotopic cardiac transplantation.

It has been reported that use of beta blockers may not be safe after cardiac transplantation because the denervated hearts may be largely dependent on circulating catecholamines to increase cardiac output. Therefore, the effects of intravenous propranolol were studied during maximal treadmill exercise in 7 patients with heterotopic and 6 with orthotopic cardiac transplantations. An average decrease of about 15% in exercise duration (p less than 0.001), a 34% reduction in systolic blood pressure increase (p less than 0.05) and a 40% attenuation in heart rate increase (p less than 0.001) were observed after beta blockade. In patients with heterotopic transplantation, beta blockade produced similar effects on heart rate in the denervated donor hearts and the innervated recipient hearts during and after mild exercise. During peak exercise, beta blockade attenuated the rate to a greater extent in the donor hearts. Although the denervated donor heart is more sensitive to beta blockade than the innervated recipient heart during exercise, no adverse effects were observed. Beta-blocker therapy should be considered for cardiac transplant patients if longer-term studies confirm their safe use in these patients.

Predicting Impending Rupture of the Ascending Aorta With Bicuspid Aortic Valve: Spatiotemporal Flow and Wall Shear Stress

Bicuspid aortic valve (BAV) is the most common congenital cardiac anomaly with a prevalence of 1% to 2% in the general populations. Acute dissection and rupture of the ascending aorta in patients of aortic stenosis due to BAV carries very poor prognosis. The aortic wall abnormality is known to be an

Severe anaemia and subcapital femur fracture in a patient with Left Ventricular Assist Device Heart Mate II: the cardiologist’s management of this rare patient

The use of Left Ventricular Assist Devices (LVADs) has increased over the last decade because of the lack of healthy donor hearts. In this report we describe for the first time a patient with an LVAD Heart Mate II (HM II) implanted 6 months before admission, who initially suffered from severe anaemia and later on underwent a successful bipolar hip replacement owing to subcapital fracture of the right femur. The patient was managed successfully by a team approach, which included a cardiologist, anaesthesiologist, orthopaedic surgeon, and LVAD technician.

Right atrial appendage myxoma following recent coronary artery bypass grafting

A 71-year-old male presented with recurrent atrial fibrillation, anaemia and thrombocytopenia. Six months ago he underwent an urgent triple coronary artery bypass-grafting elsewhere. Postoperatively he complained of fatigue and low-grade fever. Echocardiographs and magnetic resonance imaging showed a right atrial appendage mass, which afterwards was resected. Histology confirmed a benign myxoma. Patients symptoms spontaneously resolved. This report demonstrates the unusual sites that myxoma may occur, with probable serious complications in case of urgent heart operations. This case also emphasizes the need for preoperative echocardiography in open heart operations or in cases with recurrent atrial fibrillation.

Quantitative assessment of right ventricular structure and flow dynamics in pulmonary homograft obstruction

The insertion of cryopreserved homograft conduit into the pulmonary outflow tract is an effective method of relieving severe pulmonary valve dysfunction. A certain proportion of the inserted homografts undergo late degeneration resulting in progressive right ventricular outflow obstruction. When severe, this obstruction needs repeat intervention. The timing of this intervention is critical and depends on a thorough assessment of symptoms, coupled with detailed evaluation of right ventricular structure and function as well as flow dynamics in the right ventricular outflow. We report a patient who illustrates many of the issues related to management of these patients with particular reference to the use of modern imaging followed by detailed image processing.