Susan Olet

Selective downregulation of mitochondrial electron transport chain activity and increased oxidative stress in human atrial fibrillation

Mitochondria are critical for maintaining normal cardiac function, and a deficit in mitochondrial energetics can lead to the development of the substrate that promotes atrial fibrillation (AF) and its progression. However, the link between mitochondrial dysfunction and AF in humans is still not fully defined. The aim of this study was to elucidate differences in the functional activity of mitochondrial oxidative phosphorylation (OXPHOS) complexes and oxidative stress in right atrial tissue from patients without (non-AF) and with AF (AF) who were undergoing open-heart surgery and were not significantly different for age, sex, major comorbidities, and medications. The overall functional activity of the electron transport chain (ETC), NADH:O2 oxidoreductase activity, was reduced by 30% in atrial tissue from AF compared with non-AF patients. This was predominantly due to a selective reduction in complex I (0.06 ± 0.007 vs. 0.09 ± 0.006 nmol·min(-1)·citrate synthase activity(-1), P = 0.02) and II (0.11 ± 0.012 vs. 0.16 ± 0.012 nmol·min(-1)·citrate synthase activity(-1), P = 0.003) functional activity in AF patients. Conversely, complex V activity was significantly increased in AF patients (0.21 ± 0.027 vs. 0.12 ± 0.01 nmol·min(-1)·citrate synthase activity(-1), P = 0.005). In addition, AF patients exhibited a higher oxidative stress with increased production of mitochondrial superoxide (73 ± 17 vs. 11 ± 2 arbitrary units, P = 0.03) and 4-hydroxynonenal level (77.64 ± 30.2 vs. 9.83 ± 2.83 ng·mg(-1) protein, P = 0.048). Our findings suggest that AF is associated with selective downregulation of ETC activity and increased oxidative stress that can contribute to the progression of the substrate for AF.

Genetic basis of aortapathy in bicuspid valve disease

Two theories exist on the relationship between bicuspid aortic valve (BAV) and aortapathy: Hemodynamic - aortic dilation results from shear stress of diseased BAV; Genetic - aorta is genetically abnormal and dilates independently of BAV disease progression. We explored these theories in patients

Contemporary practice pattern of revascularization in a large tertiary care referral center in non-ST elevation myocardial infarction: A propensity-matched 10-year experience

We sought to compare the effects of early versus delayed percutaneous coronary intervention (PCI) on the outcomes at 1 year in patients presenting with non‐ST‐segment elevation myocardial infarction (NSTEMI).

MARKED RESPIRATORY RELATED VARIATION IN LVOT GRADIENTS IN HYPERTROPHIC CARDIOMYOPATHY IN OBESE HCM PATIENTS WITH SLEEP-DISORDERED BREATHING

Background: Left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) is sensitive to changes in left ventricular (LV) preload, afterload, and contractility; small studies suggest that LVOTO may vary with respiration. Methods: During routine transthoracic

COMPARATIVE STUDY ON CATHETER-DIRECTED THROMBOLYSIS – CONTINUOUS TISSUE PLASMINOGEN ACTIVATOR VERSUS ANGIOJET CATHETER POWER PULSE SPRAY RHEOLYTIC THROMBECTOMY OUTCOME STUDY: SINGLE-CENTER EXPERIENCE

Background: Acute arterial occlusion of native and graft vessels has a variety of treatment options, including catheter-directed thrombolysis (CDT), power pulse spray with rheolytic thrombectomy (PPSRT) and surgery. We studied acute limb ischemia (ALI) outcomes with CDT vs PPSRT with adjunctive CDT