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Articles by Z. B Popovic
Total Records ( 4 ) for Z. B Popovic
  Z. B Popovic , C Puntawangkoon , D Verhaert , N Greenberg , A Klein , J. D Thomas and R. A. Grimm
  Background—

It is unknown whether longitudinal rotation (LR), often seen in cardiac resynchronization therapy candidates, may affect mitral annular early diastolic (E') velocities and tricuspid annular motion. We assessed whether (1) LR affects the amplitude and timing of septal and lateral mitral annular E' velocities and tricuspid annular systolic and E' velocities and (2) if systolic strain heterogeneity seen in cardiac resynchronization therapy patients with LR extends into diastole.

Methods and Results—

Ninety-nine cardiac resynchronization therapy candidates with suitable baseline echocardiograms were identified. Early diastolic (E') and systolic myocardial velocities of the tricuspid annulus and E' velocities of the septal and lateral part of the mitral annulus were analyzed from tissue Doppler images. Longitudinal rotation and basal systolic and diastolic strain rates were analyzed by speckle-tracking. LR correlated with lateral mitral annular E' (r=0.45, P<0.001), tricuspid annular E' (r=–0.3, P=0.003), and with a difference between septal and lateral mitral annular E' velocities (r=–0.49, P<0.001) but not with septal mitral annular E' velocity. LR also correlated with tricuspid annular systolic velocity (r=0.60, P<0.001). After categorizing the patients according to the quartiles of their LR, we showed that with decreasing quartile number, heterogeneity of systolic (P=0.003) but not diastolic (P>0.1) strain rates increased.

Conclusions—

LR direction and magnitude correlates with the amplitude of, and relative differences between, diastolic velocities of tricuspid, lateral mitral, and septal mitral annulus, which are a cornerstone of diastolic function assessment. LR is associated with systolic but not with diastolic regional heterogeneity.

  Y Zhang , Z. B Popovic , S Bibevski , I Fakhry , D. A Sica , D. R Van Wagoner and T. N. Mazgalev
 

Background— Autonomic dysfunction, characterized by sympathetic activation and vagal withdrawal, contributes to the progression of heart failure (HF). Although the therapeutic benefits of sympathetic inhibition with β-blockers in HF are clear, the role of increased vagal tone in this setting has been less studied. We have investigated the impact of enhancing vagal tone (achieved through chronic cervical vagus nerve stimulation, [VNS]) on HF development in a canine high-rate ventricular pacing model.

Methods and Results— Fifteen dogs were randomized into control (n=7) and VNS (n=8) groups. All dogs underwent 8 weeks of high-rate ventricular pacing (at 220 bpm for the first 4 weeks to develop HF and another 4 weeks at 180 bpm to maintain HF). Concomitant VNS, at an intensity reducing sinus rate 20 bpm, was delivered together with the ventricular pacing in the VNS group. At 4 and 8 weeks of ventricular pacing, both left ventricular end-diastolic and -systolic volumes were lower and left ventricular ejection fraction was higher in the VNS group than in the control group. Heart rate variability and baroreflex sensitivity improved in the VNS dogs. Rises in plasma norepinephrine, angiotensin II, and C-reactive protein levels, ordinarily expected in this model, were markedly attenuated with VNS treatment.

Conclusions— Chronic VNS improves cardiac autonomic control and significantly attenuates HF development in the canine high-rate ventricular pacing model. The therapeutic benefit of VNS is associated with pronounced anti-inflammatory effects. VNS is a novel and potentially useful therapy for treating HF.

  D Verhaert , W Mullens , A Borowski , Z. B Popovic , R. J Curtin , J. D Thomas and W. H. W. Tang
  Background—

Right ventricular (RV) systolic dysfunction is a strong predictor of adverse outcomes in heart failure, yet quantitatively assessing the impact of therapy on this condition is difficult. Our objective was to compare the clinical significance of changes in RV echocardiographic indices in response to intensive medical treatment in patients admitted to the hospital with acute decompensated heart failure (ADHF).

Methods and Results—

Serial comprehensive echocardiography was performed in 62 consecutive patients with ADHF, and adverse events (death, cardiac transplantation, assist device, heart failure rehospitalization) were prospectively documented. RV peak systolic strain was assessed using speckle-tracking longitudinal strain analysis as the average of the basal, mid-, and apical segment of the RV free wall. Other conventional parameters of RV function (RV fractional area change, RV myocardial performance index, tricuspid annular peak systolic excursion, and tissue Doppler peak tricuspid annular systolic velocity) were measured for comparison. In our study cohort [left ventricular ejection fraction, 26±10%; cardiac index, 2.0±0.6 L/(min · m2)], overall mean RV peak systolic strain was –14±4% at baseline and –15±4% at 48 to 72 hours (P=0.27). Among all the RV functional indices measured, only RV peak systolic strain at 48 to 72 hours was associated with adverse events (P=0.02). In particular, improvement in RV peak systolic strain after intensive medical treatment was associated with lower adverse events in this patient population (26% versus 78%; hazard ratio, 0.13; 95% CI, 0.02 to 0.84; P=0.02).

Conclusion—

Dynamic improvement in RV mechanics in response to intensive medical therapy was associated with lower long-term adverse events in patients with ADHF than in patients not showing improvement.

  A Prasad , J. L Hastings , S Shibata , Z. B Popovic , A Arbab Zadeh , P. S Bhella , K Okazaki , Q Fu , M Berk , D Palmer , N. L Greenberg , M. J Garcia , J. D Thomas and B. D. Levine
  Background—

Congestive heart failure in the setting of a preserved left ventricular (LV) ejection fraction is increasing in prevalence among the senior population. The underlying pathophysiologic abnormalities in ventricular function and structure remain unclear for this disorder. We hypothesized that patients with heart failure with preserved ejection fraction (HFPEF) would have marked abnormalities in LV diastolic function with increased static diastolic stiffness and slowed myocardial relaxation compared with age-matched healthy controls.

Methods and Results—

Eleven highly screened patients (4 men, 7 women) aged 73±7 years with HFPEF were recruited to participate in this study. Thirteen sedentary healthy controls (7 men, 6 women) aged 70±4 years also were recruited. All subjects underwent pulmonary artery catheterization with measurement of cardiac output, end-diastolic volumes, and pulmonary capillary wedge pressures at baseline; cardiac unloading (lower-body negative pressure or upright tilt); and cardiac loading (rapid saline infusion). The data were used to define the Frank-Starling and LV end-diastolic pressure-volume relationships. Doppler echocardiographic data (tissue Doppler velocities, isovolumic relaxation time, propagation velocity of early mitral inflow , E/A-wave ratio) were obtained at each level of cardiac preload. Compared with healthy controls, patients with HFPEF had similar LV contractile function and static LV compliance but reduced LV chamber distensibility with elevated filling pressures and slower myocardial relaxation as assessed by tissue Doppler imaging.

Conclusions—

In this small, highly screened patient population with hemodynamically confirmed HFPEF, increased end-diastolic static ventricular stiffness relative to age-matched controls was not a universal finding. Nevertheless, patients with HFPEF, even when well compensated, had elevated filling pressures, reduced distensibility, and increased diastolic wall stress compared with controls. In contrast, LV relaxation as assessed by tissue Doppler variables appeared consistently impaired in patients with HFPEF.

 
 
 
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