The effect of renal transplantation on left ventricular function, electrocardiography, and mechanical synchrony by gated myocardial perfusion imaging.

Background: Depressed left ventricular ejection fraction (LVEF), LV mechanical dyssynchrony (LVMD), and prolonged QTc interval predict poor outcomes in end-stage renal disease (ESRD). Renal transplantation improves mortality in ESRD patients but the effects of transplantation on these indices remain undefined.

Methods: We identified patients with myocardial perfusion imaging (MPI) before and after renal transplantation.

Prognostic value of transient ischemic dilation with regadenoson myocardial perfusion imaging.

Background: Transient ischemic dilation (TID) of the left ventricle seen on myocardial perfusion imaging (MPI) is sometimes used as a marker of severe coronary artery disease. The prognostic value of TID obtained using regadenoson, a selective adenosine A2A receptor agonist, as a stress agent for MPI has not been studied.

Methods: TID ratio was measured using an automated software program on consecutive patients with normal and abnormal perfusion pattern on regadenoson MPI at a single institution.

The prognostic value of left ventricular mechanical dyssynchrony using gated myocardial perfusion imaging in patients with end-stage renal disease.

Background: Prior studies show that left ventricular mechanical dyssynchrony (LVD), measured by gated SPECT myocardial perfusion imaging (MPI), identifies patients with end-stage renal disease (ESRD) at higher risk for all-cause mortality but these were in small number of patients. We sought to assess the interaction between LVD and LV perfusion pattern in risk-stratification of a large sample size of patients with ESRD.

Methods: From the renal transplantation database maintained at the University of Alabama at Birmingham, we identified consecutive patients with ESRD who had gated SPECT MPI between 2003 and 2007.

Comparison of three commercially available softwares for measuring left ventricular perfusion and function by gated SPECT myocardial perfusion imaging.

Background: The three softwares, Quantitative Perfusion SPECT (QPS), Emory Cardiac Toolbox, and 4 Dimension-Myocardial SPECT (4DM) are widely used with myocardial perfusion imaging (MPI) to determine perfusion defect size (PDS) and left ventricular (LV) function. There are limited data on the degree of agreement between these methods in quantifying the LV perfusion pattern and function.

Methods And Results: In 120 consecutive patients who had abnormal regadenoson SPECT MPI with a visually derived summed stress score ≥4, the correlation between the softwares for measurements of PDS, reversible, and fixed defects was poor to fair (Spearman's ρ = 0.

The effect of bone marrow mononuclear stem cell therapy on left ventricular function and myocardial perfusion.

Background: Bone marrow stem cell (BMC) transfer is an emerging therapy with potential to salvage cardiomyocytes during acute myocardial infarction and promote regeneration and endogenous repair of damaged myocardium in patients with left ventricular (LV) dysfunction. We performed a meta-analysis to examine the association between administration of BMC and LV functional recovery as assessed by imaging.

Methods And Results: Our meta-analysis included data from 32 trials comprising information on 1,300 patients in the treatment arm and 1,006 patients in the control arm.

The relationship of left ventricular mechanical dyssynchrony and cardiac sympathetic denervation to potential sudden cardiac death events in systolic heart failure.

Background: Patients with heart failure (HF) are at increased risk for left ventricular (LV) dyssynchrony which is associated with sudden cardiac death (SCD). This study examined the association of LV mechanical dyssynchrony and cardiac sympathetic denervation with potential SCD events in symptomatic patients with HF and reduced ejection fraction (HFrEF).

Methods: Of the 917 HFrEF patients in ADMIRE-HF, 92 experienced adjudicated potential SCD events during a 17 months median follow-up.

Regadenoson: a focused update.

Since its approval by the Food and Drug Administration in 2008, regadenoson has become the most commonly used vasodilator in the United States. Previous reviews have summarized the pre-clinical and clinical data on the use of regadenoson for myocardial perfusion imaging (MPI). Since then, data have emerged on the safety of this agent in special groups of patients such as those with chronic kidney disease, airway disease (asthma and chronic obstructive pulmonary disease), and liver disease.

Reclassification of cardiovascular risk in patients with normal myocardial perfusion imaging using heart rate response to vasodilator stress.

Previous studies have shown that patients with normal vasodilator myocardial perfusion imaging (MPI) findings remain at a greater risk of future cardiac events than patients with normal exercise MPI findings. The aim was to assess improvement in risk classification provided by the heart rate response (HRR) in patients with normal vasodilator MPI findings when added to traditional risk stratification. We retrospectively studied 2,000 patients with normal regadenoson or adenosine MPI findings.

Implications of left bundle branch block in patient treatment.

Left bundle branch block (LBBB) causes an abnormal pattern of cardiac activation and affects regional myocardial function. Although recognition of LBBB on the surface electrocardiogram is straightforward, dissecting its effect on patient treatment and outcome can be more challenging. The altered pattern of cardiac activation in LBBB causes electrical and mechanical ventricular dyssynchrony, influences ischemia detection on the surface electrocardiogram, and affects stress testing and imaging modalities dependent on wall motion and thickening.

Comparison of the prognostic value of normal regadenoson with normal adenosine myocardial perfusion imaging with propensity score matching.

Objectives: The aim of this study was to test the hypothesis that patients with normal regadenoson myocardial perfusion imaging (MPI) have a low rate of cardiac events, similar to patients with normal adenosine MPI.

Background: Regadenoson, a new selective adenosine A(2A) receptor agonist, is now a widely used stress agent for MPI. The low rate of cardiac events in patients with normal adenosine MPI is well-documented, but the prognostic implications of a normal regadenoson MPI have not been examined and compared with those with adenosine.

Effect of ranolazine on left ventricular dyssynchrony in patients with coronary artery disease.

We previously reported that ranolazine improves exercise myocardial perfusion. Ranolazine ameliorates myocardial ischemia by augmenting myocardial blood flow; likely by a reduction in the extravascular compression of small vessels. We hypothesized that ranolazine could improve left ventricular (LV) dyssynchrony as assessed by phase analysis of gated single photon emission computed tomographic myocardial perfusion imaging.

Impact of left ventricular function and the extent of ischemia and scar by stress myocardial perfusion imaging on prognosis and therapeutic risk reduction in diabetic patients with coronary artery disease: results from the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial.

Background: The Bypass Angioplasty Revascularization Investigation 2 Diabetes trial demonstrated similar long-term clinical effectiveness of revascularization (REV) and intensive medical (MED) therapy. Comparisons of post-intervention ischemic burden have not been explored but are relevant to treatment decisions. This study examined differences in 1-year stress myocardial perfusion SPECT (MPS) abnormalities by randomized treatment.

Effect of alcohol septal ablation in patients with hypertrophic cardiomyopathy on left-ventricular mechanical dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging.

Patients with hypertrophic cardiomyopathy (HCM) may have delayed septal activation and left ventricular (LV) mechanical dyssynchrony, and may improve after alcohol septal ablation (ASA). This study used phase analysis of gated SPECT myocardial perfusion imaging (MPI) to evaluate septal activation and LV dyssynchrony in HCM patients pre- and post-ASA. Phase analysis was applied to 28 controls, and 32 HCM patients having rest MPI pre- and post-ASA to assess septal-lateral mechanical activation delay (SLD) and consequent LV dyssynchrony.

The prognostic value of the heart rate response to adenosine in relation to diabetes mellitus and chronic kidney disease.

Background: Myocardial perfusion imaging (MPI) is a useful method for risk assessment in patients with diabetes mellitus (DM) and chronic kidney disease (CKD), but these patients have a residual risk that is not accounted for by MPI. The objective of this study is to determine whether the heart rate response (HRR) to adenosine has an incremental prognostic value to MPI in high-risk patients.

Methods: The study group included 879 (age 61 ± 13 years, 48% women, 58% white, 40% DM, 49% CKD) consecutive patients who underwent adenosine MPI.

A blunted heart rate response to regadenoson is an independent prognostic indicator in patients undergoing myocardial perfusion imaging.

Background: Regadenoson myocardial perfusion imaging (MPI) is a useful method for risk assessment. We hypothesized that the heart rate response (HRR) to regadenoson carries incremental prognostic information to that derived from perfusion pattern and left ventricular (LV) ejection fraction (EF).

Methods And Results: The study population included 1,156 (60 ± 13 years, 46% women, 40% diabetes mellitus, 53% chronic kidney disease) patients.

Left ventricular dyssynchrony in patients with end-stage liver disease.

Background: Limited published data suggested that patients with end-stage liver disease (ESLD) might have "cirrhotic cardiomyopathy," which could have an earlier stage manifested by mechanical dyssynchrony before left ventricular (LV) dysfunction.

Methods And Results: We studied consecutive patients with ESLD who had a stress-gated Tc-99m sestamibi myocardial perfusion imaging between 2008 and 2010 prior to liver transplant. Patients with LVEF < 50%, abnormal perfusion, or QRS ≥ 120 ms were excluded.

The effect of ranolazine on the vasodilator-induced myocardial perfusion abnormality.

Background: We previously reported that ranolazine improved myocardial ischemia during exercise myocardial perfusion imaging (MPI). Since the mechanism of reversible perfusion defects is different in exercise than vasodilator MPI, and based on the mechanism of action of ranolazine, we hypothesized that vasodilator stress MPI may fail to show improvement in myocardial perfusion pattern.

Methods: Patients (n = 18) with known coronary artery disease and with reversible perfusion defects on a clinically indicated vasodilator stress MPI were re-studied 4 weeks after ranolazine (500-1000 mg PO BID) was added to their conventional treatment in an open-label trial.

Relation between heart rate and left ventricular mechanical dyssynchrony in patients with end-stage renal disease.

The effect of heart rate (HR) on left ventricular (LV) mechanical dyssynchrony has not been studied by phase analysis of myocardial perfusion imaging and has yielded conflicting results by echocardiography. We measured indexes of LV dyssynchrony by automated analysis of gated single-photon emission computed tomography in 140 patients with end-stage renal disease (ESRD) and 133 subjects with normal renal function (control group). Patients with abnormal perfusion pattern or QRS duration >120 ms were excluded.

Impact of ischemia on left ventricular dyssynchrony by phase analysis of gated single photon emission computed tomography myocardial perfusion imaging.

Background: There is increasing awareness of the value of phase analysis of gated tomographic myocardial perfusion imaging in assessing left ventricular (LV) dyssynchrony. A concern repeatedly raised in many studies is whether reversible defects in the stress images "ischemia" could affect the phase-derived standard deviation and bandwidth, the two commonly used dyssynchrony indices. We hypothesized that the stress and rest images should provide comparable information because the images are acquired 1 hour after the tracer injection.

Left ventricular mechanical dyssynchrony by phase analysis of gated single photon emission computed tomography in end-stage renal disease.

The presence and degree of left ventricular (LV) dyssynchrony in patients with end-stage renal disease (ESRD) has not been well studied. We hypothesized that these patients would be more likely to have mechanical dyssynchrony than a control cohort. The indexes of LV mechanical dyssynchrony were measured by automated analysis of gated single photon emission computed tomography myocardial perfusion imaging in 290 patients with ESRD and 109 control patients.

Safety of regadenoson in patients with end-stage liver disease.

Background: Regadenoson is a selective A(2A) receptor agonist that is used for vasodilator stress myocardial perfusion imaging (MPI). Since the drug is partially metabolized by the liver, its safety in patients with end-stage liver disease (ESLD) needs to be determined.

Methods And Results: We studied 168 consecutive patients with ESLD who had regadenoson stress gated single photon emission computed tomography MPI between January 2008 and March 2010 before planned orthotopic liver transplantation and compared the hemodynamic responses and safety profile to 168 control patients.

Impact of left ventricular dyssynchrony by phase analysis on cardiovascular outcomes in patients with end-stage renal disease.

Background: Cardiovascular disease is the leading cause of mortality in patients with end-stage renal disease (ESRD). While left ventricular (LV) perfusion pattern and ejection fraction (EF) are important determinant of outcome, the prognostic importance of LV dyssynchrony, which can also be assessed by gated SPECT myocardial perfusion imaging (MPI), has not been well studied in this population.

Methods And Results: The indices of LV mechanical dyssynchrony were measured by automated analysis of gated SPECT MPI in patients with ESRD who were evaluated for transplantation at our institution (2001-2004) and who had coronary angiography within 6 months of the evaluation.