Prevalence and predictors of mechanical dyssynchrony as defined by phase analysis in patients with left ventricular dysfunction undergoing gated SPECT myocardial perfusion imaging.

Background: A novel method to quantify dyssynchrony using phase analysis of single-photon emission computed tomography (SPECT) myocardial perfusion imaging has been developed. We sought to determine the prevalence of SPECT-derived mechanical dyssynchrony, and we report clinical variables which predict mechanical dyssynchrony in patients with left ventricular dysfunction.

Methods: We used a count-based Fourier analysis method to convert the regional myocardial counts from discrete frames per cardiac cycle into a continuous thickening function which allows resolution of the phase of the onset of myocardial contraction.

Use of phase analysis of gated SPECT perfusion imaging to quantify dyssynchrony in patients with mild-to-moderate left ventricular dysfunction.

Background: CRT has been shown to be beneficial in the majority of patients with NYHA class III-IV symptoms, prolonged QRS duration, and an EF < or =35%. The use of imaging modalities to quantify dyssynchrony may help identify patients who may benefit from CRT, but do not meet current selection criteria. We hypothesize that patients with mild-to-moderate LV dysfunction have significant degrees of mechanical dyssynchrony.

Left ventricular mechanical dyssynchrony as assessed by phase analysis of ECG-gated SPECT myocardial perfusion imaging.

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. The traditional criteria to select patients for CRT (NYHA class III or IV, depressed left ventricular (LV) ejection fraction, and prolonged QRS duration) result in at least 30% of the selected patients with no response to CRT. Recent studies with tissue Doppler imaging (TDI) have shown that the presence of LV dyssynchrony is an important predictor for response to CRT.

Evaluation of mechanical dyssynchrony and myocardial perfusion using phase analysis of gated SPECT imaging in patients with left ventricular dysfunction.

Background: Using phase analysis of gated single photon emission computed tomography (SPECT) imaging, we examined the relation between myocardial perfusion, degree of electrical dyssynchrony, and degree of SPECT-derived mechanical dyssynchrony in patients with left ventricular (LV) dysfunction.

Methods And Results: We retrospectively examined 125 patients with LV dysfunction and ejection fraction of 35% or lower. Fourier analysis converts regional myocardial counts into a continuous thickening function, allowing resolution of phase of onset of myocardial thickening.

Emerging role of myocardial perfusion imaging to evaluate patients for cardiac resynchronization therapy.

Left ventricular (LV) dyssynchrony is an increasingly important consideration in the evaluation and management of patients with LV systolic dysfunction. Improvements in clinical status, LV remodeling, and survival have been demonstrated with the use of cardiac resynchronization therapy (CRT). The current selection criteria for patients who undergo CRT include the presence of severe LV dysfunction, significant heart failure symptoms, and electrical dyssynchrony on surface electrocardiography (wide QRS interval).

Evaluation of combined cardiac positron emission tomography and coronary computed tomography angiography for the detection of coronary artery disease.

Background: Coronary artery disease is a leading cause of morbidity and mortality. Multiple imaging modalities are used to screen for significant coronary artery disease. We report the concordance between coronary computed tomography angiography (CTA) and stress cardiac positron emission tomography (CPET) to detect significant coronary artery disease, the feasibility of combining CTA and CPET in one diagnostic test, and the ability of CTA and CPET to detect significant coronary artery disease by comparison with cardiac catheterization.

Repeatability and reproducibility of phase analysis of gated single-photon emission computed tomography myocardial perfusion imaging used to quantify cardiac dyssynchrony.

Background: A novel method to quantify dyssynchrony has been developed using phase analysis of gated single-photon emission computed tomography perfusion imaging. We report on the effect of variability in image reconstruction on the phase analysis results (repeatability) and on the interobserver and intraobserver reproducibility of the technique.

Methods: Phase standard deviation (SD) and bandwidth are phase indices that quantify dyssynchrony.

Assessment of left ventricular mechanical dyssynchrony by phase analysis of ECG-gated SPECT myocardial perfusion imaging.

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have shown that the presence of LV dyssynchrony is an important predictor of response to CRT.

Evaluation of left ventricular mechanical dyssynchrony as determined by phase analysis of ECG-gated SPECT myocardial perfusion imaging in patients with left ventricular dysfunction and conduction disturbances.

Background: Cardiac resynchronization therapy (CRT) is approved for the treatment of patients with advanced systolic heart failure and evidence of dyssynchrony on electrocardiograms. However, a significant percentage of patients do not demonstrate improvement with CRT. Echocardiographic techniques have been used for more accurate determination of dyssynchrony.

Hemolytic anemia: a rare but potentially serious adverse effect of captopril.

Captopril was the first oral angiotensin-converting enzyme (ACE) inhibitor available and, as such, has been extensively studied and in clinical use for many years. Several studies have defined captopril's efficacy in the treatment of congestive heart failure (CHF) as well as determined its safety profile. The most common adverse hematologic reactions associated with captopril use include neutropenia and agranulocytosis.

The effect of foot placement on sit to stand in healthy young subjects and patients with hemiplegia.

Objective: To determine the effect of altering the foot placement of the dominant limb in young healthy subjects and the uninvolved limb of subjects with hemiplegia on their ability to perform sit to stand (STS).

Design: Controlled biomechanical experiment.

Setting: Research laboratory of a university health science center.