The American journal of cardiology
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This study evaluated the influence of coronary artery bypass grafting on heart rate turbulence (HRT) parameters assessed during 1-year follow-up in patients with coronary artery disease. HRT and heart rate variability (HRV) parameters significantly worsened 3 months after surgery. ⋯ Our results show that there is a marked attenuation of HRT parameters in the early postoperative period, indicating an impairment of baroreflex sensitivity after coronary artery bypass grafting. Concomitant depression of HRV parameters points to dysfunction of the autonomic nervous system, provoked by perioperative attenuation, as a potential underlying cause of impaired baroreflex response.
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The noninvasive differentiation between ischemic and nonischemic cardiomyopathy is frequently difficult. We examined the clinical value of stress electrocardiographic gated (ECG-gated) single-photon emission computed tomography (SPECT) to identify ischemic cardiomyopathy and detect coronary artery disease (CAD) in 164 patients without known CAD, ejection fraction < or =40% by ECG-gated SPECT, and subsequent coronary angiography. Summed stress, rest, and difference scores were measured from the SPECT studies, and regional wall motion variance was calculated from the ECG-gated images. ⋯ If reversibility was also taken into account (summed stress score >8, regional wall motion variance >0.114, or summed difference score >0), sensitivity further increased to 94% (95% CI 88 to 100) and specificity decreased to 32% (95% CI 23 to 41). For detection of any CAD, the combined approach using stress perfusion, reversibility, and region of wall motion had a sensitivity of 94% (95% CI 89 to 99) and a specificity of 45% (95% CI 35 to 57). Therefore, ECG-gated SPECT is very sensitive for detection of ischemic cardiomyopathy and CAD among patients with moderate to severe systolic dysfunction.