Chronic Kidney Disease as a Possible Predictor of Left Atrial Thrombogenic Milieu Among Patients with Nonvalvular Atrial Fibrillation.

Patients with chronic kidney disease (CKD) experiencing atrial arrhythmia are hypothesized to have elevated CHADS2 and CHA2DS2-VASc scores, thereby predisposed to left atrial (LA) thrombus formation and subsequent thromboembolism. We examined possible association of LA thrombogenic milieu (TM) with CKD in patients with nonvalvular atrial fibrillation. A total of 581 patients (181 women; mean age, 67 years) who underwent transesophageal echocardiography were examined. Patients were divided into 4 groups based on the estimated glomerular filtration rate (eGFR) (ml/min/1.73 m2): eGFR ≥90 (n = 29), 60≤ eGFR <90 (n = 329), 30≤ eGFR <60 (n = 209), and eGFR <30 (n = 14). TM was defined as the presence of LA thrombus, dense spontaneous echo contrast, or LA appendage velocity ≤25 cm/s. Of 581 patients, 147 (25%) had TM. The prevalence of TM increased with decreasing eGFR (4%, 18%, 36%, and 86% for each group, p <0.001). Similar trends were observed for some of the clinical and echocardiographic variables including CHA2DS2-VASc score and LA size. Multivariate logistic regression analysis revealed that every 10 ml/min/1.73 m2 decrement in eGFR was a significant independent correlate of TM (odds ratio 0.80, p = 0.005), along with nonparoxysmal atrial fibrillation (AF) (odds ratio 0.45, p = 0.004), higher CHA2DS2-VASc score (odds ratio 1.24, p = 0.012), every 5 ml/m2 increment in LA volume index (odds ratio 1.57, p <0.001), and every 10% decrement in left ventricular ejection fraction (odds ratio 0.51, p <0.001). In conclusion, CKD may be a significant risk factor for LA thrombus formation in patients with nonvalvular atrial fibrillation.

Association between Left Ventricular Postsystolic Shortening and Diastolic Relaxation in Asymptomatic Patients with Systemic Hypertension.

BACKGROUND: Few data have existed on myocardial postsystolic shortening (PSS) accounting for left ventricular (LV) diastolic dysfunction in systemic hypertension. We examined this relationship, along with clinical and other cardiac parameters, in asymptomatic patients with hypertension. METHODS: We analyzed 104 patients on pharmacological treatment for hypertension who had no signs or symptoms of heart failure for conventional and speckle tracking echocardiography. The sum of the postsystolic index for multiple LV segments (total PSI) and global longitudinal strain (GLS) was computed and used as measures for global PSS and myocardial systolic function, respectively. The tissue Doppler e' and the speckle tracking-derived global strain rate during early diastole (e'sr) were obtained as indicators of LV relaxation. The circumferential end-systolic stress was also determined noninvasively and substituted for a measure of myocardial afterload. RESULTS: Main variables that correlated with the e' and e'sr were shown to be age, LV mass index, left atrial volume index, GLS, and the total PSI. Multivariate analysis including gender, circumferential end-systolic stress, and the use of calcium channel blockers as possible covariates revealed that age (ß = -0.29, P = 0.002), total PSI (ß = -0.26, P = 0.008), and LV mass index (ß = -0.25, P = 0.017) were significant independent determinants of e' and that age (ß = -0.34, P < 0.001) and GLS (ß = -0.28, P = 0.006) were of e'sr. CONCLUSIONS: Our findings indicate that while depending on the degree of GLS, PSS may affect diastolic relaxation in patients with asymptomatic, but treated, hypertensive patients.

Left ventricular mechanical discoordination in nonischemic hearts: relationship with left ventricular function, geometry, and electrical dyssynchrony.

BACKGROUND: Mechanical discoordination (MD) is known as a myocardial deformation of opposite strain during ejection, reflecting dyssynchronous electrical activation. We used speckle tracking echocardiography to examine the relationship between MD, left ventricular (LV) function and geometry, as well as electrical dyssynchrony in various nonischemic hearts. METHODS AND RESULTS: We examined 131 subjects (left bundle branch block [LBBB] 27; dilated cardiomyopathy [DCM] without LBBB 33; LV hypertrophy 28; and normal heart 43) using circumferential strain rate analysis. Integration of positive (stretch) and negative (shortening) components during the ejection time was obtained in the mid-ventricular level for 6 myocardial segments, and MD was quantified as the stretch to shortening ratio (SSR). The SSR in the septal region (anteroseptal and septal segments) was markedly elevated in the LBBB and DCM groups compared with the other groups. With univariate analysis, SSR over the septal region was found to be correlated with QRS duration, LV end-diastolic dimension, and LV ejection fraction. Multivariate analysis revealed that QRS duration and LV ejection fraction were significant independent determinants of SSR for the septal region. CONCLUSIONS: In nonischemic hearts, electrical dyssynchrony and LV dysfunction may contribute synergistically to MD in the septal region. The finding that non-LBBB DCM patients exhibited a certain amount of SSR may provide new insight into therapeutic strategies for cardiac resynchronization therapy.

Novel attenuation correction of SPECT images using scatter photopeak window data for the detection of coronary artery disease.

BACKGROUND: Attenuation correction using segmentation with scatter and photopeak window data (SSPAC) may enable evaluation of the attenuation map in a patient-specific manner without the need for additional radiation exposure and more acquisition time. We examined the feasibility of SSPAC and compared the sensitivity, specificity, and accuracy of this new correction method with that of conventional non-corrected myocardial perfusion single-photon emission computed tomography (SPECT) among patients with suspected or diagnosed coronary artery disease. METHODS AND RESULTS: One hundred sixty-one patients who underwent both (99m)Tc-tetrofosmin stress/rest SPECT examination and invasive coronary angiography were enrolled in the study. Data from the SSPAC-corrected and non-corrected methods were analyzed quantitatively using summed stress scores. Attenuation maps were obtained successfully for 150 (93%) of the patients. The SSPAC-corrected and non-corrected methods accurately predicted coronary artery disease defined as >50% luminal stenosis verified by coronary artery angiography and/or prior myocardial infarction, for 91% and 77% patients, respectively (P < .05). For diagnosis of coronary artery disease, SSPAC improved sensitivity in the left anterior descending artery territory and specificity in the right coronary artery territory. CONCLUSIONS: Attenuation correction with SSPAC may be a feasible method of correction for myocardial perfusion SPECT and in some cases may provide better accuracy for diagnosing coronary artery disease.

Association between presystolic ventricular flash and left ventricular functional recovery after cardiac resynchronization therapy.

The presence of septal flash (SF), an early inward/outward motion of the ventricular septum, has been reported to predict a fair response to cardiac resynchronization therapy (CRT) in patients with heart failure. Using speckle tracking echocardiography, we investigated whether the extent of pre-CRT SF was associated with left ventricular (LV) functional recovery after CRT device implantation. Fifteen patients with left bundle branch block with a mean LV ejection fraction of 23 ± 9% were enrolled in this study. The extent of presystolic ventricular flash (PSVF), which was defined if there was a peak in the radial strain curve in the preejection period, was semiquantified by counting the number of PSVF-positive segments. Patients underwent radial strain analysis before and between 3 and 6 months after CRT. After CRT device implantation, LV end-diastolic and end-systolic volumes were decreased, LV ejection fraction was increased, and LV filling time corrected by RR interval was increased. The number of PSVF-positive segments at baseline showed a graded association with improvement in both LV ejection fraction and LV filling time. In conclusion, the finding that a larger number of PSVF-positive segments before CRT predicted fair LV functional recovery after CRT suggests that PSVF may represent a substrate that is amenable to functional response to CRT.