Left Atrial Volume Index at Peak Dobutamine Stress Echocardiography Predicts the Extent of Coronary Artery Disease in Patients with Normal Resting Wall Motion.

BACKGROUND: Left atrial volume indexed to body surface area (LAVI) measured at rest is an independent predictor of adverse cardiovascular outcome at long-term follow-up. We explored the value of LAVI measured at peak dobutamine stress echocardiography (DSE) to identify patients with significant coronary artery disease (CAD) and to discriminate those with multivessel CAD. METHODS: We enrolled 100 patients of 134 consecutively screened patients without resting wall-motion abnormalities (WMA) referred for DSE. LA volume was measured using the biplane area-length method at rest and at peak DSE. Significant coronary stenosis was defined as ≥50% obstruction of ≥1 sizable artery by coronary angiography. RESULTS: The mean age was 57.2 ± 10.6 years (55% males). Fifty-six patients (56%) had significant CAD by coronary angiography: 28 (28%) had single-vessel CAD, and 28 (28%) had multivessel CAD. ROC curve analysis showed that the optimal cutoff value of stress-induced LAVI that best discriminates significant CAD was 30.1 mL/m(2) . Using this cutoff value, significant CAD was identified with a sensitivity of 85.7%, specificity 95.5%, PPV 96%, and NPV 84%. The optimal cutoff value of stress-induced LAVI that best discriminates multivessel CAD was 32.7 mL/m(2) . Using this cutoff value, multivessel CAD was identified with a sensitivity of 88.7%, specificity 96.5%, PPV 97%, and NPV 89%. CONCLUSIONS: In symptomatic patients who underwent DSE for suspected CAD and had no resting WMA, LAVI measured at peak DSE predicted angiographically significant CAD with acceptable sensitivity and high specificity and predicted multivessel CAD with high sensitivity and specificity.

Pre-ejection mitral annular motion velocity responses to dobutamine infusion: A quantitative approach for assessment of myocardial viability.

BACKGROUND: Dobutamine stress echocardiography (DSE) is widely used for detection of myocardial viability. The main limitation of DSE is its subjective interpretation. Assessment of mitral annular motion velocities with tissue Doppler imaging is a simple and quantitative measurement. OBJECTIVE: To determine the relationship between myocardial viability and regional systolic mitral annular motion tissue Doppler velocities responses to dobutamine stress. METHODS: Our study group included 42 patients with previous myocardial infarction referred for coronary angiography and revascularization. We did dobutamine stress tissue Doppler echocardiography (DSTDE) measuring velocities of pre-ejection wave (pre-Ej) and peak ejection wave (Ej) at rest and during low-dose dobutamine infusion. We did follow up echocardiography after 1 month. RESULTS: After exclusion of the normokinetic walls, we analyzed 196 walls. Using receiver operator characteristic ROC curves, the optimal cut-off value for viability assessment was an increase of 1.75 cm/s in pre-ejection velocity during DSTDE (area under the curve 0.70, p < 0.001). On the other hand, the optimal cut-off value for viability assessment was an increase of 1.75 cm/s in ejection velocity during DSTDE (area under the curve 0.613, p = 0.01). The sensitivity, specificity, and total accuracy of the DSTSE (pre-Ej) versus the gold standard for detection of myocardial viability were 66.15%, 67.94%, and 67.35%, respectively. The sensitivity, specificity, and total accuracy of the DTSE (Ej) were 56.92%, 64.12%, and 61.43%, respectively. There was a good correlation between the pre-Ej at 5 ug/kg/min dobutamine infusion and the pre-Ej after revascularization (r = 0.64, p = 0.01) while the correlation with the Ej was moderate (r = 0.50, p = 0.01). CONCLUSION: Viable left ventricular myocardium could be identified easily and quantitatively with pre-ejection mitral annular velocity during dobutamine infusion. The pre-ejection wave during DSTDE showed greater sensitivity and specificity for the prediction of myocardial viability than the ejection wave.

QT Interval and QT Dispersion in Patients Undergoing Hemodialysis: Revisiting the Old Theory.

AIMS: We sought to explore the response of the corrected QT (QTc) interval duration and QT dispersion (QTD) to hemodialysis. METHODS: We enrolled 50 patients with end-stage renal disease undergoing regular hemodialysis. Blood samples were drawn for measurement of serum electrolytes, and a 12-lead ECG was performed to measure the QTc interval duration and QTD, immediately before and just after dialysis sessions. RESULTS: The mean age of the cohort was 42.8 ± 12.2 years (58% males). Both the QTc duration and QTD showed marked variability after hemodialysis. A significant correlation was found between the decrease of both serum potassium and magnesium levels after dialysis and the post-dialysis QTc interval duration, with Pearson's correlation coefficients r = -0.43 and r = -0.34, p = 0.002 and p = 0.01, respectively. Patients with a post-dialysis increase of QTc interval duration had a significantly higher percentage of reduction of serum potassium (p = 0.029), whereas patients with a post-dialysis increase of QTD had a significantly higher percentage of reduction of serum magnesium (p = 0.03). CONCLUSION: Our findings suggest a highly variable response of the QTc interval duration and QTD to hemodialysis. The post-dialysis QTc interval duration inversely correlated with the decrease of both serum potassium and magnesium levels after dialysis.

Relationship between cardiovascular risk as predicted by established risk scores and coronary artery plaque composition as detected by virtual histology intravascular ultrasound analysis: the PREDICT pilot study.

AIMS: Identification of subclinical high-risk plaques is potentially important because they may have greater likelihood for rupture and thrombosis. The aim of this study was to assess the relationship between in vivo coronary artery plaque composition using intravascular ultrasound virtual histology (IVUS-VH) and cardiovascular risk as predicted by clinical risk scores in patients with non-obstructive stable coronary artery disease. METHODS AND RESULTS: Forty patients undergoing elective coronary angiography revealing <50% coronary artery stenoses were prospectively included. Of these, 38 (29 men; mean age 65+/-9 years) underwent a satisfactory IVUS-VH investigation of the affected vessel. For each patient, the 10-year risk of cardiovascular events was calculated using the Framingham and the SCORE-Deutschland risk prediction algorithms, and compared to the VH-derived plaque composition at the site of the minimal lumen area (MLA). For both algorithms, patients at low estimated risk of events showed more fibrous tissue percentages than patients at high risk (67.4+/-9.7% versus 53.2+/-10.4% for the SCORE algorithm, and 65.6+/-13.4% versus 51.5+/-9.4% for the Framingham algorithm, p=0.002 and p=0.004, respectively). Plaques of patients with higher risk showed a non-significantly higher necrotic core percentage. For the SCORE algorithm, dense calcium percentage was higher in patients with high risk compared to patients with low risk (13.9+/-10.4% versus 4.9+/-4.9%, p=0.008). The prevalence of IVUS-derived thin cap fibro-atheromas at the MLA site was higher in patients at high risk (80% of lesions in patients at high risk using the SCORE algorithm and 92% of lesions in patients at high risk using the Framingham algorithm), whereas patients at low risk had more stable plaque phenotypes (p=0.002 and 0.003 for the SCORE and Framingham algorithms, respectively). CONCLUSIONS: In vivo plaque composition and morphology assessed by IVUS-VH were related to the cardiovascular risk predicted by established risk prediction algorithms in patients with non-obstructive coronary artery disease, suggesting a link between the higher risk for future events and the VH-derived plaque morphology.

Relationship between systolic pulsed wave tissue Doppler parameters and both invasive and noninvasive reperfusion criteria in patients with acute anterior myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: Despite normal flow in the infarct-related artery after primary percutaneous coronary intervention, patients may not achieve adequate perfusion at the tissue level. We examined the applicability of pulsed wave tissue Doppler (PTD) in detection of successful myocardial reperfusion. METHODS: In all, 24 patients with anterior infarction were enrolled. All patients underwent primary percutaneous coronary intervention. PTD was performed 2 days and 2 weeks after percutaneous coronary intervention, and recorded from 6 different locations at the mitral annular level. Peak systolic wave was determined and was related to various markers of reperfusion. RESULTS: Systolic PTD measurement in patients with myocardial blush grades 0 to 1 significantly deteriorated between second day and second week (6.5 +/- 1.1-5.3 +/- 1.1 for the anterior wall, and 6.2 +/- 1.3-5.3 +/- 1 for the anterior septum, P < .05 and P < .01, respectively). Systolic PTD parameters improved significantly in patients with myocardial blush grades 2 to 3 (6 +/- 1.5-7.2 +/- 2 for the anterior wall, and 5.4 +/- 1.1-7.1 +/- 1.6 for the anterior septum, P < .05 and P < .01, respectively). A significant relationship was observed between PTD and thrombolysis in myocardial infarction flow, S-T resolution, and creatine phosphokinase peaking. PTD recovery was highly sensitive and specific for the detection of left ventricular function recovery. CONCLUSION: We demonstrated a significant relationship between systolic PTD parameters and invasive and noninvasive markers of reperfusion. Larger studies are needed to confirm these results.