Mirza Husic

Changes in the Doppler myocardial performance index during dobutamine echocardiography: association with neurohormonal activation and prognosis after acute myocardial infarction

Objectives: To test whether an increase in Doppler myocardial performance index (MPI) during dobutamine stress echocardiography, reflecting deterioration of overall left ventricular function, is associated with increased N-terminal pro-brain natriuretic peptide (NT-pro-BNP) concentration and provides prognostic information beyond conventional systolic wall motion analysis after acute myocardial infarction (AMI). Design: Prospective, observational study. Methods: Dobutamine–atropine stress echocardiography (DASE) and NT-pro-BNP were assessed five days after AMI in 109 consecutive patients. MPI was measured at rest and at low-dose (10 μg/kg/min) and peak dobutamine infusion (⩽ 40 μg/kg/min with or without atropine). Main outcome measures: End point was a composite of cardiac death or readmission for heart failure or reinfarction. Results: In 35 patients (32%), MPI increased at low-dose DASE. This was associated with higher NT-pro-BNP concentrations (β  =  0.30, p  =  0.004). During a mean follow up of 27 (SD 7) months, 8 patients died of cardiac causes and 15 patients were readmitted for heart failure or reinfarction. On Cox regression analysis, an increase in MPI at low-dose DASE (p  =  0.02) was an independent predictor of cardiac events. In contrast, traditional wall motion analysis during DASE provided no additional prognostic information. Conclusions: An increase in MPI at low-dose DASE, reflecting early deterioration of overall left ventricular function, is associated with raised NT-pro-BNP concentration and provides prognostic information beyond conventional stress echocardiographic data after AMI.

Relation of early changes of QT dispersion to changes in left ventricular systolic and diastolic function after a first acute myocardial infarction.

Objective : To describe the relation between changes of left ventricular systolic and diastolic function and changes of QT dispersion (difference in duration between longest and shortest QT interval) following acute myocardial infarction. Design : QT dispersion was determined at admission, hospital discharge, and 1 and 3 months following myocardial infarction in 64 consecutive 1-year survivors. Patients were divided into Group A where QT dispersion was < 52 ms at all recordings or initially > 52 ms but decreased during follow-up, and Group B where QT dispersion remained increased S 52 ms at all measurements. Doppler-Echocardiography was carried out on day 1, day 5, and after 1, 3, and 12 months. Results : In 26 patients QT dispersion remained increased S 52 ms during the first 3 months after infarction. Among these a significant increase of end-systolic volume was seen whereas low or rapid normalized QT dispersion was associated with a significant decrease of ventricular volumes. After 1 year end-systolic (70 - 32 ml vs 49 - 16 ml, p = 0.006) and end-diastolic volumes (138 - 41 ml vs 105 - 22 ml, p = 0.001) were higher in Group B. In a multivariate model Group B was significantly related to an increase of end-diastolic volume ( p = 0.01). In Group A diastolic function improved in eight patients and in two it deteriorated, whereas improvement was seen in one patient and deterioration in nine patients from Group B ( p < 0.01). Conclusion : Following myocardial infarction low QT dispersion is associated with preserved left ventricular function, whereas persistently increased dispersion is associated with left ventricular dilation and deterioration of diastolic function.

Impact of a motion correction algorithm on image quality in patients undergoing CT angiography: A randomized controlled trial

AIMS To investigate the motion correction algorithm Snapshot-Freeze (SSF) compared to standard reconstruction (STD) in patients randomized to receive beta-blockers (BB) or no beta-blockers (non-BB) before coronary CT, and to investigate if SSF can replace BB. METHODS One hundred and forty patients scheduled for coronary CT were randomized. All images were reconstructed by the SSF and STD algorithms. Image quality was evaluated according to Likert score (1: excellent, 2: good, 3: adequate, 4: non-diagnostic) and presence of artifacts was noted. RESULTS Images from 64 patients in the BB group (mean HR 56±4bpm) and 51 patients in the non-BB group (mean HR 67±7bpm) were analyzed. Twenty five patients were excluded because of tachycardia, bradycardia or reconstruction errors in SSF. SSF increased the number of excellent images in both groups compared to the STD algorithm (BB: 59% vs.44%; non-BB: 25% vs. 8%), but the number of non-diagnostic images was not significantly reduced. SSF reduced motion artifacts (BB: 11% vs. 31%; non-BB: 49% vs. 75%), but despite this reduction, motion artifacts in non-BB were still more frequent compared to the BB group analyzed by STD (49% vs. 31%). CONCLUSION SSF improves image quality and reduces motion artifacts, but does not compensate for the absence of BB.