Zbigniew Tabor

Prediction of infarct size by speckle tracking echocardiography in patients with anterior myocardial infarction.

BackgroundSpeckle tracking echocardiography (STE) is based on tracing of pixel groups in grayness scale for the quantitative measurement of myocardium strain and myocardium strain rate. Recent data suggest that evaluation of STE could be a tool for myocardial function assessment similar to MRI. AimTo assess the predictive value of STE for the evaluation of infarct size in patients with anterior ST-elevation myocardial infarction (STEMI). Materials and methodsWe enrolled 39 patients with the first anterior wall STEMI (mean age 59±10 years, 29 men). All patients were treated with a primary percutaneous coronary intervention, and the time from the symptom onset to reperfusion was 298±195 min. Left ventricular ejection fraction assessed in three-dimensional echocardiography was 47±9%. On the day of discharge, STE was performed to determine the average global value of peak longitudinal strain (GLS) of 16 myocardial segments. The average value of the peak longitudinal strain for nine segments supplied by the left anterior descending artery anterior wall global longitudinal strain was assessed separately. Infarct size was assessed 3 months after STEMI by MRI using late gadolinium enhancement, and a large infarct was defined as at least 20% left ventricle myocardium covered by the scar. ResultsAccording to the results of MRI, we defined two groups: 22 patients with a large infarct (≥20%, group A) and 17 patients with a small infarct (<20%, group B). There were no differences between both groups in the demographics and cardiovascular risk factors. There was a significant correlation between GLS and the degree of myocardium injury assessed by MRI (r=0.62, P=0.001). The correlation was higher for anterior wall global longitudinal strain (r=0.68, P=0.001). With the receiver operating characteristic curve, the cut-off point for GLS was calculated (−12.3), which defined a large infarct with 82% sensitivity and 87% specificity (area under the curve=83). For segments supplied by the left anterior descending artery, the cut-off value for the prediction of a large infarct was −11.5 (sensitivity 90%, specificity 73%, area under the curve=84). ConclusionSTE seems to be a very promising tool in the prediction of infarct size in patients with anterior STEMI.

QT/RR relationship in patients after remote anterior myocardial infarction with left ventricular dysfunction and different types of ventricular arrhythmias.

Background: QT/RR relationship was found to be both rate‐dependent and rate‐independent, what suggests the influence of autonomic drive and other not‐autonomic related factors on it. The steeper QT/RR slope in patients after acute myocardial infarction (MI) was described, but the relationship to ventricular arrhythmias is unknown. The purpose of this study was to calculate differences in QT/RR relationship in patients after remote anterior MI with left ventricular dysfunction and different types of ventricular arrhythmias.

Microvascular damage prevention with thrombaspiration during primary percutaneous intervention in acute myocardial infarction.

BackgroundDespite rapid and complete recanalization of infarct-related artery with percutaneous coronary intervention, microvascular integrity is not often preserved. Several mechanical devices have been proposed to prevent distal embolization, but the impact of these devices on myocardial perfusion remains controversial. AimThe aim of our study was to assess microvascular damage reduction with quantitative myocardial contrast perfusion echocardiography among patients with the first anterior acute myocardial infarction treated with thromboaspiration during percutaneous coronary intervention. MethodsForty-two patients (57.4±10 years, 74% males) with first anterior acute myocardial infarction were randomized 1 : 1 to intracoronary thromboaspiration followed by stenting, or to a conventional strategy of stenting alone. Echocardiogram and quantitative myocardial contrast echocardiography were performed 7 days and 1 month later, respectively. Parameter A (reflecting myocardial blood volume), &bgr; (reflecting velocity, myocardial blood flow), and product of A and &bgr; as indicator of myocardial blood flow were analyzed. For each patient mean value of A, &bgr;, and A×&bgr; from all dysfunctional segments was calculated. ResultsThe study population was divided into two groups: thromboaspiration (group I, 19 patients) and stenting alone (group II, 23 patients). No difference was observed between the both groups in demographic, clinical, echocardiographic, and angiographic data. Parameter A and A×&bgr; were significantly higher in group I than in group II: 8.58±2.54 versus 5.29±3.18 dB (P<0.001) and 5.29±3.73 versus 2.78±3.03 dB/s (P<0.001). Multivariate step-down regression analysis revealed that only thromboaspiration before stenting and lower maximum troponin I have been associated with viability preservation in infarcted region. ConclusionThromboaspiration before stenting in patients with the first anterior myocardial infarction improves myocardial perfusion at the tissue level assessed by quantitative myocardial contrast echocardiography.

Impact of left ventricular remodeling on ventricular repolarization and heart rate variability in patients after myocardial infarction treated with primary PCI: prospective 6 months follow-up.

Background: The relation between postinfarction left ventricle remodeling (LVR), autonomic nervous system and repolarization process is unclear. Purpose of the study was to assess the influence of LVR on the early (QTpeak) and late (TpeakTend) repolarization periods in patients after myocardial infarction (MI) treated with primary PCI. The day‐to‐night differences of repolarization parameters and the relation between QT and heart rate variability (HRV) indices, as well left ventricle function were also assessed.

Heart rate turbulence in postinfarction patients with history of malignant ventricular arrhythmias

UNLABELLED In the study, there has been retrospectively analyzed heart rate turbulence in postinfarction patients. The cohort of 158 patients consisted of 94 patients with documented ventricular tachycardia and/or ventricular fibrillation (VT/VF) and 64 patients without history of VT/VF. Turbulence onset and slope were calculated from Holter recordings, and left ventricle ejection fraction (LVEF) ≤35% was regarded as severe left ventricle dysfunction. Study groups were similar in age and sex. Left ventricle ejection fraction was lower in the VT/VF group (P < .005). Patients with VT/VF had higher turbulence onset (-0.22% ± 1% vs -0.8% ± 2%; P = .005) and lower turbulence slope (2.6 ± 1.9 vs 4.1 ± 3.5 milliseconds per RR interval; P = .01). These trends were observed in patients with LVEF >35% but not in subjects with LVEF ≤35%. Diabetes mellitus, previous coronary artery bypass graft, and amiodarone therapy have diminished the intergroup differences significantly. CONCLUSIONS Heart rate turbulence is diminished in postinfarction patients with a history of malignant ventricular arrhythmias. It seems to separate subjects at arrhythmic risk among patients with relatively preserved left ventricle function, but it is diminished in patients with previous coronary artery bypass graft, diabetes, and amiodarone therapy.

Dynamicity of Early and Late Phases of Repolarization in Patients with Remote Anterior Myocardial Infarction: The Interlead Differences

Background: Repolarization dynamicity (QT/RR) is supposed to be a prognostic marker in post‐MI patients. However, data on the relationships between early and late phases of QT and RR intervals (QT peak/RR and T peak–T end/RR) are insufficient, and which ECG lead should be used for the analysis is unclear. We analyzed repolarization dynamicity in patients after anterior MI with and without VT/VF history using two leads of Holter recordings‐ modified V5 and V3. The daytime and nighttime periods were also analyzed.

Microvolt T-wave alternans predicts cardiac events after acute myocardial infarction in patients treated with primary percutaneous coronary intervention

BACKGROUND Current risk stratification after acute myocardial infarction (MI) depends on left ventricular ejection fraction. Microvolt T-wave alternans (MTWA) is one of promising markers to predict cardiac events in patients after acute MI treated according to current guidelines. METHODS In this single center study, 112 consecutive patients with the first anterior ST-elevation MI undergoing PCI <12 hours from symptom onset, were enrolled prospectively. Demographics, established risk factors, myocardial contrast echocardiography (MCE) perfusion, index event data and MTWA were assessed. Composite cardiac events (CCE) defined as: death, recurrent MI, sustained ventricular tachycardia (sVT) or readmission for acute heart failure (HF) were recorded during follow-up. RESULTS MTWA test was negative in 76, positive in 18 and undetermined in 7 patients. MTWA negative patients had significantly higher LVEF at 30 days. At 4 years, 26 patients experienced CCE (10 died, 2 reinfarcted and 14 HF events). In multivariate Cox proportional hazard model maximum CKMB, non-negative MTWA and reduced LVEF made the best model to predict CCE. Four year CCE free survival was 77% and was significantly lower for non-negative MTWA (94% vs 50%, p<0.003). CONCLUSIONS Non-negative MTWA with infarct size index and reduced LVEF could predict cardiac events in patients with anterior STEMI treated with primary PCI. MTWA non-negative patients have significantly worse outcome.