Computed Tomography Myocardial Perfusion Imaging With Transesophageal Atrial Pacing Stress Test in Patients With Borderline Stenoses in the Coronary Arteries: a Comparison With Fractional Flow Reserve.

Aim      To evaluate the diagnostic accuracy of cardiac perfusion computed tomography (PCT) with transesophageal electrocardiostimulation (TE ECS) for detection of ischemia in patients with borderline coronary stenosis (50-75 %) compared to measurements of fractional flow reserve (FFR).Material and methods  The study included 25 patients with borderline (50-75 %) coronary stenosis as per data of computed tomography angiography (CTA) or coronary angiography (CAG). Later the patients underwent invasive measurement of FFR and cardiac PCT on a 320-row detector tomograph in combination with the TE ECS stress test.  FFR values <0.8 indicated the hemodynamic significance of stenosis. Myocardial perfusion was evaluated visually based on consensus of two experts.Results All patients completed the study protocol. Cardiac pacing duration was 6 min for all patients. Four patients required intravenous administration of atropine sulphate. PCT with TE ECS detected significant for FFR stenoses with sensitivity, specificity, and predictive value of a positive result and predictive value for a negative result of 47, 90, 87, and 53 %, respectively.Conclusion      PCT with TE ECS in combination with CTA can be considered as an informative method for simultaneous evaluation of the condition of coronary arteries and detection of myocardial ischemia. This method is particularly relevant for assessing the hemodynamic significance of borderline coronary stenoses.

Correlations between clinical and laboratory findings and prognostically unfavorable CMR-based characteristics of acute ST-elevation myocardial infarction.

Aim To evaluate factors associated with unfavorable predictive characteristics of ST-segment elevation acute myocardial infarction (STEMI) as per data of magnetic resonance imaging (MRI).Material and methods The study included 52 patients with STEMI who underwent a primary percutaneous coronary intervention (pPCI). Contrast-enhanced cardiac MRI was performed for all patients on days 3-7. Delayed contrast-enhancement images were used for assessing infarct size, presence of microvascular obstruction (MVO) areas, and heterogeneity zones.Results Multifactorial analysis showed that independent predictors of MVO were type 2 diabetes mellitus (DM) (relative risk (RR) 1.9, confidence interval (CI): 1.1-3.26, р=0.012), increased levels of brain natriuretic peptide (BNP) (RR 2.04, CI: 1.39-2.99, р=0.004) and creatine kinase (CK) (RR 2.06, CI: 0.52-0.80, р=0.02), and infarct size (IS) (RR 2.81; CI: 1.38-5.72, р=0.0004). Construction of ROC curves provided the quantitative values of study indexes, at which the risk of MVO increased. For BNP, this value was ≥276 pg/ml (sensitivity, 95.7 %; specificity, 37.9 %); for CK ≥160 U/l (sensitivity, 74.1 %; specificity, 61.9 %); and for IS ≥18.8 % (sensitivity, 79.3 %; specificity, 69.6 %). Correlation analysis of risk factors for increased size of the heterogeneity zone showed significant correlations of the heterogeneity zone size with older age of patients (r=0.544, р<0.0001), higher concentrations of BNP (r=0.612, р<0.0001), CK (r=0.3, 95 % CI: 0.02-0.5, р=0.03), and C-reactive protein (CRP) (r=0.59, CI: 0.3-0.7, р=0.0001). Increased levels of CK (r=0.53, 95 % CI: 0.29-0.70, р=0.0001) and BNP (r=0.55, 95 % CI: 0.28-0.70, p=0.0003) significantly correlated with increased IS.Conclusion Risk of MVO formation as per MRI data increased in the presence of type 2 DM and IS ≥18.8 % (р<0.05). Formation of MVO in patients with STEMI was associated with increased levels of BNP ≥276 pg/ml and CK ≥160 U/l (р<0.05). Increased levels of BNP, CK, and CRP were associated with a larger size of heterogeneity zone according to data of the correlation analysis. A larger heterogeneity zone was more typical for older patients. Increased levels of CK and BNP were also associated with larger IS. The correlation analysis did not show any significant interactions between the size of heterogeneity zone, IS, and MVO size (р>0.05).

[Computed Tomography Coronary Angiography Possibilities in "High Risk" Plaque Identification in Patients with non-ST-Elevation Acute Coronary Syndrome: Comparison with Intravascular Ultrasound].

Aim      To evaluate structural characteristics of atherosclerotic plaques (ASP) by coronary computed tomography arteriography (CCTA) and intravascular ultrasound (IVUS).Material and methods  This study included 37 patients with acute coronary syndrome (ACS). 64-detector-row CCTA, coronarography, and grayscale IVUS were performed prior to coronary stenting. The ASP length and burden, remodeling index (RI), and known CT signs of unstable ASP (presence of dot calcification, positive remodeling of the artery in the ASP area, irregular plaque contour, presence of a peripheral high-density ring and a low-density patch in the ASP). The ASP type and signs of rupture or thrombosis were determined by IVUS.Results The IVUS study revealed 45 unstable ASP (UASP), including 25 UASP with rupture and 20 thin-cap fibroatheromas (TCFA), and 13 stable ASP (SASP). No significant differences were found between distribution of TCFA and ASP with rupture among symptom-associated plaques (SAP, n=28) and non-symptom-associated plaques (NSAP, n=30). They were found in 82.1 and 73.3 % of cases, respectively (p>0.05), which indicated generalization of the ASP destabilization process in the coronary circulation. However, the incidence of mural thrombus was higher for SAP (53.5 and 16.6 % of ASP, respectively; p<0.001). There was no difference between UASP and SASP in the incidence of qualitative ASP characteristics or in values of quantitative ASP characteristics, including known signs of instability, except for the irregular contour, which was observed in 92.9 % of UASP and 46.1 % of SASP (p=0.0007), and patches with X-ray density ≤46 HU, which were detected in 83.3 % of UASP and 46.1 % of SASP (р=0.01). The presence of these CT criteria 11- and 7-fold increased the likelihood of unstable ASP (odd ratio (OR), 11.1 at 95 % confidence interval (CI), from 2.24 to 55.33 and OR, 7.0 at 95 % CI, from 5.63 to 8.37 for the former and the latter criterion, respectively).Conclusion      According to IVUS data, two X-ray signs are most characteristic for UASP, the irregular contour and a patch with X-ray density ≤46 HU. The presence of these signs 11- and 7-fold, respectively, increases the likelihood of unstable ASP.

[Factors associated with an increase in spatial and frontal QRS-T angles in patients with anterior myocardial infarction].

Aim    To determine existence of a relationship between any clinical, echocardiographic and coronarographic factors and increased spatial QRS-T (sQRS-T) angle and frontal QRS-T (fQRS-T) angle in patients with anterior myocardial infarction.Material and methods    This study included 137 patients aged 62 [53; 72] years with anterior acute myocardial infarction managed at the A.L. Myasnikov Institute of Clinical Cardiology. fQRS-T was calculated as the module of difference between the frontal plane QRS complex axis and the T wave axis. sQRS-T was calculated as a spatial angle between QRS and T integral vectors from a synthesized vectorcardiogram.Results    fQRS-T values for a group (median [25th; 75th percentile]) were 81 [37; 120]°; sQRS-T values were 114 [80; 141]°. The correlation coefficient between fQRS-T and sQRS-T values was 0.41 (p<0.001). fQRS-T weakly but statistically significantly correlated with patients' age (r=0.28; p=0.001), left ventricular ejection fraction (LV EF, r= -0.22; p=0.01), and glomerular filtration rate (r=-0.32; p=0.0002). sQRS-T weakly but statistically significantly correlated with left ventricular end-diastolic dimension (r=0.24; p=0.0048), LV EF (r=-0.28; p=0.0009), and the number of affected segments according to echocardiography data (r=0.27; p=0.002). fQRS-T values were significantly higher in the presence of concurrent arterial hypertension. sQRS-T values were significantly higher in the presence of a history of chronic heart failure. Both fQRS-T and sQRS-T values increased with increasing number of affected blood vessels and Killip class of acute heart failure.Conclusion    In patients after anterior acute myocardial infarction, increases in fQRS-T and sQRS-T are associated with more severe damage of the vasculature, decreased LV EF, and, thus, more severe clinical course of disease.

[Possibilities of Stress Computed Tomography Myocardial Perfusion Imaging in the Diagnosis of Ischemic Heart Disease].

Computed tomography angiography (CT-angiography, CTA) allows noninvasive visualization of coronary arteries (CA). This method is highly sensitive in detecting coronary atherosclerosis. However, standard CTA does not allow evaluation of the hemodynamic significance of found CA stenoses, which requires additional functional tests for detection of myocardial ischemia. This review focuses on possibilities of clinical use, limitations, technical aspects, and prospects of a combination of CT-angiography and CT myocardial perfusion imaging in diagnostics of ischemic heart disease.

[Factors Associated with the Increase in Spatial and Frontal QRS-T Angles in Patients with Inferior Myocardial Infarction].

Aim      To identify clinical, echocardiographic, and angiographic factors related with an increase in the frontal QRS-T angle (fQRS-T) and the spatial QRS-T angle (sQRS-T) in patients with inferior myocardial infarction.Material and methods  The study included 128 patients aged (median [25th percentile; 75th percentile]) 59.5 [51.5; 67.0] years diagnosed with inferior wall acute myocardial infarction. fQRS-T was calculated as a module of difference between the QRS axis and the Т axis in the frontal plane. sQRS-T was calculated by a synthesized vectorcardiogram as a spatial angle between the QRS and Т integral vectors.Results The fQRS-T for the group was 54.0 [18; 80] and sQRS-T was 80.1 [53; 110]. The correlation coefficient for fQRS-T and sQRS-T values was 0.42 (p<0.001). Both fQRS-T >80° and sQRS-T >110° compared to their lower values were associated with a higher frequency of history of postinfarction cardiosclerosis (44% and 12 %, respectively; p<0.05), a lower left ventricular ejection fraction (51 [47; 60]% at fQRS-T >80° and 55 [50; 60]% at fQRS-T <80° (p<0,05); 49 [44; 57]% at sQRS-T >110° and 57 [51; 60] % at sQRS-T <110° (p<0.01); more frequent development of acute heart failure (16 and 2 %, respectively; p<0.05); and early postinfarction angina (13 and 2 %, respectively; p<0.05). The increased fQRS-T was associated with a higher incidence of damage to the circumflex artery (45 and 20 %, respectively; p<0.05). The increased sQRS-T was associated with a history of arterial hypertension (97 and 76 %, respectively; p<0.05), chronic heart failure (22 and 3 %, respectively; p<0.05), chronic kidney disease (19 and 4 %, respectively; p<0.05), and a larger myocardial lesion (mean number of damaged segments by echocardiography was 3.8 [2; 6] at sQRS-T >110° and 2.6 [1; 4] at sQRS-T <110°; p<0.01). sQRS-T was significantly greater in multivascular damage (87 [68; 121]° than in one- or two-vascular damage (72 [51; 100]°; p<0.05). sQRS-T values were significantly lower with spontaneous reperfusion (66 [29; 79] than without spontaneous reperfusion (77 [55; 115]°; p<0.05).Conclusion      In patients after inferior wall acute myocardial infarction, increases in fQRS-T and sQRS-T were associated with more severe damage of coronary vasculature, decreased left ventricular ejection fraction, and more severe course of disease.

[Spontaneous Coronary Artery Dissection].

During several recent decades spontaneous coronary artery dissection (SCAD) has been known as one of causes of development of acute coronary syndrome (ACS). It has been assumed that this condition is extremely rarely met and is associated with pregnancy and postpartum period. The use in clinical practice of high sensitivity troponin, coronary angiography (CAG) in early period of ACS, in conjunction with the growing awareness of doctors about this pathology led to a revision of the viewse on prevalence of the disease. At present SCAD is considered as one of the causes of ACS in young and middle-aged women. In this review we present results of studies of pathogenesis, diagnostics, and treatment of SCAD, describe various angiographic types of this disease, and discuss problems of choice of optimal strategy of management of patients with SCAD.

[Endovascular closure of a ventricular septal defect from Takotsubo Syndrome].

Takotsubo Syndrome is a transient condition characterized by left ventricular systolic dysfunction. Although the prognosis is excellent in most cases, rare cases of serious complications can occur. We present a case of a 81-year - old woman with Takotsubo Syndrome complicated by ventricular septal rupture that was successfully closed with an occluder Occlutech with good immediate and long - term outcomes.

[Myocardial Hypoenhancement on Multidetector Computed Tomography in Patients With Non-ST Elevation Acute Coronary Syndrome].

The purpose of our study was analysis of myocardial hypoenhancement areas (MHAs) found by multidetector computed tomography (MDCT) in patients with non-ST elevation acute coronary syndrome (NSTEACS) and comparison of these findings with results of standard methods of diagnostics of myocardial infarction and ischemia [electrocardiography (ECG) and echocardiography (ECHO)]. METHODS: MHAs were found in 18 of 21 patients with non-ST segment elevation myocardial infarction (NSTEMI) (85.7%) and only in 3 of 22 patients with unstable angina (UA) (13.6%, p.

[Computed Tomography in the Evaluation of Coronary Atherosclerotic Plaques: Comparison With Intravascular Ultrasound].

PURPOSE: Determination of computed tomography angiography (CTA) informativeness in assessment of state of atherosclerotic coronary plaque (ACP) and identification of signs of its instability compared with intravascular ultrasound (IVUS). MATERIALS AND METHODS: Coronary CTA was carried out in 52 patients with clinical presentation of non-ST elevation (NSTE) acute coronary syndrome on the first day of hospitalization. ACPs were identified in 32 of 52 patients (61.5%). IVUS was performed in 32 patients (mean age 58+/-11.4 years, 27 men, 5 women, 22 with unstable angina, 10 with NSTE myocardial infarction) and 50 plaques in 45 coronary arteries were characterized (39 with spectral analysis of IVUS data). All data were compared with the results of coronary CTA. RESULTS: Sensitivity and specificity of CTA in the detection of stenosis >50% were 97.67 and 71.40%, respectively. Correlation analysis showed a high comparability of methods in determining plaque burden (r=0.80, 95% confidence interval [CI] 0.67 - 0.88, p<0.0001), plaque length (r=0.75, 95%CI 0.60 - 0.85, p<0.0001), and remodeling index (r=0.62, 95%CI 0.40 - 0.77, p<0.0001). Threshold value for "low-density areas" of plaques typical for thin cap fibroatheroma was less or equal 41 Hounsfield units (sensitivity 82%; specificity 86%; area under the curve 0.824; 95% CI 0.615 - 0.947, p<0.0005). CONCLUSION: Coronary CT is a non-invasive method for rapid characterization of ACP. CT results correlate well with IVUS data, including identification of such important signs of plaque instability as presence of "low-density zone" and positive remodeling at the plague level.

[Capabilities of Multidetector Computed Tomography in Assessment of Atherosclerosis of Coronary Arteries].

The prevalence of ischemic heart disease (IHD) as well as high mortality from its exacerbations led to an active search and study of diagnostic methods to predict the possible development of acute coronary events. At the moment, it is proved that the morphological properties of atherosclerotic plaque largely determine the course of IHD. Contemporary multidetector computed tomography (MDCT) is the only non-invasive method which allows to study the state of coronary arteries. In this review we have analyzed capabilities of MDCT in assessing the severity of stenosis and calcification in the coronary arteries, as well as the structure of atherosclerotic plaques, including signs of "instability".

[Assessment of Coronary Plaques in Patients With Acute Coronary Syndrome Without Persistent ST-Segment Elevation].

AIM: to analyze morphological features of atherosclerotic plaques in culprit and non-culprit coronary lesions in patients with non ST-elevation acute coronary syndrome (NSTE-ACS) by multidetector spiral computed tomography (MDCT). RESULTS. In culprit lesions (n = 70) compared to non-culprit lesions (n = 144) frequency of soft plaques (60 vs 43%, p = 0.003), positive remodeling (70.2 vs 54.3%, p = 0.03) and uneven contour (91.7 vs 68.7%, p = 0.0002) were significantly higher. Minimal plaque density was significantly lower and length of plaque was significantly higher in culprit coronary segments (40.1 ± 25.3 vs 74.1 ± 116.8 Hounsfield units [HU], p = 0.02 and 16.8 ± 13.4 vs 13.2 ± 6.9 mm, p = 0.01, respectively). Receiver-operator characteristic curve analysis identified optimal cutoff value of minimum plaque density and length for discrimination between culprit and non-culprit lesion as 40 HU and 13.5 mm, respectively. The combination of soft plaque with a minimal density < 40 HU and uneven contour occurred in one third of culprit lesions and almost two times less in non-culprit (31.67 and 17.91%, respectively, p = 0.04) and was characterized by high specificity (82.1%) and negative predictive value (72.7%). CONCLUSION: The most specific features of culprit lesions in patients with NSTE-ACS were positive vascular remodeling, length > 13.5 mm, minimal CT-density < 40 HU, soft plaque's type and presence of uneven contour, as well as a combination of the last 3 features.

[The role of multispiral computed tomography in assessment of viability of the myocardium and prognostication of left ventricular remodeling in patients with ST-elevation myocardial infarction].

Aim of the study was to assess perfusion defect and viability of the myocardium by the method of multispiral computed tomography (MSCT) in patients with ST-elevation acute myocardial infarction (AMI) and to assess their prognostic role in development of remodeling of the left ventricle (LV). We included into the study 117 patients with AMI. MSCT with intravenous contrast enhancement was carried out on days 3-4 and at 12 months after AMI. In the arterial phase we estimated volume of myocardial perfusion defect, LV end diastolic and end systolic volumes (LVEDV and LVESV), and LV ejection fraction (EF). Three types of myocardial opacification were distinguished on tomograms in delayed phase of MSCT: type I - subendocardial residual defect (RD), type II - transmural RD, type III - transmural delayed hyper enhancement (DE). Patients were divided in 3 groups: (1) with subendocardial RD (n=63), (2) with transmural RD (n=28), (3) with transmural DE (n=26). Development of LV remodeling was registered if at repeat MSCT LVEDV increased more or equal 20% from baseline. In patients with signs of viable myocardium (group 1) volume of perfusion defect was substantially smaller than in patients with nonviable myocardium (groups 2 and 3): 1cm3 (0.4-2.4) vs. 7.3 cm3 (5.3-10.0) and 6.3 cm3 (5.0-15.0), respectively, p<0.001. Compared with groups 2 and 3 patients of group 1 more often were female (p=0.04), had inferior MI (p<0.001), and spontaneous reperfusion (p<0.001). After 12 months LV remodeling was registered in 19.3% of patients, all had signs of nonviable myocardium in more or equal 3 LV segments. In patients with perfusion defect more or equal 10 cm3 probability of development of LV remodeling exceeded 50%. Disturbances of perfusion abnormalities and number of nonviable LV segments were main predictors of LV remodeling.

[Comparison of characteristics of atherosclerotic plaques in patients with acute coronary syndrome and stable ischemic heart disease: data of multispiral computed tomography].

AIM: To elucidate possibilities of multispiral computed tomography (MSCT) for assessment of morphology of atherosclerotic plaques in coronary arteries of patients with acute coronary syndrome (ACS) or stable ischemic heart disease (SIHD). MATERIAL AND METHODS: Assessment of internal relief of coronary arteries and composition of atherosclerotic plaques was carried out in 85 patients with ACS and 41 patients with SIHD. MSCT was performed with the use of computed tomograph. Visual assessment included determination of plaque type (calcified, soft, and heterogeneous) and contour (regular, irregular). Quantitative assessment included determination of plaque density and index of remodeling. RESULTS: Among patients with ACS we found 194 plaques (60--soft, 72--heterogeneous, and 62--calcified). Plaques in symptom related compared with non-symptom related arteries had higher index of remodeling (1.4 +/- 0.3 and 1.2 +/- 0.2, respectively, p < 0.0001), and more frequently had irregular contour (60.0 and 12.8%, respectively, p < 0.0005). Soft plaques and plaques with irregular contour prevailed in ACS group (68.0%) while calcified plaques were more frequent in SIHD group (66.4%). Plaques with irregular contour were more frequent and index of remodeling was higher in ACS compared with SIHD group (33.5 vs 7.2%, p < 0.0005, and 1.3 +/- 0.2 vs 1.0 +/- 0.2, p < 0.001, respectively). CONCLUSION: According to MSCT data main characteristics of atherosclerotic plaques in patients with ACS were low density and inclusions of microcalcinates. Specific features of plaques in symptom related arteries were irregular contour and positive remodeling index.

[Comparison of multislice spiral computed tomography and stress echocardiography in the evaluation of myocardial viability in patients with acute myocardial infarction].

The purpose of the investigation was to analyze the data of 64-multislice spiral computed tomography (MSCT-64) versus those of low-dose dobutamine echocardiography (stress EchoCG) used to diagnose the viable myocardium in patients with acute myocardial infarction (AMI). The investigation enrolled 49 patients with AIM. Contrast-enhanced MSCT-64 and low-dose dubutamine stress EchoCG were performed in patients in the early periods of AMI. The viable myocardium was examined in 780 segments of the left ventricle (LV). The data of delayed MSCT and stress EchoCG agreed in 759 (97.3%) segments, did not in 21 (2.7%) segments; Cohen's kappa coefficient was 0.88. The affected segment index (As index) was introduced into the investigation, which is an integral indicator of the number of segments with perfusion defect and nonviable segments detected by MSCT. There was a statistically significant correlation of the As index with the asynergy index (r = 0.91; p = 0.000) and LV ejection fraction (r = -0.75; p = 0.000). Our previous study has demonstrated that MSCT-64 is an informative method to evaluate myocardial viability; the signs of myocardial perfusion and structural derangements can serve as predictors of diminished LV contractility.

[Spontaneous reperfusion of the infarct-related artery in patients with ST elevated myocardial infarction].

AIM: To characterize a clinical course of ST elevation myocardial infarction (STEMI) and spontaneous reperfusion of the coronary arteries (SR) as well as in patients after reperfusion thrombolytic therapy (TLT) and/or transluminal balloon coronary angioplasty (TBCA); to compare effectiveness of different approaches to treatment of SR patients: conservative--early medication and active--TBCA on the first postmyocardial 24 hours. MATERIAL AND METHODS: We studied 479 patients admitted to hospital not later than 6 hours since STEMI onset and either having SR (n = 49) or treated using active methods of coronary circulation restoration--prehospital thrombolysis (n = 127), thrombolysis after hospitalization (n = 127), primary TBCA (n = 60) and TBCA after initiation of TLT (n = 116). We made a more detailed analysis on the sample of 149 SR patients. RESULTS: SR was diagnosed in 10.2% cases with STEMI and occurred much earlier than recovery of coronary circulation due to TLT and/or TBCA. Patients with SR developed Q-MI, right ventricular infarction, cardiac failure and atrioventricular block less frequently. They had the lowest peak activity of creatin phosphokinase and a higher left ventricular ejection fraction versus patients without SR (50.7 +/- 6.8 and 45.4 +/- 6.6%, respectively; p < 0.05). As shown by coronaroangiography, SR patients had no "no reflow" phenomenon (0% and 17%, respectively). Active policy of SR patients treatment had no significant advantages over conservative treatment. CONCLUSION: Early SR had more favourable course of MI, less mass of the affected myocardium and better contractile function of the left ventricle. The conservative policy of STEMI treatment in the presence of SR is more effective than the active one if a due control over the patients' condition is provided.

[The role of multidetector computed tomography in detection of myocardial infarction].

UNLABELLED: The aim of the study was to assess the diagnostic value of multidetector computed tomography (MDCT) in detection of myocardial infarction (MI) in acute and chromic stages. MATERIAL AND METHODS: 49 patients with suspected MI were included in the study. In 44 patients the diagnosis of acute MI had been confirmed according to standard criteria. Contrast-enhanced MDCT of the heart and vessels was performed with 4-row MDCT scanner. RESULTS: MDCT detected areas of MI in 39 of 44 patients with proven MI. In 66,7% of cases they were transmural and in 33,3% -- subendocardial. In arterial phase the density of infarcted area was significantly lower than in normal myocardium (mean, 32,6 +/- 3,7 HU versus 101,9 +/- 3,7 HU, correspondingly, p < 0,0001). Mean values of myocardial density in the area of the MI did not change during follow-up (32,6 +/- 3,7 HU vs 41,3 +/- 4,5 HU, ns). In comparison to SPECT, sensitivity and specificity of MDCT in detection of transmural MI were 96,9% and 100%. corr. In the whole group of patients, taking results of troponin test as a gold standard, the sensitivity of MDCT in detection of Q-MI and non-Q MI were 89,1% and 93,5%, correspondingly. CONCLUSION: Cardiac MDCT can reliably detect and localize areas of acute and chronic MI. Contrary to SPECT, it also gives information about stenosis and occlusions in the coronary arteries.

[QT rate dependence in norm and myocardial infarction].

AIM: To assess QT/RR relationship in healthy subjects and in patients with acute myocardial infarction (AMI) using long term 12-lead ECG monitoring. MATERIAL AND METHODS: We studied separately diurnal and nocturnal QT interval rate-dependence using a linear model "QT=beta+alphaxRR" in 42 patients with AMI on 2-nd week of the disease and in 14 healthy volunteers. All necessary parameters were automatically calculated from 24-hour 12 lead ECG recordings using special programs. Myocardial perfusion and infarct size were assessed using 99mTc-MIBI gated SPECT. RESULTS: Long-term ECG monitoring permitted: 1) to detect the ECG lead with most pronounced QT/RR relationship delineated by alpha(max); 2) to determine value of "deltaalpha=alpha(max)-alpha(min)", that characterized spatial heterogeneity of QT/RR relationship. In norm diurnal values of alpha(max) were significantly higher than nocturnal ones (0.207+/-0.037 vs. 0.151+/-0.035, respectively; p<0.01). The alpha(max) values correlated with the size of MI (r=0.42-0.43, p<0.01). Therefore in patients with anterior AMI who demonstrated significantly larger defects of 99mTc-MIBI uptake than patients with inferior AMI, diurnal mean value of amax remained high despite therapy with b-blockers (0.225+/-0.037), and nocturnal alpha(max) value significantly exceeded respective amax value in healthy subjects (0.216+/-0.097 vs 0.151+/-0.035, respectively; p<0.01). Patients with AMI demonstrated an increased mean Da value when compared to normal subjects (in anterior AMI 0.098+/-0.057 vs. 0.039+/-0.014, respectively; p<0.001--diurnal period; 0.104+/-0,042 vs. 0.039+/-0.022, respectively; p<0.001--nocturnal period). In anterior AMI Da values correlated with infarct size (r=0.62, p=0.001). CONCLUSIONS: A new approach to the assessment of QT rate dependence with the use of 12-lead Holter monitoring widens possibilities of the method, firstly, because of selection of most informative ECG lead that shows maximal QT/RR relationship dynamic, and, secondly due, to discovery of the new field of ventricular repolarization research by assessment of space dispersion of QT/RR relationship. In patients with AMI when compared with healthy subjects we observed a decrease of QT/RR circadian modulation, increase of the slope and space dispersion of QT/RR rate dependence.

[Impairment of cardiac sympathetic function in patients with acute myocardial infarction and unstable angina]. / Narusheniia simpaticheskoi innervatsii serdtsa u bol'nykh s ostrym infarktom miokarda i nestabil'noi stenokardiei

AIM: To assess the state of sympathetic innervation of the heart in patients with acute coronary syndrome. MATERIAL: Patients with Q-myocardial infarction (MI, n=36), non-Q-MI (n=13), and unstable angina (UA, n=9). METHODS: Each subject underwent single-photon emission computed tomography (SPECT) and planar scintigraphy using iodine-123 metaiodobenzylguanidine ((123)I-MIBG) for assessment of cardiac sympathetic function. We analyzed early (15 minutes) and delayed (4 hours) images after (123)I-MIBG administration. Resting (99m)Tc-MIBI myocardial scintigraphy was performed for evaluation of myocardial perfusion. Location, extent (%) and severity (Un.) of defects were determined using <> program. (123)I-MIBG did not accumulate in myocardium of 3.5% patients. All other patients demonstrated (123)I-MIBG accumulation defects. These defects were colocolized with (99m)Tc-MIBI uptake abnormalities. However both extent and severity of sympathetic innervation defects exceeded those of perfusion defects in all patients. Mean extent and severity of sympathetic neuronal damage areas were the greatest in patients with Q-MI (41+/-8% and 1119+/-377 Un. respectively) and the least in patients with UA (22+/-12% and 602+/-353 Un., respectively). On the contrary the mean extent of areas with sympathetic endings dysfunction but normal perfusion was the largest in UA group and the least in Q-MI group (18+/-11 and 10+/-7%, respectively, p<0,05). CONCLUSION: Impairment of cardiac sympathetic function in patients with acute coronary syndrome could be detected by SPECT with (123)I-MIBG. Locations of (123)I-MIBG and (99m)Tc-MIBI defects were similar but sympathetic dysfunction areas were larger than areas with reduced perfusion. This result suggests higher sensitivity of sympathetic endings to ischemia compared with cardiomyocytes. Myocardial areas with sympathetic endings dysfunction but normal perfusion can be defined as myocardium at risk.