Decrease In ST Segment Elevation Research Articles

Sono-assisted-thrombolysis by three-dimensional diagnostic ultrasound improves epicardial recanalization and microvascular perfusion in acute myocardial infarction.

BackgroundThis study aimed to evaluate the multiple interactions between therapeutic ultrasound (TUS), microbubbles (MB), and recombinant tissue plasminogen activator (r-tPA) by using three-dimensional (3D) ultrasound to examine the impact of thrombolysis with r-tPA on epicardial recanalization and microcirculation in patients with acute ST-segment-elevation myocardial infarction (STEMI).MethodsAcute thrombotic occlusion of the left anterior descending (LAD) artery was induced in 32 Bama pigs, who were fed a high-cholesterol diet and randomized into four groups: (I) a 3D-sono-assisted-thrombolysis (3D/TUS + MB + r-tPA) group; (II) a 3D/TUS + MB group; (III) a full-dose r-tPA group; and (IV) a 3D/TUS alone group. Epicardial angiographic recanalization rate, microcirculation in the at-risk myocardium, ST-segment elevation on electrocardiogram, and changes in the at-risk myocardium and the myocardial infarct area were compared between the groups.ResultsAfter treatment, distal LAD recanalization was observed in 87.5% (7/8) of pigs in the 3D/TUS + MB + r-tPA group, which was significantly higher than the rates observed in the 3D/TUS + MB (37.5%) and the full-dose r-tPA (50.0%) groups (all P<0.05). The average acoustic intensity in the 3D/TUS + MB + r-tPA group (193.78±10.15 dB) was also significantly higher than that in the 3D/TUS + MB (154.29±31.94 dB) and the r-tPA (141.42±28.31 dB) groups (all P<0.05). The decrease in ST-segment elevation in the 3D/TUS + MB + r-tPA group (1.31±1.22 mm) was significantly higher than that in the 3D/TUS + MB (5.38±1.77 mm) and the r-tPA (4.30±2.08 mm) groups (all P<0.05). Furthermore, the ratio of the infarcted myocardial area divided by the at-risk myocardial area was markedly lower in the 3D/TUS + MB + r-tPA group (0.51±0.14) than in the 3D/TUS + MB (0.69±0.28) and r-tPA (0.75±0.23) groups (all P<0.05).ConclusionsThree-dimensional sono-assisted-thrombolysis directly improves infarct-related recanalization rates, enhances microcirculation, reduces r-tPA dosage, and ameliorates the thrombolytic effect of r-tPA in acute STEMI.

Bergenin from Bergenia Species Produces a Protective Response against Myocardial Infarction in Rats

Bergenin is a phenolic glycoside that has been reported to occur naturally in several plant species, reported as a cardioprotective. However, bergenin, one of the important phytochemicals in these plants, is still not reported as a cardioprotective. The present study was designed to investigate the cardioprotective effects of bergenin on isoproterenol-induced myocardial infarction in rats. Bergenin and atenolol were administered through intraperitoneal (i.p.) injection to Sprague Dawley (SD) rats in separate experiments for five (5) days. At the end of this period, rats were administered isoproterenol (80 mg/kg s.c.) to induce myocardial injury. After induction, rats were anaesthetized to record lead II ECG, then sacrificed, blood was collected to analyze cardiac marker enzymes, and a histopathological study of the heart tissues was also performed. Pretreatment with bergenin showed a significant decrease in ST-segment elevation, deep Q-wave, infarct size, and also normalized cardiac marker enzymes (cTnI, CPK, CK-MB, LDH, ALT, and AST), particularly at 3 mg/kg, as compared to isoproterenol treated group. Our findings revealed, for the first time, the use of glycoside bergenin as a potential cardioprotective agent against the isoproterenol-induced MI in rats.

The stability of myocardial area at risk estimated electrocardiographically in patients with ST elevation myocardial infarction

In patients with ST-elevation myocardial infarction (STEMI) the amount of myocardial area at risk (MaR) indicates the maximal potential loss of myocardium if the coronary artery remains occluded. During the time course of infarct evolution ischemic MaR is replaced by necrosis, which results in a decrease in ST segment elevation and QRS complex distortion. Recently it has been shown that combining the electrocardiographic (ECG) Aldrich ST and Selvester QRS scores result in a more accurate estimate of MaR than using either method alone. Therefore, we hypothesized that the combined Aldrich and Selvester score, indicating MaR, is stable until myocardial reperfusion therapy.In a retrospective analysis of a study population of 114 patients, 33 patients were included. The combined Aldrich and Selvester score was determined in ECGs recorded in the ambulance (ECG1) and in the hospital before reperfusion (ECG2). The combined Aldrich and Selvester score was considered stable if the difference between ECG1 and ECG2 was <4.5-percentage point.Stability of the combined Aldrich and Selvester score was observed in 12/33 patients (36.4%), and in regards to anterior and inferior ST elevation in 4/14 patients (28.6%) and 8/19 patients (42.1%), respectively. The median time between the recording of ECG1 and ECG2 was 75minutes, however the changes in ECG scores were independent of the time between ECG recordings. Patients not meeting the stability criterion either had a decrease (9 patients) or increase (12 patients) of the combined Aldrich and Selvester score.In conclusion, the ECG estimated MaR was stable between the earliest recording time and initiation of reperfusion treatment only in a subgroup of the patients with STEMI. The findings of this study may suggest heterogeneity in regards to the development of the MaR and could indicate a potential need for differentiation in the acute treatment.

Cardioprotective Effect of Paeonol and Danshensu Combination on Isoproterenol-Induced Myocardial Injury in Rats

BackgroundTraditional Chinese medicinal herbs Cortex Moutan and Radix Salviae Milthiorrhizaeare are prescribed together for their putative cardioprotective effects in clinical practice. However, the rationale of the combined use remains unclear. The present study was designed to investigate the cardioprotective effects of paeonol and danshensu (representative active ingredient of Cortex Moutan and Radix Salviae Milthiorrhizae, respectively) on isoproterenol-induced myocardial infarction in rats and its underlying mechanisms.MethodologyPaeonol (80 mg kg−1) and danshensu (160 mg kg−1) were administered orally to Sprague Dawley rats in individual or in combination for 21 days. At the end of this period, rats were administered isoproterenol (85 mg kg−1) subcutaneously to induce myocardial injury. After induction, rats were anaesthetized with pentobarbital sodium (35 mg kg−1) to record electrocardiogram, then sacrificed and biochemical assays of the heart tissues were performed.Principal FindingsInduction of rats with isoproterenol resulted in a marked (P<0.001) elevation in ST-segment, infarct size, level of serum marker enzymes (CK-MB, LDH, AST and ALT), cTnI, TBARS, protein expression of Bax and Caspase-3 and a significant decrease in the activities of endogenous antioxidants (SOD, CAT, GPx, GR, and GST) and protein expression of Bcl-2. Pretreatment with paeonol and danshensu combination showed a significant (P<0.001) decrease in ST-segment elevation, infarct size, cTnI, TBARS, protein expression of Bax and Caspase-3 and a significant increase in the activities of endogenous antioxidants and protein expression of Bcl-2 and Nrf2 when compared with individual treated groups.Conclusions/SignificanceThis study demonstrates the cardioprotective effect of paeonol and danshensu combination on isoproterenol-induced myocardial infarction in rats. The mechanism might be associated with the enhancement of antioxidant defense system through activating of Nrf2 signaling and anti-apoptosis through regulating Bax, Bcl-2 and Caspase-3. It could provide experimental evidence to support the rationality of combinatorial use of traditional Chinese medicine in clinical practice.

Hyperlipidemia Prevents the Expected Reduction of Myocardial Ischemia on Repeated Balloon Inflations During Angioplasty

Controversy exists regarding inhibition of ischemic preconditioning in hyperlipidemic animals. In this study, we tested the hypothesis that hyperlipidemia inhibits the normal reduction of myocardial ischemia on repeated balloon inflations (BIs) during angioplasty. We studied 33 patients undergoing coronary angioplasty. All underwent a minimum of three BIs. Patients were grouped according to the following plasma cholesterol levels: 13 patients had total cholesterol levels < 200 mg/dL (the normal cholesterol group); and 20 patients had total cholesterol levels > or = 200 mg/dL (the elevated cholesterol group). Surface ST-segment elevations were recorded at the end of each BI. In the normal cholesterol group, the mean (+/- SD) ST-segment elevation decreased from 0.21 +/- 0.15 mV during the first BI to 0.11 +/- 0.11 mV during the third BI (p < 0.05). In the elevated cholesterol group, the respective decrease was from 0.18 +/- 0.16 to 0.14 +/- 0.15 mV (p = not significant) [between-group comparisons: F = 3.97; p = 0.02]. The decrease in ST-segment elevation was correlated with the total cholesterol levels (r = -0.48; p = 0.005), the low-density lipoprotein (LDL) cholesterol levels (r = -0.50; p = 0.003), and the high-density lipoprotein/LDL levels (r = 0.44; p = 0.01). Hyperlipidemia prevents the normal reduction of myocardial ischemia on repeated BIs during angioplasty. This leads to the clinical implication that reduction of cholesterol plasma levels, apart from its other known benefits, could also have a beneficial effect on cardioprotection.

Change in ST segment elevation 60 minutes after thrombolytic initiation predicts clinical outcome as accurately as later electrocardiographic changes

ObjectiveTo compare prospectively the prognostic accuracy of a 50% decrease in ST segment elevation on standard 12-lead electrocardiograms (ECGs) recorded at 60, 90, and 180 minutes after thrombolysis initiation in...

Effect of time interval between two balloon inflations on ischemic preconditioning during coronary angioplasty

Ischemic preconditioning, defined as a reduction in myocardial ischemia caused by repeated brief episodes of coronary occlusions, is observed during percutaneous transluminal balloon angioplasty (PTCA). To elucidate the effects of the length of the interval between consecutive balloon inflations on ischemic preconditioning during PTCA, we examined 62 patients with chronic stable angina (48 males and 14 females; mean age 62 ± 10 yr). PTCA was performed on the left anterior descending artery lacking in collateral vessels. A 2-min balloon inflation was performed twice and the extent of ST segment elevation in the electrocardiogram and the severity of chest pain (scored from 0 to 10) for each inflation were determined and compared. Patients were divided into three groups according to the interval between the two inflations: 1 min, Group 1; 2 min, Group 2; and 5 min, Group 5. In Groups 2 and 5, ST-segment elevation was significantly decreased during the second balloon inflation, as compared with that during the first inflation (P < 0.01, P < 0.001). A significant decrease was also observed in the severity of chest pain (P < 0.05, P < 0.01). However, Group 1 showed no significant decrease in ST-segment elevation or severity of chest pain between the first and second inflations. ST-segment elevation and chest pain were reduced to a greater extent in Group 5 than in Group 2. Results suggest that an interval of more than 2 min between balloon inflations is required to achieve ischemic preconditioning during PTCA. Cathet. Cardiovasc. Diagn. 42:263–267, 1997. © 1997 Wiley-Liss, Inc.

Effect of time interval between two balloon inflations on ischemic preconditioning during coronary angioplasty.

Ischemic preconditioning, defined as a reduction in myocardial ischemia caused by repeated brief episodes of coronary occlusions, is observed during percutaneous transluminal balloon angioplasty (PTCA). To elucidate the effects of the length of the interval between consecutive balloon inflations on ischemic preconditioning during PTCA, we examined 62 patients with chronic stable angina (48 males and 14 females; mean age 62 +/- 10 yr). PTCA was performed on the left anterior descending artery lacking in collateral vessels. A 2-min balloon inflation was performed twice and the extent of ST segment elevation in the electrocardiogram and the severity of chest pain (scored from 0 to 10) for each inflation were determined and compared. Patients were divided into three groups according to the interval between the two inflations: 1 min, Group 1; 2 min, Group 2; and 5 min, Group 5. In Groups 2 and 5, ST-segment elevation was significantly decreased during the second balloon inflation, as compared with that during the first inflation (P < 0.01, P < 0.001). A significant decrease was also observed in the severity of chest pain (P < 0.05, P < 0.01). However, Group 1 showed no significant decrease in ST-segment elevation or severity of chest pain between the first and second inflations. ST-segment elevation and chest pain were reduced to a greater extent in Group 5 than in Group 2. Results suggest that an interval of more than 2 min between balloon inflations is required to achieve ischemic preconditioning during PTCA.

Non-invasive assessment of reperfusion of the infarct-related artery during coronary thrombolysis and its relation with left ventricular function

We monitored ST segment continuously for at least 3 h after the beginning of lytic treatment in 103 patients undergoing early coronary thrombolysis for acute myocardial infarction in order to ascertain whether this technique, which has been shown to be useful to assess recanalization of the infarct-related artery, is also able to identify the improvement in left ventricular function associated with successful reperfusion. Global left ventricular function (assessed in the 30° right anterior oblique projection with the area/length method) and infarct zone wall motion (studied with the centerline method) were evaluated at least 4 weeks after the event. Reperfusion was thought to be achieved when ST segment elevation dropped>50% relative to the most abnormal peak documented at any time in the study. Eighty patients (78%) met the criterium for successful reperfusion (group 1), and 23 (22%) did not (group 2). Both groups had similar clinical and angiographic characteristics. All indexes of global left ventricular function were significantly better in group 1 than in group 2 patients (end-diastolic volume: 176 ± 51 vs. 209 ± 76 ml, end-systolic volume: 66 ± 40 vs. 97 ± 55 ml, ejection fraction: 65 ± 13 vs. 57 ± 11%, respectively, all P < 0.02). Also the severity (−1.6 ± 1.3 vs. − 2.6 ± 1.01 S.D./chord, respectively, P < 0.001) and the extension of hypokinesia in the infarct zone (number of chords with>2 S.D.: 13 ± 16 vs. 28 ± 17, respectively, P < 0.0001) were less in group 1 than in group 2 patients. Furthermore, in reperfused patients, both global left ventricular function and regional wall motion were better in those admitted < 60 min from onset of pain. In conclusion, patients with rapid (> 50%) decrease of ST segment elevation have smaller infarct size and better global left ventricular function than patients without electrocardiographic signs of reperfusion as assessed by continuous ST segment monitoring. This suggests that this non-invasive technique is a powerful tool able to identify patients most benefiting from thrombolytic therapy.

Is arrhythmogenicity related to the speed of reperfusion during thrombolysis for myocardial infarction?

The objective of this study was to relate the number of ventricular arrhythmias (VA) to the normalization time of the ST segment during thrombolysis for acute myocardial infarction. The 24 h Holter recordings, begun on start of intravenous thrombolytic therapy, and the 12-lead electrocardiograms of 41 patients with a patent infarct-related artery according to coronary angiography were analysed. The mean time from onset of chest pain to angiography was 30.5 +/- 3.1 h, < or = 24 h in 59%. The normalization time of the ST segment, assessed by the time of decrease of ST segment elevation from start of Holter recording to normal or steady state was < or = 60 min in 13 patients (group 1), 60 to 180 min in 15 patients (group 2) and > 180 min in 13 patients (group 3). The incidence of VA was similar in all groups, except for ventricular tachycardias (VT) > 15 beats (group 1:69%, group 2:13%, group 3:15%, P = 0.002). The frequency of accelerated idioventricular rhythms (AIVR), early AIVR (< or = 6 h) and of VT was significantly higher in group 1 than in group 3 with a 8-, 30- and 6-fold increase, respectively (back transformed mean). We conclude that the number of VAs is related to the normalization time of the ST segment during reperfusion. This may suggest that faster reflow is more arrhythmogenic.

Relationship between changes in ST segment elevation and patency of the infarct-related coronary artery in acute myocardial infarction

Forty-one patients with acute myocardial infarction and ST segment elevation were studied to determine the relationship between early changes in ST segment elevation, time to peak serum creatine kinase (CK), peak serum CK, left ventricular function, and patency of the infarct-related artery. ST segment elevation decreased by more than 40% within 8 hours of peak ΣST in all patients with inferior infarction and in 10 of the 13 patients with anterior infarction and subtotal occlusion, but in none of the patients with anterior infarction and total occlusion ( p = 0.003). The time to peak serum CK was related to the rate of decrease of ST segment elevation in patients with anterior ( r = 0.59) and inferior ( r = 0.71) infarction. In patients with anterior infarction, peak serum CK tended to be lower and left ventricular ejection fraction (EF) higher in those with rapid resolution of ST segment elevation than in those with persistent ST elevation (1721 ± 1422 U/L vs 3285 ± 1148 U/L, p < 0.10, for peak CK; and 50.3 ± 18.5% vs 41.2 ± 12.8%, p = NS, for EF), but there was no difference in the patients with inferior infarction. Early resolution of ST segment elevation is an index of early spontaneous antegrade or collateral reperfusion in patients with acute myocardial infarction.

Intravenous Clonidine Treatment in Acute Myocardial Infarction (with Comparison to a Nitroglycerin-Treated and Control Group)

This study describes the effects of intravenous clonidine treatment in a group of 24 patients with acute myocardial transmural anterior and/or lateral wall infarction. Clonidine was administered as a bolus injection of 1-2 µg/kg body weight and repeated every 1-3 h. The range of the time of administration varied from 20 min to 4 h, with the maximal range of doses from 37 to 150 µg, depending on the hemodynamic status. The effects were measured by precordial electrocardiographic mapping and compared with similar effects obtained in the nitroglycerin-treated group (30 patients) and a control group (12 patients). A large decrease in ST segment elevation was observed. The ST reduction after 24 h was 37% of initial value (compared with 52% in the nitroglycerin group, 140% in the control group); after 48 h there was a 30% reduction (compared with 55% in the nitroglycerin group and 120% in the control group). After 24 h there was a fall in NST of 45% (71% with nitroglycerin and 145% in the control group); after 48 h there was a 41% decrease (compared with 65% in the nitroglycerin group and 142% in the control group). New Q waves increased after 24 h to 135% of the initial value (compared with 122% in the nitroglycerin group and 156% in the control group); after 72 h this increased to 137% (128% in the nitroglycerin group and 167% in the control group). Detailed analysis revealed a correlation between the dosage and favorable dynamics of mapping parameters. Hemodynamic, antiarrhythmic, and, in particular, adrenolytic activity were noted. The clonidine treatment caused a distinct deterioration in daily adrenalinuria mean values to 5.99 µg in the first day (control 14.20) and even lower in the following days. A temporal association between diminished adrenalinuria and a clinical improvement and limitation of infarct size was also observed. Therapy with intravenous clonidine requires meticulous attention to the dosage depending on the individual patient's hemodynamic status.

Importance of myocardial blood flow changes in the protective action of diltiazem in a new model of myocardial ischaemia.

The effect of diltiazem was studied in a new model of myocardial ischaemia in which in addition to a critical constriction of the left circumflex branch (LCX), the left anterior descending coronary artery (LAD) was suddenly occluded. This model is probably more relevant to the clinical situation in which multivessel coronary artery disease is common. In this model diltiazem exerted a beneficial effect, manifested by an increase in myocardial blood flow (MBF) within the stenosed area of the LCX; by a marked reduction of the enhanced preload (LVEDP); by a diminution of the inhomogeneity of electrical activation and by a decrease in ST-segment elevation. Diltiazem also caused a significant reduction both in the number of extrasystoles and in the incidence of ventricular fibrillation. Increased MBF within the stenosed area was associated with enhanced blood flow to the ischaemic myocardium, i.e. diltiazem directed flow to the ischaemic zone by improvement of the collateral circulation. The beneficial electrophysiological changes caused by diltiazem are probably at least partly due to the drug-induced improvement of myocardial blood supply to the ischaemic area.

Intravenous clonidine in acute myocardial infarction in men

We studied the effects of intravenous clonidine treatment in a group of 24 patients with acute myocardial transmural anterior and/or lateral wall infarction. Clonidine, known as an antihypertonic agent, was administered as a bolus of 1–2 μg/kg body weight and repeated every 2–3 hr. However, maximal range of the time interval was 20 min to 4 hr, maximal range of doses 37 to 150 μg, depending on the hemodynamic status. The effects were measured by precordial electrocardiographic mapping as well as serial creatine phosphokinase determinations. A big decrease in ST-segment elevation was observed: ΣST reduction after 24 hr was 37% of initial value (140% in control group), after 48 hr - 30% (120% - control). NST fall after 24 hr - 45% (145% - control), after 48 hr - 41% (142% - control). NQ increased after 24 hr to 135% of initial value (156% - control), after 72 hr to 137% (167% - control). Detailed analysis revealed undoubted correlation between the dosage and favourable dynamics of precordial mapping parameters. Hemodynamic, antiarrhythmic and above all adrenolytic activity were noted. The treatment caused a distinct deterioration in daily adrenalinuria mean values to 5.99 μg in the first day (14.20 - control) and lower in the following days. No side effects were observed but sudden discontinuation of the therapy caused an unfavorable reaction. A temporal association between diminished adrenalinuria and both clinical improvement and limitation of infarct size was observed. Therapy with intravenous clonidine requires meticulous individualization of clonidine dosage depending on the patient's initial hemodynamic status.

The effect of left ventricular aneurysmectomyon the electrocardiogram: A study of 77 patients and review of the literature

Electrocardiograms (ECGs) were reviewed in patients undergoing left ventricular aneurysmectomy. Post-operatively, significant decreases were noted in ST segment elevation (p less than 0.001) and anterior (p less than 0.03) and inferior R wave heights (p less than 0.002). In addition, abnormal Q waves disappeared in 50% of patients. Comparison of ECG changes between survivors and patients dying of cardiac related events revealed that patients with a preoperative axis of greater than or equal to 60 degrees, postoperative leftward axis shifts and a marked decrease in ST segment elevation and/or R wave height had significantly higher mortality. 1) Left ventricular aneurysmectomy affects ventricular depolarization as evidenced by a significant loss of R wave height and changes in infarct pattern; 2) LVA affects ventricular repolarization as evidenced by a significant decrease in ST elevation; 3) the ventricular aneurysm appears to contain "viable muscle" that contributes to ventricular depolarization and remains partially depolarized during diastole; and 4) there are prognostic electrocardiographic parameters, which correlate with mortality during postoperative follow-up.