Value of the intracoronary electrocardiogram to monitor myocardial ischemia during percutaneous transluminal coronary angioplasty

To enhance detection of ischemia during percutaneous transluminal coronary angioplasty (PTCA), unipolar intracoronary electrocardiograms (ECGs) were recorded during PTCA in 25 patients from the tips of guidewires positioned distal to stenoses being dilated. Surface electrocardiographic leads chosen to reflect likely areas of reversible ischemia during PTCA were recorded simultaneously. In 21 of 29 stenoses dilated (72%), ST segment elevation and/or T wave peaking in intracoronary ECG appeared during balloon inflation and disappeared after deflation, accompanied by transient angina on 19 occasions. Two patients had transient ST segment elevation in intracoronary ECGs during PTCA without associated angina. ST changes in the surface ECG during PTCA were seen on only nine occasions (31%), always accompanied by ST segment elevation in the intracoronary ECG that appeared earlier and was of much greater magnitude. Five patients with prior myocardial infarction and aneurysm formation had fixed ST segment elevation in the intracoronary ECG unrelated to balloon inflation. Myocardial ischemia during PTCA can be detected easily with intracoronary ECGs and with greater sensitivity than that of the surface ECG. Furthermore, intracoronary ECGs may help to clarify the nature of chest pain during balloon inflation or during suspected complications.     

The effects of intracoronary adenosine on preconditioning during coronary angioplasty

There is evidence that the first balloon inflation during coronary angioplasty provides a preconditioning stimulus leading to decreased ischemia during subsequent balloon inflations. Endogenous adenosine release may play a role in ischemic preconditioning. Therefore, intracoronary adenosine administration prior to the first balloon inflation during percutaneous transluminal coronary angioplasty (PTCA) might modify the preconditioning response to the first balloon inflation. Forty-one patients underwent double-blind randomization to treatment with 100 mcg of intracoronary adenosine or placebo prior to coronary angioplasty. Twenty patients (11 adenosine, 9 placebo) had complete resolution of ischemia between inflations allowing comparison between the first and second inflation. An angioplasty guidewire was used to obtain an intracoronary electrocardiogram. The mean reduction in ST elevation during the second inflation compared with the first was 4.8 mm in the placebo group and -0.8 in the adenosine group (p<0.05 placebo vs. adenosine). Seven of 9 placebo patients had a decrease in ischemia during the second inflation compared with the first, while only 2 of 11 adenosine patients showed a reduction. It was concluded that (1) the first inflation during PTCA is a preconditioning stimulus leading to a decrease in ischemia during later inflations, and (2) intracoronary adenosine administration prior to PTCA modifies the preconditioning effect of the first inflation. These data suggest that adenosine plays a role in ischemic preconditioning in humans.     

直接经皮冠状动脉腔内成形术中冠状动脉内心电图判定存活心肌的价值

目的 应用99mTc-MIBI心肌断层显像(SPECT)评价冠状动脉内心电图(IC-ECG)判定急性心肌梗死(AMI)存活心肌的价值。方法 56例急性前壁心肌梗死患者，接受了直接经皮冠状动脉腔内成形术(PTCA)，梗死相关动脉前降支(LAD)达到TIMI3级血流后IC-ECG自PTCA导引导丝尾端引出作为参照基线，在进一步球囊扩张时IC-ECG ST段再次抬高大于0．2mV时认为具有判定梗死相关部位有存活心肌的意义。测定并比较急性期及恢复期左心室梗死相关区域节段性缩短率(LVSS)与射血分数(LVEF)，梗死区域存活心肌通过恢复早期静息与硝酸甘油介入两次99mTc-MIBI SPECT量化判定。结果 4l例病人(A组)行直接PTCA时IC-ECG ST段明显抬高，15例(B组)未出现相应变化，A组INSS、INEF。在恢复期均显著大于B组，两次99mTc-MIBISPECT显示，硝酸甘油介入后显像A组梗死缺损区面积明显减少，核素放射性计数百分比亦明显增加，B组则无明显改变，说明A组梗死区域有较多存活心肌，与IC-ECT ST段抬高意义一致。结论 直接PTCA过程中可通过球囊扩张时IC-ECG ST段抬高变化初步判定梗死相关区域的心肌活性。     

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.     

Optimal ECG monitoring during percutaneous transluminal coronary angioplasty of the left anterior descending artery

During percutaneous transluminal coronary angioplasty (PTCA) frontal ECG leads are routinely monitored. The detection of ST segment deviation during the procedure is important for decisions regarding guiding catheter seating and the timing of balloon inflation and deflation. ST segment deviation appears on intracoronary electrograms in the absence of changes on the surface ECG in many patients, while the reverse is true in some individuals. When a precordial lead is employed, V5 or V6 is most commonly selected. The surface ECG leads most sensitive for monitoring ischemia during left anterior descending angioplasty are not known. In nine lead surface ECGs recorded during balloon inflation, a small degree of ST segment elevation occurred in leads I, aVL, and V5. Lead V2 demonstrated an increase in ST displacement from 0.0 ± 0.03 mV to 0.29 ± 0.25 mV during coronary occlusion (p<0.01). We conclude that if V5 or V6 is used as a single precordial lead, surface ECG alterations are easily overlooked. During left anterior descending occlusion the most sensitive surface lead is V2. Optimal ECG monitoring during PTCA in some cases should involve surface lead V2 or the intracoronary lead.     

Myocardial protection during transient coronary artery occlusion in man: beneficial effects of regional beta-adrenergic blockade

The goal of this study was to verify whether myocardial protection could be achieved via the intracoronary administration of propranolol in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). Accordingly, 21 patients undergoing PTCA were randomly assigned to receive either intracoronary placebo (group A, n = 10) or intracoronary propranolol (group B, n = 11). Three balloon inflations (i.e., coronary artery occlusions) were performed in each patient. Inflations I and II (maximum duration 60 sec) served as control occlusions. Inflation III (maximum duration 120 sec) was performed either after intracoronary administration of saline (2 ml) or propranolol (1.1 +/- 0.2 mg). The following electrocardiographic index of myocardial ischemic injury were measured: (1) time to development of ST segment elevation equal to 0.1 mV and (2) magnitude of ST segment elevation after 60 sec of coronary artery occlusion. Both indexes did not differ significantly between the groups during inflations I and II. In group A the time to development of ST segment elevation of 0.1 mV remained unchanged between the second and third occlusions (25 +/- 5 and 26 +/- 4 sec during inflations II and III, respectively). In group B subselective injection of propranolol into the affected coronary artery significantly prolonged the time to ST segment elevation of 0.1 mV from 19 +/- 4 sec (inflation II) to 53 +/- 9 sec (inflation III; p less than .001). Administration of placebo did not change the magnitude of ST segment elevation 60 sec after coronary artery occlusion between the second and third occlusion in group A (0.16 +/- 0.02 and 0.18 +/- 0.03 mV, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

经皮冠状动脉腔内成形术中冠状动脉内心电图的应用研究

目的　探讨冠状动脉内心电图（ＩＣ－ＥＣＧ）在经皮冠状动脉腔内成形术（ＰＴＣＡ）术中的应用。方法对４４例冠心病病人的５１支冠状动脉行ＰＴＣＡ时记录ＩＣ－ＥＣＧ和体表ＥＣＧ,分析心绞痛组、心肌梗塞溶栓再通组、溶栓未通组ＩＣ－ＥＣＧ的缺血性心电图改变情况,并与体表监护导联ＥＣＧ相比较。结果９６．１％的血管行球囊扩张时ＩＣ－ＥＣＧ有缺血性改变;心绞痛组、心肌梗塞溶栓再通组及溶栓未通组的ＩＣ－ＥＣＧ的ＳＴ段上移程度有明显差别。结论ＩＣ－ＥＣＧ比体表ＥＣＧ在反映心肌缺血方面更敏感,ＰＴ－ＣＡ时ＩＣ－ＥＣＧ的ＳＴ段变化能一定程度地反映残余心肌的成活情况。     

The impact of numeric and graphic displays of ST-segment deviation levels on cardiologists' decisions of reperfusion therapy for patients with acute coronary occlusion

The study purpose is to determine whether numeric and/or graphic ST measurements added to the display of the 12-lead electrocardiogram (ECG) would influence cardiologists' decision to provide myocardial reperfusion therapy. Twenty ECGs with borderline ST-segment deviation during elective percutaneous coronary intervention and 10 controls before balloon inflation were included. Only 5 of the 20 ECGs during coronary balloon occlusion met the 2007 American Heart Association guidelines for ST-elevation myocardial infarction (STEMI). Fifteen cardiologists read 4 sets of these ECGs as the basis for a “yes/no” reperfusion therapy decision. Sets 1 and 4 were the same 12-lead ECGs alone. Set 2 also included numeric ST-segment measurements, and set 3 included both numeric and graphically displayed ST measurements (“ST Maps”). The mean (range) positive reperfusion decisions were 10.6 (2-15), 11.4 (1-19), 9.7 (2-14), and 10.7 (1-15) for sets 1 to 4, respectively. The accuracies of the observers for the 5 STEMI ECGs were 67%, 69%, and 77% for the standard format, the ST numeric format, and the ST graphic format, respectively. The improved detection rate (77% vs 67%) with addition of both numeric and graphic displays did achieve statistical significance (P < .025). The corresponding specificities for the 10 control ECGs were 85%, 79%, and 89%, respectively. In conclusion, a wide variation of reperfusion decisions was observed among clinical cardiologists, and their decisions were not altered by adding ST deviation measurements in numeric and/or graphic displays. Acute coronary occlusion detection rate was low for ECGs meeting STEMI criteria, and this was improved by adding ST-segment measurements in numeric and graphic forms. These results merit further study of the clinical value of this technique for improved acute coronary occlusion treatment decision support.     

Enhancement of coronary reactive hyperemia in patients with ischemic myocardial tolerance during angioplasty

Summary The purpose of this study was to elucidate the effect of repeated brief coronary occlusions on reactive hyperemia during percutaneous transluminal coronary angioplasty (PTCA) in patients with or without ischemic tolerance. Seventeen patients undergoing PTCA for chronic stable angina were studied. Patients with well developed collateral vessels were excluded. After successful predilatation, coronary flow velocity was recorded with the use of a Doppler flow guide wire, and reactive hyperemia was assessed immediately after each of two 2-min coronary occlusions followed by 2 mins of reperfusion. The intracoronary electrocardiogram (icECG) was recorded via the flow guide wire placed in the center of the ischemic zone. Patients were divided into two groups: those who showed a reduction of ST elevation in the icECG recorded at the time of the second coronary occlusion (group I), and those who showed no difference in ST elevation between the two occlusions (group II). There were no significant differences in blood pressure, heart rate, or baseline coronary flow velocity between the two groups before the first occlusion, but the ST elevation at the time of the first coronary occlusion was greater in group I than in group II (8.9 ± 6.2 versus 1.1 ± 2.0mm,P < 0.01). Reactive hyperemia was significantly greater after the second coronary occlusion than after the first in group I (22.1 ± 15.8 versus 30.4 ± 21.0cm/s,P < 0.05), but it did not change in group II (25.6 ± 13.0 versus 23.5 ± 11.2cm/s NS). Reactive hyperemia was enhanced in patients with ischemic tolerance who showed a reduction in ST elevation in the icECG. These results suggest that observed reactive hyperemia does not necessarily reflect the severity of ischemia.     

Continuous monitoring of coronary venous oxygen saturation during PTCA and its relation to electrocardiographic ST changes]

The purpose of this study was to investigate change in coronary venous oxygen saturation (CSO2-Sat) during percutaneous transluminal coronary angioplasty (PTCA) and to compare the results with those of standard 12-lead ECGs (s-ECG) and epicardial ECG induced using an intracoronary guidewire (ic-ECG). CSO2-Sat was measured continuously in 10 patients undergoing PTCA; 5 patients with lesions in the left anterior descending coronary artery (LAD), one with lesions in the left circumflex artery (LCX), and 4 with right coronary artery (RCA) lesions. The results were as follows: 1. In all 6 patients with stenotic lesions in the left coronary artery, CSO2-Sat decreased by 5 to 22% immediately after balloon inflation. Significant changes in ic-ECG (ST deviation > or = 0.1 mV) were observed in 5 of the 6 patients, while significant changes in s-ECG (ST deviation > or = 0.1 mV) were observed in only 3 of the 6 patients. The s-ECG did not seem to be sensitive enough to represent myocardial ischemia in the LCX. 2. The interval from the balloon inflation to the significant change was shorter for CSO2-Sat than for the ECGs in 4 of the 5 patients with LAD lesions, except Case 4. The recovery time of CSO2-Sat to the basal level on balloon deflation was longer than the recovery times of ic-ECG and s-ECG. 3. There was no significant change in the CSO2-Sat in 3 of the 4 patients undergoing PTCA for RCA lesions, while significant changes were observed in the ic-ECG and s-ECG in all 4 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intracoronary Ketanserin Augments Coronary Collateral Blood Flow and Decreases Myocardial Ischemia During Balloon Angioplasty

Aims: To test the hypothesis that ketanserin augments coronary collateral blood flow and decreases myocardial ischemia during balloon angioplasty. Methods and Results: Forty-four patients with single vessel disease and stable angina were studied. Collateral flow was determined during balloon inflations, based on the distal velocity time integral (13 patients) or on coronary wedge/mean arterial pressure measurements (10 patients). The 2nd and 3rd inflations lasted the same time and between them 1.5 mg intracoronary ketanserin in 10 ml normal saline was administered over 3 min. In 21 control subjects normal saline alone was given. In the flow velocity group the velocity time integral was 78.5 ± 53.1 mm during the 2nd inflation and 106.0 ± 43.2 mm during the 3rd (p < .05), while the ST deviation was 1.1 ± .7 and .7 ± .7 mm, respectively (p. < .05). In the intracoronary pressure group the CWP/MBP was .40 ± .10 during the 2nd inflation and .45 ± .11 during the 3rd (p. < .05), while the ST deviation was 1.2 ± .8 and .8 ± .8 mm respectively (p. < .05). In the controls no variables changed during the tested inflations. Conclusion: Intracoronary administration of ketanserin augments coronary collateral flow and decreases myocardial ischemia during balloon angioplasty. This could be of clinical significance in the management of acute ischemic syndromes.     

Aminophylline Reduces Cardiac Ischemic Pain During Percutaneous Transluminal Coronary Angioplasty

Objectives. We investigated the effect of aminophylline, an antagonist of the adenosine P₁ receptor, on cardiac pain experienced during percutaneous transluminal coronary angioplasty (PTCA).

Background. Adenosine may mediate cardiac pain because the administration of adenosine provokes cardiac pain like angina. However, it is not known whether endogenous adenosine released during myocardial ischemia is responsible for cardiac pain.

Methods. This was a single-blind, placebo-controlled randomized study. Of 21 men with stable effort angina with one-vessel coronary artery disease who underwent balloon inflation four times during PTCA, 11 received intravenously administered aminophylline before the fourth balloon inflation and the other 10 were given saline solution. The severity of cardiac pain based on the pain score and ST segment elevation on standard surface and intracoronary electrocardiograms were assessed.

Results. All patients experienced cardiac pain during balloon inflation. Aminophylline significantly prolonged the duration of both the symptom-free interval (from 42 ± 13 to 64 ± 27 s, mean ± SD, p < 0.05) and inflation time (from 79 ± 23 to 103 ± 20 s, p < 0.05), and it significantly reduced the pain score from 7.6 ± 1.4 to 4.6 ± 2.3 (p < 0.01). However, aminophylline did not affect ST segment elevation. Saline solution did not affect any of these variables. Balloon diameter and pressure were not different between the third and the fourth inflation in either group.

Conclusions. Aminophylline significantly reduced the severity of cardiac pain during PTCA without affecting ST segment elevation. These findings suggest that the activation of P₁ receptors by endogenous adenosine may be partially responsible for cardiac pain during ischemia.

(J Am Coll Cardiol 1996;28:1725–31)>     

Postoperative follow-up of coronary artery bypass patients receiving calcium antagonist diltiazem

We performed a prospective, randomized clinical study on 211 elective coronary artery bypass patients to assess the antiischemic and antiarrhythmic effects of the calcium channel blocker diltiazem. Patients received perioperatively continuous 24-hour infusions of either diltiazem (0.1 mg/kg/hour; n=104) or nitroglycerin (1 µg/kg/minute; n=107). Patients randomized to the diltiazem group were kept on continuous oral diltiazem medication postoperatively (3×50 mg/day). After a postoperative follow-up period of 2 years, 119 of the 211 patients were available for a clinical evaluation: 56 patients randomized to the diltiazem group and 63 patients randomized to the control group. Twenty patients from the diltiazem and 14 control patients did not follow their medicamentation and were excluded from further study. The two groups did not differ with respect to preoperative and surgical data. Postoperatively, the incidence of atrial fibrillation (4.8% vs 18.6%,p<0.05) and the frequency of ventricular premature couplets (VPC)/hour (22±6 vs 37±11,p<0.05), Lown II arrhythmias (VPC >30/hour) (99±19 vs 254±58,p<0.05), and ventricular runs/hour (7±15 vs 38±25,p<0.05) were significantly lower in the diltiazem group. Furthermore, patients of the diltiazem group had significantly lower peak values of ischemia-sensitive laboratory parameters: creatine kinase-MB (17.6±14.3 vs 25.3±16.3 U/L,p<0.05), CK-MB-mass concentration (35.2±38.4 vs 51.5±33.9 µg/L,p<0.05), and troponin-T (0.98±0.7 vs 1.7±0.8 µg/L,p<0.05). Two years after coronary artery bypass surgery, fewer patients randomized to the diltiazem group showed signs of cardiac failure (0 vs 6.1%), ST-segment alterations during exercise (5.5% vs 13.2%,p<0.05), symptoms of angina during exercise (18.5% vs 22.4%, n.s.), atrial fibrillation (0 vs 2.0%), and new left bundle branch block (0 vs 8.2%), compared with controls. It is concluded that the calcium antagonist diltiazem is effective in reducing incidence and extent of arrhythmias and myocardial ischemia perioperatively and provides potent postoperative antiischemic and antiarrhythmic protection in patients after coronary artery bypass surgery.     

The lay of the land

To evaluate the presence and clinical significance of electrical alternans during PTCA, intracoronary electrocardiography (ic-ECG) was performed in 65 consecutive lesions. ST-T alternans, defined as a beat-to-beat difference in the ST elevation ?1 mm, was present in five lesions (7.7%), all in the proximal left anterior descending (LAD) coronary artery. The phenomenon was seen only after 130 sec (mean 174 ± 57) of balloon inflation. Only two of the five showed ST-T alternans simultaneously on both surface and ic-ECG. One of five patients had premature ventricular contractions following ST-T alternans. Three of these five lesions required a second balloon inflation with duration of ? 300 sec; there was no ST-T alternans on the second inflation in any of these lesions. We conclude: (1) the detection of ST-T alternans during PTCA is enhanced by use of ic-ECG, (2) electrical alternans during PTCA was seen only in proximal LAD lesions, implicating a large amount of ischemic myocardium as a requisite for the phenomenon, (3) electrical alternans is not immediate, requiring a certain duration of balloon occlusion and hence ischemia to occur, and (4) the absence of ST-T alternans during second balloon inflations suggests ischemic preconditioning may abolish this phenomenon.     

Nicorandil, a hybrid between nitrate and ATP-sensitive potassium channel opener, preconditions human heart to ischemia during percutaneous transluminal coronary angioplasty.

The human heart progressively becomes more tolerant to ischemia after repeated balloon inflations during percutaneous transluminal coronary angioplasty (PTCA). The present study investigated whether nicorandil, a hybrid between nitrate and an ATP-sensitive potassium channel opener, affects this ischemic preconditioning. Sixteen patients with stable angina pectoris caused by left anterior descending artery lesions were subjected to 2 balloon inflations of 2-min duration with a 3-min reperfusion period. Seven of these patients served as the control group and in the remaining 9 patients, nicorandil was administered intravenously (6 mg/h) throughout the PTCA procedure (nicorandil group). The lactate extraction ratio (LER) was obtained at 30 s after each ischemic event (LERpost-1 and LERpost-2) in both groups. In the control group, LERpost-1 was more negative than LERpost-2 (-185.7+/-74.2 vs -98.0+/-37.3%, p<0.01). The ratio of the sum of the ST elevation in the precordial leads during the second inflation (sumST-2, 0.94+/-0.66 mV) to that during the first inflation (sumST-1, 1.43+/-1.17 mV) was 0.72+/-0.16 in the control group, which was less than the ratio in the nicorandil group (1.06+/-0.13, p<0.01). Nicorandil abolished the difference between the 2 ischemic events (LERpost-1, -45.1+/-41.6 vs LERpost-2, -43.5+/-51.1%; sumST-1, 1.38+/-0.80 vs sumST-2, 1.46+/-0.90 mV). LER was less negative in the nicorandil group than that in the control group (LERpost-1, -45.1+/-41.6 vs -185.7+/-74.2%, p<0.01; LERpost-2, -43.5+/-51.1 vs -98.0+/-37.3%, p<0.05). Thus, nicorandil improved lactate metabolism during PTCA without significantly influencing ST-elevation. In conclusion, intravenous pre-administration of nicorandil appears to precondition the human heart during PTCA.     

Intracoronary electrocardiogram for early detection of myocardial viability during coronary angioplasty in acute myocardial infarction.

PURPOSE: The clinical value of the intracoronary electrocardiogram (ECG) for detecting myocardial viability in acute myocardial infarction was evaluated by thallium-201 scintigraphy and left ventriculogram at the chronic stage. METHODS: Intracoronary ECGs, recorded from the tip of a guidewire during emergency coronary angioplasty, were obtained in 65 patients with reperfused anterior myocardial infarction. Further ST segment elevation of greater than 0.2 mV detected during the balloon inflation was taken as significant. The left ventricular segmental shortening was measured from left ventriculograms recorded at acute and chronic stages. The infarct area was defined as viable when a thallium uptake of more than 50% was detected on thallium-201 myocardial scintigraphy at the chronic stage. RESULTS: During emergency coronary angioplasty, significant ST segment elevation was noted in 45 patients (Group A); however, the ST segment was not significantly elevated in the other 20 patients (Group B). The infarct area of 42 patients in Group A and three patients in Group B was viable on scintigraphy. Improvement left ventricular wall motion of the infarct area was observed in 39 of the 42 patients in Group A and the three patients in Group B. Therefore, intracoronary ECG can predict reversible dysfunction with excellent sensitivity (92.9%) and specificity (73.9%). CONCLUSIONS: The myocardium within an infarct area can be regarded as viable when a further ST segment elevation occurs on intracoronary ECG during emergency coronary angioplasty. It is useful, therefore, to monitor the intracoronary ECG during coronary angioplasty balloon inflation to assess the myocardial viability of the infarct area.     

Similar antiischemic effects of intracoronary atenolol and nifedipine during brief coronary occlusions in humans

Summary To compare the antiischemic effects of intracoronary administration of a beta blocker, atenolol, and of a calcium antagonist, nifedipine, on the clinical and electrocardiographic signs of myocardial ischemia induced by balloon occlusion of the coronary artery, we studied 32 consecutive patients undergoing routine PTCA. In each patient at least three balloon inflations were performed: the first served to verify the occurrence of ischemia (ST segment depression/elevation >1.5 mm); the second was used as a control occlusion; the third was performed after the patients were assigned to receive either atenolol 1.0 mg IC (group 1, N=16) or nifedipine V=0.2 mg IC (group 2, N=16). In a control population of 10 patients, the time to return to baseline of the ECG tended to be progressively shorter during the three consecutive inflations, but the other clinical and ECG parameters did not change significantly. In group 1 and group 2, two patients did not show ECG signs of ischemia at the third inflation; the time to ischemia increased in group 1 (+76%, p < .001) and group 2 (+85%, p < .01; NS group 1 versus group 2); ST segment displacement at 30 seconds decreased in group 1 (-38%, p < .01) and group 2 (-36%, p < .01; NS group 1 versus group 2). In group 1, 2/16 patients were symptom free, and the time to chest pain was significantly delayed (+47%, p < .01) at the third inflation; in group 2 no patient became asymptomatic at the third inflation, and the time to chest pain did not change (+5%, NS; NS group 1 versus group 2). In conclusion, the regional cardioplegia obtained through the blockade of the slow calcium channels with IC nifedipine or of the beta receptors with IC atenolol reduced myocardial ischemia to a similar extent during ballon occlusion of the coronary artery. Atenolol was also very effective on chest pain, though not significantly more than nifedipine.     

Intracoronary ST segment evolution during primary coronary stenting predicts infarct zone recovery

In patients with acute myocardial infarction (AMI), early ST segment elevation resolution on ECG predicts myocardial reperfusion and LV recovery. Intracoronary ECG is more sensitive than surface ECG to detect regional ischemia. In patients undergoing primary percutaneous coronary intervention (PCI), we investigated if failed myocardial reperfusion, despite successful infarct vessel recanalization, could be rapidly and easily identified by intracoronary ST segment monitoring from guidewire recording. We recorded intracoronary and standard ECG during primary coronary stenting (PCI) in 50 patients with AMI (59 ± 11 years; anterior AMI in 66%). All patients had a successful PCI and underwent 2D echocardiography soon after PCI and 6 months later. Following PCI, intracoronary ST resolution ≥ 50% from baseline was documented in 39 patients (78%; group A; from 11 ± 8 to 1 ± 2 mm) but not in 11 (22%; group B; from 11 ± 8 to 8 ± 5 mm). Group A had slightly shorter ischemic time (202 ± 94 vs. 238 ± 112 min in B; P = 0.2) and smaller peak CK values (2,752 ± 2,038 vs. 4,802 ± 3,671 U/L in B; P = 0.02). After PCI, ST resolution was found on standard ECG in 34 (87%) group A and in 3 (27%) group B patients. At 6‐month follow‐up, left ventricular ejection fraction was greater in group A (47% ± 8% vs. 39% ± 8% in B; P < 0.001) with improved wall motion score index (from 2.2 ± 0.3 to 1.7 ± 0.3 in A; from 2.3 ± 0.4 to 2.1 ± 0.4 in B; P < 0.001). There were no significant differences between intracoronary and standard ECG for sensitivity (92% vs. 86%) and specificity (62% vs. 57%) to predict improved infarct zone recovery after 6 months. ST elevation resolution on intracoronary recording during PCI predicts infarct zone recovery. Monitoring ST segment evolution by intracoronary ECG allows prompt and inexpensive identification in the catheterization laboratory of those patients without myocardial reperfusion, who may require adjunctive therapeutic interventions after successful infarct vessel recanalization. Catheter Cardiovasc Interv 2005;64:53–60. © 2004 Wiley‐Liss, Inc.     

The relationship of ST segment elevation shape with preserved myocardium and signal-averaged electrocardiography in acute anterior myocardial infarction

Although a relation between magnitude of ST segment elevation and myocardial damage has been shown in the early period of acute myocardial infarction (AMI), such a relation between the shape of the ST segment elevation, myocardial damage, and the clinical course remains obscure. For this purpose 62 first anterior AMI patients admitted in the first 6 h were enrolled for the study. On the basis of precordial V3 derivation prior to thrombolytic therapy, the shape of the ST elevation was separated into three groups: concave (n = 26), straight (n = 24), or convex types (n = 12). The relation between the shape of the ST elevation recorded on admission, and the results of predischarge low-dose dobutamine stress echocardiography (LDE) performed (n = 53) and signal-averaged ECG values were investigated. The basal wall motion score index (WMSI) and response to LDE in the concave group were better in the infarct zone. Additionally, the average akinetic segment number in the infarct zone was higher, and improvement in these segments was less in the convex and straight groups (concave 3.78 ± 2 vs 2.17 ± 2.1, P < 0.01; straight 5.15 ± 2.7 vs 4.45 ± 2.8, not significant (NS); convex 5.4 ± 2.3 vs 4.8 ± 2.1, NS; basal vs LDE). While only 13% (3/23) of the patients did not respond to LDE (P < 0.05 vs group B and P < 0.01 vs group C), 35% (7/20) of group B and 60% (6/10) of group C patients did not respond to LDE. Although no relation was found between better left ventricular function (WMSI < 2) and shape of the ST elevation in basal evaluation by multiple logistic regression analysis (P = 0.06), an independent relation was found between them following LDE (P = 0.01, odds ratio (OR) 4.5, 95% Confidence Interval (CI) 1.3–14.7). The incidence of ventricular late potential (LP) positivity was 11% (3/26) in the concave group, 16% (4/24) in the straight group, and 58% (7/12) in the convex group (P < 0.001 vs concave and P < 0.05 vs straight groups). We found that shape of the ST elevation could significantly predict the presence of late potentials in multiple logistic regression analysis (P = 0.003, OR 10.7, 95% CI 2.2–51.7). There was no in-hospital death in the concave group, whereas five patients died in either the straight or the convex group. Furthermore, arrhythmia was lower in the concave group during this period (P < 0.05), and exercise capacity was lower. In conclusion, we determined that there was a higher viable myocardium, and lower LP(positivity) and in-hospital mortality in patients with concave ST elevation on admission. Received: August 6, 2001 / Accepted: December 18, 2001     

Difference vectors to describe dynamics of the ST segment and the ventricular gradient in acute ischemia

Background

The ECG is important in the diagnosis and triage of the acute coronary syndrome (ACS), especially in the hyperacute phase, the “golden hours,” during which myocardial salvage possibilities are largest. An important triaging decision to be taken is whether or not a patient requires primary PCI, for which, as mentioned in the guidelines, the presence of an ST elevation (STE) pattern in the ECG is a major criterion. However, preexisting non-zero ST amplitudes (diagnostic, but also non-diagnostic) can obscure or even preclude this diagnosis.

Methods

In this study, we investigated the potential diagnostic possibilities of ischemia detection by means of changes in the ST vector, ΔST, and changes in the VG (QRST integral) vector, ΔVG. We studied the vectorcardiograms (VCGs) synthesized of the ECGs of 84 patients who underwent elective PTCA. Mean ± SD balloon occlusion times were 260 ± 76 s. The ECG ischemia diagnosis (ST elevation, STE, or non-ST-elevation, NSTE), magnitudes and orientations of the ST and VG vectors, and the differences ΔST and ΔVG with the baseline ECG were measured after 3 min of balloon occlusion.

Results

Planar angles between the ΔST and ΔVG vectors were 14.9 ± 14.0°. Linear regression of ΔVG on ΔST yielded ΔVG = 324·ΔST (r = 0.85; P < 0.0001, ΔST in mV). We adopted ΔST > 0.05 mV, and the corresponding ΔVG > 16.2 mV·ms as ischemia thresholds. The classical criteria characterized the ECGs of 46/84 (55%) patients after 3 min of occlusion as STE ECGs. Combined application of the ΔST and ΔVG criteria identified 73/84 (87%) of the patients as ischemic.

Conclusion

Differential diagnosis by ΔST and ΔVG (requiring an earlier made non-ischemic baseline ECG) could dramatically improve ECG guided detection of patients who urgently require catheter intervention.