High mortality early reinfarction with first nontransmural myocardial infarction

Layer-specific strain analysis: investigation of regional deformations in a rat model of acute versus chronic myocardial infarction

Myocardial infarction (MI) injury extends from the endocardium toward the epicardium. This phenomenon should be taken into consideration in the detection of MI. To study the extent of damage at different stages of MI, we hypothesized that measurement of layer-specific strain will allow better delineation of the MI extent than total wall thickness strain at acute stages but not at chronic stages, when fibrosis and remodeling have already occurred. After baseline echocardiography scans had been obtained, 24 rats underwent occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion. Thirteen rats were rescanned at 24 h post-MI and eleven rats at 2 wk post-MI. Next, rats were euthanized, and histological analysis for MI size was performed. Echocardiographic scans were postprocessed by a layer-specific speckle tracking program to measure the peak circumferential strain (S(C)(peak)) at the endocardium, midlayer, and epicardium as well as total wall thickness S(C)(peak). Linear regression for MI size versus S(C)(peak) showed that the slope was steeper for the endocardium compared with the other layers (P < 0.001), meaning that the endocardium was more sensitive to MI size than the other layers. Moreover, receiver operating characteristics analysis yielded better sensitivity and specificity in the detection of MI using endocardial S(C)(peak) instead of total wall thickness S(C)(peak) at 24 h post-MI (P < 0.05) but not 2 wk later. In conclusion, at acute stages of MI, before collagen deposition, scar tissue formation, and remodeling have occurred, damage may be nontransmural, and thus the use of endocardial S(C)(peak) is advantageous over total wall thickness S(C)(peak).

Frequency, significance, and cost of recurrent ischemia after thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Early postinfarction angina implies an unfavorable prognosis. Most published information on this outcome represents data collected in the prethrombolytic era, in which definitions and populations differed considerably. Our purpose was to evaluate the incidence and importance of recurrent ischemia after administration of thrombolytic therapy. We studied patients enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction studies. Patients were enrolled into 5 studies with similar entry criteria; 552 patients were treated with tissue plasminogen activator (t-PA), 293 were treated with urokinase, and 385 received both thrombolytic agents. Recurrent ischemia was defined as symptoms in association with electrocardiographic changes; reinfarction was defined as a reelevation of creatine kinase myocardial band isoenzyme in an appropriate clinical setting. Both recurrent ischemia and reinfarction occurred in 42 patients (3.4%), recurrent ischemia alone occurred in 226 (18%), whereas neither occurred in 964 (78%). Although baseline characteristics were similar among the 3 groups, in-hospital cardiac events (total 73 deaths, 253 heart failure episodes) were not: in-hospital mortality in patients with reinfarction was 21%; with recurrent ischemia, 11%; and with neither event, 4% (p < 0.0001). The in-hospital heart failure rate of patients with reinfarction was 50%; with recurrent ischemia alone, 31%; and with neither event, 17% (p < 0.0001). As expected, median in-hospital costs were highest in patients with reinfarction ($26,802), intermediate for those with recurrent ischemia alone ($18,422), and lowest in patients with neither event ($15,623). Recurrent myocardial ischemia after thrombolytic therapy is a frequent, important, and expensive adverse clinical outcome, making it a critical target for therapeutic intervention.

Comparative study of left ventricular function in patients with unstable angina, non-Q wave myocardial infarction and stable angina pectoris: assessment with atrial pacing and digital ventriculography

To compare left ventricular global and segmental function at rest and during right atrial pacing in patients with unstable angina, non-Q wave myocardial infarction, and stable angina (class III angina), low-dose digital subtraction ventriculography was performed at rest and after abrupt cessation of pacing in 42 patients with unstable angina, 8 patients with non-Q wave myocardial infarction and 15 patients with stable angina during selective coronary arteriography. Left ventricular ejection fraction was significantly lower at rest in patients with unstable angina (P < 0.01) and non-Q wave myocardial infarction (P < 0.05) and during pacing (P < 0.01). These two groups of patients had significantly higher values of left ventricular end-diastolic and end-systolic volumes at rest and during pacing as compared with stable angina group. In comparing various clinical patterns of unstable angina, ejection fraction was significantly (P < 0.05) lower during pacing in patients with crescendo angina than in new-onset angina. However, ejection fraction was significantly (P < 0.01) lower in crescendo angina only at rest as compared with rest angina. The length of zone of severe hypokinesia was greater in unstable angina (P < 0.01) as well as in non-Q wave myocardial infarction (P < 0.05) both at rest and during pacing as compared with stable angina. Contractility of region of hypokinesia during pacing was higher (P < 0.01) in stable angina than in unstable angina and non-Q wave myocardial infarction. In analyzing segmental function in various subgroups of unstable angina, the authors found that the length of total hypokinesia was significantly higher (P < 0.05) during pacing in crescendo angina than in new-onset angina. Contractility of region of hypokinesia was lowest at rest and during pacing in patients with crescendo angina. This study demonstrates that patients with unstable angina as well as non-Q wave myocardial infarction were characterized by more pronounced global and segmental left ventricular dysfunction at rest and during pacing as compared with patients with stable angina, which may explain the poorer prognosis in the former two groups. This study also shows that patients with crescendo angina have more profound left ventricular global and regional dysfunction as compared with patients with new-onset as well as rest angina.

Significance of location (anterior versus inferior) and type (Q-wave versus non-Q-wave) of acute myocardial infarction in patients undergoing percutaneous transluminal coronary angioplasty for postinfarction ischemia

Predictors of increased risk for recurrent cardiac events and death after acute myocardial infarction include postinfarction myocardial ischemia, anterior location of the infarct, and non-Q-wave versus Q-wave infarction. Although coronary angioplasty is performed in patients with postinfarction ischemia to alleviate symptoms, the outcome according to location and type of infarction and the effect on prevention of subsequent myocardial infarction and death are not known. To determine if location and type of myocardial infarction provide prognostic information in patients with postinfarction ischemia, we analyzed morbidity and mortality during and after coronary angioplasty according to the location (anterior vs inferior) and type (Q-wave vs non-Q-wave) of myocardial infarction in 505 consecutive patients. The incidence of recurrent angina, repeat coronary angioplasty, coronary bypass surgery, reinfarction, and death during long-term follow-up after hospital discharge (mean 34 +/- 19 months) for the 440 patients with an initial successful angioplasty was also compared. During the procedure, there was no difference in the primary success rate or mortality among the different groups; however, more patients with anterior non-Q-wave myocardial infarction underwent emergent bypass grafting after unsuccessful coronary angioplasty (p = 0.001). Multivariate Cox proportional-hazards analyses controlling for age, gender, number of diseased vessels, location, type of infarction, and year of coronary angioplasty revealed that more patients with anterior infarction had > or = 1 cardiac event (repeat angioplasty, coronary artery bypass grafting, reinfarction, or death) than did those with inferior infarction (RR 1.80, 95% confidence interval [Ci] 1.22 to 2.65, p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Pacing-induced ST segment deviation in patients with unstable angina: clinical, angiographic, and hemodynamic correlation

To assess the clinical, coronary arteriographic, and hemodynamic differences between the unstable angina patients manifesting ST segment depression and those showing ST segment elevation as well as those demonstrating chest pain only without ST segment deviation during pacing, low-dose digital subtraction ventriculography was performed in 33 patients before and after abrupt cessation of atrial pacing during selective coronary arteriography. Transient ST segment depression during pacing was observed in 17 patients (52%), whereas 6 patients (18%) showed ST segment elevation; however, 10 patients (30%) did not manifest any ST segment deviation in spite of typical chest pain. Hypertension and a history of myocardial infarction were observed in a significantly higher (P < 0.05) proportion of patients with ST segment depression than in those with ST elevation. Patients who manifested ST segment depression during pacing had a higher incidence of triple-vessel disease (65 vs 17%; P < .05) as compared with the patients with ST segment elevation. Indirect evidence of intracoronary thrombi (complicated lesion, abrupt occlusion, and intraluminal filling defect) was noticed in a higher frequency (P < 0.05) in the group of patients with ST elevation during pacing. In patients with ST segment depression, no significant changes of global left ventricular (LV) functional parameters were observed. However, the length of the LV severe hypokinetic region was increased significantly (6.2 +/- 3.1 vs 23.5 +/- 6.2%; P < 0.005) during pacing in this group of patients. The shortening of the affected segments of the left ventricle was decreased significantly (52.3 +/- 3.6 vs 38.3 +/- 4.9%; P < 0.05) in these patients during pacing. In the group of patients with ST segment elevation during pacing, decrease in ejection fraction was associated with significant (P < 0.01) increase in midwall equatorial diastolic stress as compared with the patients with pacing-induced ST segment depression as well as patients without ST segment deviation. In the group of patients without ST segment deviation during pacing there was no considerable aggravation of LV global or regional function. This distinction should be taken into consideration in evaluating patients with unstable angina for diagnostic and therapeutic intervention.

Arteriographic morphology and intracoronary thrombus in patients with unstable angina, non-Q wave myocardial infarction and stable angina pectoris

Coronary artery lesions were compared in 71 patients with unstable angina, 15 patients with non-Q wave myocardial infarction (MI), and 40 patients with stable angina. In the unstable angina group, 29 patients had new-onset angina, 31 had crescendo angina, and 11 had rest angina. In a subgroup of patients with unstable angina, three-vessel disease was less frequently (P < 0.05) seen in patients with new-onset angina (10.3%) than in the patients with crescendo angina (51.6%) or rest angina (54.5%). An angina-producing artery could be identified in 59 patients with unstable angina, in 11 with non-Q wave MI, and in 30 with stable angina. Type II eccentric stenosis (asymmetric narrowing with narrow neck and overhanging irregular edges) was present in 31 patients (52.5%; P < 0.01) with unstable angina, in 7 (63.6%; P < 0.01) with non-Q wave MI, and in only 2 (6.7%) with stable angina. Abrupt occlusion of a vessel was observed in 7 patients (11.9%) with unstable angina and in 2 (18.2%) with non-Q wave MI. None of the patients with stable angina had this type of occlusion. In the group of unstable angina and non-Q wave MI, angiographic evidence of intracoronary thrombi was present in 16 (27.1%) and 3 patients (27.3%), respectively, but in stable angina in only 1 patient (3.3%; P < 0.05). Intracoronary thrombi were most frequently found in rest angina (88%; P < 0.001) and crescendo angina (33.3%; P < 0.01) compared with new-onset angina (3.7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of coronary angiographic findings during the first six hours of non-Q-wave and Q-wave myocardial infarction

The angiographic features of non-Q-wave acute myocardial infarction (AMI) soon after symptom onset have not been previously reported. Accordingly, this study reviewed the coronary angiographic findings of 86 patients with AMI studied within 6 hours of symptom onset: 58 had Q-wave and 28 had non-Q-wave AMI. Patients with Q-wave and non-Q-wave AMI were comparable in terms of clinical characteristics, frequency of 1-vessel disease, and infarct-related artery location. Thrombus was observed in 49 patients (84%) with Q-wave AMI versus 12 (43%) with non-Q-wave AMI (p = 0.0002). Whereas complete occlusion of the infarct-related artery was present in 53 patients (91%) with Q-wave AMI, total coronary occlusion was present in only 11 (39%) with non-Q-wave AMI (p = 0.0001). Collaterals to occluded infarct arteries were seen in 10 patients (19%) with Q-wave AMI versus 5 (45%) with non-Q-wave AMI (p = 0.06). Residual perfusion of the infarct artery by either anterograde or collateral flow was typical of patients with non-Q-wave AMI (22 of 28, 79%) but was uncommon in those with Q-wave AMI (15 of 58, 26%) (p = 0.0001). Thus, coronary angiography performed within 6 hours of symptom onset demonstrates important differences between Q-wave and non-Q-wave AMI. Non-Q-wave AMI is characterized by partial perfusion of the infarct-related artery by either anterograde or collateral flow, and a lower incidence of thrombus than Q-wave AMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term prognostic significance of ST segment depression during acute myocardial infarction. The Multicenter Diltiazem Postinfarction Trial Research Group

OBJECTIVES

The purpose of this study was to evaluate the long-term prognostic value of ST segment depression on the electrocardiogram (ECG) in patients with acute myocardial infarction.

BACKGROUND

The prognostic importance of ST segment depression on the ECG has been studied in small groups of patients with infarction, but larger numbers are needed.

METHODS

Coronary care unit ECGs of 1,234 patients who survived the coronary care unit with acute Q wave (n = 896) or non-Q wave (n = 338) myocardial infarction were analyzed for the presence of ST segment depression. Patients were followed up for up to 4 years.

RESULTS

ST segment depression was present in 607 patients. Those with ST segment depression had a 1-year mortality rate of 10.3% compared with a rate of 5.6% for those without ST segment depression (p = 0.002). This effect was seen in both the Q wave and non-Q wave subgroups. Of the 437 patients with anterior ST segment elevation, those with ST segment depression in other regions had a 13.6% 1-year mortality rate compared with a rate of 6.9% for those with no ST segment depression (p = 0.0005). Of the 514 patients with inferior ST segment elevation, those with ST segment depression in other leads had an 11.0% 1-year mortality rate compared with a 1.8% rate for those with no ST segment depression (p = 0.0001). The Cox proportional hazards model showed that ST segment depression was an independent predictor of mortality over the follow-up period.

CONCLUSIONS

ST segment depression on the admitting ECG in patients with acute myocardial infarction is a predictor of increased mortality in the year after infarction.

Preexisting cardiovascular conditions and long-term prognosis after initial myocardial infarction: the Framingham Study

Preexisting cardiovascular conditions (angina pectoris, intermittent claudication, stroke or transient ischemic attack, and congestive heart failure) were evaluated in relation to long-term prognosis after an initial MI in 828 subjects from the Framingham Heart Study. Preexisting angina pectoris and intermittent claudication in men were associated with increased risk of coronary mortality and recurrent MI, whereas congestive heart failure increased coronary mortality. In women, prior angina pectoris increased the risk of recurrent MI and congestive heart failure increased the coronary mortality. Adjusting for the major cardiovascular risk factors measured before MI, these results held for men but no significant adverse effects persisted in women. Among subjects who survived to return for subsequent examinations, only prior congestive heart failure in men increased the risk after adjusting for post-MI risk factors. In women who returned, angina pectoris and intermittent claudication were associated with poor post-MI prognosis. These results suggest that atherosclerosis is a diffuse disease of the circulatory system, and one in which post-MI prognosis is influenced by the presence of other preexisting cardiovascular conditions. Hence a patient who has an MI after prior expression of cardiovascular disease requires more vigorous preventive management.

Effects of diltiazem on recurrent myocardial infarction in patients with non-Q wave myocardial infarction

Diltiazem has been reported to reduce the short-term in-hospital reinfarction rate in patients with a non-Q wave myocardial infarction. In the long-term Multicenter Diltiazem Postinfarction Trial, there were 514 patients with non-Q wave myocardial infarction; 279 patients were randomized to the placebo group and 235 to the treatment group. The average follow-up period was 25 months. There was no difference in baseline clinical characteristics between the two groups. Early reinfarction (less than or equal to 6 months) occurred in 17 patients in the placebo group and in 2 patients in the diltiazem group (p less than 0.001). Late reinfarction (greater than 6 months) occurred in 13 patients in the placebo group and in 14 patients in the diltiazem group (p = NS). Initial and reinfarction electrocardiograms (ECGs) were analyzed by using a coding system that permitted identification of standard anatomic areas involved in the infarction process. Thirty-one of the 46 patients had a localized infarction on index and reinfarction ECGs. In the early reinfarction group, 10 (77%) of 13 infarctions occurred in the same ECG region in which the initial infarction had occurred; all 10 were in patients in the placebo group. Among the 18 patients with late reinfarction, the site of the second infarction was the same as that of the first in 9 patients and differed in 9. There was no difference between the placebo and diltiazem groups with respect to location of the infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Natural history of the first non-Q wave myocardial infarction in the placebo arm of the Beta-Blocker Heart Attack Trial

Despite extensive investigation, the prognostic significance of the first non-Q wave acute myocardial infarction (AMI), when compared with Q wave AMI, remains controversial. The placebo arm of the Beta-Blocker Heart Attack Trial (BHAT) provides a unique opportunity to compare the long-term cardiac events in patients suffering from their first and uncomplicated Q wave or non-Q wave AMI. Of a total 3837 patients enrolled in the BHAT, 3375 were classifiable in terms of appearance or absence of Q waves during the prerandomization period. Of these, 1444 patients with their first AMI were randomized to placebo. Of these, 1186 experienced a Q wave AMI; the remaining 258 suffered a non-Q wave AMI. At 36 months of follow-up, the mortality was 8.4% in the Q wave AMI group and 7.4% in the non-Q wave AMI group. Sudden death was 5.4% in the Q wave AMI group and 4.7% in the non-Q wave AMI group. The reinfarction rate was 5.5% in the Q wave AMI patients and 7.4% in the non-Q wave AMI patients. More patients developed angina (44.6%) in the non-Q wave AMI group compared with 35.2% in the Q wave AMI group. Despite similar long-term cardiac event rates within the two groups, the 1-year mortality rate for patients with Q wave AMI appeared higher than in the non-Q wave AMI group, 5.2% versus 3.1%, respectively. In contrast, the rate of reinfarction appeared higher at the 12-month follow-up period in the non-Q wave AMI group, 4.7% versus 3.4%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)c

Recovery of regional myocardial dysfunction after successful coronary angioplasty early after a non-Q wave myocardial infarction

More aggressive therapy has been suggested for patients who have a non-Q wave myocardial infarction (MI) because of the frequency of subsequent unstable angina, recurrent MI, and high mortality rate compared to patients with Q wave MI. The present study was undertaken to investigate the effect of coronary angioplasty on regional myocardial function of the infarct zone in patients with angina early after a non-Q wave MI. The study population consisted of 36 patients undergoing successful coronary angioplasty within 30 days of a non-Q wave MI, in whom sequential left ventricular angiograms of adequate quality were obtained before the initial procedure and at follow-up angiography. The global ejection fraction increased significantly from 60 +/- 9% to 67 +/- 6% (p = 0.0003). This significant increase in the global ejection fraction was primarily due to a significant improvement in the regional myocardial function of the infarct zone. The results of the present study show not only that ischemic attacks early after a non-Q wave MI may lead to prolonged regional myocardial dysfunction but more important that this depressed myocardium has the potential to achieve normal contraction after successful coronary angioplasty.

Cardiac event rate after non-Q-wave acute myocardial infarction and the significance of its anterior location

To correlate cardiac event rate with infarct location on the electrocardiogram in patients recovering from a non-Q-wave acute myocardial infarction (AMI), 135 consecutive patients with enzymatically proven non-Q-wave AMI were followed prospectively for a median of 9.9 months. Of these, 65 patients were classified as having had an anterior non-Q-wave AMI, defined as new ST- or T-wave changes, or both, in leads V1 through V4 (group 1). The remaining 70 patients were classified as having had inferior or lateral non-Q-wave AMI, or both, defined as ST- or T-wave changes in 2 consecutive leads (II, II aVF; II and aVL or V5 and V6) (group 2). At baseline group I was older and had a higher incidence of previous AMI than group 2. After adjusting for baseline variables, the patients in group I had a 29% reinfarction and 32% mortality rate, which was significantly higher (p less than 0.002 for both) when compared to group 2, which had a reinfarction and mortality rate of 8 and 9%, respectively. Patients with anterior non-Q-wave AMI are at very high risk for developing a major cardiac event very soon after the index AMI. This high risk is probably related to a larger area of residual ischemic but viable myocardium in the infarct-related artery when compared to inferolateral non-Q-wave AMI.

Calcium-channel blockers in acute myocardial infarction

The calcium-channel blockers are useful in treating a variety of cardiovascular disorders. Due to their antiischemic and spasmolytic properties, these agents have been studied in the prophylaxis and treatment of acute myocardial infarction. This article reviews this application with respect to reduction of mortality, infarct size, and reinfarction rate. Of the agents currently available for clinical use, nifedipine has been studied most extensively. This agent shows no beneficial effects in this setting and its use may in fact be harmful. Of the few trials that have been conducted with verapamil, none have shown decreased mortality. Verapamil may reduce infarct size although further confirmation is required. Diltiazem is the only agent that has been shown to have short- and long-term benefits in the patient with acute myocardial infarction. Proper patient selection is of utmost importance in ensuring successful therapy. In particular, those patients with non-Q-wave infarctions and/or normal left ventricular function can be expected to derive the most benefit in terms of reducing mortality and reinfarction rate associated with the acute event.

Risk stratification in patients with first non-Q wave infarction: limited value of the early low level exercise test after uncomplicated infarcts. The Multicenter Post-Infarction Research Group

Risk stratification using clinical and historical variables plus early low level exercise testing was performed in 141 patients with a first non-Q wave myocardial infarction. The 111 patients who performed the exercise test had a 3.6% cardiac mortality rate in the first year compared with 13.3% in the 30 patients who could not exercise (p = 0.063), and a 1 year incidence rate of recurrent cardiac events (cardiac death or recurrent nonfatal myocardial infarction) of 10.8% compared with 23.3% (p = 0.127). Patients who developed ischemia (ST depression or angina) during the test had an increased incidence of cardiac events in the year after the infarction (odds ratio greater than 3, p less than 0.05). When patients were subgrouped by the presence or absence of pulmonary congestion, the discriminatory value of the exercise test was seen to reside primarily in the cohort with pulmonary congestion. For example, ST depression during exercise in this group identified patients with a 71% incidence of cardiac events in the year after the infarction compared with 5.3% for those without ST depression (odds ratio 45, p = 0.002). In the patients without pulmonary congestion, the exercise test had no discriminatory value. It is concluded that early low level exercise testing has a limited role after an uncomplicated non-Q wave infarction, but is useful in patients with clinical markers of higher risk.

"Non-Q wave," alias "nontransmural," myocardial infarction: a specific entity

Although Q wave and non-Q wave MI are often referred to as "transmural" and "nontransmural," there is no anatomic evidence to justify this distinction. Nevertheless, a distinction is important, because the two entities have a different prognosis. At the present time, between 25% and 35% of MIs are non-Q wave. They are frequently observed in patients with previous coronary events. They occur in a relatively older population and involve a slightly higher proportion of women than do Q wave MIs. The degree of cardiac damage is less, reflected by a smaller rise in enzyme level and less impairment of left ventricular ejection fraction; early reperfusion may occur, after spontaneous thrombolysis or resolution of coronary spasm. The immediate mortality rate is half that of Q wave MI but identical in the long term. Reinfarction and angina are more frequent because of a peri-infarction zone of ischemia maintained by a high-grade coronary stenosis and inadequate collateral circulation. Early characterization of those MIs likely to progress is important. Diltiazem seems effective in this context if given between 24 and 72 hours of the onset of the event. Other therapeutic approaches need further assessment.

Short- and long-term clinical outcome after Q wave and non-Q wave myocardial infarction in a large patient population

Prognosis for patients with non-Q wave myocardial infarction is controversial although a number of studies have shown a less favorable outlook after hospital discharge for patients with non-Q wave than for those with Q wave infarction. Therefore, the in-hospital and 1-year prognosis was investigated in a sufficiently large patient population (n = 2,024) to allow stratification by subgroups, in particular by age and previous myocardial infarction. Patients with non-Q wave infarction (n = 444; 22% of the total study population) were somewhat older (65 vs. 63 years, p less than 0.001) and had an increased incidence of previous myocardial infarction (46% vs. 24%, p less than 0.001) and congestive heart failure (21% vs. 8%, p less than 0.001) than patients with Q wave infarction. In-hospital mortality of patients with non-Q wave infarction was lower (8.1% vs. 11.5%; p less than 0.06), whereas their 1-year mortality after hospital discharge was significantly higher (13.7% vs. 9.2%, p less than 0.05) than for patients with Q wave infarction. However, total mortalities at 1 year were nearly equal. When patients were subgrouped by presence or absence of a previous myocardial infarction, patients in both subgroups exhibited mortality patterns typical of the entire population with Q wave or non-Q wave infarction. However, when stratified by age and previous infarction, in-hospital mortality for patients with non-Q wave infarction was significantly lower only in patients older than 70 years of age. Similarly, the higher mortality after hospital discharge in patients with non-Q wave infarction occurred only in patients older than 70 years of age without previous myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic significance of angina pectoris before first acute myocardial infarction

To delineate the clinical significance and prognostic importance of a history of chronic or new onset angina pectoris before acute myocardial infarction (AMI), 732 consecutive patients admitted for a first AMI were studied and divided into 3 groups. Two hundred patients (27%) had chronic angina before AMI (greater than 1 month); 247 patients (34%) had new onset angina before AMI (less than 1 month) and the 285 remaining patients (39%) never had angina before AMI. All clinical characteristics were similar in the group of patients with chronic angina and in the group of patients with new onset angina, including in-hospital mortality (10 vs 9%) and 3-year post-hospital mortality (16 vs 16%). Compared to the 285 patients without angina, the 447 patients with angina before AMI were older, more likely to be women, and had a higher frequency of anterior AMI and early post-infarction angina. Both groups had a similar in-hospital mortality (10 vs 8%, not significant), but patients with angina had a higher 3-year post-hospital mortality (16 vs 7%, p less than 0.001). In the group of patients with angina before AMI who were discharged from the hospital, the comparison of nonsurvivors and survivors showed that the patients who died were older, presented more frequently with a non-Q-wave myocardial infarct and more often had left ventricular failure and complete bundle branch block during hospital stay. Chronic and new onset angina before AMI have the same clinical characteristics and deleterious long-term prognostic significance.

Q and non-Q wave myocardial infarction: current views

The new terminology "Q and non-Q wave myocardial infarction" (MI) tends to replace the traditional terms "transmural" and "subendocardial" MI since the anatomy cannot be accurately predicted by electrocardiography. Although some subtypes of non-QMI display a favorable early or in-hospital prognosis, the long-term outlook seems less benign, particularly when early or late recurrence of MI occurs. Coronary arteriograms show an equal number of diseased vessels in both types of MI, but complete coronary artery occlusion is less frequent in non-QMI. The management of patients with non-QMI should be mainly directed to preventing extension or recurrence of MI by using either drugs such as thrombolytic agents and drugs against coronary artery spasm or invasive techniques like percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty for angina pectoris after a non-Q-wave acute myocardial infarction

Despite initially favorable prognosis in patients with non-Q-wave acute myocardial infarction (AMI), long-term mortality in this subset of patients appears to be similar to or even greater than that in patients with Q-wave AMI. The relatively poor late prognosis is primarily due to a high incidence of unstable angina and recurrent AMI. Between January 1982 and January 1987, 114 patients with suitable coronary narrowing underwent percutaneous transluminal coronary angioplasty (PTCA) for angina pectoris (present either at rest or during mild exertion, and despite optimal pharmacologic therapy), a median of 31 (range 2 to 362) days after a non-Q-wave AMI. Success was achieved in dilating the obstructed artery in 98 patients (113 of the 129 dilated arteries). Emergency bypass surgery was performed in 7 patients. Mean clinical follow-up of 20 (range 3 to 59) months was obtained in all patients and revealed no deaths. Of the 98 patients with successful PTCAs, 6 (6%) developed a nonfatal recurrent AMI and 62 (63%) were asymptomatic. However, recurrent angina affected 31 patients (32%) and was treated by repeat PTCA (n = 18), coronary bypass surgery (n = 5) or pharmacologic therapy (n = 8). At follow-up, 74% of the patients (73 of 98) were asymptomatic after a successful PTCA and, if necessary, a repeat PTCA, without incidence of recurrent AMI, coronary bypass surgery or death. The high initial success rate, low incidence of subsequent death and late recurrent AMI and sustained symptomatic benefit suggest that PTCA is an effective initial treatment strategy in these selected patients.

Myocardial infarct extension. Identification of subgroups by the pattern of the serum CKMB level

To examine the clinical course of patients with acute myocardial infarction complicated by "extension", we studied prospectively 141 patients who had been diagnosed as having acute myocardial infarction. The serum CKMB level of these patients was determined at 8-h intervals during the first 5 days following admission. The patients were classified into 3 groups. Group A (early extension): patients who showed CKMB re-elevation before the CKMB values reached normal levels (28%). Group B (late extension): patients who showed CKMB re-elevation after the normalization of serum CKMB levels (21%). Group C (control group): patients without CKMB re-elevation (51%). Patients in group A showed the most unfavourable clinical course with a greater rate of haemodynamic deterioration compared with patients in the B or C groups, and a higher rate of recurrent ischemic pain. We found no significant differences in these parameters between the B and C groups. We were unable to find any risk factor associated with the development of extension. The pattern of the serum CKMB curve may allow a separation of two different subgroups of patients with acute myocardial infarct extension: patients with early extension, who show a high prevalence of haemodynamic deterioration, and patients with late extension, characterized by small infarcts and a benign clinical course.

Initial and late results of coronary angioplasty for early postinfarction unstable angina

Unstable angina that occurs in the early postinfarction period is associated with an increased incidence of unfavorable cardiac events despite aggressive medical therapy. We examined the results of coronary angioplasty in 47 consecutive patients with postinfarction unstable angina who were referred for the procedure 12.9 +/- 7 days following myocardial infarction, 14 of which were Q wave and 33 of which were non-Q-wave. Coronary angioplasty was performed on a total of 55 arteries with a mean predilatation stenosis of 95 +/- 8%. These included 46 infarct-related arteries and nine noninfarct arteries. Double-vessel angioplasty was performed in eight patients. Successful coronary angioplasty (greater than 30% reduction of predilatation stenosis) was achieved in 43 patients (91%), with a mean residual stenosis of 33 +/- 28%. There was one in-hospital death, one patient required emergency bypass surgery, and two patients had early reocclusion resulting in myocardial infarctions. The 39 patients who had successful angioplasty procedures and who were discharged from the hospital without an unfavorable outcome were followed for 16.3 +/- 7 months, and repeat coronary angioplasty was required in five patients from 45 to 105 days after the initial procedure. Two patients had subsequent elective bypass surgery, one had a recurrent myocardial infarction, and one patient had a noncardiac death. For selected patients with suitable coronary anatomy, coronary angioplasty appears to offer an efficacious therapeutic option for early postinfarction unstable angina.

Predictive importance of clinical findings and a predischarge exercise test in patients with suspected unstable coronary artery disease

The prognostic information of clinical variables and a predischarge exercise test was studied in 400 patients (282 men, 118 women) admitted to the coronary care unit with suspected unstable coronary artery disease, that is, recurring chest pain of new onset, increasing anginal pain in formerly stable angina pectoris or suspected nontransmural acute myocardial infarction. Forty-nine coronary events occurred in the 276 men who performed the exercise test during the following year, whereas only 5 coronary events occurred among the 118 women. The only variable of prognostic importance in women was nontransmural myocardial infarction. In men, the clinical variables increasing age, duration of angina, ST- or T-segment changes on the rest electrocardiogram and increasing angina or nontransmural myocardial infarction as inclusion criteria were associated with increased occurrence of coronary artery bypass surgery, transmural myocardial infarction or cardiac death. Findings of ST-segment depression, limiting chest pain or low rate-pressure product during the exercise test were of greater value than any clinical variable in prediction of coronary artery bypass surgery, transmural myocardial infarction or cardiac death. Within all clinical subgroups of men, the results of the exercise test had an additive predictive value for future coronary events. Combinations of clinical data and exercise test results enabled the best identification of patients with high or low risk for coronary events.

Usefulness of percutaneous transluminal coronary angioplasty for unstable angina pectoris after non-Q-wave acute myocardial infarction

Without revascularization, patients with non-Q-wave acute myocardial infarction (AMI) are predisposed to angina, recurrent AMI and cardiac death. Percutaneous transluminal coronary angioplasty (PTCA) was performed in 68 patients with angina an average of 2.3 months after non-Q-wave AMI (41 anterior, 27 inferior). Mean diameter stenosis was 95%, with collateralized total occlusion of the infarct-related artery in 23 patients. PTCA was successful in 87% (59 of 68), with a mean residual stenosis of 30%. One patient had emergency bypass surgery. Long-term follow-up (average 17 +/- 10 months) was available for 58 of the 59 patients in whom PTCA was successful. Recurrent angina developed in 41% (24 of 58), but was relieved by repeat PTCA in 14, by late coronary artery bypass surgery in 4 and by medical therapy in 6. There was 1 nonfatal AMI, due to progressive disease in a nondilated vessel, and 1 noncardiac death At last follow-up, 46 of 58 patients (79%) were asymptomatic and fully active or employed. Thus, patients undergoing PTCA for angina after non-Q-wave AMI appear to have a relatively high clinical restenosis rate, but with repeat PTCA have a low incidence of subsequent angina, AMI and cardiac death.

Non-Q-wave myocardial infarction

The rationale for introducing the term "non-Q-wave myocardial infarction" is identified. The incidence, pathology, pathogenesis, and diagnostic criteria for this condition, previously identified as nontransmural or subendocardial infarction, are reviewed. In reviewing the diagnostic criteria, the various noninvasive techniques that may be applied are discussed. The clinical course, prognosis, and management are discussed under the headings of early postinfarction period, late clinical course, predischarge evaluation, and long-term care. The issues of the management of infarct extension and acute interventional therapy are raised and reviewed. Suggestions regarding specific aspects of therapy in non-Q-wave myocardial infarction are included in the summary.

Coronary arteriographic findings soon after non-Q-wave myocardial infarction

Complete occlusion of the infarct-related coronary artery is a frequent finding soon after Q-wave (transmural) myocardial infarction. We performed coronary arteriography to study the frequency of total coronary occlusion and of angiographically visible collateral vessels in 341 patients within one week of non-Q-wave myocardial infarction. In this cross-sectional study, 192, 94, and 55 patients underwent coronary arteriography within 24 hours of peak symptoms, between 24 and 72 hours after peak symptoms, and between 72 hours and seven days after peak symptoms, respectively. In the three groups, total occlusion of the infarct-related vessel was found in 26 percent (49 of 192), 37 percent (35 of 94), and 42 percent (23 of 55) of the patients, respectively (P less than 0.05). The presence of visible collateral vessels increased in parallel: 27 percent (52 of 192), 34 percent (32 of 94), and 42 percent (23 of 55), respectively (P less than 0.05). The frequency of subtotal occlusion (i.e., greater than or equal to 90 percent stenosis) decreased inversely: 34 percent (65 of 192), 25.5 percent (24 of 94), and 18 percent (10 of 55), respectively (P less than 0.05). Thus, in contrast to Q-wave infarction, total coronary occlusion of the infarct-related vessel is infrequently observed in the early hours of non-Q-wave infarction, but it increases moderately in frequency over the next several days. These cross-sectional data suggest that non-Q-wave infarction may be related to a preserved but marginal blood supply, which sufficiently disrupts the relation between the supply of and the demand for myocardial oxygen to cause tissue necrosis.

Subendocardial infarction in retrospect: pathologic, cardiographic, and ancillary features

Fifty-three patients with subendocardial infarction (SEMI) were studied at autopsy; all were elderly and the group was equally divided by sex. About half had more than one SEMI; the recurrences or extensions often involved superjacent, but not infrequently adjacent, areas. Six showed fibrinous pericarditis. This larger study showed more widespread and severe coronary narrowing than an earlier report. Six patients had thrombi in the right coronary artery. Six showed electrocardiographic evidence of concomitant anteroseptal and inferior (Roesler-Dressler) infarction, and 12 had intraventricular block generally preceding higher-grade block or arrhythmias. At some time during their terminal hospitalization, 27 patients, or half, developed distinctive protracted RS-T depression or T wave inversion. Twenty-four of the SEMIs were diagnosed on accepted criteria as transmural infarct; that diagnosis was sustained in only four. Thus neither the presence of changes in RS-T segment or T wave nor the absence of QRS changes are mandatory for the diagnosis of SEMI; this invalidates the common assumption that the diagnosis is not justified unless these conditions are met.