Coronary angiography and left ventriculography in survivors of transmural and nontransmural myocardial infarction

Association Between Early Q Waves and Reperfusion Success in Patients With ST-Segment–Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

Background—

Pathological early Q waves (QW) are associated with adverse outcomes in patients with ST-segment–elevation myocardial infarction (STEMI). Primary percutaneous coronary intervention (PCI) may therefore be less beneficial in patients with QW than in patients without QW. Myocardial salvage index and microvascular obstruction (MVO) are markers for reperfusion success. Thus, to clarify the benefit from primary PCI in STEMI patients with QW, we examined the association between baseline QW and myocardial salvage index and MVO in STEMI patients treated with primary PCI.

Methods and Results—

The ECG was assessed before primary PCI for the presence of QW (early) in 515 STEMI patients. The patients underwent a cardiac magnetic resonance imaging scan at day 1 (interquartile range [IQR], 1–1) and again at day 92 (IQR, 89–96). Early QW was observed in 108 (21%) patients and was related to smaller final myocardial salvage index (0.59 [IQR, 0.39–0.69] versus 0.65 [IQR, 0.46–0.84]; P <0.001) and larger MVO (1.4 [IQR, 0.0–5.4] versus 0.0 [IQR, 0.0–2.4]; P <0.001) compared with non-QW. QW remained associated with both final myocardial salvage index (β=−0.12; P =0.03) and MVO (β=0.18; P =0.001) after adjusting for potential confounders.

Conclusions—

Patients presenting with their first STEMI and early QW in the ECG had smaller myocardial salvage index and more extensive MVO than non-QW despite treatment within 12 hours after symptom onset. However, final myocardial salvage index in patients with QW was substantial, and patients with QW still benefit from primary PCI.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01435408.

Prognostic Value of Viable Myocardium in Patients with Non-Q-wave and Q-wave Myocardial Infarction

This study assessed the amount and prognostic value of myocardial viability in patients with non-Q-wave myocardial infarction (NQMI) and Q-wave myocardial infarction (QMI). A total of 175 patients with MI and an ejection fraction ≤ 45% underwent dobutamine stress echocardiography. On the basis of clinical criteria and myocardial viability, 110 patients were revascularized. The amount of viable myocardium and the clinical outcome were compared in the NQMI and QMI groups. Patients with NQMI exhibited a larger amount of viable myocardium compared with those with QMI. The mortality rate was 6% in patients with NQMI with viable myocardium and subsequent revascularization, 33% in patients with NQMI without viable myocardium or revascularization, 27% in patients with QMI with viable myocardium and subsequent revascularization, and 33% in patients with QMI without viable myocardium or revascularization. In conclusion, our data suggest that patients with NQMI and viable myocardium have the best prognosis after revascularization.

Influence of previous aspirin treatment and smoking on the electrocardiographic manifestations of injury in acute myocardial infarction

OBJECTIVE

To examine demographic and clinical characteristics of patients with acute myocardial infarction in order to identify factors affecting the electrocardiographic evolution of injury.

METHODS

Prospective cohort study of 1399 consecutive patients with a first myocardial infarction. Baseline clinical data associated with ST elevation and Q wave development were identified and 12 month survival was estimated.

RESULTS

Smoking had complex effects on the evolution of injury, increasing the odds of ST elevation (odds ratio (OR) 1.61; 95% confidence interval (CI) 1.08 to 2.36), but reducing the odds of Q wave development (OR 0.69, 95% CI 0.49 to 0.96). The effects of previous aspirin treatment were more consistent with reductions in the odds of ST elevation (OR 0.57, 95% CI 0.35 to 0.94) and Q wave development (OR 0.53, 95% CI 0.34 to 0. 84). ST elevation and Q wave development were both associated with an adverse prognosis, with estimated 12 month survival rates of 80. 6% (95% CI 78.2% to 83.1%) and 80.0% (95% CI 77.5% to 82.5%), respectively, compared with 86.5% (95% CI 81.2% to 91.9%) and 89.9% (95% CI 86.2% to 93.7%) for patients without these ECG changes.

CONCLUSIONS

The thrombogenicity of the blood may be a major determinant of infarct severity. Smoking increases thrombogenicity and the likelihood of ST elevation, but because coronary occlusion is relatively more thrombotic in smokers, responses to both endogenous and exogenous thrombolysis are better, reducing the risk of Q wave development. Previous aspirin treatment reduces thrombogenicity, protecting against ST elevation and Q wave development.

Prognostic value of dobutamine echocardiography in patients after Q-wave or non-Q-wave acute myocardial infarction

We investigated the role of dobutamine echocardiography in predicting future spontaneous events in patients with Q-wave or non-Q-wave first acute myocardial infarction (AMI). DE was performed in 168 patients with a Q-wave AMI and 105 patients with a non-Q-wave AMI. Patients were observed for hard events (cardiac death and nonfatal reinfarction) and all spontaneous events (hard events and unstable angina). When compared to patients with a Q-wave AMI, patients with non-Q-wave AMI had a higher rate of positive dobutamine echocardiographic results (51.8% vs 80.0%, p <0.0001), greater changes in wall motion score index (WMSI) (0.31+/-0.17 vs 0.42+/-0.23, p = 0.001), and more remote zone ischemia (27.9% vs 43.8%, p = 0.0072). Patients with non-Q-wave infarct had a higher all-event rate, but a similar hard-event rate. In patients with a positive dobutamine echocardiogram (DE), the rate of hard or all events was similar, regardless of different infarct patterns. Patients with a negative DE had a higher event-free survival rate for all events in both Q-wave (85.2% vs 60.9%, p <0.0001) and non-Q-wave (76.2% vs 52.4%, p = 0.0083) groups. By stepwise analysis in the Q-wave group, the most important predictors were peak stress WMSI and diabetes for hard events, and a positive DE and baseline WMSI for all events. However, in the non-Q-wave group, the strongest predictors were dobutamine time for hard events and positive DE for all events. We conclude that a positive DE is a powerful predictor of future spontaneous events in patients after either a Q-wave or non-Q-wave AMI. However, for hard events, high-risk patients with different infarct patterns were recognized with variable efficiency by different dobutamine echocardiographic variables.

Q wave and Non-Q wave myocardial infarction after thrombolysis

OBJECTIVES

We studied the clinical outcome of Q wave and non-Q wave infarction after thrombolytic therapy.

BACKGROUND

Controversy exists over the clinical significance of Q waves after thrombolysis.

METHODS

We studied postthrombolytic angiographic results and short- and long-term clinical outcome in 150 patients with acute myocardial infarction classified as Q wave and non-Q wave on the 24-h and discharge electrocardiograms (ECGs). The results from the two groups were then compared.

RESULTS

Eighty percent of patients had a Q wave and 20% a non-Q wave infarction on the 24-h ECG. The latter patients had lower peak creatine kinase (CK) levels (p < 0.001), but the two groups did not differ significantly otherwise. In 18 patients with a Q wave infarction on the 24-h ECG, pathologic Q waves disappeared. However, in seven patients with a non-Q wave infarction on the 24-h ECG, pathologic Q waves appeared throughout the hospital period. Q wave regression was associated with lower peak CK levels (p < 0.001) and an improvement in left ventricular ejection fraction (p < 0.01). Thus, only 72% of patients had a Q wave and 28% a non-Q wave infarction on the discharge ECG. Patients with a non-Q wave infarction on the discharge ECG had higher patency of the infarct-related artery (p < 0.04), lower mean peak CK levels (p < 0.0001), a higher ejection fraction (p = 0.001) and a lower incidence of heart failure (p = 0.06) than patients with a Q wave infarction on the discharge ECG. Although the 2-year incidence of reinfarction and revascularization was higher in patients with a non-Q wave infarction on the discharge ECG (p < 0.05), 2-year mortality was lower (p = 0.08).

CONCLUSIONS

Although the early postthrombolytic distinction between Q wave and non-Q wave infarction conveys no significant information, during the hospital period, non-Q wave infarction is associated with a smaller infarct area, improved left ventricular function and lower mortality.

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)

Early and 1-year clinical outcome of patients' evolving non-Q-wave versus Q-wave myocardial infarction after thrombolysis. Results from The TIMI II Study

BACKGROUND

There are few data comparing clinical outcome and potential indications for routine post-myocardial infarction cardiac catheterization and revascularization of patients who sustain a non-Q-wave versus Q-wave infarct after thrombolytic therapy.

METHODS AND RESULTS

A secondary analysis of 2634 patients enrolled in the TIMI II trial with a first myocardial infarction was performed to determine 6-week and 1-year cardiac event rates and identify clinical and angiographic differences between the 1867 patients (70.9%) who evolved a Q-wave infarct and the 767 patients (29.1%) who sustained a non-Q-wave infarct after treatment with intravenous thrombolytic therapy. Male sex (85.3% versus 75.6%; P < .001) and anterior wall infarcts (53.8% versus 43.7%; P < .001) were more frequent in the Q-wave versus the non-Q-wave group. During recombinant tissue-type plasminogen activator (rTPA) infusion, a greater percentage of non-Q-wave patients (37.3% versus 23.5%; P = .001) had normalization of initial ST-segment elevation. Infarct-related artery patency (TIMI flow grade 2 or 3) (P = .02), complete infarct-related artery reperfusion (TIMI 3 flow grade) (P < .001), and the percentage of patients with a predischarge resting left ventricular ejection fraction > 55% (P < .001) were greater in the non-Q-wave group. New congestive heart failure during hospitalization developed more frequently in Q-wave patients (18.9% versus 11.6%; P < .001). After 42 days, the occurrences of reinfarction (P = .76), death (P = .76), and combined death or reinfarction (P = .43) were similar in patients assigned to the invasive or conservative postlytic management strategy, regardless of infarct type. One-year mortality was 3.4% versus 4.4% for non-Q-wave versus Q-wave infarct type, respectively (P = .25).

CONCLUSIONS

Angiographic and clinical differences were observed between patients who present with initial ST-segment elevation and evolve early non-Q-wave versus Q-wave myocardial infarcts after treatment with rTPA, heparin, and aspirin. Early mortality and adverse clinical cardiac events in these patients are not significantly different after a conservative compared with an invasive treatment strategy, regardless of whether the infarct type is non-Q wave or Q wave.

Early versus late congestive heart failure after initially uncomplicated anterior wall acute myocardial infarction

We determined the incidence and clinical, noninvasive, and angiographic variables contributing to postdischarge early (< or = 3 months) and late (> 3 months) congestive heart failure (CHF) after anterior wall acute myocardial infarction. The patient cohort consisted of 94 consecutive patients < 65 years of age who underwent predischarge exercise thallium-201 planar scintigraphy, rest radionuclide angiography, and coronary arteriography. At a mean of 49 months of follow-up, 10 of the 68 medically managed patients developed early CHF, and 10 had late CHF. The 10 patients with early CHF had significantly higher peak creatine kinase values (2,494 vs 1,032 IU/L, p = 0.01), and at discharge, a lower left ventricular (LV) ejection fraction (28 +/- 11% vs 41 +/- 11%, p < 0.02), more persistent thallium-201 defects (3.4 +/- 1.2 vs 2.1 +/- 1.2, p < 0.02), and fewer stress-induced redistribution defects (1.4 +/- 1.1 vs 0.4 +/- 1.1, p < or = 0.05) than those with late CHF. The early group had less multivessel disease (40% vs 90%, p < or = 0.03). Fifty percent (5 of 10) of patients who developed late CHF did so after a recurrent infarction compared with 10% (1 of 10) in the early CHF group (p < 0.07) and 8% in the group without CHF (p < 0.003). The 26 patients who underwent bypass surgery within 3 months had an LV ejection fraction and extent of ischemia and extent of angiographic stenoses comparable to patients with late CHF. None required hospitalization for CHF or had sustained a recurrent infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphologic correlate of pathologic Q waves as assessed by gradient-echo magnetic resonance imaging

To assess the morphologic correlate of the presence and absence of pathologic Q waves in the electrocardiogram, 30 patients with and 17 patients without pathologic Q waves and chronic myocardial infarction (infarct age > 4 months) and 15 patients without previous myocardial infarction but significant coronary artery disease (> 70% diameter stenoses) were studied by gradient-echo magnetic resonance imaging (MRI). Short-axis MRI tomograms were evaluated on a segmental basis by calculating end-diastolic wall thickness and systolic wall thickening. All segments were graded transmural scar (end-diastolic wall thickness < end-diastolic wall thickness of a healthy control group [n = 21]-2.5 SD and lack of systolic wall thickening), hypokinetic (end-diastolic wall thickness > or = end-diastolic wall thickness of the control group-2.5 SD and systolic wall thickening < or = 2 mm), or normal (end-diastolic wall thickness > or = end-diastolic wall thickness of the control group-2.5 SD and systolic wall thickening > 2 mm) by MRI criteria. Myocardial infarcts were defined as transmural if at least 1 segment fulfilled the MRI criteria for transmural scar. Of 30 patients with Q-wave infarction, 26 (87%) had a transmural defect, and 6 of 17 patients (35%) with non-Q-wave infarction had a transmural infarct. Segmental evaluation yielded 129 of 480 scar segments (27%) for patients with Q-wave infarction, 20 of 272 scar segments (7%) for patients with non-Q-wave infarction, and no scar segments for patients without previous myocardial infarction.(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)

Comparison of coronary angiographic findings in acute and chronic first presentation of ischemic heart disease

BACKGROUND

It is generally assumed that the clinical manifestations of ischemic heart disease occur randomly on the same underlying pathological process. Therefore, coronary angiographic findings should be similar whether the first presentation of ischemic heart disease is acute myocardial infarction or uncomplicated chronic stable angina.

METHODS AND RESULTS

We studied 102 patients (men < or = 60 years old, women < or = 65 years old) presenting with either acute myocardial infarction as first manifestation of coronary artery disease with a concomitant coronary angiogram (55 patients; mean age, 50.2 years) or stable angina for at least 2 years with no history, ECG, or left ventriculographic evidence of any acute event and with an angiogram performed at least 2 years after initial symptoms (47 patients; mean age at symptom onset, 51.7 years). These angiograms were evaluated blindly for severity (number of vessels diseased, stenoses > or = 50%, occlusions), extent of disease (with an index derived by assigning a score of 0-3 per segment, depending on the proportion of lumen length irregularity and dividing the sum by the number of visualized segments), and pattern (discrete: three or fewer loci of disease never involving more than 50% of the length of any segment or diffuse: anything exceeding this). Patients with unheralded myocardial infarction had fewer vessels diseased, fewer stenoses and occlusion, and a lower extent index than those with uncomplicated stable angina (mean +/- SD of 1.3 +/- 0.8 versus 2.1 +/- 0.8, p < 0.001; 2.1 +/- 1.8 versus 3.9 +/- 1.8, p < 0.001; 0.6 +/- 0.6 versus 1.0 +/- 0.9, p < 0.02; and 0.6 +/- 0.5 versus 1.2 +/- 0.5, p < 0.001, respectively). A discrete pattern was present in 54.5% of patients with unheralded infarction and in only 8.5% of those with uncomplicated angina (p < 0.001).

CONCLUSIONS

These very different angiographic findings suggest that unheralded acute myocardial infarction and uncomplicated chronic stable angina do not occur randomly on a common atherosclerotic background but rather that additional factors, such as a varying propensity to thrombosis, may predispose to one or the other of these two clinical syndromes.

Risk stratification in survivors of acute myocardial infarction: routine cardiac catheterization and angiography is a reasonable approach in most patients

Noninvasive risk assessment in survivors of AMI can effectively subdivide patients into groups with differing risk profiles after hospital discharge, but some patients at risk for late death or recurrent AMI may be incorrectly identified; data from cardiac catheterization and angiography provide complementary and generally more powerful prognostic information. Many patients may derive particular benefit from early cardiac catheterization and angiography, including: (1) patients with AMI complicated by recurrent myocardial ischemia, congestive heart failure, and/or complex ventricular arrhythmias; (2) patients with abnormal or inconclusive results of noninvasive testing or those patients unable to perform an exercise test; (3) patients with abnormal left ventricular global systolic function and those with increased left ventricular end-systolic volume; (4) "young" patients (younger than 50 years of age?); (5) older patients (older than 65 to 70 years of age?); (6) patients with non-Q wave AMI; and (7) patients who are receiving thrombolytic therapy. Performance of early cardiac catheterization and angiography in virtually all survivors of AMI, with selective use of appropriate noninvasive tests, may provide a more efficacious means of risk assessment after AMI; if all tests are performed judiciously, the cost of such an approach need not be excessive. A combination of invasive and selected noninvasive tests probably provides optimal information. The risks to the routine performance of diagnostic cardiac catheterization and angiography in all survivors of AMI are: (1) adequate care and attention may not be paid to proper performance of the procedure(s) and to detailed and proper analyses of the data; (2) the need for additional noninvasive testing in selected patients may be ignored; and most importantly, (3) premature or unnecessary revascularization procedures may be performed subsequently. For optimal patient care, the clinician must obtain all necessary data, avoid unnecessary and repetitive tests, know the accuracy of individual tests at his or her own facility, interpret all data in proper context, and then counsel patients objectively about available management strategies. With this approach, all patients who might appropriately benefit from coronary artery revascularization will be correctly identified, and patients who are truly at very low risk (minimal residual coronary artery disease and preserved left ventricular function particularly if associated with a patent infarct-related artery) may be similarly identified and managed appropriately with elimination of unnecessary additional testing and pharmacologic therapy. Finally, whatever approach to risk stratification one chooses for an individual patient, the importance of and the need to correct and/or ameliorate risk factors for coronary artery disease must be recognized and undertaken.

Prognostic importance of delayed Q-wave evolution 3 to 24 hours after initiation of thrombolytic therapy for acute myocardial infarction

The timing of Q-wave evolution and its prognostic significance was studied in 201 patients who received thrombolytic therapy for a first acute myocardial infarction (AMI). One hundred forty-one patients (70%) had evidence of a Q-wave AMI within 3 hours of the initiation of thrombolytic therapy, 31 (16%) developed Q waves after 3 hours but before hospital discharge, and 29 (14%) were discharged with a non-Q-wave AMI. Laboratory indicators of myocardial damage and in-hospital morbidity and mortality were greater among patients with Q-wave AMIs than with non-Q-wave AMIs. When these indexes were examined with respect to the timing of Q-wave evolution, the prognosis of patients with delayed Q-wave development was similar to that of patients with non-Q-wave AMIs. Thus, compared to patients with early (less than or equal to 3 hours) Q-wave evolution, patients with delayed Q-wave evolution or with a non-Q-wave AMI had a smaller creatine kinase peak (mean 661 to 1,081 vs 1,251 to 1,541 IU; p = 0.005), better preservation of left ventricular function as measured by radionuclide ventriculography before discharge (mean +/- standard deviation 54 +/- 11% vs 47 +/- 13%; p less than 0.01), and a lower incidence of congestive heart failure at discharge (3 vs 15%; p = 0.02). In-hospital mortality was lower among patients with delayed Q-wave evolution or with a non-Q-wave AMI (5 of 141 vs 0 of 60; difference not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

The prognostic significance of first myocardial infarction type (Q wave versus non-Q wave) and Q wave location. The Multicenter Diltiazem Post-Infarction Research Group

The prognostic significance of the type of first acute myocardial infarction (Q wave versus non-Q wave) and Q wave location (anterior versus inferoposterior) was determined from a multicenter data base involving 777 placebo-treated patients who were participants in the Multicenter Diltiazem Post-Infarction Trial. There were 224 patients (29%) with a non-Q wave infarction, 326 (42%) with an inferoposterior Q wave infarction and 227 (29%) with an anterior Q wave infarction. Mean left ventricular ejection fraction was significantly (p less than 0.001) lower in patients with an anterior Q wave infarction than in the other two groups (anterior Q wave 0.39; inferior Q wave 0.52; non-Q wave 0.53). Nevertheless, the total cardiac mortality rate during the follow-up period (average 25 months per patient) was only marginally higher (p = 0.42) in the anterior Q wave group (8.4%) than in the other two groups (inferoposterior Q wave 7.1%; non-Q wave 6.3%). The total first recurrent cardiac event was somewhat higher (p = 0.08) in the anterior Q wave group (18.1%) than in the other two groups (inferoposterior Q wave 11.7%; non-Q wave 15.6%). Survivorship analyses extending over 3 years revealed that electrocardiographic classification of the type of first infarction and Q wave location did not make significant independent contributions to the risk of postinfarction cardiac death or first recurrent cardiac event, either before or after adjustment for baseline clinical variables.

Lack of diurnal variation in the onset of non-Q wave infarction

Data concerning the time of onset of myocardial infarction were obtained for 540 of the 544 patients with creatinine kinase (CK)-MB-confirmed non-Q wave myocardial infarction enrolled in the multicenter Diltiazem Reinfarction Study. Data were also collected for 627 patients who were screened but excluded. Among the 1,167 patients, no diurnal pattern of onset could be found at either 2- or 6-hour intervals. Among the 540 patients enrolled in the trial, no pattern could be found at these intervals either, although at 8-hour intervals, 27% of infarctions occurred between midnight and 8:00 AM, compared with 37% between 8:00 AM and 4:00 PM and 36% between 4:00 PM and 12:00 AM (p = 0.02). In contrast to the patterns previously noted for Q wave myocardial infarction, there was no preponderance of non-Q wave infarction in the late morning. Circadian rhythm was also absent among patients not treated with beta-blockers as well as among patients presenting with ST segment elevation on their enrollment electrocardiograms. Diabetics, women, and patients with first infarction were more likely to present during the afternoon hours. We conclude that the late morning preponderance seen for Q-wave myocardial infarction is not discernable in patients with non-Q wave myocardial infarction. This observation suggests that the pathogenesis of these two infarct subtypes is different or that the process of thrombotic coronary occlusion in Q wave infarction (sustained) differs from that in non-Q wave infarction (nonsustained).

Initial ECG in Q wave and non-Q wave myocardial infarction

The initial ECGs in 440 patients admitted for suspected acute myocardial infarction were retrospectively analyzed to determine predictive values of these ECGs for acute myocardial infarction and to determine differences in the initial ECG for Q wave and non-Q wave myocardial infarction. One hundred (23%) of the study patients were diagnosed as having an acute myocardial infarction. Acute injury was seen in 47% of these patients (positive predictive value [PPV], 84%; 95% confidence interval [CI], 72% to 92%), ischemia in 15% (PPV, 39%; 95% CI, 24% to 57%), and left ventricular hypertrophy with strain in 11% (PPV, 19%; 95% CI, 4% to 29%). Forty-three patients were diagnosed as having a Q wave infarction and 50 patients as having a non-Q wave infarction. Seventy-two percent of the patients with a Q wave infarction had acute injury as the initial ECG interpretation compared with 38% in the non-Q wave infarction group (P less than .001). In contrast, only 17% of patients with Q wave infarction had an initial ECG interpretation of ischemia or strain as compared with 36% of patients with non-Q wave infarction (P = .03). Because of the relatively high incidence of acute myocardial infarction in patients admitted with an initial ECG interpretation of ischemia or left ventricular hypertrophy with strain, prospective studies must be performed to determine if selective patients with acute ST segment depression or ischemic T wave inversion in the setting of suspected acute myocardial infarction may benefit from early thrombolytic therapy.

"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.

Pericarditis in acute myocardial infarction: characterization and clinical significance

To determine the significance of pericarditis following acute myocardial infarction, the hospital course and 12-month follow-up were analyzed in 703 patients enrolled in the Multicenter Investigation of the Limitation of Infarct Size (MILIS). Pericarditis, defined by the detection of a pericardial rub, occurred in 20% of the patients (n = 141) and was more likely to follow Q wave than non-Q wave infarction (25% vs 9%, p less than 0.001). Patients with pericarditis experienced more serious myocardial damage compared to those without pericarditis, as evidenced by a larger infarct size (25 +/- 1 vs 17 +/- 1 MB-CK gm-Eq/m2, p less than 0.001), a lower admission left ventricular ejection fraction (42 +/- 1% vs 48 +/- 1%, p less than 0.001), and a higher incidence of congestive heart failure (47% vs 26%, p less than 0.001) and atrial tachyarrhythmias (16% vs 10%, p less than 0.05). When patients were classified by the presence of Q or non-Q wave infarction, these differences persisted although statistical significance was not always achieved due to smaller sample size. Mortality at 12-month follow-up for patients with pericarditis was 18% compared with 12% for patients without pericarditis (p = 0.055). This mortality difference could be accounted for in part by the lower ventricular ejection fraction in patients with pericarditis (p = 0.20 after adjustment).

The ECG in acute myocardial infarction

The initial ECG is the most rapid and readily available tool in the emergency department for the evaluation of patients presenting with suspected myocardial infarction. However, studies have shown that the initial ECG is diagnostic of acute myocardial infarction in only a minority of patients. This paper discusses the importance of the initial ECG and other information in aiding the disposition of patients with suspected myocardial infarction. Classic electrocardiographic descriptions are discussed as well as the newer terminology of Q wave versus non-Q wave infarction and ST segment versus T wave infarction. A brief review is made of the electrophysiology of the ECG changes seen in myocardial infarction. Finally, clinical studies are presented that establish a definite role for the use of the initial ECG.

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.

Postinfarction angina

In conclusion, the PIA patient is at high risk, with higher early as well as late mortality. The pathophysiology of PIA is complex and may vary from patient to patient. The concepts of ischemia at a distance and ischemia in the infarct zone have led to a better understanding of early PIA. Coronary spasm may play an important role in most PIA patients as in the general population of patients with angina pectoris. Medical therapy is efficacious in many, although it may on rare occasion aggravate myocardial ischemia. Urgent coronary arteriography is generally safe and should be performed as soon as possible for medically refractory PIA. CABG appears to be safe in experienced hands, but its timing must be individualized. The IABP should be reserved for more unstable patients for fear of vascular complications. Randomized controlled trials such as the BARI Trial will further compare PTCA with CABG.

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: recent changes in occurrence and prognosis--a community-wide perspective

A community-wide study of patients hospitalized with validated acute myocardial infarction (MI) in all 16 hospitals in the Worcester metropolitan area, during the calendar years 1975, 1978, and 1981, is examining time trends in the incidence rates, in-hospital case fatality rates, and long-term survival rates of 2451 patients hospitalized with acute MI further classified into those with Q wave and those with non-Q wave MI. The age-adjusted hospital attack rates (per 100,000) of initial events of Q wave MI increased from 153 in 1975 to 197 in 1981 (p less than 0.05), while the attack rates of non-Q wave MI increased from 46 in 1975 to 89 in 1981 (p less than 0.001). Patients with non-Q wave MI were at significantly decreased risk of dying during hospitalization (12.0%) as compared to those with Q wave MI (25.2%), overall as well as for each of the three time periods studied (p less than 0.05). For patients discharged alive from the hospital, however, there were no significant differences in long-term survival rates according to MI type over an 8-year follow-up period. These results, obtained from a community-wide sample of patients with validated acute MI, indicate a significant change in the occurrence rates and/or recognition of non-Q wave MI, a significantly lower in-hospital case fatality rate for patients with non-Q wave MI, and comparable long-term prognosis for patients with Q wave and non-Q wave acute MI.

Acute non-Q wave myocardial infarction associated with early ST segment elevation: evidence for spontaneous coronary reperfusion and implications for thrombolytic trials

The clinical significance of early ST segment elevation in patients with non-Q wave infarction is unknown. Therefore, 150 consecutive patients with creatine kinase isoenzyme-confirmed acute uncomplicated myocardial infarction who had ST segment elevation of 1 mm or more in at least two contiguous leads on the admission electrocardiogram were analyzed. None received thrombolytic therapy or acute coronary angioplasty. Predischarge angiography, radionuclide ventriculography and exercise thallium-201 scintigraphy were performed 10 +/- 3 days after myocardial infarction. Based on serial electrocardiograms (on days 1, 2, 3 and 10), all 150 infarcts were classified as Q wave (n = 115 [77%]) or non-Q wave (n = 35 [23%]). Although patients with Q wave infarction exhibited greater ST elevation, the amount observed in the non-Q wave group was appreciable, as reflected by the number of leads with ST elevation (3.8 +/- 1.8 versus 3.1 +/- 1.2, p = 0.007) and the sum of the ST elevation (9.6 +/- 7.4 versus 6.2 +/- 6.2 mm, p = 0.016). When compared with the Q wave group, patients with non-Q wave infarction had a shorter time to peak creatine kinase (23.0 +/- 9.1 versus 15.8 +/- 7.9 hours, p = 0.0001), a higher infarct vessel patency rate (24 versus 57%, p = 0.001), lower peak creatine kinase values based on 4 hour sampling (1,372 +/- 964 versus 664 +/- 924 IU/liter, p = 0.0002) and a higher left ventricular ejection fraction (46 +/- 12% versus 54 +/- 9%, p = 0.0003).(ABSTRACT TRUNCATED AT 250 WORDS)

Design of a multicenter, double-blind study to assess the effects of prophylactic diltiazem on early reinfarction after non-Q-wave acute myocardial infarction: diltiazem reinfarction study

This protocol describes the design of an international study to examine the potential prophylactic effect of 14 days of diltiazem therapy to prevent early reinfarction in patients initially presenting with non-Q-wave acute myocardial infarction. Reinfarction was defined by the detection of a secondary elevation of plasma MB-creatine kinase. The results of clinical trials, instrumental in this protocol design, that established the increased propensity for early reinfarction after initial non-Q-wave infarction are described and the implications of the present study are discussed.

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.

Management of acute myocardial infarction

This article presents plans of therapy based on current knowledge of pathophysiologic mechanisms, taking into consideration the rapid changes in availability of new drugs (or new experiences with old drugs) and new therapeutic interventions. Persistence of ischemic pain in the acute phase, or its recurrence during early convalescence, is a signal of a high-risk state for additional coronary events, and aggressive measures are required to prevent them. The indications, and the role of invasive hemodynamic monitoring in the treatment of left ventricular failure and/or hypotension, are discussed.

The prevalence and clinical significance of residual myocardial ischemia 2 weeks after uncomplicated non-Q wave infarction: a prospective natural history study

Despite having smaller infarct size and better left ventricular function, patients with non-Q wave myocardial infarction (NQMI) appear to have an unexpectedly high long-term mortality that is ultimately comparable to that of patients with Q-wave myocardial infarction (QMI). Patients with NQMI may lose their initial prognostic advantage because there is more viable tissue in the perfusion zone of the infarct-related vessel, rendering myocardium more prone to reinfarction. We tested this hypothesis in a prospective study of 241 consecutive patients 65 years of age or younger with acute uncomplicated myocardial infarction confirmed by creatine kinase levels (MB fraction). All patients received customary care and none underwent thrombolytic therapy or emergency angioplasty. Predischarge coronary angiography, radionuclide ventriculography, 24 hr Holter monitoring, and quantitative thallium-201 (201T1) scintigraphy during treadmill exercise were performed 10 +/- 3 days after infarction. Infarcts were designated as QMI (n = 154) or NQMI (n = 87) by accepted criteria applied to serial electrocardiograms obtained on days 1, 2, 3, and 10. The baseline Norris coronary prognostic index, angiographic jeopardy scores, and prevalence of Lown grade ventricular arrhythmias were similar between groups despite evidence for less necrosis with NQMI vs QMI, reflected by lower peak creatine kinase levels (520 vs 1334 IU/liter; p = .0001, 4 hr sampling), higher resting left ventricular ejection fraction (53% vs 46%; p = .0001), fewer akinetic or dyskinetic segments (1.2 vs 2.4; p = .0001), and fewer persistent 201Tl defects in the infarct zone (0.9 vs 1.9; p = .0001). Patients with NQMI also had more patent infarct-related vessels (54% vs 25%; p less than .0001) and a shorter time from onset of infarction to peak creatine kinase level (16.9 vs 22.5 hr; p = .0001). Importantly, the prevalence and extent of quantitatively determined 201Tl redistribution within the infarct zone on exercise scintigraphy was greater in patients with NQMI vs those with QMI (60% vs 36%, p = .007; and 0.98 vs 0.53 myocardial segments, p = .0003); when the two groups were stratified on the basis of the infarct-related vessel, subset analysis revealed the same findings. During 30 months median follow-up, cardiac mortality was low, 8.4% in the QMI group and 9.2% in the NQMI group (p = NS).(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of clinical features of non-Q wave and Q wave myocardial infarction

The clinical spectrum and outcome of 119 patients with acute non-Q wave myocardial infarction (NQMI) were studied, in comparison with those of 354 patients with acute Q wave myocardial infarction (QMI). The patients with NQMI had a significantly higher incidence of preinfarction angina (73% vs 63%), previous myocardial infarction (43% vs 22%), multivessel disease (73% vs 51%), postinfarction angina (55% vs 21%), and recurrent myocardial infarction during follow-up for an average of 25 months (17% vs 8%). NQMI patients also had a lower rate of complication of pump failure and smaller infarct size estimated by peak creating phosphokinase (CPK) levels (1361 +/- 1243 vs 2711 +/- 1684 IU/L) than those with QMI. There was no difference in in-hospital mortality between the two groups (17% vs 17%). However, death due to cardiac rupture was exclusively noted in the QMI group. The present study suggests that NQMI is more unstable than QMI in the clinical course.

Inhospital prognosis of patients with their first transmural or subendocardial infarction and comparison of their coronary arteriogram and ventriculogram

The inhospital clinical course and early prognosis were studied prospectively in 500 patients who suffered their first transmural or subendocardial myocardial infarction, and were admitted in the coronary care unit of our hospital over the last four years. The coronary arteriogram and left ventriculogram of 300 patients out of the 500 was also compared. 434 patients developed transmural and 66 subendocardial infarction, as judged by electrocardiographic criteria. Both groups of patients had the same range of sex, age, coronary risk factors and history of previous angina. There was no statistical difference in in-hospital prognosis and early clinical course. There was no difference in prevalence of single, double or triple vessel coronary artery disease. The hemodynamic parameters (ejection fraction, left ventricular end-diastolic pressure), as well as the number of hypokinetic, akinetic or dyskinetic segments did not show any significant statistical difference between the two categories of patients. The same extent of coronary artery lesions and degree of left ventricular dysfunction may explain the similarity of early clinical course. 12% of patients who were admitted with subendocardial infarction developed transmural infarction during their hospitalization.

Classification of non-Q-wave myocardial infarction according to electrocardiographic changes

The characteristics of 93 patients in whom electrocardiographic recordings were obtained within 12 hours of the onset of non-Q-wave myocardial infarction were studied. Patients were divided into the three groups according to what electrocardiographic changes were seen. Forty nine patients had ST segment depression, 35 had ST segment elevation, and nine had T wave changes. Patients with ST segment depression had a higher rate of pump failure and multivessel disease than the other two groups. There were no significant differences in peak serum creatine kinase activity among the three groups. Twelve of 13 patients who died of non-Q-wave myocardial infarction in hospital had ST segment depression. Furthermore nine of them had attacks of non-Q-wave myocardial infarction with severe ST segment depression in many leads. At necropsy five of six patients who had shown severe ST segment depressions in many leads at the onset of non-Q-wave myocardial infarction were found to have circumferential subendocardial lesions with triple vessel disease. This study suggests there are electrocardiographic subtypes of non-Q-wave myocardial infarction that are associated with specific patient characteristics.

Chest pain after nontransmural infarction: the absence of remediable coronary vasospasm

To assess the contribution of coronary vasospasm to chest pain in patients with nontransmural myocardial infarction, we performed a controlled trial of prophylactic antivasospastic therapy. Fifty patients with nontransmural infarction received either nifedipine or placebo in a double-blind randomized trial. Chest pain occurred in 52% of treated patients (38 episodes on 35 days) compared to 48% of control patients (42 episodes on 33 days). Concurrent therapy was comparable in the two groups. Recurrent infarction occurred in 12% and was comparable between groups. Ejection fraction was similar and was unchanged throughout the study in both groups. Logistic regression failed to identify predictors for recurrent chest discomfort. These data indicate that potent antivasospastic therapy does not reduce the incidence of recurrent chest pain or infarction. Thus, remediable coronary vasospasm is not likely to be a major cause of post infarction ischemia in patients with nontransmural infarction.

Cardiovascular responses to early exercise in inferior wall ST acute myocardial infarction

The heart rate and blood pressure responses to standardized exercise tests were studied in a group of patients with electrocardiographic evidence of inferior wall acute myocardial infarction (AMI). The tests were done on a bicycle ergometer at 8 to 10 days and 10 to 12 weeks after AMI. At 8 to 10 days after AMI, those with ST AMI (n = 12) had a significantly reduced heart rate response to exercise compared with patients with Q-wave AMI (n = 25). This difference was not evident at 10 to 12 weeks. The systolic blood pressure response in patients with ST AMI was lower than that of Q-wave AMI patients during the first exercise test, although the difference did not attain statistical significance but was significantly lower than the responses of both groups at the second test. The patients with ST AMI had smaller amounts of myocardial damage than those with Q-wave AMI as indicated by plasma creatine kinase values (p less than 0.01). These differences in the heart rate responses appeared to result from the preferential activation of nonmyelinated afferent fibers in the subepicardial region of the inferior wall of the myocardium.

Q wave, S-T segment, and T wave myocardial infarction. Useful clinical distinction

Abundant experimental and clinical evidence now suggests that the presence or absence of Q waves on surface electrocardiography does not permit distinction between pathologic transmural and subendocardial myocardial infarction. It has been recommended, therefore, that use of certain electrocardiographic descriptors of myocardial infarction be avoided. One hundred fourteen consecutive patients with first myocardial infarction were studied. The lack of development of Q waves accompanying acute myocardial infarction delineated a group of patients with low in-hospital mortality. Left ventricular ejection fraction was less after Q wave (0.48 +/- 0.16) than after non-Q wave (0.67 +/- 0.10) infarction (p less than 0.0001). Left ventricular end-diastolic pressure was greater after Q wave (16.1 +/- 5.9 mm Hg) than after non-Q wave (11.7 +/- 2.7 mm Hg) infarction (p less than 0.02). Fixed thallium perfusion scintigraphic defects were more common in survivors of Q wave (98 percent [41 of 42]) than in survivors of non-Q wave (64 percent [seven of 11]) infarction (p less than 0.002). Objectively demonstrable myocardial ischemia was more common after non-Q wave (68 percent [13 of 19]) than after Q wave (32 percent [16 of 50]) infarction (p less than 0.01). The incidence of late cardiac events (sudden death plus reinfarction) did not differ after Q wave or non-Q wave infarction. Q wave, S-T segment, and T wave myocardial infarctions differ physiologically, clinically, and prognostically. It is of little consequence to the clinician managing patients whether such useful electrocardiographic descriptors also accurately define groups that differ anatomically with regard to the thickness of the injured myocardial wall.

Submaximal exercise testing early after myocardial infarction. Difficulty of predicting coronary anatomy and left ventricular performance

Impaired left ventricular function and extensive coronary artery disease are important determinants of prognosis after acute myocardial infarction. The ability of clinical and predischarge submaximal exercise test variables to predict multivessel coronary artery disease and impaired left ventricular function was assessed in 62 survivors of acute myocardial infarction. Abnormal exercise blood pressure response and short exercise performance were predictors of multivessel disease, but exercise induced ST segment changes and clinical variables were not. Q wave infarction, high grade Killip classification, and exercise induced ST segment elevation predicted statistically significant impairment of resting left ventricular function, whereas other clinical and exercise test variables did not. Exercise induced ST segment changes were therefore of little value in detecting extensive coronary disease, although exercise induced ST elevation was an indicator of poor resting left ventricular function. Although abnormal exercise haemodynamics may detect extensive coronary artery disease, other physiological markers of reversible myocardial ischaemia are probably necessary to plan optimal management in these patients.

Prognosis after extension of myocardial infarct: the role of Q wave or non-Q wave infarction

We examined whether or not subsets of patients with extension of myocardial infarct were at high risk for early and late mortality. Some data suggest increased risk in patients with non-Q wave infarcts and we hypothesized that infarct extension in this group might be associated with a poorer prognosis than that for patients with extension of Q wave infarcts. A total of 1253 patients with acute myocardial infarction who were included in our data base were followed prospectively. The patients were classified according to electrocardiographic results into the following groups: those with non-Q wave (n = 277) infarcts and those with Q-anterior (n = 462) and Q-inferior (n = 497) infarcts. Extension was diagnosed by two of the following criteria: (1) recurrent chest pain 24 hr or more after admission to the hospital, (2) new persistent electrocardiographic changes, and (3) elevation or reappearance of creatine kinase. By these criteria 85 (6%) patients had extension (8% of non-Q wave infarcts, 6% of Q-anterior infarcts, and 6% of Q-inferior infarcts). Hospital mortality in patients with extension was 15% in those with Q wave infarcts vs 43% in those with non-Q wave infarcts (p less than .01). Nine hundred and fifty-two patients were followed for 1 year. In 24% of those who did not survive 1 year there was extension of infarct; only 6% of survivors had extension (p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of the Q wave in acute myocardial infarction

Acute myocardial infarction may be associated with the development of Q waves on the electrocardiogram (ECG), or with changes limited to the ST segment or T wave. The ECG changes do not accurately differentiate transmural from nontransmural infarction. However, the presence or absence of a Q wave does correlate with some aspects of the clinical course of patients after myocardial infarction, and is therefore of prognostic value. Q-wave infarctions are more likely to be complicated by congestive heart failure during hospitalization. The in-hospital mortality is also higher after a Q-wave infarction than after a non-Q infarction. Both of these findings are probably due to the association of a Q wave with a larger mass of infarcted myocardium. The long-term mortality, however, is the same for Q-wave and non-Q-wave infarctions. This is probably due to an increased late mortality after non-Q infarctions, related in part to a higher rate of reinfarction. The differences between Q-wave and non-Q-wave infarctions are not due to obvious differences in extent and location of coronary artery obstructions. However, there may be differences in the collateral circulation, with more extensive collaterals associated with non-Q infarcts. Appreciation of the prognostic significance of the ECG changes in acute myocardial infarction may help direct the evaluation and management of the patient after myocardial infarction.

Electrocardiographic ST-T wave patterns, extent of coronary artery disease, and left ventricular performance following non-Q-wave myocardial infarction

Subendocardial, nontransmural, or non-Q-wave myocardial infarction (NQM) carries a serious prognosis. Many previous studies of NQMI include only patients without new Q waves at the time of infarction. Since the site of transmural MI (by Q waves) has implications concerning extent of coronary disease (CAD) and left ventricular (LV) dysfunction, we wondered what the extent of CAD and LV dysfunction is among acute MI patients who have neither new nor old Q waves. Furthermore, we sought to determine whether ST-T wave patterns or resting LV ejection fraction (EF), alone or combined, could separate NQMI patients with significant CAD from those with normal or nearly normal coronaries. Therefore, we retrospectively examined angiographic and electrocardiographic data in 55 symptomatic patients with NQMI. ST-T wave patterns on admission were classified as either ischemic (transient ST elevation, persistent horizontal ST depression, or persistent deep T wave inversion) or nonspecific. Eleven patients (20%) had normal or nearly normal coronaries (N); ten patients (18%) had one, seven patients (13%) had two, and 19 patients (34%) had three vessel CAD; eight patients (15%) had left main (LM) disease. Six of the 11 N patients had ergonovine tests and all six were negative. Segmental LV wall motion abnormalities (WMA) were commonly observed; however, diffuse LVWMA were present only among patients with three vessel and LM disease. EF was below 0.50 in 48% of patients with three vessel or LM disease. Although ischemic ST-T wave patterns were more common (P less than 0.05) among patients with significant CAD than among N patients, neither the ST-T wave pattern nor EF, alone or in combination, allowed confident separation of N patients from significant CAD patients. We conclude 1) A large proportion of NQMI patients have LM disease, three vessel disease, or normal or nearly normal coronaries. 2) Despite the absence of Q waves, LV dysfunction is common and the degree of LV impairment is worse among patients with more extensive CAD. 3) NQMI patients who may have normal or nearly normal coronaries cannot be reliably separated from NQMI patients with significant CAD on the basis of ST-T wave patterns or resting LVEF. 4) Coronary angiography appears warranted to assess the extent of CAD in symptomatic NQMI patients.

Q- versus non-Q-wave myocardial infarction: clinical characteristics and 6-month prognosis

A prospective study of 208 consecutive survivors of acute myocardial infarction was undertaken to determine the differences between Q- and non-Q-wave infarction, concerning data from the history, clinical course, and 6-month follow-up. There were 177 patients with Q-wave infarction and 31 patients with non-Q-wave infarction. There were no significant differences for the following variables: age, sex, diabetes mellitus, smoking, positive family history, hypertension, obesity, previous infarction, history of unstable angina, heart failure or chronic obstructive pulmonary disease (COPD), Killip class in the Coronary Care Unit (CCU), arrhythmias and conduction defects in the CCU as well as drugs used. Patients with non-Q wave infarction had a higher incidence of stable angina before the myocardial infarction and a lower value of creatine kinase (CK) and serum glutamic oxalacetic transferase (SGOT). During the 6-month follow-up, 9 cardiac deaths and 17 reinfarctions occurred, while 74 patients presented angina. There were no differences between the two groups concerning the incidence of cardiac death or angina, but patients with non-Q-wave infarction had a higher incidence of reinfarction at 6 months (p less than 0.001). We conclude that although patients with non-Q-wave myocardial infarction have a lesser degree of myocardial damage, they have a high incidence of early reinfarction which puts them in a high-risk group.

Comparison of the influence of acute transmural and nontransmural myocardial infarction on ventricular function

In order to assess the relative impact on left and right ventricular function of nontransmural and transmural acute myocardial infarction (AMI), we performed radionuclide ventriculography in 86 patients (54 men and 32 women) within 16 hours after a first infarct. Nontransmural infarction was present in 19 patients (11 anterior and 8 inferior). Transmural infarction was found in 67 patients (30 anterior and 37 inferior). Left ventricular ejection fractions were higher (0.57 +/- .014 vs 0.46 +/- 0.14, p less than 0.005) and left ventricular end-systolic volume lower (29 +/- 11 vs 42 +/- 20 ml/m2, p = 0.013) in patients with nontransmural infarction compared to those with transmural infarction. Right ventricular ejection fraction also may have been different in the two groups (0.63 +/- 0.15 vs 0.55 +/- 0.13, p = 0.057). In patients with inferior infarction, left and right ventricular ejection fractions were similar in patients with nontransmural and transmural infarction (0.60 +/- 0.09 vs 0.55 +/- 0.10, p = 0.119 and 0.58 +/- 0.14 vs 0.51 +/- 12, p = 0.226). On the other hand, patients with anterior transmural infarction had lower left ventricular ejection fractions (0.36 +/- 0.12 vs 0.54 +/- 0.17, p = 0.003) but similar right ventricular ejection fractions (0.60 +/- 0.13 vs 0.66 +/- 0.14, p = 0.14) compared to those with nontransmural anterior infarction. In 29 additional patients with a history of previous infarction, no differences in any of the parameters studied were found between those with transmural and those with nontransmural infarcts.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognosis after an initial non-Q-wave myocardial infarction related to coronary arterial anatomy

Eighty-six consecutive hospital survivors (aged less than or equal to 60 years) of a first non-Q-wave acute myocardial infarction (MI) were followed up prospectively. Coronary arteriography was performed a median of 2 weeks after MI. The size of the MI was small (as judged by a mean peak creatine kinase level of 906 IU/liter); 90% were in Killip class I, and the mean left ventricular ejection fraction was 60 +/- 11% (+/- standard deviation). Forty-nine patients had 1 vessel significantly narrowed by disease (greater than or equal to 70% luminal diameter reduction), 19 had 2-vessel, 2 had 3-vessel, 3 had left main (greater than or equal to 50% luminal diameter reduction), and 13 minimal or no coronary artery disease (CAD). Complete occlusion of the MI-related vessel was present in 33 patients. All 33 and an additional 5 patients had collateral vessels to the MI area. During a mean follow-up of 25 months, 1 cardiac death and 4 recurrent infarcts (3 with non-Q-wave MI) occurred. Angina occurred in 53 patients (62%) and responded medically in all but 7 who underwent coronary artery surgery. Angina after MI occurred frequently in patients with severe proximal left anterior descending CAD (greater than or equal to 90%), and in those with CAD (greater than or equal to 50%) in a vessel supplying collaterals to the infarct area. Because angina can be managed medically in most patients and the outcome is good, routine coronary angiography is not indicated in asymptomatic survivors less than or equal to 60 years of a first non-Q-wave MI.

Long-term prognosis after first Q-wave (transmural) or non-Q-wave (nontransmural) myocardial infarction: analysis of 593 patients

Follow-up results in 593 patients less than or equal to 7 years (mean 4.7) after hospital discharge for their first myocardial infarction (MI) are presented. Patients were grouped according to the presence or absence of Q waves on electrocardiograms after the MI and by peak serum glutamic oxalacetic transaminase (SGOT) level during hospitalization. Cardiac mortality varied. Patients with Q-wave infarcts and an SGOT level less than or equal to 240 IU/liter had a cardiac mortality of 3.1% per year, whereas patients with Q-wave MI and an SGOT level greater than 240 IU/liter had an 11% 6-month mortality and a 3.8% per year cardiac mortality thereafter. However, patients with non-Q-wave (nontransmural) MI had a excellent survival rate for 2 years (96.8%) which continued in patients aged less than or equal to 60 years thereafter. However, patients with non-Q-wave infarcts aged greater than 60 years had a 12% per year cardiac mortality in the third post-MI year and an additional 12% died each year thereafter. Early mortality was related to enzyme level, whereas late mortality was a function of type (Q-wave or non-Q-wave) and age.

Exercise testing early after myocardial infarction

A consecutive series of 179 survivors of acute myocardial infarction had a symptom-limited 12-lead electrocardiographic treadmill exercise test, coronary angiographic studies, and left ventriculograms six to eight weeks after infarction. The exercise-induced ST-segment responses were correlated with the presence of multivessel disease, the presence of advanced left ventricular wall motion abnormalities (LVWMA), and ejection fraction. Each type of ST-segment response in patients after infarction has its own specific predictive value. ST-segment depression indicated multivessel disease. ST-segment elevation indicated advanced LVWMA and low ejection fraction. Concomitant ST-segment depression and ST-segment elevation indicated both multivessel disease and advanced LVWMA.