Wave Infarction Research Articles

Exercise-induced Silent Myocardial Ischemia in Single Vessel Coronary Artery Disease Associated with Q Wave Infarction: Assessment by Thallium 201 Single-Photon Emission Computed Tomography

To examine the relationship between the symptom of ischemia and the amount of abnormally perfused myocardium, coronary arteriography and exercise and redistribution thallium 201 single-photon emission computed tomography (SPECT) were analyzed. The study group consisted of 153 patients with single-vessel coronary artery disease; 53 patients had no pathologic Q waves (group 1) and 100 patients had pathologic Q waves consistent with the area supplied by the diseased vessel (group 2). Twenty normal subjects were used as control subjects. The apical, mid, and basal left ventricular levels of the short-axis view and apical portion of the long-axis view were divided into 20 segments, and segmental images were scored blindly on a 0 (normal) to 4 (severely reduced uptake) scale. The redistribution score was defined as the thallium 201 defect score of exercise subtracted from that of the redistribution image and was used as a measure of the amount of ischemic myocardium. The redistribution score in 20 control subjects was 0.20 +/- 2.06, and the upper limit of normal redistribution score was defined as mean + 2 x SD (4.32). In group 1, 40 of 53 patients had a redistribution score above the normal range. In group 2, 34 of 100 patients had a redistribution score above the normal range. Of 40 patients in group 1, angina during exercise was observed in 22 patients (55 percent). Twenty-two patients who had angina had a redistribution score of 15.2 +/- 6.7, while those who did not have angina had a score of 13.7 +/- 5.2 (p = NS). Of 34 patients in group 2, angina was observed in 10 patients (29 percent) during exercise. Ten patients with angina had a redistribution score of 10.1 +/- 4.4, and those without angina had a score of 9.9 +/- 3.4 (p = NS). Thus, the incidence of silent ischemia without the Q wave infarct zone was found to be higher than that within the ischemic zone without Q wave. Patients with silent and symptomatic ischemia during exercise have similar amounts of ischemic myocardium demonstrated by tomographic thallium 201 imaging; this was found in patients who had Q wave infarction and in those who did not.

Intracoronary stenting compared with conventional therapy for abrupt vessel closure complicating coronary angioplasty. A matched case-control study

Objectives. A case-control analysis was performed to compare clinical outcome after intracoronary stenting with that after conventional therapy for abrupt vessel closure.Background. Previous studies have demonstrated that stenting after abrupt vessel closure results in marked angiographic improvement and preservation of coronary flow, leading to the anticipation of similar improvement in clinical outcome.Methods. Sixty-one of 92 consecutive patients treated at two clinical sites by intracoronary stenting for abrupt vessel closure were matched, according to angiographic features of closure and estimated left ventricular mass threatened by ischemia, with patients treated conventionally during the 18 months before stent availability. In 33 pairs of matched patients, vessel closure was established; in 28 pairs, it was threatened (coronary dissection or worsening stenosis with preservation of normal anterograde flow). Baseline clinical and angiographic characteristics were comparable in the two matched groups. Patients with indeterminate mechanisms of total occlusion (31%) or dissections <15 mm long (43%) predominated; patients with visible thrombus (8%) or dissections > 15 mm long (18%) were infrequently represented. Stents were successfully deployed in 60 of 61 patients at a median of 52 min (range 3 to 269) after the onset of closure.Results. When compared with conventional treatment, stenting resulted in less residual stenosis (26% vs. 49% diameter stenosis, p < 0.001), a greater likelihood of restoration of Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow (97% vs. 72%, p < 0.001) and a reduction in the need for emergency bypass surgery (4.9% vs. 18%, p = 0.02). However, the incidence of Q wave myocardial infarction was nearly the same in the two groups (32% vs. 20%, respectively, p = NS). In the group with stenting, peak creatine kinase level and the frequency of Q wave infarction after established vessel closure increased with the time to stent placement (p = 0.001 and 0.054, respectively); the incidence of procedure-related Q wave infarction in patients who underwent stenting within 45 min of closure was very low (3.9%). In-hospital death occurred in 3.3% of patients in each treatment group. At a mean of 6.3 months of follow-up after hospital discharge, survival free from late cardiac death, myocardial infarction; bypass surgery or coronary angioplasty was 74.9% and 81.3% in the stent and the control treatment group, respectively (p = NS).Conclusions. Although early treatment of established vessel closure by intracoronary stenting was associated with a low incidence of both myocardial infarction and emergency bypass surgery, the likelihood or severity of infarction was not reduced among those in whom stents were implanted later. Patients with threatened vessel closure could not be shown to benefit from stent treatment. These data provide preliminary indications for stent placement in the acute period to be validated in larger randomized studies.

Functional significance of coronary collateral vessels in patients with previous ‘Q’ wave infarction: relation to aneurysm, left ventricular end diastolic pressure and ejection fraction

The importance of coronary collateral circulation in relation to the left ventricular function, aneurysm formation and size was investigated in 100 patients with previous ‘Q’ wave myocardial infarction who underwent coronary angiography. Aneurysms were present in 20% of patients. The majority of these (80%) patients had severe or total occlusion of the left anterior descending artery. Thirty four percent of patients without aneurysm had significant collaterals whereas 25% of patients with aneurysms had collaterals ( P > 0.05). However, the size of the aneurysm was smaller when adequate collateral circulation was present (Collateral Index 2 or above). The incidence of hypertension and diabetes was similar in both groups. Collateral circulation was more frequently seen in the anterior (60%) as compared to inferior myocardial infarction (40%), but Collateral Index was higher in right coronary artery disease. The number of patients with an elevated left ventricular end-diastolic pressure (> 12) or poor ejection fraction was similar in the two groups with and without collaterals. Thus, there was no beneficial effect of collateral circulation on left ventricular function. The incidence of aneurysm was not significantly lower, although the size of the aneurysm was significantly smaller in the presence of collateral circulation.

Mechanical dilatation rather than plaque removal as major mechanism of transluminal coronary extraction atherectomy.

Atherectomy with the transluminal extraction endarterectomy catheter (TEC) is a new approach for treatment of coronary artery disease, which continues to undergo FDA investigational studies. The major mechanism of the TEC device should be excision of plaque and its removal due to suction applied through an attached vacuum. We report about the acute results in 24 patients treated with TEC atherectomy in native vessels and the outcome of 18 patients who, until recently, underwent follow-up catheterization after 6 months. The procedure was successful (residual stenosis less than 50%) in 7 of 24 patients with TEC atherectomy alone (29%); 15 of 24 patients (65%) required additional PTCA in order to achieve angiographic success (10 of 24) or to treat total occlusion (2 of 24) or distal embolization (3 of 24) following atherectomy. One TEC attempt failed due to guiding catheter problems, another major complication was a vessel perforation leading to a non-Q wave infarction. The minimal residual diameter after passage of the stenosis (prior to additional PTCA) with the 5.5 Fr catheter (n = 14) was 1.5 +/- 0.2 mm, with the 6 Fr catheter (n = 9) 1.8 +/- 0.4 mm, and 2.2 +/- 0.2 mm using the 7 Fr catheter (n = 10). The histologic findings revealed intimal cells, fibrous tissue, and homogenate with no identifiable tissue in five cases (21%), whereas in 17 patients (72%) light microscopy could only assess blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary rotational ablation: Initial experience in 302 procedures

Objectives. The aim of this study was to assess the utility of percutaneous transluminal coronary rotational ablation in the treatment of coronary artery disease.Background. Although numerous advances have been made in the treatment of coronary artery disease, there are lesions with complex morphology that are not amenable to current intravascular therapy.Methods. A consecutive series of 242 patients having 302 coronary rotational ablasion procedures was analyzed. One hundred nineteen (49%) of tbe patients had previously undergone attempted coronary angioplasty, which was unsuccessful in 31 patients (13%). The left ventricular ejection fraction was normal in 196 patients (81%). The ablation procedure was attempted in 308 vessels and 346 lesions. Of the 346 lesions treated, 26 (7.5%) were classified as American College of Cardiology/American Heart Association type A, and 320 (92.5%) as either type B or type C.Results. Procedural success was achieved in 284 (94%) of the 302 procedures and 330 (95.4%) of the 346 lesions in which ablation was attempted. Five procedures (1.7%) were unsuccessful, but no cardiac event occurred during the hospital stay. A major cardiac event occurred in 13 cases (4.3%); 9 (3%) of these complications were due to the ablation procedure. Six patients sustained a Q wave myocardial infarction alone, two had a Q wave infarction and required emergency surgery and one needed emergency surgery but did not have a Q wave infarction. No procedural deaths were attributed to the ablation procedure. Follow-up has been obtained in 182 of the 242 patients at a mean interval of 9 ± 5 months. Of the 182 patients, 174 (95, 6%) were alive and free of myocardial infarction. Angiographic follow-up is available thus far in 87 patients. By combining angiographic and clinical outcome, an overall estimated restenosis rate of 37.4% (68 of 182) was calculated.Conclusions. These data suggest that coronary rotational ablation can be performed on lesions with a variety of morphologic features with high initial success rates. The overall rate of restenosis is similar to that of balloon angioplasty.

Residual myocardial ischaemia in first non-Q versus Q wave infarction: maximal exercise testing and ambulatory ST-segment monitoring.

In a prospective study of 123 consecutive survivors of a first myocardial infarction (43 non-Q wave, 80 Q wave), we determined the total residual ischaemic burden by use of pre-discharge maximal exercise testing and post-discharge 36 h ambulatory ST-segment monitoring initiated 11 +/- 5 days after the infarction. The prevalence of exercise-induced ischaemic manifestations in the infarct types was similar: chest pain 14% vs 16% and ST-segment depression 54% vs 54%. The ischaemic threshold did not differ either (heart rate at 1 mm of ST-segment depression 120 +/- 27 vs 119 +/- 25 beats.min-1). During early post-discharge daily activities, more patients with non-Q wave infarction demonstrated transient episodes of ST-segment depression: 28% vs 14% (ns). Furthermore, ischaemic episodes were significantly longer (42.5 +/- 50.1 vs 22.0 +/- 20.6 min; P < 0.001), and the ischaemic threshold was significantly lower in non-Q wave infarction (heart rate at onset of ST-segment depression 84 +/- 11 vs 88 +/- 9 beats.min-1; P < 0.05). During 3.5 +/- 0.9 years of follow-up the proportion of patients with > or = 1 ischaemic event (non-fatal reinfarction, angina pectoris, revascularization) was significantly higher in non-Q wave infarction (51%) as compared to Q wave infarction (31%) (P < 0.05). In both infarct types the presence of ST-segment depression on ambulatory recording and exercise testing significantly predicted the development of future angina pectoris, whereas patients at increased risk for subsequent non-fatal reinfarction or cardiac death were not identified.

Quality of life in the first 100 days after suspected acute myocardial infarction--a suitable trial endpoint?

The aim was to determine the loss of quality of life following admission to hospital with suspected myocardial infarction. The study involved a cohort of admissions, with interview and follow up for 100 days. Main outcome measures were the quality of life prior to admission and at each stage of convalescence, estimated using the Rosser-Kind matrix: the calculated number of quality adjusted days during a 100 d follow up period. The study took place in a teaching hospital in Scotland. 206 patients were admitted with suspected acute myocardial infarction. Infarction was confirmed in 160 (Q wave infarcts 100, non-Q-wave infarcts 60), and unconfirmed in 46. The quality of life scores before the suspected heart attack were similar for patients whose final diagnosis was Q wave infarction, non-Q-wave infarction, or non-infarction. Of the 160 patients with confirmed infarction, only 54 (34%) had regained their previous quality of life scores at the end of 100 days, compared with 26 of 46 (57%) patients with unconfirmed infarction (p < 0.01). The mean numbers of quality adjusted days lost to patients with Q wave infarction, non-Q-wave infarction, and non-infarction were 17.0, 12.4, and 5.9 respectively (infarction v non-infarction, p < 0.0001). Measurements of both quantity and quality of life contributed to these results. The number of quality adjusted days lost after acute myocardial infarction is a practicable measurement that is relevant to patients' lives. It might be suitable as an outcome measure for clinical trials of thrombolytic therapy.

Prodromal chest pains: clues to the pathogenesis of non-Q wave acute myocardial infarction?

Prodromal chest pains were recorded from consecutive admissions to a single coronary care unit and the symptoms of those with Q wave and non-Q wave acute myocardial infarction were compared. Of 809 admissions there were 201 with Q wave ad 88 with non-Q wave infarction. The non-Q wave infarction group was older, included more women and a greater proportion had suffered a previous myocardial infarct. Effort angina was equally common in both groups, but in the Q wave infarction group, angina was more often of recent, within the previous 4 weeks. Symptoms to indicate worsening angina, more prolonged, intense or frequent pain, were equally common in both groups. These findings suggest that although the extent of coronary artery disease may differ, Q wave and non-Q wave myocardial infarction share a common pathogenic mechanism.

Long-term efficacy of triple-vessel angioplasty in patients with severe three-vessel coronary artery disease

Between May 1982 and December 1988, a total of 103 patients underwent angioplasty of all three major coronary arteries at a single institution. Angiographic success was achieved in 334 of 352 vessels (95%) and in 441 of 460 lesions (96%). No patients required urgent bypass surgery, and none died during the procedure; six had non-Q wave infarctions. The mean length of follow-up time was 49 ± 15 months (range 28 to 107 months). There have been 11 deaths, and one patient has undergone cardiac transplantation. Thirty-six patients had a clinical recurrence; 30 had repeat angioplasty and five had bypass surgery. Another nine patients eventually had bypass surgery after the clinical recurrence. At 48 months actuarial event-free rates are myocardial infarction, 98%; bypass surgery, 88%; and death, 89%. Of 86 current survivors, 58 are in functional class O to I, 21 are in class II, and seven are in class III.

Symptom-limited versus low level exercise testing before hospital discharge after myocardial infarction

Objective. This study was undertaken to compare a low level and a symptom-limited test performed before hospital discharge after an uncomplicated myocardial infarction.Background. Exercise testing after myocardial infarction provides useful prognostic information. Usually either a low level test is performed before hospital discharge or a symptom-limited test is performed at 3 weeks.Methods. The study group comprised 202 patients with an uncomplicated myocardial infarction; 58 patients had a non-Q wave infarction and 115 patients had received thrombolytic therapy. Both a low level and a symptom-limited exercise test were performed in 200 of the 202 study patients in randomized order on consecutive days, a mean of 7.4 ± 2.3 days after infarction.Results. The symptom-limited test required a considerably greater effort than the low level test: exercise duration was 554 ± 209 versus 389 ± 125 s (p < 0.0001), and peak work load was 5.7 ± 1.8 versus 4.2 ± 1.1 METs (p < 0.0001). The peak heart rate was higher during the symptom-limited test (121 ± 20 vs. 108 ± 14 beats/min, p < 0.0001), as was the rate-pressure product. The number of patients who developed ST segment depression ⩾ 1 mm increased from 56 during the low level test to 89 during the symptom-limited test (p < 0.0001). ST segment depression ⩾ 2 mm occurred in 22 patients during the low level test and in 41 patients during the symptom-limited test, an 86% increase (p < 0.0001). The number of patients with either angina or ST depression ⩾ 1 mm increased from 66 to 105 (p < 0.0001) with the symptom-limited test. Exercise test results were similar for patients with a Q wave or a non-Q wave infarction. Exercise duration was longer and exercise-induced ST depression less frequent in patients who had received thrombolytic therapy.Conclusions. A symptom-limited exercise test performed before hospital discharge after uncomplicated myocardial infarction provides a significantly greater cardiovascular stress than does a low level test and is associated with aa ischemic response nearly twice as frequently. The prognostic significance of a positive response at higher work loads bas not been defined.

Functional impact of remodeling during healing after non-Q wave versus Q wave anterior myocardial infarction in the dog

Objectives. This study was undertaken to compare changes in left ventricular remodeling and function during healing after a first anterior non-Q wave versus a Q wave myocardial infarction in the dog.Background. Whether ventricular remodeling is more severe after anterior Q wave than after anterior non-Q wave infarction has not been studied systematically.Methods. Serial remodeling and functional variables (two-dimensional echocardiography), electrocardiography and hemodynamic data were recorded over 6 weeks in 58 instrumented dogs subjected to left anterior descending coronary artery ligation or ligation plus collateral obliteration. Postmortem topography and transmurality (by planimetry) and infarct collagen (hydroxyproline) were measured at 6 weeks.Results. At 6 weeks, infarct collagen was similarly increased in both groups, but the Q wave group had greater infarct size (7.2% vs. 4.5%, p < 0.025) and greater transmurality (88% vs. 58%, p < 0.001), higher left atrial pressures, more infarct expansion (expansion index 2.62 vs. 2.31, p < 0.001), more thinning (thinning ratio 0.62 vs. 0.72, p < 0.001), greater cavity dilation (diastolic volume 88 vs. 72 ml, p < 0.001), more regional bulging in the short-axis view (depth 4.9 vs. 1.9 mm, p < 0.001), more regional asynergy (18% vs. 7%, p < 0.001), lower global ejection fraction (40% vs. 48%, p < 0.001), more endocardial and epicardial bulging in the long-axis view and greater incidence of aneurysm (82% vs. 36%, p < 0.005), left ventricular thrombus (64% vs. 0%, p < 0.0005) and ventricular arrhythmias. Echocardiograms obtained during a 6-week period indicated that left ventricular topographic deterioration and dysfunction were present in the earliest postinfarction study at 2 days in both groups but were more frequent in the Q wave group. Regional myocardial blood flow (24 dogs) was lower in the Q wave than in the non-Q wave group. Scanning electron microscopy (10 dogs) revealed preservation of the epicardial collagen matrix in the non-Q wave but not the Q wave group.Conclusions. Anterior Q wave infarction is associated with greater transmurality and more postinfarction left ventricular remodeling and dysfunction than is non-Q wave infarction.

Impact of increased infarct transmurality on remodeling and function during healing after anterior myocardial infarction in the dog.

To determine the impact of greater infarct transmurality on changes in left ventricular remodeling and function after acute anterior myocardial infarction, serial topographic and functional parameters (two-dimensional echocardiograms) and hemodynamics over 6 weeks, and postmortem topography (planimetry) at 6 weeks, were measured in chronically instrumented dogs randomized to standard coronary artery ligation (group 1) or a modified lower ligation plus collateral obliteration to decrease collateral inflow and increase transmurality (group 2). At 6 weeks, postmortem scar size and collagen were similar in the two groups, but group 2 had greater transmurality associated with more necrosis relative to area at risk, Q waves, infarct expansion, thinning, regional bulging, and cavity dilatation. Over the 6 weeks, group 2 showed more early expansion, late thinning and regional bulging in the short axis, larger diastolic and systolic volumes, and more apical aneurysmal bulging in the long-axis, reflecting more topographic deterioration. More important, group 2 showed greater regional and global left ventricular dysfunction over 6 weeks, lower ejection fraction at 2 days with further decrease over 6 weeks, and more left ventricular thrombus, ventricular arrhythmias, and deaths. In addition, transmurality correlated with the severity of remodeling and dysfunction. The findings indicate that transmurality is a major determinant of remodeling and left ventricular dysfunction during healing after anterior infarction.

Progressive changes in ventricular structure and function during the year after acute myocardial infarction

To investigate the long-term changes in left ventricular structure and function after myocardial infarction, 51 patients with a first myocardial infarction (17 anterior, 23 inferior, and 11 non-Q wave) were studied by two-dimensional echocardiography at the time of entry into the hospital, at 3 months, and 1 year after infarction. The left ventricular endocardial surface was reconstructed from these echocardiograms, and the endocardial surface area (ESA) index (in cm 2/m 2) and area of abnormal wall motion (AWM in cm 2) were quantitated. Despite different trends in the ESA index between entry and 3-month values in those with and without early infarct expansion, a decrease in the ESA index from 3 months to 1 year was noted in anterior and non-Q wave infarctions (anterior with early expansion: 96.3 ± 8.6 to 81.5 ± 4.2 cm 2/m 2, p < 0.05; anterior without early expansion: 59.7 ± 2.0 to 54.7 ± 2.0 cm 2/m 2, p < 0.01; non-Q wave: 64.1 ± 3.5 to 57.9 ± 4.4 cm 2/m 2, p < 0.01). The mean decline in ESA from 3 months to 1 year of 8.9 ± 2.5 cm 2 was independent of initial infarct size. Regional function, as represented by the area of AWM, was also improved but the timing of the improvement was related to the location and size of the infarction. Although decreases in AWM were noted in both the inferior and non-Q wave groups from entry to 3 months (inferior: 27.1 ± 3.3 to 21.8 ± 3.4 cm 2, p < 0.5; non-Q wave: 18.9 ± 4.5 to 12.1 ± 5.5 cm 2, p < 0.05), decreases in AWM in anterior infarctions were not present until the 3-month to 1-year time period (anterior with expansion: 79.1 ± 18.6 to 59.8 ± 14.9 cm 2, p < 0.05; anterior without expansion: 27.7 ± 6.2 to 16.5 ± 4.9 cm 2, p < 0.05). Even in the absence of intervention, global left ventricular size decreases and regional wall motion improves in both Q wave and non-Q wave infarctions when quantitated 1 year after i infarction.

Magnum/Magnarail versus conventional systems for recanalization of chronic total coronary occlusions: A randomized comparison

The Magnum/Magnarail system consists of “over-the-wire” balloon catheters and a 0.021 inch (0.53 mm) guide wire with a 1 mm olive-shaped tip. To compare it to conventional systems, 100 consecutive unselected patients with chronic total coronary occlusions were randomly assigned to one of two groups. If the balloon could not be placed within 20 minutes of fluoroscopy time with the allocated system, a crossover to the other system was imposed. The Magnum group comprised 50 patients and 52 occlusions, and the conventional group included 50 patients and 51 occlusions. There were no significant differences with regard to the length of the occlusions (Magnum 1.4 ± 1.3 mm, conventional 1.6 ± 1.7 mm) or the duration (Magnum 1.4 ± 1.9 months, conventional 1.4 ± 1.8 months). The primary success rate before crossover with the Magnum/Magnarail system was 67% versus 45% with conventional systems ( p < 0.05). The Magnum/Magnarail system as a second tool after crossover was successful in 11 of 28 patients (39%) versus 2 of 16 patient (12%) in whom success was achieved with a conventional system as a second tool ( p < 0.05). An increase in the creatine kinase level (more than twice normal) was seen in one patient (2%) in the Magnum/Magnarail group and none in the conventional group. Q wave infarctions were not seen. There was one in-hospital death (2%) in the conventional group. There were no significant differences with regard to the number of guiding and ballon catheters or fluoroscopy time. The Magnum/Magnarail system proved superior to conventional systems for balloon recanalization of chronic total coronary occlusions in terms of higher success rates.

Antithrombotic therapy in left ventricular thrombosis and systemic embolism

Left ventricular (LV) thrombi are responsible for significant morbidity and mortality in our society. Twenty-five percent of cardiogenic emboli are associated with acute and chronic myocardial infarction. With the development of noninvasive imaging techniques LV thrombi have been increasingly recognized as an important clinical entity; the imaging method of choice is two-dimensional echocardiography. LV mural thrombi occur in one third of Q wave anterior myocardial infarctions; their occurrence in patients with non-Q wave infarction and inferior Q wave myocardial infarction is less than 5%. More than half of all LV thrombi are formed within 48 hours of acute myocardial infarction, and nearly all thrombi have been formed within a week of infarction. The development of an LV thrombus is associated with some risk of systemic embolization. To prevent LV thrombosis and systemic embolism, full-dose heparin followed by warfarin therapy for at least 3 months is indicated for patients with large anterior infarctions and those with heart failure. The use of thrombolytic therapy does not reduce the risk of LV thrombus formation; few data exist on whether early coronary angioplasty reduces the risk of LV thrombus formation and the risk of embolization. The proper treatment for patients with chronic LV thrombi remains unknown.

Accuracy of a portable interpretive ECG machine in diagnosis of acute evolving myocardial infarction.

From a study of 526 patients having automatic ECG analysis, criteria were established which diagnosed acute evolving Q wave myocardial infarction with 71% sensitivity and 98% specificity. Specificity was 100% when patients with known previous Q wave infarction were excluded. In pre-hospital practice the high sensitivity and specificity were maintained. This method appears appropriate, when other criteria are met, for paramedic-initiated pre-hospital thrombolysis with remote supervision of a cardiologist by telephone.

The secondary prevention of myocardial infarction by drug treatment; excluding lipid lowering agents.

About 10% of survivors of an acute myocardial infarction will die in the following year. Thereafter the risk declines but reinfarction is still an important cause of mortality and morbidity. The post infarction trials have clearly shown that the best proven agents to mitigate this toll are aspirin, beta adrenoceptor blockers, and verapamil (but not other calcium blockers, except diltiazem for non Q wave infarction). In the context of hypertension treatment these post infarction trials may have important lessons for drug selection and ancillary treatment since the majority of subjects will ultimately die of ischaemic heart disease. Although the newer agents such as ACE and renin inhibitors, newer calcium channel blockers and alpha blockers have many promising properties in terms of risk factor reduction, no convincing mortality data exists; it is needed. This review will deal with the known effects (both good and bad) of antihypertensive agents and will also review other drug strategies relevant to the hypertensive patient. It will also point out large areas of ignorance.

Treatment of acute myocardial infarction: a cardiologist's perspective.

The treatment of acute myocardial infarction can generally be organized along three pathways. First, interventions directed toward alleviating acute myocardial ischemia include oxygen, sublingual nitroglycerin, morphine, aspirin, heparin, and intravenous nitroglycerin. Appropriate patients may also benefit from beta-adrenergic blockers, thrombolytic agents, intra-aortic balloon counterpulsation, and revascularization with either coronary angioplasty or bypass graft surgery. Second, interventions directed toward assessing and treating acute left ventricular dysfunction include invasive hemodynamic monitoring and echocardiography; maximizing preload; correcting blood gas, serum electrolyte, acid-base, or hemoglobin abnormalities; controlling heart rate; and maintaining AV conduction. Pharmacological agents to consider include diuretics, nitroglycerin, nitroprusside, dobutamine, dopamine, norepinephrine, and amrinone. Support devices, coronary angioplasty, and cardiac surgery are also occasionally needed. Third, interventions directed toward preventing or treating arrhythmias and conduction disturbances include atropine, isoproterenol, beta-blockers, verapamil, digitalis, adenosine, lidocaine, procainamide, bretylium, amiodarone, countershock, and cardiac pacing. All of the above information has been drawn from studies in nonsurgical patients. Unfortunately, there is little in the cardiology literature about treatment of patients with perioperative MI [17]. It is of interest to note that most perioperative MI occurs in the postsurgical period, not intraoperatively, and is often painless. As discussed throughout this volume, controlling postoperative stresses--including surgical complications, pulmonary complications, fluid and electrolyte abnormalities, and heart rate and blood pressure responses--is probably important. Serial cardiac enzymes and electrocardiograms improve the diagnostic yield. Treatment options are limited by the fact that many events are non-Q wave infarctions. Also, the increased risk of bleeding from the operative site precludes use of antiplatelet, anticoagulation, and thrombolytic agents. Hemodynamically or electrically unstable patients should be referred for emergency cardiac catheterization and probable coronary angioplasty. Patients at risk for large Q wave MI, heralded by ST-segment elevation in several electrocardiographic leads, should also be considered for invasive treatment. Further clinical investigation of the natural history, diagnosis, and treatment of perioperative MI is sorely needed.

Quantification of antimyosin uptake and infarct size at various stages of myocardial infarction

We studied with quantitative techniques the clinical efficacy of indium-111 antimyosin at a later stage of myocardial infarction in 18 patients at various stages after infarction. Antimyosin accumulation was detected irrespective of infarct age and size and quantified as an infarct weight with a tomographic technique. Higher intensities in a planar image were observed in anterior Q wave infarct group (36 ± 5 g) but not in inferior and non-Q wave anterior infarct groups because of the smaller infarct weights (8 ± 3 g, 13 ± 6 g, respectively). Infarct area calculated from thallium-201 tomography significantly correlated with left ventricular ejection fraction in both recent (less than 2 weeks) and older (2-week- to 6-month-old) infarct groups ( r = −0.969, P < 0.001; r = −0.860, P < 0.001, respectively), whereas there was a significant negative correlation between infarct weight and left ventricular ejection fraction in the recent infarct group ( r = −0.731, P < 0.05) but not in the older infarct group. Thus, antimyosin tomography can detect myocardial necrosis with a high sensitivity regardless of infarct age, size, and location. However, the accumulation might be affected by infarct age and correspond to necrotic mass but not necessarily to infarct volume itself at a later stage probably because of the presence of necrosed and scarred tissues in infarcted myocardium.

Post-myocardial infarction exercise testing. Non-Q wave versus Q wave correlation with coronary angiography and long-term prognosis.

The presence or absence of baseline diagnostic Q waves has been believed to compromise the accuracy of standard exercise electrocardiography in identifying severe coronary artery disease (three-vessel and/or left main disease); therefore, a retrospective analysis was performed using a personal computer data base of exercise test responses and cardiac catheterization results to evaluate this premise, and follow-up was performed to observe how Q waves and/or severe coronary disease impacted on survival. Two hundred fifty-three male patients who had survived a myocardial infarction were studied. Patients on digitalis, those with left bundle branch block or left ventricular hypertrophy on their baseline electrocardiogram, those with previous revascularization procedures, and those with significant valvular or congenital heart disease were excluded. All patients performed either a low-level predischarge or a sign/symptom limited exercise test and underwent diagnostic coronary angiography within 32 days of each test (range, 0-90 days). Long-term follow-up on patients was performed for an average of 45 months (+/- 17 months). Group NQMI comprised 103 post-myocardial infarction patients lacking Q waves at the time of exercise testing and group QMI comprised 150 patients who developed Q waves with their myocardial infarction. The cut points of greater than or equal to 1 mm (chi 2 = 14.39, p less than 0.001) and greater than or equal to 2 mm (chi 2 = 26.11, p less than 0.001) of exercise-induced ST segment depression were reliable markers of severe coronary disease in Q wave infarct survivors. This was also true for non-Q wave infarct survivors as greater than or equal to 1 mm (chi 2 = 6.02, p = 0.01) and greater than or equal to 2 mm (chi 2 = 4.37, p = 0.04) of ST segment depression were reliable markers of severe coronary disease. Receiver operating characteristic curve analysis revealed that exercise-induced ST segment depression had discriminating power for the identification of severe coronary artery disease in both the Q wave myocardial infarction patients (area = 0.735, z = 4.47, p less than 0.001) and the non-Q wave infarct patients (area = 0.700, z = 3.20, p less than 0.001). After 4.4 years of cumulative follow-up, patients with severe coronary disease had an infarct-free survival rate of 72% (95%, CI, 50.0-86.0%), whereas those without severe disease had an 86% (95% CI, 76.5-91.5%) infarct-free survival rate (Cox chi 2 = 4.00, p = 0.045). Non-Q wave patients had an infarct-free survival rate of 81% (95% CI, 66.0-89.5%), whereas those with Q waves had an infarct-free survival rate of 85% (95% CI, 73.9-91.3%) (Cox chi 2 = 0.0005, p = NS). The presence or absence of diagnostic Q waves has no significant effect on the ability of the exercise electrocardiogram to identify severe coronary artery disease in survivors of myocardial infarction. Long-term infarct-free survival of patients with myocardial infarction is more related to the presence of severe coronary disease rather than if they suffered a non-Q wave or Q wave infarction.