Clinical significance and prognostic importance of left ventricular hypertrophy in non-Q-wave acute myocardial infarction

Left ventricular (LV) hypertrophy is known to be an independent risk factor for cardiac death, but its significance in non-Q-wave acute myocardial infarction (AMI) has not been assessed previously. In a randomized diltiazem-placebo-controlled therapeutic trial of non-Q-wave AMI confirmed by creatine kinase-MB (CK-MB), 126 of 544 patients (23%) exhibited LV hypertrophy using standard voltage criteria. Compared to patients without LV hypertrophy, patients with LV hypertrophy were significantly older (65 vs 60 years, p less than 0.0001) and had smaller peak adjusted CK levels (490 +/- 376 vs 666 +/- 726 IU/liter, p less than 0.001) than patients without LV hypertrophy. Patients with and without LV hypertrophy did not differ significantly in acute mortality during hospitalization, progression to Q waves, reinfarction by CK-MB criteria or angina associated with transient electrocardiographic changes. Compared with patients without LV hypertrophy, those patients with non-Q-wave AMI and LV hypertrophy had a 2-fold higher incidence of reinfarction (24 vs 12%, p less than 0.005) and death (19 vs 9%, p = 0.044) during the first year of follow-up. Multivariate regression analysis revealed that the relative risk of death and reinfarction during the initial year after AMI was increased by a factor of 1.7 and 2.1 among patients with LV hypertrophy, respectively. It was therefore concluded that, although patients with LV hypertrophy and non-Q-wave AMI have smaller enzymatic infarcts and the same short-term prognosis as do patients without LV hypertrophy, their reinfarction and mortality rates are significantly increased during the first year of follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of the addition of nifedipine in patients with mixed angina compared to patients with classic exertional angina: a multicenter, randomized, double-blind, placebo-controlled clinical trial

Episodes of myocardial ischemia in patients with coronary artery disease may be due to transient increases in coronary vasomotor tone superimposed on a fixed atherosclerotic obstruction. The purpose of this study was to determine whether identification of the clinical pattern of angina could predict the therapeutic response to the addition of nifedipine to a regimen of beta blockers and/or long-acting nitrates. Seventy-two patients with stable exertional angina were divided into two groups: "classic exertional angina" (17 patients), defined as exertional angina with a stable threshold; and "mixed angina" (55 patients), defined as exertional angina provoked by a variable threshold and/or at least two episodes of rest angina within the 3 months prior to screening. Patients were studied with nifedipine and placebo in a 6-week, double-blind, crossover design that used serial anginal diaries, exercise treadmill tests, and 24-hour ambulatory ECG monitoring. In patients with mixed angina, nifedipine reduced the frequency of angina compared to that during placebo treatment (13.1 vs 9.9 episodes/3 weeks, p less than 0.01) and reduced nitroglycerin consumption (11.7 vs 7.5 tablets/3 weeks, p less than 0.05); while in patients with classic exertional angina, nifedipine had no symptomatic effect (7.9 vs 6.8 anginal episodes/3 weeks, NS; 6.4 vs 5.8 nitroglycerin tablets/3 weeks, NS). Patients in both groups experienced a significant decrease in the manifestations of ischemia during exercise testing. Patients with mixed angina experienced a reduction in the daily frequency of painful episodes of ST segment depression during nifedipine treatment compared to placebo (0.6 vs 0.2 episodes, p less than 0.05), but there was no effect on the frequency of episodes of silent ischemia (4.2 vs 3.4 episodes, NS). In patients with classic exertional angina, the addition of nifedipine had no effect on any measure of ambulatory ischemia. We conclude that patients with mixed angina are more likely to benefit symptomatically from the addition of nifedipine therapy than patients with classic exertional angina. The lack of a consistently preferential response to nifedipine in patients with mixed angina, however, suggests that episodic coronary vasoconstriction may not be the only mechanism responsible for ischemia in these patients, and/or that nifedipine may not necessarily provide additional therapeutic benefit beyond that conferred by a regimen of beta blockers and/or nitrates.

Prognostic significance and beneficial effect of diltiazem on the incidence of early recurrent ischemia after non-Q-wave myocardial infarction: results from the Multicenter Diltiazem Reinfarction Study

Of 576 patients with non-Q-wave acute myocardial infarction enrolled in the Diltiazem Reinfarction Study, 246 (43%) had 1 or more episodes of angina at rest or with minimal effort during 10.5 days of treatment with either diltiazem (90 mg every 6 hours) or placebo. Reinfarction (12.2% vs 3.6%, p less than 0.0001) or death (6.1% vs 1.5%, p = 0.003) was more likely to occur within 2 weeks of randomization in patients with postinfarction angina than in those without angina. Based on serial electrocardiographic data, 115 of the 246 patients with angina had transient ST-T changes and 131 did not. Comparison of the 14-day event rates in these 2 groups showed that the 115 patients with electrocardiographic evidence of ischemia had a higher frequency of reinfarction (20% vs 5.3%, p less than 0.001), more extensive damage as assessed by peak MB-creatine kinase levels (91 +/- 76 vs 37 +/- 19 IU/liter, p = 0.059 [Wilcoxon rank sum]) and a higher mortality rate (11.3% vs 1.5%, p = 0.001). Angina associated with transient ST-T changes occurred in 70 of the 289 patients in the placebo group but in only 45 of the 287 patients in the diltiazem group--a 28% reduction in cumulative life-table incidence (p = 0.0103 [2-tail, log rank]; 95% confidence interval, 9.3 to 53.8%). It is concluded that patients with early postinfarction angina are at increased risk of reinfarction and death, and angina associated with transient electrocardiographic changes identified a very high risk subset. This subset appeared to have a larger area of viable but jeopardized myocardium and benefited from prophylactic therapy with diltiazem.

Electrocardiographic evolution of posterior acute myocardial infarction: importance of early precordial ST-segment depression

Precordial ST-segment depression is typically observed in anterior non-Q-wave acute myocardial infarction (AMI), and is generally not regarded as an indication for acute thrombolytic therapy. Of 544 patients with creatine kinase (CK)-MB-confirmed non-Q-wave AMI randomized to the prospective multicenter Diltiazem Reinfarction Study, 50 patients (9.2%) had isolated precordial ST-segment depression of 1 mm or more in 2 or more contiguous precordial electrocardiographic leads (V1-V4). Serial electrocardiograms recorded at study entry (mean 50.5 hours after onset of chest pain), on study day 2, study day 3 and at predischarge showed that in 23 of 50 patients (40%) electrocardiographic evidence of posterior AMI evolved, defined as an R wave of 0.04 second or more in lead V1 and an R:S greater than or equal to 1 in lead V2. In 18 of these 23 patients (78%), posterior AMI had evolved by study day 3, and none had an abnormal reelevation of CK-MB (every 12-hour sampling) for up to 14 days of hospitalization. Compared with the remaining 27 patients who had electrocardiographic features of anterior non-Q-wave AMI only, the 23 with initial precordial ST segment depression in whom posterior AMI developed had significantly higher mean peak CK values (1,051 +/- 172 vs 663 +/- 89 IU, p less than 0.009) and greater mean precordial ST-segment depression in lead V1 (0.28 vs + 0.19 mm, p = 0.01), in lead V2 (1.3 vs 0.26 mm, p = 0.003) and in lead V3 (2.0 vs 0.93 mm, p = 0.0004).(ABSTRACT TRUNCATED AT 250 WORDS)

Asymmetric distribution of left ventricular asynergy in coronary artery disease and its relation to coronary stenoses

In 100 patients with coronary artery disease (CAD), the prevalence and severity of asynergy was determined for 9 left ventricular (LV) segments by both radionuclide and contrast angiography. The anterior, septal and lateral LV walls had significantly more prevalent and more severe asynergy in the medial segments than in the basal segments. In contrast, the inferior LV wall exhibited equally severe asynergy in both the medial and basal segments. In general, asynergy was most severe in the apical, medial septal, medial inferior and basal inferior LV segments. This asymmetric distribution of LV asynergy could not be explained by the distribution of occlusions or significant stenoses in the arterial tree, which were relatively uniformly distributed among the left anterior descending (32%), left circumflex (29%) and right (26%) coronary arteries. It is postulated instead that the asymmetric distribution of LV asynergy results from asymmetry of the coronary arterial tree supplying the left ventricle and that the prevalence of asynergy in an LV segment is directly related to its vascular distance from the coronary ostia. Unlike the relatively direct supply of the left anterior descending and circumflex arteries to the basal segments of the anterior, septal and lateral LV walls, the arterial supply to the basal inferior wall begins only after the right or dominant circumflex artery has traversed the length of the atrioventricular groove, significantly increasing its susceptibility to the pressure attenuation and occlusive jeopardy of more proximal stenoses.

No increase in serum digoxin concentration with high-dose diltiazem

The effect of incremental diltiazem dosing during concomitant digoxin administration over a four-week period in eight healthy adult volunteers (mean age, 28 +/- 4 years) was studied. The study group received 0.25 mg of digoxin twice daily for two days, after which they received 0.25 mg daily for the duration of the study. Following baseline electrocardiographic evaluation and measurement of trough digoxin levels, all subjects received 120 mg of diltiazem daily for one week, then 240 mg daily for one week, followed by 360 mg daily for one week. Resting electrocardiographic parameters (heart rate, P-R interval), renal function, electrolyte values, and digoxin and diltiazem concentrations were measured weekly. Daily administration of 360 mg of diltiazem plus 0.25 mg of digoxin resulted in a significant decrease in heart rate (from 68 +/- 9 beats per minute to 61 +/- 10 beats per minute; p less than 0.05), a marginal increase in P-R interval (from 169 +/- 22 msec to 179 +/- 21 msec; p = 0.08), and no significant change in trough serum digoxin concentration (from 0.85 +/- 0.08 ng/ml to 0.90 +/- 0.08 ng/ml; p = NS). The administration of up to 360 mg of diltiazem per day with 0.25 mg of digoxin per day was not associated with significant increases in serum digoxin concentrations in healthy subjects.

Diltiazem and reinfarction in patients with non-Q-wave myocardial infarction. Results of a double-blind, randomized, multicenter trial

We performed a multicenter, double-blind, randomized study to evaluate the effect of diltiazem on reinfarction after a non-Q-wave myocardial infarction. Nine centers enrolled 576 patients: 287 received diltiazem (90 mg every six hours) and 289 received placebo. Treatment was initiated 24 to 72 hours after the onset of infarction and continued for up to 14 days. The primary end point, reinfarction, was defined as an abnormal reelevation of MB creatine kinase in plasma within 14 days. Reinfarction occurred in 27 patients in the placebo group (9.3 percent) and in 15 in the diltiazem group (5.2 percent)--a 51.2 percent reduction in cumulative life-table incidence (P = 0.0297; 90 percent confidence interval, 7 to 67 percent). Diltiazem reduced the frequency of refractory postinfarction angina (a secondary end point) by 49.7 percent (P = 0.0345; 90 percent confidence interval, 6 to 73 percent). Mortality was similar in the two groups (3.1 and 3.8 percent, respectively, in the placebo and diltiazem groups), but adverse drug reactions (most of which were mild) were more common in the diltiazem group. Nevertheless, the drug was well tolerated, despite concurrent treatment with beta-blockers in 61 percent of the patients. We conclude that diltiazem was effective in preventing early reinfarction and severe angina after non-Q-wave infarction and that it was also safe and generally well tolerated.

Beneficial effects of high-dose diltiazem in patients with persistent effort angina on beta-blockers and nitrates: a randomized, double-blind, placebo-controlled cross-over study

The effects of orally administered diltiazem combined with maximally tolerated doses of beta-blockers and nitrates were assessed in 12 patients, who during stress testing exhibited persistent effort angina and continued objective evidence for inducible myocardial ischemia. Patients performed multistage semisupine exercise on a bicycle ergometer during equilibrium-gated radionuclide angiography after consecutive 2 week treatment periods of placebo or diltiazem 90 mg qid (mean dose 340 mg/day) combined with maximally tolerated propranolol (mean dose 178 mg/day) and isosorbide dinitrate (mean dose 137 mg/day). All medications (including diltiazem or placebo) were administered four times daily for the duration of the study. Diltiazem or placebo was administered according to a double-blind design, with randomized cross-over at the end of each 2 week treatment period. The average number of angina attacks decreased during the double-blind cross-over phase of the trial (7 +/- 7 episodes/week at baseline vs 4 +/- 3 on placebo vs 2 +/- 2 on diltiazem; p = .08). Angina pectoris was abolished during peak exercise in eight of 12 patients on diltiazem (p less than .05 vs placebo). Diltiazem increased total exercise duration from 276 +/- 92 to 310 +/- 78 sec (p less than .005 vs baseline). Diltiazem likewise increased the time to onset of angina from 231 +/- 84 sec at baseline to 305 +/- 77 sec (p less than .005), as well as the time to the onset of 1 mm ischemic ST segment depression (p = .01). Diltiazem decreased heart rate at rest, during submaximal workload, and at peak exercise (p less than .05), and decreased systolic blood pressure at peak exercise only (p less than .05). A significant decline in rate-pressure product at submaximal and peak exercise was noted (p less than .05). At any given workload there was significantly less ST segment depression during submaximal (p = .05) and peak exercise (p less than .025).(ABSTRACT TRUNCATED AT 250 WORDS)

Nifedipine-induced hypotension and myocardial ischemia in refractory angina pectoris

Combined nitrate/beta-blocker/nifedipine therapy is commonly used to treat refractory angina pectoris. We have observed "paradoxical" myocardial ischemia in ten patients with refractory angina (seven receiving combined beta-blocker and nitrate therapy, and three receiving nitrate treatment alone) in whom nifedipine (mean dosage, 92 mg/day; range, 60 to 120 mg/day) induced a decrease in blood pressure, angina pectoris (10/10 patients), and ischemic ECG changes (7/10 patients). These ten patients, all of whom regularly reported angina within 20 to 30 minutes of nifedipine ingestion, were prospectively studied before and after usual nifedipine dose administration, while blood pressures, heart rate, and ECGs were recorded. Mean systolic BP fell from 109 to 94 mm Hg after nifedipine (P less than .001, paired t test); mean heart rate increased from 64 to 68 beats per minute (P less than .05); seven patients developed transient ECG changes (five with ST-T wave depression and two with ST-T wave elevation) during the hypotensive period. Nifedipine may provoke angina and myocardial ischemia in certain patients with refractory angina pectoris receiving concomitant beta-blocker and nitrate therapy.

Inferoseptal myocardial infarction: another cause of precordial ST-segment depression in transmural inferior wall myocardial infarction?

Electrocardiographic ST-segment depression in the anterior precordial leads is a frequent observation during the initial hospital phase of acute transmural inferior myocardial infarction (MI), but is of uncertain significance. No available clinical studies have examined the prevalence of inferoseptal necrosis complicating inferior MI. Therefore, the clinical course, electrocardiographic features, radionuclide angiograms and cardiac enzyme changes in 57 patients with transmural inferior MI who did not have prior anterior or concomitant "true posterior" MI, associated anterior or posterolateral asynergy by radionuclide ventriculography, or left or right bundle branch block were reviewed retrospectively. Patients were categorized according to the presence (group A) or absence (group B) of precordial ST-segment depression and according to the presence (group I) or absence (group II) of radionuclide septal wall motion abnormalities. There were no significant differences in global left ventricular ejection fraction (group A, 49 +/- 8, group B, 52 +/- 41; group I, 51 +/- 7, group II, 51 +/- 6), right ventricular ejection fraction (group A, 45 +/- 9, group B, 42 +/- 7; group I, 43 +/- 8, group II, 41 +/- 8), or clinical outcome in the hospital. However, chi-square analysis revealed a significant (p less than 0.05) association between the presence or absence of septal asynergy and the presence or absence of precordial ST depression. In addition, average peak creatine kinase elevation (group I, 761 +/- 164 IU; group II, 698 +/- 178 IU) attained marginal significance by paired t test (p = 0.06). Precordial ST-segment depression during transmural inferior MI is frequently associated with septal asynergy by gated radionuclide angiography (15 of 26 patients, 58%).(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular asynergy in electrocardiographic "posterior" myocardial infarction

P2 300 selected patients, scalar electrocardiograms and contemporaneous radionuclide angiograms were analyzed retrospectively to assess the association between prominent right precordial R waves (duration greater than or equal to 0.04 second, R greater than or equal to S in lead V1 or V2), traditionally considered diagnostic of "posterior" infarction, and asynergy in various left ventricular segments. Mathematical methods for analysis of association between nonparametric variables clearly demonstrated that prominent right precordial R waves were strongly associated with asynergy of the basal lateral left ventricular wall, although asynergy of adjacent inferior and lateral segments was common. With the exclusion of right ventricular hypertrophy and bundle branch block, a prominent R wave in lead V1 exhibited a high specificity (greater than to 99%), a high positive predictive value (91%) and a low sensitivity (36%) for diagnosing basal lateral myocardial infarction. A prominent R wave in lead V2 exhibited a higher sensitivity (61%), a somewhat lower specificity (95%) and a significantly lower positive predictive value (76%). A newly developed criterion for such infarction--a prominent R wave in lead V2 and a Q wave inferior infarction--had intermediate characteristics and may be more clinically useful. The most common reasons for the decreased sensitivities of all three criteria were left ventricular hypertrophy or associated anterior myocardial infarction. These data demonstrate that prominent right precordial R waves are clinically useful in identifying inferior and lateral wall infarctions that involve the basal lateral left ventricular segment. Confusion results primarily from inappropriate use of the electrocardiographic term "posterior" for such infarctions.

Unstable angina with episodic ST segment elevation and minimal creatine kinase release culminating in extensive, recurrent infarction

The syndrome of episodic angina at rest, recurrent ST segment elevation (mean = 9 mV) and nontransmural infarction characterized by minimal serum creatine kinase (CK) (mean 243 IU; upper normal limit 132 IU) was studied in 15 patients who presented with these findings. All were initially managed with intensive nitrate and beta-receptor blocker therapy. Eleven patients underwent intraaortic balloon counterpulsation for refractory angina and 13 underwent cardiac catheterization. High grade (greater than or equal to 90%) stenosis of the proximal left anterior descending coronary artery was demonstrated in 11 patients, and coronary spasm without significant, fixed occlusive disease was noted in 2 patients. Urgent aortocoronary bypass surgery was performed in seven patients with recurrent pain or electrocardiographic injury, or both, unresponsive to maximal medical therapy. The initial mean ST segment elevation and CK elevation for this group was 10 mV and 232 IU, respectively. No surgical patient developed recurrent infarction; there was one late death after reoperation. Eight patients whose condition stabilized initially on medical therapy did not undergo urgent surgery. However, five subsequently developed large transmural anterior reinfarction despite intensive medical therapy, and three died from pump failure. These patients on medical therapy did not differ from the surgical group in magnitude of ST segment elevation or increase in serum CK. Their initial mean ST segment elevation and CK elevation were 8 mV and 254 IU, respectively (difference not significant). Thus, repetitive episodes of rest angina with marked anterior wall ST segment elevation and mild CK elevations may define a subset of patients who appear to progress rapidly from minimal nontransmural necrosis to massive transmural infarction. Prompt recognition of this syndrome, followed by cardiac catheterization and urgent aortocoronary bypass surgery, may prevent extensive cardiac muscle loss.

Bioprosthetic endocarditis due to Cryptococcus neoformans

Fungal prosthetic endocarditis continues to be a lethal complication of cardiac valve replacement. We describe a patient with culture-proved Cryptococcal endocarditis and myocarditis whose non-regurgitant xenograft aortic prosthesis was successfully replaced urgently upon the occurrence of new 1st degree A-V block in the third postoperative week. Operative intervention, including vigorous debridement of the aortic root, is effective in postoperative prosthetic fungal infections involving the myocardium. The patient described herein is now infection-free, with a non-regurgitant valve, one and one-half years following operation.

Anaphylactoid pulmonary edema ("shock lung") and hypotension after radiologic contrast media injection

This report illustrates a severe anaphylactoid reaction to sodium diatrizoate infusion during intravenous urography that was characterized chiefly by noncardiogenic pulmonary edema ("shock lung") and protracted hypotension. This occurred in an otherwise previously healthy adult without prior exposure to organic iodides.

Exercise-induced coronary spasm with S-T segment depression and normal coronary arteriography

The unique association of both exercise-induced coronary arterial spasm and S-T segment depression with normal findings on selective coronary arteriography is described. The patient had a prior history of typical effort angina that had recently progressed to angina at rest. Despite the change in anginal pattern, the electrocardiogram disclosed S-T segment depression that was consistent with subendocardial ischemia, during both exercise testing and spontaneous chest pain. Exercise thallium-201 scintigraphy demonstrated the presence of large perfusion defects of the anterior and septal walls of the left ventricle. Coronary arteriographic findings, in the absence of symptoms, were entirely normal. Severe localized, reversible coronary spasm of the proximal left anterior descending coronary artery was subsequently demonstrated during spontaneous angina, isometric arm exercise and after the administration of ergonovine maleate. After treatment with isosorbide dinitrate and nifedipine, the patient had no further chest pain or electrocardiographic changes, and a repeated thallium-201 stress test revealed normal findings and greatly improved exercise tolerance.

The effect of verapamil on mechanical performance of acutely ischemic and reperfused myocardium in the conscious dog

The effect of verapamil, an inhibitor of transmembrane calcium flux, was studied in intact conscious dogs with myocardial ischemia produced by inflating a balloon cuff implanted on the left anterior descending coronary artery. Six dogs received a continuous infusion of verapamil (10 microgram/kg per min) beginning prior to coronary occlusion, and six received normal saline infusions. Systolic ejection shortening (SES) was measured from subendocardial ultrasonic crystals implanted in the central ischemic zone (IZ) and border zone (BZ), and in a nonischemic control zone (CZ). Hearts were paced at a constant heart rate with periodic introduction of closely coupled extrasystoles. SES was measured both for normally paced beats and during postextrasystolic potentiation (PESP). Regional myocardial blood flow was measured by injecting radioactive microspheres before, during, and after coronary occlusion. There were no significant differences between verapamil-treated dogs and saline control dogs in mean aortic pressure, heart rate, left ventricular end-diastolic pressure or dP/dt, cardiac output, or regional myocardial blood flow in IZ, BZ, or CZ. Differences in mechanical performance between two groups were noted, however. In the IZ, SES was abolished completely for normally paced beats in both groups but was significantly preserved for PESP beats in the verapamil-treated animals. In the BZ, SES was significantly reduced for normally paced beats only in the saline controls, and PESP responses were preserved to a significantly greater degree in the verapamil-treated animals. These results indicate that verapamil pretreatment exerts beneficial effects upon mechanical performance of ischemic myocardium. Since no changes in systemic hemodynamics or regional myocardial blood flow were observed, the effect may be due to the calcium-antagonistic properties of the agent.

Experimental myocardial infarction. XVI. The detection of inotropic contractile reserve with postextrasystolic potentiation in acutely ischemic canine myocardium

Postextrasystolic potentiation after a single closely coupled extrasystole may identify residual ventricular contractile performance in acutely ischemic myocardium without producing sustained secondary ischemic depression of myocardial function. Postextrasystolic potentiation was systematically used in eight open chest dogs to assess the progression of regional contraction abnormalities during a 10 minute occlusion of the left anterior descending coronary artery. Segment function was determined from pressure-length loop areas inscribed during right ventricular pacing at 128 +/- 3 (mean +/- standard error of the mean) beats/min, and after single closely coupled (179 +/- 3 msec) extrasystoles. Despite a 50 percent decrease in border zone segment function, postextrasystolic potentiation consistently augmented mechanical performance to control levels throughout the ischemic period. Central ischemic zone segment function deteriorated more profoundly, with the development of holosystolic aneurysmal bulging within 30 seconds after occlusion. Nonetheless, postextrasystolic potentiation produced marked inotropic augmentation, but not to control levels, for up to 10 minutes of ischemia. These results suggest that latent viability and contractile reserve may exist during brief periods of coronary occlusion.