Ergonovine testing to detect spontaneous remissions of variant angina during long-term treatment with calcium antagonist drugs

What is the meaning of provoked spasm phenotypes by vasoreactivity testing?

Coronary artery epicardial spasm is involved in the pathogenesis of many cardiac disorders. Vasoreactivity testing, such as intracoronary injection of acetylcholine (ACH) or ergonovine (ER), is the gold standard method for the diagnosis of vasospastic angina. Provoked epicardial spasm phenotypes are classified as focal spasm and diffuse spasm. Multiple factors, including sex, ethnicity, and use of coronary vasoactive stimulators, are related to the provoked phenotypes of epicardial spasm. Diffuse-provoked spasm is often observed in females, where focal-provoked spasm is markedly more common in males. ACH provokes more diffuse and distal spasms, whereas ER induces more focal and proximal spasms. Yellow plaque and coronary thrombi are often observed in lesions with focal spasms, and intimal thickness with a sonolucent zone is significantly more common in lesions with focal spasm. Furthermore, clinical outcomes in patients with focal spasm are unsatisfactory compared with those in patients with diffuse spasm. However, the reproducibility and eternality of provoked spasm phenotypes by vasoreactivity testing is uncertain. Coronary atherosclerosis or endothelial damage may affect coronary vasomotor tone. Although coronary artery spasm may persist in the same coronary artery, provoked coronary spasm phenotypes may exhibit a momentary coronary reaction by intracoronary ACH or ER testing.

Myocardial Ischemic Syndromes, Heart Failure Syndromes, Electrocardiographic Abnormalities, Arrhythmic Syndromes and Angiographic Diagnosis of Coronary Artery Spasm: Literature Review

In coronary artery spasm (CAS), an excess coronary vasoconstriction causing total or subtotal vessel occlusion could lead to syncope, heart failure syndromes, arrhythmic syndromes, and myocardial ischemic syndromes including asymptomatic myocardial ischemia, stable and unstable angina, acute myocardial infarction, and sudden cardiac death. Although the clinical significance of CAS has been underrated because of the frequent absence of symptoms, affected patients appear to be at higher risk of syncope, serious arrhythmias, and sudden death than those with classic Heberden's angina pectoris. Therefore, a prompt diagnosis has important therapeutic implications, and is needed to avoid CAS-related complications. While a definitive diagnosis is based mainly on coronary angiography and provocative testing, clinical features may help guide decision-making. We perform a literature review to assess the past and current state of knowledge regarding the clinical features, electrocardiographic abnormalities and angiographic diagnosis of CAS, while a discussion of mechanisms is beyond the scope of this review.

Variant Angina and Aborted Sudden Cardiac Death

PURPOSE OF REVIEW

Variant angina, which is characterized by recurrent chest pain and transient ECG changes along with angiographic evidence of coronary artery spasm, generally has a favorable prognosis. However, episodes of ischemia caused by vasospasm may lead to potentially life-threatening ventricular arrhythmias and cardiac arrest, even in patients with no history of prior cardiac disease. This review describes the epidemiology, pathogenesis, clinical spectrum, and management of variant angina, as well as outcomes in patients who present with aborted sudden cardiac death (ASCD).

RECENT FINDINGS

Contrary to prior opinions, evidence from recent observational studies indicate that patients with variant angina presenting with ASCD face a worse prognosis than those without this type of presentation. Predictors of ASCD include age, hypertension, hyperlipidemia, family history of sudden cardiac death, multi-vessel spasm, and left anterior descending artery spasm. Medical therapy alone with calcium channel blockers and nitrates may not be sufficiently protective in these patients and there is lack of concrete data on the optimal management strategy. Current guidelines recommend implantable cardiac defibrillator (ICD) therapy in patients who are survivors of cardiac arrest caused by ventricular fibrillation or unstable ventricular tachycardia after reversible causes are excluded, and should strongly be considered in these patients. Although medical therapy is absolutely imperative for patients with variant angina and a history of ASCD, ICD therapy in these patients is justified. Further large-scale studies are required to determine whether ICD therapy can improve survival in this high-risk group of patients.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

Coronary artery spasm: review and update

Coronary artery spasm (CAS), an intense vasoconstriction of coronary arteries that causes total or subtotal vessel occlusion, plays an important role in myocardial ischemic syndromes including stable and unstable angina, acute myocardial infarction, and sudden cardiac death. Coronary angiography and provocative testing usually is required to establish a definitive diagnosis. While the mechanisms underlying the development of CAS are still poorly understood, CAS appears to be a multifactorial disease but is not associated with the traditional risk factors for coronary artery disease. The diagnosis of CAS has important therapeutic implications, as calcium antagonists, not β-blockers, are the cornerstone of medical treatment. The prognosis is generally considered benign; however, recurrent episodes of angina are frequently observed. We provide a review of the literature and summarize the current state of knowledge regarding the pathogenesis of CAS.

An unusual cause of blackout with transient loss of consciousness: Prinzmetal angina

The authors present the case of a 61-year-old woman who was troubled by regular episodes of throat discomfort, headache, dyspnoea and tingling sensation in the upper limbs. These were associated with occasional episodes of transient loss of consciousness accompanied by urinary incontinence over a period of 5 years. As these episodes became increasingly frequent, she was referred to a neurologist. Initial neurological assessment and investigations had a negative diagnostic yield and she was therefore referred for cardiac review. A repeat 24 h Holter revealed intermittent episodes of significant ST-segment elevation associated with a Mobitz type II atrio-ventricular block correlating with her symptoms. Her echocardiography and coronary angiography were normal; hence a diagnosis of Prinzmetal angina was made. She was treated appropriately with nitrates and a calcium channel blocker and followed up in cardiology clinic with no further recurrence of symptoms.

Vasospastic angina: control of disease activity and efficacy of drug treatment using the prolonged hyperventilation test

Sixteen consecutive patients with vasospastic angina underwent a control provocation test in the coronary care unit or the cardiac catheterization laboratory in order to evaluate the disease activity and the efficacy of long-term calcium antagonist treatment. In patients without angina at rest, the prolonged hyperventilation test was negative in 10/10 patients on calcium antagonist treatment (group A + B) and in 4/5 patients without medication (group C). The test was positive in 1/1 patient with angina at rest without medication (group D). However, the test provoked vasospastic angina in 1/5 patients who were asymptomatic without medication. In both the latter patients the prolonged hyperventilation test became negative after the restart of calcium antagonist treatment. During a mean follow-up period of 18 months (range 16-19) after the control hyperventilation test, no relapse of angina at rest, arrhythmias, syncopes, deaths or myocardial infarctions were registered. Thus, a negative test is compatible with low disease activity and/or efficacy of calcium antagonist treatment. Further, the test may reveal a subclinical tendency to coronary artery spasm.

Coronary vasospasm and the regulation of coronary blood flow

Under physiologic conditions, epicardial arteries contribute minimally to coronary vascular resistance. However, in the presence of endothelial dysfunction, stimuli that normally produce vasodilation may instead cause constriction. Examples include neural release of acetylcholine or norepinephrine, platelet activation and production of serotonin and thrombin, and release of local factors such as bradykinin. This shift from a primary endothelial-mediated vasodilator influence to one of endothelial dysfunction and unchecked vasoconstriction is precisely the milieu in which coronary vasospasm is observed. This condition, which typically occurs during periods of relatively sedentary activity, is associated with focal and transient obstruction of an epicardial arterial segment resulting in characteristic echocardiographic changes and symptoms of myocardial ischemia. This review highlights the current understanding of mechanisms regulating the coronary circulation during health and examines the pathophysiologic changes that occur with coronary spasm. Genetic and other predisposing conditions are addressed, as well as novel therapies based on recent mechanistic insights of the coronary contractile dysfunction associated with coronary spasm.

Limitations of medical therapy in patients with pure coronary spastic angina

OBJECTIVES

To assess the efficacy of medication for the treatment of pure coronary spastic angina, 71 consecutive patients with this diagnosis who had undergone coronary arteriography in a hospital with a follow-up of at least 2 years were studied.

METHODS AND RESULTS

All 71 patients without significant organic stenosis were treated with long-acting calcium antagonists. The disappearance of chest pain attacks while receiving medical therapy was observed in 27 patients (38%), whereas the remaining 44 patients (62%) had chest pain attacks. Of special interest, 30 patients had more than one attack per month irrespective of the administration of calcium antagonists or isosorbide dinitrate. Medical treatment showed a good response in female patients (63% vs 31%, respectively; p < 0.05) and those with ST-segment elevation during selective spasm provocation tests (63% vs 30%, respectively; p < 0.05). In contrast, patients with a longer history of chest pain attacks before hospital admission and those with diffuse spasms (77% vs 34%, respectively; p < 0.01) had poor responses to medical treatment. In this study, neither sudden death nor acute myocardial infarction was observed during the follow-up periods.

CONCLUSION

The limitations of medical therapy, including the administration of long-acting calcium antagonists, were observed in 30 of 71 patients (42%) with pure coronary spastic angina. Medical treatment was effective in only 38% of patients with pure coronary spastic angina in Japan.

Major complications during spasm provocation tests with an intracoronary injection of acetylcholine

This study sought to clarify major complications associated with acetylcholine testing. Serious major complications, such as sustained ventricular tachycardia, shock, and cardiac tamponade were determined in 4 of 715 patients (0.56%), but no cases of death or irreversible complications occurred. The spasm provocation test using acetylcholine should be performed carefully, although it is considered a safe and reliable method.

Long lasting spasticity in controlled vasospastic angina

OBJECTIVE

To evaluate changes in coronary artery spasticity in patients with vasospastic angina who had been stable for years under continuous drug treatment.

METHODS

Follow up coronary angiography was performed under intracoronary ergonovine provocation in 27 well controlled patients with vasospastic angina and no organic stenosis; the tests were done > 24 months after the initial coronary angiography, in which occlusive spasm had been induced by the same regimen of ergonovine provocation.

RESULTS

The mean (SD) follow up period was 47.2 (21.6) months. All patients had been free from angina attack for more than 24 months under treatment with antianginal drugs. During this follow up period, organic stenosis developed in only one case. Occlusive spasm was observed during follow up coronary angiography in 23 patients. Spasm with 90% narrowing was observed in three other patients, and diffuse significant narrowing was seen in the final patient. No significant difference was found in spasticity (p = 0.75) between the initial and the follow up tests.

CONCLUSIONS

Repeated ergonovine provocation during coronary angiography after a controlled period of several years showed that coronary spasm remains inducible in most patients. Discontinuance of drug treatment during the remission from anginal attacks achieved by medication may put the patient at high risk.

Hyperventilation as a specific test for diagnosis of coronary artery spasm

The hyperventilation test has been used as a clinical tool to induce coronary spasm. However, its diagnostic and prognostic values have not been fully elucidated. This study was designed to establish the sensitivity and specificity of the hyperventilation test and to clarify the characteristics of hyperventilation test-positive patients. We examined 206 patients in whom coronary spasm was documented by angiography (spasm group), and 183 patients without angina at rest in whom acetylcholine failed to induce spasm (nonspasm group). All patients performed vigorous hyperventilation for 6 minutes in the early morning. Of the spasm group patients, 127 showed positive responses to the test, including ST elevation (n = 111), ST depression (n = 15) and negative U wave (n = 1). None in the nonspasm group showed any ischemic electrocardiographic change. Thus, the sensitivity and specificity of this test for diagnosis of coronary spasm were 62% and 100%, respectively. In the spasm group, there were no significant differences between hyperventilation test-positive and test-negative patients in age, sex, the prevalence of hypertension, diabetes mellitus, obesity, smoking, and the number of diseased vessels. When clinical characteristics were compared, the proportions of the patients with high disease activity (> or =5 attacks a week), with severe arrhythmias (second- or third-degree atrioventricular block and/or ventricular tachycardia) during attacks, and with multivessel spasm were significantly higher in the hyperventilation test-positive patients than in the negative patients (69% vs 20%, p <0.0001; 31% vs 11%, p <0.005; and 58% vs 34%, p <0.01, respectively). These findings imply that hyperventilation is a highly specific test for the diagnosis of coronary artery spasm, and that hyperventilation test-positive patients are likely to have life-threatening arrhythmias during attacks and multivessel spasm.

Association between type a behavior pattern and coronary artery spasm in japanese patients

The relations between the Jenkins Activity Survey (JAS) Type A score and coronary atherosclerosis and spasm were examined in 192 patients (115 men and 77 women) undergoing coronary angiography. Thirty-nine men (34%) and 12 women (16%) had significant (>or=75%) coronary stenosis. In 97 patients (54 men and 43 women) with no significant coronary stenosis, a coronary spasm provocation test by 0.2 to 0.4 mg of ergometrine was performed, by which a significant focal spasm (>or=75% reduction of luminal diameter) was induced in 22 men (40%) and 5 women (12%). Men who showed a significant focal spasm had a higher Type A score than men who showed no such spasm (1.9 +/- 8.4 vs. -2.4 x 8.3, p < 0.05). Discriminant analysis in male patients revealed that the induction of coronary spasm can be predicted by the JAS Type A score and smoking habit (p = 0.04). No such association was found for female patients. These results suggest that the Type A behavior pattern as assessed by the JAS may be associated with coronary spasm in Japanese men without significant coronary stenosis.

Sympathetic nerve activity in the spasm-induced coronary artery region is associated with disease activity of vasospastic angina

OBJECTIVES

We assessed the relation between sympathetic nerve activity and disease activity of vasospastic angina.

BACKGROUND

The autonomic nervous system has been proposed to play a key role in attacks of vasospastic angina. A unique feature of vasospastic angina attacks is periodic fluctuation, which complicates the assessment of disease activity.

METHODS

Twenty-five patients with left anterior descending coronary artery (LAD) spasm were studied: 12 with recent onset of chest pain (group 1) and 13 free of angina for more than 3 months after discontinuing medication (group 2). Group 1 underwent iodine-123 metaiodobenzylguanidine (MIBG) imaging (in the active phase) and atropine-stress MIBG imaging early after diagnostic angiography, and repeat MIBG imaging when they were free of angina for more than 3 months with medication (in the stable phase). Group 2 also underwent MIBG imaging (in remission). On a bull's-eye map, quantitative analysis of percent uptake and washout rate of MIBG was performed regionally.

RESULTS

In group 1 in the active phase, the washout rate of the LAD territory was significantly lower than the rates in the stable phase, in remission and during atropine-stress MIBG imaging. The regional washout rate of the territories of the right coronary artery and the circumflex artery in the active phase was also significantly lower than that during atropine-stress MIBG imaging. The washout rate of the LAD territory in the active phase was significantly lower than the rates of the other two regions. In contrast, there were no significant differences in the distribution of regional percent uptake in every image. A similar distribution of washout rate was observed among group 1 patients in the stable phase, in group 1 patients during atropine-stress MIBG imaging and in group 2 patients.

CONCLUSIONS

The MIBG washout rate of the spasm-induced coronary artery territory changed according to the degree of disease activity. Thus, sympathetic nerve activity could reflect disease activity of vasospastic angina.

Nicorandil: a potassium channel opening drug for treatment of ischemic heart disease

Nicorandil is the first oral potassium channel activating drug to be used for the treatment of symptomatic coronary artery disease. It appears to relax vascular smooth muscle through membrane hyperpolarization via increased transmembrane potassium conductance and, like nitrates, through an increase in intracellular cyclic GMP. In addition, nicorandil, in a nitrate-like manner, dilates normal and stenotic coronary arteries and reduces both ventricular preload and afterload. In contrast to nitrates, however, nicorandil does not appear to cause tolerance with long-term administration. In placebo and comparison clinical trials, nicorandil has demonstrated some efficacy and safety in patients with both stable and vasospastic angina pectoris, and it was found to be a myocardial protective agent in animal studies. The antianginal activity of nicorandil, however, is relatively short lived after dosing, which will necessitate the development of extended-release formulations of the drug.

Relation of basal coronary tone and vasospastic activity in patients with variant angina

OBJECTIVE

To examine the vasoconstrictor response to ergonovine and the vasodilator response to isosorbide dinitrate in spastic and non-spastic coronary segments from 31 patients undergoing serial angiographic follow up of variant angina.

METHODS

Coronary angiograms and ergonovine provocation tests were repeated at an interval of 45 (SD 15) months apart. While all 31 patients showed a positive response to ergonovine initially, vasospastic responsiveness persisted in only 16 patients at follow up (group 1) and not in the other 15 patients in whom symptoms of variant angina had resolved (group 2). Mean luminal diameter of 170 normal or near normal entire coronary segments (American Heart Association classification) were measured (a) at baseline, (b) after the administration of ergonovine, and (c) after the administration of isosorbide dinitrate, during both the initial and follow up angiograms using a computer based quantitative angiography analysis system (CAAS II).

RESULTS

In vasospastic patients (initial and follow up angiograms in group 1, and initial angiogram in group 2), basal tone was significantly higher in spastic segments compared to adjacent segments or segments in non-spastic vessels. The diagnostic sensitivity and specificity at 20% increase in basal coronary tone for the prediction of vasospasm were 77% and 73%, respectively.

CONCLUSIONS

Coronary artery tone may change in proportion to the activity of variant angina over several years. Contrary to some previous reports, the estimation of basal coronary tone may be useful in the assessment of vasospastic activity in patients with variant angina.

Fluctuation of spastic location in patients with vasospastic angina: a quantitative angiographic study

OBJECTIVES

This study sought to determine whether the location of coronary spastic activity may change over time in patients with persistent variant angina.

BACKGROUND

Although electrocardiographic studies have provided indirect evidence to indicate that the location of ischemia may change in patients with variant angina, it has not been tested by quantitative angiography whether the location of vasospastic activity may change over time.

METHODS

Paired ergonovine provocation tests and coronary angiography were performed at a mean (+/- SD) interval of 43 +/- 13 months apart in patients with persistent symptoms of vasospastic angina in the absence of significant atherosclerosis. A total of 87 spastic and nonspastic segments of 87 major vessels in 29 patients were analyzed by quantitative angiography at baseline, after the administration of ergonovine and after isosorbide dinitrate at the initial and follow-up tests.

RESULTS

In 13 patients (group 1), coronary spasm was observed in the same 16 coronary segments at both the initial and follow-up ergonovine provocation tests. In 16 patients (group 2), the following angiographic changes occurred between the initial and follow-up tests in 48 major vessels: Of the 23 segments that developed spasm at the initial test, 10 did not have spasm at the follow-up test; of the 25 vessels that did not demonstrate spasm on the initial test, 12 demonstrated spasm on the follow-up test (a new site of spasm). Thus, in 22 (46%) of 48 vessels, fluctuation of spastic location was observed at follow-up.

CONCLUSIONS

Quantitative coronary angiography and repeated ergonovine tests revealed that some patients with persistent vasospastic angina demonstrate fluctuation of vasospastic location, whereas others exhibit a fixed location of vasospasm. Vasospastic angina may not only be a transient disease restricted in location, but may also be a persistent and variable condition involving multiple vessels over many years.

Progression and regression of coronary stenosis in the long-term follow-up of vasospastic angina

BACKGROUND

Whether focal vasospasticity plays a pathogenic role in the progression or regression of coronary atherosclerosis is unknown. To determine whether evidence for such a role exists, we studied long-term changes in coronary luminal measurements in patients with vasospastic angina.

METHODS AND RESULTS

Quantitative coronary angiography and repeated ergonovine provocation tests were performed 45 +/- 16 months apart in 30 patients. All patients had vasospastic anginal symptoms and coronary spasm on the initial provocation test. On the 30 patients, 16 had persistent symptoms of vasospastic angina and showed coronary spasm at the same site on the follow-up angiogram (group 1), while the remaining 14 whose vasospastic anginal symptoms disappeared at follow-up demonstrated a negative response to ergonovine on the follow-up tests (group 2). There was no significant difference in patients' baseline characteristics between the two groups. Long-term changes in minimal (MLD) and mean (MEAN) luminal diameter were measured (in millimeters) after administration of isosorbide dinitrate in 19 spastic and 93 nonspastic segments in group 1 and in 17 previously spastic and 81 nonspastic segments in group 2. Both MLD and MEAN were measured in 210 coronary segments of the 30 patients at baseline and after administration of ergonovine and isosorbide dinitrate by use of a computer-based quantitative coronary angiography system. Stenosis progression and regression of individual lesions were defined as a change in MLD of > or = 0.40 mm. In group 1, both the MLD and MEAN of 19 spastic segments were significantly smaller (progression) at follow-up compared with the initial angiogram (MLD, 2.21 +/- 0.54 initially versus 1.95 +/- 0.65 at follow-up, P < .01; MEAN, 2.80 +/- 0.56 initially versus 2.56 +/- 0.58 at follow-up, P < .01), whereas the MLD and MEAN of 93 nonspastic segments in group 1 were not significantly different between the initial and follow-up angiograms (MLD, 2.47 +/- 0.67 initially versus 2.44 +/- 0.69 at follow-up, P = NS; MEAN, 2.96 +/- 0.69 initially versus 2.91 +/- 0.68 at follow-up, P = NS). In group 2, the MLD of the 17 previously spastic segments significantly improved (regression) at follow-up (MLD, 1.99 +/- 0.68 initially versus 2.24 +/- 0.54 at follow-up, P < .05); the MLD and MEAN of the 81 nonspastic segments were not significantly different (MLD, 2.36 +/- 0.59 initially versus 2.39 +/- 0.60 at follow-up, P = NS; MEAN, 2.81 +/- 0.58 initially versus 2.81 +/- 0.61 at follow-up, P = NS). In group 1, significant stenosis progression of individual lesions was observed more frequently at spastic than nonspastic segments (6 of 19 versus 10 of 93, P < .05), whereas stenosis regression was observed in no spastic and 3 nonspastic segments (P = NS). In group 2, stenosis progression was observed at 1 previously spastic segment and 4 nonspastic segments (P = NS), while significant stenosis regression of individual lesions was seen more commonly in previously spastic than nonspastic segments (6 of 17 versus 7 of 81, P < .01).

CONCLUSIONS

These results have demonstrated in patients an association between persistent vasospastic activity and progression of atherosclerosis and an association between cessation of vasospastic activity and regression of atherosclerosis.

Values of intravenous ergonovine test with two-dimensional echocardiography for diagnosis of coronary artery spasm

The purpose of this study was to evaluate the clinical validity of the bedside ergonovine test with digital echocardiography and the side-by-side continuous cineloop display method (ergonovine echocardiography) as a noninvasive diagnostic tool for coronary artery spasm. Bedside ergonovine test was performed in 66 patients who showed coronary vasospasm during coronary angiography including provocation testing (group with variant angina) and 39 patients with normal angiograms and no evidence of coronary artery spasm (group with nonanginal pain). A bolus of ergonovine maleate (0.025 or 0.05 mg) was injected at 5-minute intervals up to total cumulative dosage of 0.35 mg, and 12-lead electrocardiography and two-dimensional echocardiography were recorded every 3 minutes after each injection. Left ventricular wall motion was analyzed with a commercially available quad system. The positive criteria of bedside ergonovine test included reversible ST segment elevation or depression on electrocardiograms (ECG criteria) and reversible regional wall motion abnormalities by echocardiography (Echo criteria). The overall sensitivity and specificity of ECG criteria were 53% (35/66; 95% confidence interval 41% to 65%) and 100%, respectively. By Echo criteria the sensitivity increased to 89% (59/66; 95% confidence interval 81% to 97%), with a specificity of 95% (37/39).(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of diltiazem hydrochloride in human serum by high-performance liquid chromatography

A simple and sensitive reversed-phase high-performance liquid chromatographic method for the determination of diltiazem in human serum has been developed. The method involves a one-step deproteinization of serum for sample clean-up using acetonitrile. A LiChrosorb RP-8 column (30 cm x 4.1 mm I.D.) was eluted isocratically with acetonitrile-0.01 M dibasic sodium phosphate (40:60, v/v) containing 0.01% triethanolamine. Diltiazem was monitored at 237 nm and 0.1 a.u.f.s. The completion time for assay was less than 15 min, and the lower limit of quantitation was 10 ng/ml for a 100-microliters injection volume. Using this method, the pharmacokinetic parameters were calculated from a serum concentration versus time profile of diltiazem.

Cardiac arrest and sudden unexpected death in variant angina: complications of coronary spasm that can occur in the absence of severe organic coronary stenosis

Experiences in 81 patients with variant angina were reviewed with the goal of determining which clinical features were associated with the greatest risk of angina-linked cardiac arrest (13 patients) or sudden unexpected death (9 patients). The risk of occurrence of one of these actually or potentially fatal events was approximately tripled by the presence of either a history of angina-linked syncope or documentation of serious arrhythmia complicating attacks. An unexpected finding was that the risk was increased 1.5-fold by the absence of high-grade organic coronary stenosis. Cardiac arrest and sudden death are important risks of variant angina, which can occur without the presence of severe organic coronary stenosis. These risks can be reduced by adequate vasodilator therapy that includes a calcium channel blocker.

Long-term study of recurrent vasospastic angina using coronary angiograms during ergonovine provocation tests

Chronologic changes of coronary spasm were examined by repeated ergonovine provocation tests during angiography. A total of 322 patients who had variant angina without severe atherosclerosis demonstrated a positive response to the first test. Ninety of these patients had recurrent variant anginal symptoms after an angina-free period of 38 +/- 12 months (mean +/- SD). Of these 90 patients, 76 (84%) had symptoms or electrocardiographic (ECG) findings similar to those of the first test. The initial 9 of these 76 patients underwent a second provocation test and showed coronary responses analogous to those on the first test. Of the 90 patients, 14 (16%) had different symptoms or ECG findings from those elicited at the first episode. All 14 patients again had a positive response to a second ergonovine test and the following angiographic changes were observed in the three major vessels between the two tests. Of the 21 vessels that had spasm on the first test, eight vessels (19%) did not have spasm on the second test. Of the 21 vessels that did not demonstrate spasm on the first test, 10 (24%) demonstrated spasm on the second test. In the present study it is concluded that the majority of patients with recurrent angina seemed to have consistency in the location of coronary spasm, while in some patients the fluctuation of coronary spasm was confirmed by two ergonovine provocation tests.

A new strategy for the reduction of acute myocardial infarction in variant angina

To study the effects of stepwise early treatment in variant angina pectoris, frequencies of cardiac events and complications were examined after three different types of treatment. The subjects of the study consisted of 159 consecutive patients with variant angina pectoris, who were in need of hospitalization. The three treatment modalities were the introduction of calcium antagonists, nicorandil and nitroglycerin infusion, and percutaneous transluminal coronary angioplasty (PTCA), respectively. The cardiac event rate for this series of patients was 16% (25 of 159). The cumulative cardiac event rate was 22% at 1 year and 23% at 3 years in the first treatment period; 11% at the same intervals in the second treatment period; and 6% at the same intervals in the third treatment period. Our results suggest that it is important in the treatment of variant angina pectoris not only to prevent anginal attacks by the use of fast-acting coronary vasodilators, but also to initiate early revascularization.

Effect of nifedipine on oxygen delivery in patients with angina pectoris: relation between blood viscosity and hematocrit

The effect of nifedipine on blood viscosity and hematocrit was investigated. Blood was sampled from eight patients with angina pectoris (mean age: 59 +/- 8 yr) treated with nifedipine (20-30 mg/day) for 5 months. Using a cone-plate type viscometer, blood viscosity was determined at the shear rates of 37.5 and 375 sec-1 at 37 degrees C. Hematocrit was also measured at the same time. Since the ratio of hematocrit to blood viscosity at a shear rate of 375 sec-1 can be considered to reflect oxygen delivery, this ratio (oxygen delivery index) was also calculated. Blood viscosity at a shear rate of 37.5 sec-1 was significantly (P less than .05) decreased by nifedipine treatment, but hematocrit and the blood viscosity at a shear rate of 375 sec-1 were not changed. The oxygen delivery index, however, was significantly (P less than .01) increased after the administration of nifedipine. These results suggest that oxygen delivery increased by the treatment with nifedipine and inhibited erythrocyte aggregation by decreasing blood viscosity at low shear rate.

Determination of diltiazem hydrochloride enantiomers in dog plasma using chiral stationary-phase liquid chromatography

The separation and determination of d- and l-diltiazem hydrochloride in dog plasma by a two-column high-performance liquid chromatographic technique are described. Diltiazem hydrochloride and its metabolites were extracted from dog plasma and analyzed on a conventional column (Nucleosil 5C18) with a volatile buffer system. The column effluent of diltiazem hydrochloride was collected and evaporated. The enantiomeric ratio of the collected diltiazem was determined using a chiral column (Chiralcel OC). The method was accurate and sensitive.

Ergonovine maleate test detects anginal patients with poorly reproducible exercise tests

The aim of the study is to evaluate the reproducibility of exercise testing and to determine whether there is any correlation between the reproducibility of exercise test and response to the ergonovine maleate test. Thirty-eight patients with mixed angina and documented coronary artery disease underwent an ergonovine maleate test and four exercise tests on consecutive days in the same basal conditions. The ergonovine test was positive in 20 patients (Group I) and negative in 18 patients (Group II). There were no significant differences in the clinical and angiographic data of the two groups. All 152 exercise tests were positive. The variability of the response of the repeated tests was assessed by means of an analysis of the following parameters: heart rate, blood pressure, rate-pressure product, watts, and minutes were recorded at the onset of ischemia (ST decreases greater than or equal to 0.1 mV). Range (maximal-minimal obtained value), ratio between range and maximal obtained value, and coefficient of variation (standard deviation/mean of the four parameters) were calculated for each patient. The analysis of these values demonstrated that while the test was reproducible in some patients, a high individual variability was present in others. Moreover, the individual variability results were higher in Group I than in Group II, with a statistically significant difference for all considered parameters. In conclusion, it is possible to have a poorly reproducible exercise test in patients with mixed angina. The correlation between a positive ergonovine test and a poorly reproducible exercise test suggests that abnormal coronary vasomotion may sometimes be present during exercise and may affect the reproducibility of the test.

Sustained-release nifedipine (nifedipine-L) suppresses plasma thromboxane B2 and 6-keto prostaglandin F1 alpha in both young male smokers and nonsmokers

Sustained-release nifedipine (nifedipine-L) (40 mg twice a day) was administered orally to healthy young adult male smokers and nonsmokers for 10 days, and its effects on platelet aggregation, beta-thromboglobulin and platelet factor 4 levels, and plasma thromboxane B2 (TxB2) and 6-ketoprostaglandin F1 alpha (6-Keto-PGF1 alpha) concentrations were studied. The plasma nifedipine-L concentration in smokers (46.0 +/- 7.4 ng/ml) was significantly lower than that in nonsmokers (88.2 +/- 1.2 ng/ml). Nifedipine-L did not affect platelet aggregation induced by adenosine diphosphate, collagen, or epinephrine in either smokers or nonsmokers. The plasma beta-thromboglobulin level on the tenth day of nifedipine-L administration in nonsmokers was lower than that in smokers, but there were no significant differences either with or without nifedipine-L or between nonsmokers and smokers. Nifedipine-L had no effect on the concentration of platelet factor 4 in either smokers or nonsmokers. On the other hand, nifedipine-L significantly decreased the plasma TxB2 and 6-keto-PGF1 alpha concentrations in both smokers and nonsmokers. Thus we concluded that nifedipine-L suppressed the production of plasma TxB2 from platelets and also subsequently suppressed the production of 6-keto-PGF1 alpha and that this action was not affected by cigarette smoking.

Spontaneous coronary artery spasm in variant angina is caused by a local hyperreactivity to a generalized constrictor stimulus

To assess whether spontaneous coronary artery spasm in patients with variant angina results from local coronary hyperreactivity to a generalized constrictor stimulus or from a stimulus generated only at the site of the hyperreactive segment, the behavior of spastic and nonspastic coronary segments was studied in six patients with variant angina in whom focal coronary spasm developed spontaneously during cardiac catheterization. None of the patients had critical (greater than 50% luminal diameter reduction) organic coronary stenoses. Coronary diameters were measured by computerized quantitative arteriography during control, spontaneous spasm and ergonovine-induced spasm and after intracoronary nitrates were given. During spontaneous spasm, the luminal diameter of spastic and both proximal and distal nonspastic coronary segments was significantly reduced from control values, 64.2%, 13.2% and 14.8%, respectively. Average diameter reduction of unrelated arteries was 12.3%. Ergonovine, which was also administered to four patients, provoked focal spasm at the same site as spontaneous spasm. During intravenous ergonovine, luminal diameter of spastic segments was reduced by 91.5%, that of nonspastic proximal segments by 17.8% and that of nonspastic distal segments by 11.5%. Luminal diameter of unrelated arteries during ergonovine-induced spasm was reduced by 17.7%. Constriction of spastic segments was greater during ergonovine-induced spasm (p less than 0.05), whereas the extent of diameter reduction of nonspastic segments was not significantly different during spontaneous spasm and ergonovine-induced spasm. Intracoronary isosorbide dinitrate dilated spastic and nonspastic coronary segments to a similar extent from control (20.7%, 18% and 16.5%, respectively; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of diltiazem in human whole blood and plasma by high-performance liquid chromatography using a polymeric reversed-phase column and utilizing a salting-out extraction procedure

A rapid, simple and sensitive reversed-phase high-performance liquid chromatography method for the separation and measurement of the concentration of diltiazem in human whole blood and plasma has been developed. The method involves a simple one-step solvent extraction of the drug from biological samples followed by salting-out the organic solvent using ammonium sulfate. A 15 cm x 4.1 mm, PRP-1, pH-stable (pH 1-13) polymeric reversed-phase column was used with an isocratic elution of acetonitrile-0.01 M tetrabutylammonium hydroxide (60:40, v/v). Diltiazem was monitored at 254 nm and 0.50-0.005 a.u.f.s. The completion time for assay was less than 15 min, and the limit of detection was 10 ng/ml at a signal-to-noise ratio of 3 for a 50-microliters injection volume. Using this method, the pharmacokinetic parameters (elimination rate constant, elimination half-life and area under the curve) were calculated from a whole blood concentration versus time profile of diltiazem.

Time-related decrease in sensitivity to ergonovine in patients with variant angina

Eighteen patients with variant angina, a positive ergonovine test, and a favorable response to calcium antagonists were studied by serial ergonovine tests and Holter monitoring to assess the long-term changes in response to ergonovine and the relationship with the spontaneous activity of the disease. The number of patients with a positive test decreased from 18 of 18 in the acute phase to 12 of 18 (66%) at 3 months, 10 of 17 (59%) at 6 months, and five of 17 (29%) at 12 months. The mean dose level of ergonovine associated with a positive response and the percentage of positive tests with ST segment depression increased progressively during follow-up. The results of the ergonovine test were well correlated with the spontaneous activity of the disease in 94%, 83%, 76%, and 71% of the patients at initial observation and at 3, 6 and 12 months, respectively. Thus in patients with variant angina and a favorable response to calcium antagonists, a time-related decrease in sensitivity to ergonovine develops during follow-up. In most patients the response to ergonovine is well correlated with the spontaneous activity of the disease; thus the ergonovine test may be a useful tool in the assessment of the natural evolution of vasospastic angina.

Early evolution of symptoms and long-term prognosis in variant angina: importance of the functional component of coronary arterial disease

PURPOSE

Most investigations describing the long-term outcome of large groups of patients with variant angina pectoris have focused on such endpoints as myocardial infarction, coronary artery surgery, and death, and have asked how the risk of these events is related to the severity of existing organic coronary disease. It is also possible to ask what is the relative importance of organic and functional components in causation of symptoms and outcomes, as was done in this study.

PATIENTS AND METHODS

The early and long-term clinical course was observed in a group of 80 patients with variant angina and a low prevalence of severe organic coronary disease (diameter stenosis greater than 70 percent of one vessel in 28.3 percent, of two or more vessels in 2.7 percent). Patients were seen at the UCLA Medical Center between July 1963 and June 1985.

RESULTS

The following observations were made: Compared with those experiencing a first episode of angina at rest, subjects whose first episode of vasospastic angina occurred during strenuous effort were more likely subsequently to have a positive exercise test result and a more stable but long-term anginal course. A good initial response to vasodilator therapy indicated a likelihood of being alive and symptom-free without an intervening myocardial infarction by five years after diagnosis, which was twice the rate as if initial response to such treatment was poor. The presence or absence of severe coronary artery obstruction as detected by angiography could not be predicted from the nature or severity of angina, the historical presence of effort angina, or the occurrence of a positive result on an exercise test. The existence of severe coronary stenosis in at least one vessel was not associated with an increased incidence of myocardial infarction, cardiac arrest, or death in the first nine years after diagnosis.

CONCLUSION

These findings are consistent with the hypothesis that manifestations of ischemic heart disease in these patients were more directly caused by coronary vasospasm than by the degree of organic coronary obstruction seen by coronary arteriography. In addition, the presence of severe organic stenosis in one coronary artery did not appear to be associated with measurably increased adverse effects on clinical course or survival over the first nine years after diagnosis.

Long-term prognosis of medically treated patients with vasospastic angina and no fixed significant coronary atherosclerosis

The clinical course of 48 consecutive patients with vasospastic angina and minor coronary atherosclerosis (no stenoses greater than 50%) was analyzed during an average follow-up period of 47 months. The study group consisted of 37 men and 11 women. Patients were treated with usual doses of calcium antagonists. One patient died (2%) and three had myocardial infarctions (6%). Seventy-one percent were asymptomatic or had infrequent angina; 13% had recurrences but had periods of remission lasting at least 10 months. Only 16% had persistent angina. None of the clinical or angiographic findings at the time of diagnosis were predictive of myocardial infarction or death, and they could not separate angina-free patients from those with recurrences. Thus, vasospastic angina without fixed coronary narrowing has a good prognosis despite the possibility of recurrences. However, there is a slight risk of myocardial infarction and death. This fact should be considered if there are plans to discontinue treatment.

Systemic alkalosis as a provocative test for coronary artery spasm in patients with infrequent resting chest pain

Systemic alkalosis was used to detect coronary spasm in 237 patients with infrequent, resting, angina-compatible chest pain. The provocative test was performed without previous coronary arteriography but only in patients with negative submaximal exercise test results. Rapid infusion of alkaline solution followed by maximal hyperventilation raised arterial pH above the 7.65 value necessary for diagnostic significance in 196 (83%) patients. In 24 (12%) of these patients the provocative test induced significant ischemic ST segment changes. In all patients with a positive response, coronary artery disease, which was predominantly vasospastic (19 patients) or atheromatous with a vasospastic contribution (five patients), was demonstrated by coronary arteriography followed, if necessary, by ergot derivative injection. Chest pain and ECG changes were always reversed within 5 minutes by intravenous nitroglycerin. Coronary arteriography was not performed in all patients with a negative response; therefore, the sensitivity of the procedure could not be assessed. However, 36 patients with a negative response to hyperventilation underwent coronary arteriography; 33 (92%) had normal arteriograms and a negative response to ergot derivatives. Hyperventilation appears to be a safe and specific diagnostic procedure in a subset of patients in whom the probability of coronary artery disease may not be judged sufficient to warrant coronary arteriography as a primary diagnostic approach.

Nicardipine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy, in the treatment of angina pectoris, hypertension and related cardiovascular disorders

Nicardipine is an antagonist of calcium influx through the slow channel of the cell membrane and has been shown to be an effective and relatively well-tolerated treatment for stable effort angina and rest angina due to coronary artery spasm, and mild to moderate hypertension. Although its exact mechanism of action in these disease states has not been precisely defined, the potent coronary and peripheral arterial dilator properties of nicardipine, with concomitant improvements in oxygen supply/demand and reductions in systemic vascular resistance, are of major importance. Clinical studies have shown that nicardipine appears to be effective in the treatment of chronic stable exercise-induced angina pectoris and possibly in angina at rest due to coronary artery spasm. In the treatment of stable angina, nicardipine has proved to be equally as effective as nifedipine. However, haemodynamic and clinical studies indicate that nicardipine may have a further advantage of not depressing cardiac conduction or left ventricular function, even in patients with compromised cardiac pumping ability. Nicardipine also appears to be useful as initial monotherapy or in combination with other antihypertensive drugs when used in the treatment of mild to moderate hypertension, and may have some advantages over other vasodilators in this regard in that it may not be as frequently associated with fluid retention or weight gain as other similar drugs. In the treatment of hypertension nicardipine has been shown to be as effective as drugs such as hydrochlorothiazide, cyclopenthiazide, propranolol and verapamil in short term studies although confirmation of its long term usefulness in well-designed clinical trials is still required. Similarly, although the use of nicardipine in other disorders such as congestive heart failure and cerebrovascular disease has provided encouraging preliminary results, more studies are needed to clarify its place in their treatment. Side effects appear to be dose related and more frequent within the first few weeks of therapy. Most of these effects are minor and transient in nature and include headache, flushing and peripheral oedema. Thus, there is no doubt that nicardipine provides a suitable alternative to other drugs available for the treatment of angina and hypertension. However, further well-designed comparative clinical trials are needed to clarify its relative place in the long term management of these disorders.

Spontaneous remission of variant angina documented by Holter monitoring and ergonovine testing in patients treated with calcium antagonists

Twenty-four patients with Prinzmetal's variant angina showing a favorable initial response to calcium antagonist treatment were studied to assess the evolution of the disease and the frequency and time course of spontaneous remission. At 3, 6 and 12 months from the acute phase, patients underwent in-hospital control studies, with 48-hour Holter monitoring and ergonovine testing carried out during treatment and after its interruption. During calcium antagonist therapy complete protection from spontaneous attacks was documented in 22 of 24 patients at 3 months, in 19 of 21 at 6 months and in all 21 at 12 months; ergonovine test results were negative in 16 of 23 patients at 3 months, in 16 of 20 at 6 months and in all 20 studied at 12 months. After stopping treatment spontaneous attacks did not reappear in 7 of 24 patients (29%), 14 of 21 (66%) and 16 of 21 (76%) at 3, 6 and 12 months respectively, while the ergonovine test response remained negative in 6 of 21 (28%), 7 of 18 (39%) and 13 of 20 (65%) of the patients controlled at 3, 6 and 12 months. Thus, complete remission of angina documented by both Holter recording and ergonovine testing occurred in 5 of 24 patients (21%) at 3 months, in 7 of 21 (33%) at 6 months and in 12 of 21 (57%) at 12 months. Patients with remission of angina had a shorter duration of symptoms and more often showed normal or not critically diseased coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium antagonists for Prinzmetal's variant angina, unstable angina and silent myocardial ischemia: therapeutic tool and probe for identification of pathophysiologic mechanisms

The calcium antagonists provide a unique tool to reduce myocardial oxygen demand and prevent increases in coronary vasomotor tone. For patients with Prinzmetal's variant angina, diltiazem, nifedipine and verapamil are extremely effective in preventing episodes of coronary vasospasm and symptoms of ischemia. Unstable angina pectoris is a more complex pathophysiologic syndrome with episodes of ischemia due to increases in coronary vasomotor tone, intermittent platelet aggregation or alterations in the underlying atherosclerotic plaque. Each of the calcium antagonists is effective as monotherapy in decreasing the frequency of angina at rest. Nifedipine is the only calcium antagonist that has been studied in a combination regimen with beta blockers and nitrates for patients with unstable angina, and control of angina is better with the combination regimen than with either form of therapy alone. Although symptoms of myocardial ischemia in unstable angina are reduced by calcium antagonists, these agents do not seem to decrease the incidence of adverse outcomes. Antiplatelet therapy appears to improve morbidity and mortality in patients with unstable angina, suggesting that thrombus formation may play a central role in that disorder. Episodes of silent or asymptomatic myocardial ischemia, identified by ST-segment monitoring, occur in a variety of disorders of coronary disease. Among patients with Prinzmetal's variant angina and unstable angina, episodes of silent ischemia appear to be as frequent as episodes of angina and the calcium antagonists are effective in decreasing episodes of ischemia regardless of the presence or absence of symptoms. Persisting episodes of silent ischemia among patients with unstable angina despite maximal medical therapy identify patients at high risk for an early unfavorable outcome. Among patients with stable exertional angina, episodes of silent ischemia may be up to 5 times as frequent as episodes of angina, and may be due to increases in coronary vasomotor tone, transient platelet aggregation or increases in myocardial oxygen demand. Preliminary experience suggests that calcium antagonists and beta blockers are effective in decreasing episodes of silent ischemia in patients with stable exertional angina and that a combination regimen may be more effective than either form of therapy alone.

Calcium channel blockers cannot prevent pure vasospastic myocardial infarction

Coronary artery spasm is a recognized cause of myocardial infarction. This report describes a case of myocardial infarction attributed to pure coronary spasm which was halted by a double perfusion with streptokinase and nitroglycerin. Further coronary artery spasm leading to a myocardial infarction could not be avoided several weeks later, although the patient was left on calcium channel blocker therapy. The two attacks were not preceded by warning angina pectoris, contrary to accepted belief. The best objective of end-point drug therapy and its assessment in vasospastic angina are discussed.

The long-term outcome of patients who suffered and survived an acute myocardial infarction in the midst of recurrent attacks of variant angina

Twenty-one patients, ranging in age between 28 and 59 years, who survived hospitalization for an acute myocardial infarction in association with repetitive attacks of variant angina, were followed prospectively for 59.1 +/- 5.1 (SEM) (range 17-120) months. Four patients died, one of sudden death 17 months after admission, one of congestive heart failure at 33 months, and two of cancer at 43 and 45 months of follow-up. Three patients had four new myocardial infarctions at 22, 32, 33, and 61 months of follow-up. Six patients were readmitted for angina or other cardiac reasons. Twelve patients remained asymptomatic throughout the follow-up and one more patient was asymptomatic before and after his recurrent myocardial infarction. No relapse of variant angina was documented. Thus, the long-term course of patients with variant angina culminating in acute myocardial infarction is relatively benign, despite the highly unstable features of their initial presentation.

Regression to the mean: a potential source of error in clinical pharmacological studies

The design and interpretation of clinical trials in clinical pharmacology must avoid certain pitfalls to be useful in guiding drug therapy decisions. Here, we discuss one important problem in clinical trial design, the problem of regression to the mean. Because certain disease states tend to wax and wane in severity and because patients tend to present for treatment when disease activity is high, the expected course of the disease is improvement. Therefore, any treatment begun will appear to lessen disease activity. We give four examples of diseases where improper and inadequate recommendations for drug therapy have been made based on clinical trials that ignored the problem of regression to the mean: vasospastic angina, rheumatoid arthritis, chronic congestive heart failure, and renal stones. Studies of drug therapy in diseases such as these should be conducted with concurrent placebo controls rather than having each patient serve as his own control.

New insights into the cellular mechanisms of vasospasm

Previous attempts to define the etiology of coronary artery spasm have focused on such mechanisms as autonomic nervous system dysfunction or enhanced platelet activation leading to high levels of circulating vasoconstrictors. More recent evidence, however, suggests that the basic abnormality may be hypercontractility of the arterial wall associated with the atherosclerotic process itself. Results of both animal experiments and clinical studies support a role for certain cellular events in atherogenesis, including endothelial injury, presence of mitogenic factors and leukotrienes generated by platelets and macrophages, changes in histamine and serotonin receptor density of vascular smooth muscle and neovascularization of atherosclerotic plaque. The mechanisms postulated to underlie coronary vasospasm are discussed, relative to the clinical characteristics of vasospastic angina and the possible therapeutic implications.

Effect of the combination of diltiazem and atenolol on exercise-induced regional myocardial ischemia in conscious dogs

The effect of combination therapy with diltiazem and atenolol on the regional myocardial blood flow-function relationship was studied in eight conscious dogs with chronic coronary artery stenosis. An ameroid constrictor and hydraulic occluder were placed around the left circumflex coronary artery, sonomicrometers were implanted for measuring wall thickness in control and ischemic regions, and regional myocardial blood flow was measured with the microsphere method. Eighteen days (average) after surgery, resting regional myocardial function and blood flow were normal, but treadmill exercise induced severe regional myocardial dysfunction in the posterior wall (wall thickening during systole reduced from 25.5% to 2.7%, a 90% reduction). Subendocardial blood flow decreased by 68% from the control standing value, while subepicardial flow increased. An identical exercise bout was performed 3 hr after administration of atenolol (1.0 mg/kg orally) and 15 min after administration of diltiazem (0.3 mg/kg iv). Heart rate during running was significantly lower as were left ventricular peak systolic pressure, end-diastolic pressure, and peak dP/dt. Wall thickening in the control region was not augmented during exercise after atenolol and diltiazem. There was less dysfunction in the ischemic region (35% reduction) and the improved performance was accompanied by a substantial increase in subendocardial perfusion (0.31 +/- 0.14 vs 0.61 +/- 0.30 ml/min/g, a 36% reduction from rest). Epicardial flow was unchanged, and the endocardial/epicardial ratio increased (0.27 +/- 0.13 vs 0.62 +/- 0.29). Recovery time for regional wall thickening also improved. The beneficial effects of the combination of atenolol and diltiazem in a preparation of single-vessel chronic coronary stenosis were shown to be significantly greater than those of either drug alone.

Abnormal heart rate control in vasospastic angina: effects of calcium antagonists

We examined the effects of administration of calcium antagonists on the heart rate response to treadmill exercise in 11 patients with vasospastic angina and 8 healthy young volunteers. The exercise test was performed by walking on a treadmill at a constant speed and grade according to a scheme of pseudo-randomized sequence for 19 min. The dynamic property of heart rate response to exercise was evaluated by using a frequency analytic procedure. The exercise test was also studied in 21 age-matched normal controls without drug administration. Administration of calcium antagonists revealed no significant effects on heart rate and blood pressure at rest in young healthy subjects or in patients with vasospastic angina. Young volunteers showed the same normal properties of heart rate response to exercise before and after calcium antagonists. Vasospastic angina showed abnormal heart rate response to exercise and revealed characteristically different transfer function from that in normal controls. These characteristics were not affected by treatment with calcium antagonists except for a slight, uniform decrease of gain of the system over the whole frequency range. Accordingly, the present exercise test can feasibly be used in the diagnosis and management of vasospastic angina even when calcium antagonists are administered to the patients.

Significance of adventitial inflammation of the coronary artery in patients with unstable angina: results at autopsy

A quantitative analysis of adventitial inflammation of the coronary artery with intimal lesions is described in 12 patients who suffered coronary death and had had unstable angina (crescendo angina) at rest (group 1). After autopsy in these patients we examined epon-embedded cross sections by light and electron microscopy, paying particular attention to the adventitia, and compared these results with those in six patients who had had angina but died of noncardiac causes (group 2) and those in 22 patients who did not have angina (group 3). Of the 132 segments from group 1 patients, 39 (30%) were narrowed 76% to 100% by atherosclerotic plaque (group 2, 27%; group 3, 1%), and 23 (17%) had occlusive thrombi. Of the 264 sections (two from each segment) from group 1 that were examined, 98 (37%) (group 2, 15%; group 3, 9%) revealed clustered infiltration of inflammatory cells in the adventitia, half of which were associated with vascular nerve involvement. These findings in the adventitia may be related to the vasospastic component of unstable angina.

Prophylactic effect of intravenous tiapamil on methylergometrine-induced coronary artery spasm in patients with variant angina: randomized double-blind trial

Tiapamil is a new calcium entry blocker. The ability of its intravenous form to prevent methylergometrine-induced coronary artery spasm was studied in 11 consecutive patients with angiographically documented vasospastic angina. The study was designed as a double-blind crossover trial of tiapamil vs placebo. Each patient received, in a randomized order, either tiapamil, as a 1.5 mg/kg intravenous bolus followed by a 50 micrograms/kg/min infusion lasting 3 hours, or a matched placebo. Immediately after the infusion, methylergometrine tests were performed with up to 0.4 mg of methylergometrine or until a positive ECG was recorded. Compared to the values obtained after placebo infusion, tiapamil significantly lowered systolic and diastolic blood pressure (respective pre- and posttiapamil values: 119.9 +/- 17.7 vs 142.1 +/- 25.5 mm Hg, p less than 0.01; and 72.0 +/- 9.1 vs 82.4 +/- 9.3 mm Hg, p less than 0.02); the drug exerted no significant effect on heart rate (63.9 +/- 13.3 vs 67.6 +/- 16.5 bpm, NS), PR interval (0.180 +/- 0.020 vs 0.177 +/- 0.017 sec NS), or QTc interval (404.4 +/- 16.5 vs 396.0 +/- 26.6 msec, NS). After placebo, 10 patients had positive methylergometrine tests following single doses ranging from 0.1 to 0.4 mg. The remaining patient developed ventricular bigeminy, which resolved immediately after administration of isosorbide dinitrate; his test was therefore considered negative in the evaluation of the results. In contrast, after tiapamil, eight patients had negative tests for doses of up to 0.4 mg methylergometrine, and three had positive tests for the same methylergometrine doses as after the placebo.(ABSTRACT TRUNCATED AT 250 WORDS)