Provocation of microvessel spasm by low-dose acetylcholine in patients with suspected coronary artery disease--two case reports

Endothelial dysfunction plays an important role in the pathogenesis of cardiac syndrome X, and intracoronary low-dose acetylcholine infusion is a widely used diagnostic modality for studying the coronary artery endothelial function. The authors herein report 2 cases of cardiac syndrome X with coronary artery endothelial dysfunction and microvessel spasm. The findings of non-invasive testing were positive for ischemia. Coronary angiograms appeared entirely normal in both cases. However, the intracoronary infusion of low-dose (1.5-15 microg/minute) acetylcholine demonstrated an impairment of the coronary blood flow response and consequently provoked an ST-segment elevation in an electrocardiogram. The coronary angiograms showed no spasm in the epicardial arteries. These patients are thus suggested to have cardiac syndrome X with microvessel spasms associated with coronary artery endothelial dysfunction.     

Vitamin C attenuates abnormal vasomotor reactivity in spasm coronary arteries in patients with coronary spastic angina

Objectives. This study sought to examine effect of vitamin C, an antioxidant, on the abnormal vasomotor reactivity in spasm coronary arteries.Background. Oxygen free radicals generated in the arterial walls have been shown to cause endothelial vasomotor dysfunction.Methods. Responses of the epicardial arterial diameters of the left coronary arteries to the intracoronary infusion of acetylcholine (ACh) (10 and 50 μg/min) were measured by quantitative coronary angiography before and during combined intracoronary infusion of vitamin C (10 mg/min) or saline as a placebo in 32 patients with coronary spastic angina and in 34 control subjects.Results. Vitamin C infusion suppressed the constrictor response of the epicardial diameter to ACh in spasm coronary arteries but had no significant effect in the control coronary arteries (percent change in distal diameter in response to 10 μg/min of ACh [constriction (−), dilation (+), mean ± SEM] before vitamin C: −8.2 ± 2.9% in spasm arteries, +8.4 ± 2.9%1 in control arteries; during vitamin C: +0.2 ± 3.8%1 in spasm arteries, +7.2 ± 1.3%1 in control arteries [1p < 0.01 vs. spasm arteries before vitamin C]). The coronary sinus–arterial difference in plasma thiobarbituric acid reactive substances during ACh infusion, an indicator of lipid peroxidation in coronary circulation, was higher in patients with coronary spastic angina than in control subjects (p < 0.01) but was suppressed in patients with coronary spastic angina to comparable levels in control subjects by combined infusion of vitamin C. Saline infusion had no effect.Conclusions. The results indicate that vitamin C attenuates vasomotor dysfunction in epicardial coronary arteries in patients with coronary spastic angina. Oxygen free radicals may at least in part play a role in the abnormal coronary vasomotor reactivity in response to ACh in spasm coronary arteries.     

The mystery of coronary artery spasm

Coronary artery spasm is an important cause of chest pain and myocardial ischaemia. It can be defined as an exaggerated contractile response of epicardial coronary artery smooth muscle to various stimuli but the underlying mechanism is not well understood. Recent studies have shown that the loss of endothelial vasodilatory function in conjunction with an increase in vascular smooth muscle constrictor sensitivity to calcium are the likely predisposing conditions for coronary spasm. This review highlights current understanding of the pathophysiology, predisposing factors, diagnostic and therapeutic approaches for coronary spasm.     

Platelet inhibitory effect of nitric oxide in the human coronary circulation: impact of endothelial dysfunction

OBJECTIVES: We sought to determine whether coronary vascular nitric oxide (NO) release in vivo modulates platelet activation. BACKGROUND: Nitric oxide modulates vasodilator tone and platelet activity via the cyclic guanosine monophosphate (cGMP) pathway, but whether coronary endothelial dysfunction influences platelet activation in humans is unknown. METHODS: In 26 patients, we measured coronary blood flow, epicardial diameter and coronary sinus platelet cGMP content during intracoronary infusions of acetylcholine (ACH), L-NG monomethyl arginine (L-NMMA) and sodium nitroprusside. RESULTS: Acetylcholine increased platelet cGMP content (p = 0.013), but its magnitude was lower in patients with endothelial dysfunction; thus, patients with epicardial constriction with ACH had a 7 +/- 6%, p = ns change compared with a 32 +/- 13%, p = 0.05 increase in platelet cGMP in those with epicardial dilation. Similarly, patients with atherosclerosis or its risk factors had a smaller increase (9 +/- 6%) compared with those having normal coronary arteries without risk factors (51 +/- 22%, p = 0.019). L-NG monomethyl arginine decreased platelet cGMP content to a greater extent in patients with epicardial dilation with ACH (- 15 +/- 7%, p = 0.06) compared to those with constriction (+5 +/- 6% change, p = 0.5). Sodium nitroprusside produced a similar increase in platelet cGMP content in patients with and without endothelial dysfunction (p = 0.56). The effects of sodium nitroprusside, but not ACH or L-NMMA, were reproduced in vitro. CONCLUSIONS: Platelet cGMP levels can be modulated by basal and stimulated release of NO. The platelet inhibitory effect of NO is reduced in patients with endothelial dysfunction, which may explain their increased risk from thrombotic events and the improved survival associated with strategies designed to improve vascular function.     

Coronary microvascular spasm triggers transient ischemic left ventricular diastolic abnormalities in patients with chest pain and angiographically normal coronary arteries

Aims

Impaired coronary microvascular dilatory function can lead to exercise induced myocardial ischemia and angina pectoris even in patients without significant (>50%) obstructive coronary atherosclerosis (APWOCA). Diffuse distal vessel epicardial spasm and microvascular spasm have been also proposed as a plausible explanation for angina at rest in these patients. However, objective systematic evidence for the latter i.e. echocardiographic wall motion abnormalities during angina, is lacking at present. Coronary epicardial and microvascular spasm can be triggered in susceptible patients by the administration of intracoronary acetylcholine (Ach). We sought to assess whether Ach induced diffuse distal epicardial coronary artery spasm (≥75% diameter reduction) and coronary microvascular spasm can cause transient ischemic left ventricular dysfunction, as assessed by echocardiography.

Methods

50 patients (19 men aged 60.5 ± 8.9 years) with stable APWOCA were assessed for coronary spasm and myocardial ischemia with intracoronary Ach infusion, 2D transthoracic echocardiography (before and during Ach testing), continuous 12-lead ECG monitoring, and ultrasensitive cardiac troponin (US-cTn) measurement before and within 4 h after Ach testing.

Results

14 patients (28%) had a “negative” Ach test, 14 (28%) developed coronary microvascular spasm and 17 (34%) had diffuse distal epicardial spasm. In 5 patients (10%) the test was inconclusive. Echocardiographic variables including deceleration time, EF slope and E/A, as well as ultrasensitive-cTn concentrations were abnormal during Ach induced ischemic ECG changes. Conclusions: We have, for the first time, demonstrated that Ach induced coronary microvascular spasm is associated with echocardiographic changes and ultrasensitive-cTn elevations, indicative of myocardial ischemia.     

Acetylcholine-induced coronary spasm with a history of Kawasaki disease: case report.

A 21-year-old woman without any known coronary risk factors was found at coronary catheterization to have normal coronary angiograms, but demonstrated acethylcholine (ACh)-induced coronary spasm. She had a history of Kawasaki disease (KD) at 19 months of age and, although coronary angiography was not performed at that time, no coronary aneurysms were detected by echocardiography. To the best of our knowledge, this is the first case report of ACh-induced coronary spasm associated with normal coronary angiograms in a young person with a history of KD. The findings suggest that subclinical, persistent coronary endothelial dysfunction may exist in this patient; furthermore, the dysfunction appears diffuse and might be unrelated to coronary aneurysm formation. The long-term significance of coronary endothelial dysfunction in patients with KD, as suspected by coronary spasm, remains unknown but may be an important risk factor for future atherosclerosis.     

非编码RNA在冠状动脉微循环障碍中的研究进展

据统计,67%女性和33%男性心绞痛患者以及10%急性心肌梗死患者行冠状动脉造影(CAG)时并未见心外膜冠状动脉管腔有明显狭窄。在排除冠状动脉痉挛、血栓自溶、精神等因素后,CAG未见明显狭窄但患者仍有心肌缺血的症状,提示存在冠状动脉微循环障碍(CMD)。CMD机制尚不明确,目前普遍认为导致CMD的机制主要有冠状动脉微循环栓塞(CME)、内皮功能障碍(ED)、心肌缺血再灌注损伤(MIRI)以及自主神经功能障碍(AD)。非编码RNA(ncRNA)数量庞大且种类众多,大量研究发现其可通过上述机制参与CMD的发生发展。文章将着重综述微小RNA(microRNA,miRNA)、长链非编码RNA(lncRNA)和环状RNA(circRNA)在CMD发病和治疗中调控作用的研究进展。     

Angiotensin type 1 receptor antagonism reverses abnormal coronary vasomotion in atherosclerosis

OBJECTIVES: This study was performed to determine whether angiotensin type 1 (AT1) receptor inhibition improves abnormal coronary vasomotion and endothelial dysfunction in patients with atherosclerosis or its risk factors. BACKGROUND: Endothelial dysfunction, an early feature of atherosclerosis, contributes to abnormal vasomotion during stress. Angiotensin II may contribute to endothelial dysfunction in atherosclerosis. METHODS: In 25 patients, mean age 59 +/- 2 years, with atherosclerosis or its risk factors, we measured coronary vasomotion during flow-mediated dilation (FMD) in response to adenosine, cold pressor test (CPT) and exercise before and after AT1 receptor blockade with intracoronary losartan (5 mg). RESULTS: Losartan did not alter resting coronary vascular tone, but epicardial FMD improved from 5.6 +/- 1.5% to 8.9 +/- 1.8% (p = 0.02). Abnormal epicardial vasomotion during CPT and exercise also improved with losartan from -1.7 +/- 0.8% to 1.5 +/- 0.1% (p = 0.02) and -0.6 +/- 0.9% to 3.4 +/- 1.2% (p = 0.009), respectively. Improvement in epicardial vasomotion was most prominent in segments with baseline endothelial dysfunction evidenced as constriction during stress. Microvascular dilation during adenosine, an endothelium-independent response, was unchanged with losartan. CONCLUSIONS: Inhibition of the coronary vascular AT1 receptors in patients with atherosclerosis improves epicardial vasomotion during stress, probably by improving endothelial dysfunction. Whether AT1 receptor blockade will provide long-term therapeutic benefits in atherosclerosis needs further investigation.     

Angina Pectoris with a Normal Coronary Angiogram

Abstract Angina in the setting of a normal angiogram (NOCAD) occurs in 20–30% of patients undergoing coronary angiography. The etiologies of NOCAD can be anatomically classified into three groups: epicardial disease, coronary microvascular dysfunction, and noncoronary disease. Epicardial disease resulting in NOCAD includes endothelial dysfunction, coronary artery spasm, and coronary artery bridging. Microvascular dysfunction may be secondary to hypertension, cardiomyopathy, infiltrative disease, valvular disease, or idiopathic. Noncoronary artery disease states involving other organs systems such as the pulmonary, gastrointestinal, or musculoskeletal systems can also result in NOCAD. This review focuses on the coronary etiologies of NOCAD. The pathophysiology of disease is discussed as well as a systematic diagnostic strategy. Potential therapeutic options and prognosis are also reviewed.     

Repeated epicardial coronary artery endothelial injuries lead to a global spontaneous coronary artery spasm

OBJECTIVES: This study was conducted to develop a spontaneous coronary spasm model. MATERIALS AND METHODS: Balloon endothelial denudation was carried out in the epicardial left anterior descending coronary artery (LAD) every 2 weeks, for a total of four times, in 12 pigs. Changes in the denuded site diameter and LAD blood flow caused by acetylcholine or serotonin were assessed before each denudation and at week 8. Blood pressure, electrocardiogram (ECG) from the LAD area and LAD blood flow were monitored continuously in conscious and unrestrained pigs. RESULTS: Spontaneous ECG ST depression with a decrease in LAD blood flow appeared at around 2 weeks. In accordance with this, 0.5 microg/kg acetylcholine induced similar ECG and LAD blood flow changes without denuded site narrowing, suggesting microvascular spasm. Thereafter, ECG ST depression or elevation by serotonin via a denuded site spasm was found after 6 weeks and spontaneous ECG ST changes due to epicardial coronary artery spasm were observed. CONCLUSION: Epicardial coronary artery endothelial injury may induce spontaneous vasospasticity in the downstream coronary microvessels as well as in the denuded portion, suggesting functional abnormality through the entire coronary arterial tree.     

乙酰胆碱诱发冠状动脉痉挛时的心电图改变及其与血管内皮功能关系

目的探讨血管内皮细胞功能紊乱与乙酰胆碱试验诱发冠状动脉痉挛时心电图ST段变化与缓慢型心律失常的关系。方法选择以静息性胸痛为主要临床表现、接受乙酰胆碱激发试验的患者为研究对象,根据是否发生冠状动脉痉挛分为阳性组和阴性组,冠状动脉痉挛发作时心电图变化分为ST段抬高和非ST段抬高组以及缓慢型心律失常和无缓慢型心律失常组,测定其血浆一氧化氮和内皮素1浓度,比较各组一氧化氮和内皮素1水平以及痉挛血管的分布。结果ST段抬高组一氧化氮水平显著低于阴性组,而内皮素1显著高于阴性组(P<0.01),非ST段抬高组一氧化氮水平亦显著低于阴性组,但高于ST段抬高组(P<0.05),而内皮素1显著高于阴性组但低于ST段抬高组(P<0.05);缓慢型心律失常组和无缓慢型心律失常组的血浆一氧化氮和内皮素1水平以及痉挛血管的分布差异无统计学意义(P>0.05)。结论乙酰胆碱试验诱发的冠状动脉痉挛以及ST段变化与血管内皮细胞功能紊乱有关,乙酰胆碱试验中的缓慢型心律失常与血管内皮细胞功能或痉挛血管的分布无关。     

The alternative "ischemic" cascade in coronary microvascular disease

The conceptual model of the classical "ischemic cascade" has served cardiologists well for decades. It correctly predicts clinical findings during imaging stress testing in the presence of coronary artery disease or epicardial coronary artery spasm, where perfusion and wall motion abnormalities provide a substantially higher sensitivity than ECG changes. However, empirical experience has taught us that stress-induced ischemic-like ECG changes, often accompanied by perfusion abnormalities, are the rule rather than the exception in pathophysiological conditions during which the occurrence of ischemia usually cannot be proven, characterized by angiographically normal arteries and reduced flow reserve, such as syndrome X, arterial hypertension and hypertrophic cardiomyopathy. These stress-induced "echocardiographically silent" ST segment changes may be associated with impaired coronary flow reserve and systemic endothelial dysfunction. In hypertrophic cardiomyopathy stress-induced ischemic-like ST segment depression is linked to higher long-term incidence of adverse events. It is entirely likely that our monolithic view of ischemia mirrored in the classical ischemic cascade should be integrated by the awareness of the reverse or alternative "ischemic" cascade best describing microvascular disease, with ECG changes coming first, perfusion abnormalities second, and echocardiographic changes usually being absent. Not all forms of myocardial ischemia are the same, and milder, patchy degrees of myocardial ischemia--as those hypothesized, but not proven, in microvascular angina--remain silent in its mechanical functional manifestations and may well represent a physiological scotoma of stress echocardiography. "Anatomic lies" on the ECG may be overturned into "physiologic truths" when coronary flow reserve or systemic endothelial function is considered.     

Increased ambulatory pulse pressure is a strong risk factor for coronary endothelial vasomotor dysfunction

OBJECTIVES: This study was aimed to determine the relationship between pulse pressure (PP) and coronary vasomotor dysfunction, a predictor of coronary events. BACKGROUND: Pulse pressure is a strong risk factor for coronary artery disease (CAD). However, the mechanisms by which an increase in PP affects the pathogenesis of CAD are unclear. METHODS: Ambulatory blood pressure (BP) monitoring for 24 h was performed in 103 consecutive patients with normal coronary angiograms (51 hypertensive and 52 normotensive; age 42 to 70 years). The relationship between changes in coronary arterial diameter and blood flow during an intracoronary infusion of acetylcholine (ACh) (5, 10, 50 microg/min), and BP parameters, and other traditional risk factors was evaluated using univariate and multivariate linear regression analyses. RESULTS: With multivariate analyses, the 24-h PP showed an inverse correlation with the epicardial coronary dilator response to ACh independently of other covariates including age, smoking, and 24-h systolic BP in normotensive as well as hypertensive patients. Furthermore, multivariate analysis showed that the 24-h PP was inversely and independently correlated with the increase in coronary blood flow in response to ACh. The dilator response of epicardial coronary arteries to nitrate was not significantly correlated with 24-h PP. CONCLUSIONS: Increased 24-h PP is independently associated with endothelial vasomotor dysfunction in conduit and resistance coronary arteries irrespective of the presence of hypertension. Increased ambulatory PP may have an intimate relation to coronary endothelial vasomotor dysfunction.     

Acetylcholine Rechallenge: A First Step Toward Tailored Treatment in Patients With Coronary Artery Spasm

ObjectivesThe present study aimed to assess the feasibility and clinical value of acetylcholine (ACh) rechallenge for the detection of coexisting epicardial and microvascular spasm and to determine the efficacy of nitroglycerin in these spasm endotypes.BackgroundThe coexistence of epicardial and microvascular spasm is difficult to identify; thus, its frequency is unknown. Nitroglycerin treatment is equally recommended for both epicardial and microvascular coronary spasm despite contradictory data.MethodsIn this multicenter study, 95 patients with coronary spasm were included to undergo ACh rechallenge, which consisted of repeated ACh provocation 3 minutes after intracoronary nitroglycerin administration using the same dose that previously induced spasm.ResultsIn total, 95 patients (age 61 ± 12 years, 69% female) were included. Fifty-five patients (58%) had microvascular spasm, and 40 patients (42%) had epicardial spasm during initial ACh provocation. In 48% of patients with epicardial spasm, ACh rechallenge revealed coexisting nitroglycerin-persistent microvascular spasm. Nitroglycerin administration before ACh rechallenge prevented reinducibility of epicardial spasm in all patients with focal spasm and in 80% of patients with diffuse spasm. Microvascular spasm was prevented in only 20% by prior nitroglycerin administration but was attenuated in another 49% of patients.ConclusionsThis study demonstrates a high frequency of epicardial spasm with coexisting nitroglycerin-persistent microvascular spasm. Intracoronary nitroglycerin was very effective in preventing reinducibility of epicardial spasm, whereas it prevented microvascular spasm in only 20% of patients. ACh rechallenge is a novel method that facilitates the detection of coexisting spasm endotypes and may pave the way towards tailored treatment of vasospastic angina.     

Tetraethylammonium induced coronary spasm in isolated perfused rabbit heart: a hypothesis for the mechanism of coronary spasm

The vasoactive effect of tetraethylammonium, which is known to reduce potassium conductance of the membrane of arterial smooth muscle cells, was tested on large epicardial coronary arteries in isolated perfused rabbit hearts. These hearts were perfused selectively through the right and left coronary arteries. Left coronary angiography was performed using Krebs-Henseleit solution containing phenolsulfonphthalein under constant pressure, and the epicardial electrogram was recorded. In 59 of 114 hearts 30 mmol.litre-1 tetraethylammonium induced severe constriction of the left epicardial coronary artery, which was associated with electrocardiographic ST segment elevation in some cases. The induced spasm was prevented by diltiazem (200 nmol.litre-1), glyceryl trinitrate (2 mumol.litre-1), or nicorandil (10 mumol.litre-1), but not by phentolamine (1 mumol.litre-1) or atropine (1 mumol.litre-1). In hearts in which tetraethylammonium did not induce spasm, subsequent addition of ergonovine (100 nmol.litre-1) or alkalinisation of the perfusate (pH 7.65-7.70) provoked spasm. The tetraethylammonium induced spasm resembled the coronary spasm seen in patients with variant angina and was a reproducible in vitro model of coronary spasm. These observations support the hypothesis that the primary defect in patients with coronary spasm is decreased potassium permeability of the membrane of coronary arterial smooth muscle cells.     

Systemic endothelial function is preserved in men with both active and inactive variant angina pectoris

To test the hypothesis that coronary spasm could be a coronary manifestation of systemic endothelial dysfunction and that the activity of coronary spasm could influence systemic endothelial function, we examined brachial flow-mediated, endothelium-dependent vasodilation and nitroglycerin-induced endothelium-independent vasodilation with high-resolution ultrasound in 11 men with variant angina pectoris (6 active and 5 inactive) without established coronary atherosclerosis. Endothelium-dependent vasodilation in peripheral circulation was preserved in men with active and inactive variant angina pectoris, suggesting that systemic endothelial dysfunction is not involved in either the pathogenesis or the activity of coronary spasm.     

The Glu298Asp polymorphism in the endothelial nitric oxide synthase gene is strongly associated with coronary spasm

BACKGROUND: Coronary spasm seems to be associated with coronary nitric oxide deficiency. OBJECTIVES: We investigated whether the Glu298Asp polymorphism in the endothelial nitric oxide synthase (eNOS) gene is a definite risk factor for coronary spasm and whether diffuse spasm involving normal-looking coronary artery correlates significantly with the Glu298Asp polymorphism, in contrast with focal spasm superimposed on an atherosclerotic plaque. METHODS: A polymerase chain reaction followed by restriction fragment length polymorphism analysis was performed in 118 control participants and in 102 patients with variant angina and a similar degree of atherosclerotic burden. Patients with coronary spasm were divided into diffuse spasm and focal spasm subgroups according to morphological criteria. RESULTS: There was a significantly higher incidence of the Glu298Asp polymorphism in the coronary spasm group than in the control group (21.5% compared with 8.5%, P=0.006). Multiple logistic regression analysis using risk factors and the Glu298Asp polymorphism showed that the most important predictive factor for coronary spasm was the Glu298Asp polymorphism (odds ratio 2.83, 95% confidence interval 1.25-6.41, P=0.009). The diffuse spasm subgroup had a significantly higher frequency of the Glu298Asp polymorphism than the control group (25.9% compared with 8.5%, P=0.002). However, the focal spasm subgroup did not differ from the control group in the frequency of Glu298Asp polymorphism. CONCLUSION: The Glu298Asp polymorphism in the eNOS gene is a definite risk factor for coronary spasm, especially for diffuse coronary spasm. This result supports the notion that diffuse coronary spasm is significantly associated with endothelial dysfunction, in contrast to focal spasm.     

A study on coronary hemodynamics during acetylcholine-induced coronary spasm in patients with variant angina: endothelium-dependent dilation in the resistance vessels.

The epicardial coronary artery of patients with variant angina is hyperreactive to the constrictive effect of acetylcholine, but it is not known whether the coronary microvasculature also constricts in response to acetylcholine. Incremental doses of acetylcholine were injected into the left coronary artery of 57 patients with variant angina and with spasm in this artery. By measuring coronary sinus blood flow, coronary hemodynamic status just before angiographic documentation of spasm was examined. Acetylcholine induced spasm in the left coronary artery in all patients. It also decreased the diameter of the nonspasm artery by 36 +/- 19% from baseline. For all patients, coronary sinus blood flow was 89 +/- 38 ml/min at baseline and increased to 104 +/- 61 ml/min during an acetylcholine-induced anginal attack (p less than 0.01). In 10 patients with spasm in both the left anterior descending and left circumflex arteries (that is, multivessel spasm), coronary sinus blood flow decreased from 84 +/- 21 to 52 +/- 26 ml/min (p less than 0.01). In the other 47 patients with spasm in only one of these two arteries (that is, single-vessel spasm), coronary sinus blood flow increased from 90 +/- 41 to 115 +/- 61 ml/min (p less than 0.01) without change in the rate-pressure product. It is concluded that in patients with variant angina, acetylcholine induces spasm and constriction in the epicardial coronary artery, whereas it dilates the resistance vessels presumably through the release of the endothelium-dependent relaxing factor.     

The role of vascular failure in coronary artery spasm

Coronary artery spasm plays an important role in the pathogenesis of angina pectoris as well as acute coronary syndrome and sudden death. The prevalence of coronary spasm is greater in East Asian populations than in other parts of the world. Although the mechanism of coronary spasm is still unclear, both endothelial and smooth muscle dysfunction have been reported to play a role. We recently proposed a new concept termed 'vascular failure' that represents an integration of endothelial and smooth muscle abnormalities. Thus, vascular failure is the primary cause of coronary artery spasm.     

Tako-tsubo-like left ventricular dysfunction with ST-segment elevation: a novel cardiac syndrome mimicking acute myocardial infarction

Background Peculiar asynergy, which consists of hypokinesis or akinesis from the mid portion to the apical area and hyperkinesis of the basal area on contrast left ventriculogram, is rare. Because the end-systolic left ventriculogram looks like a “tako-tsubo,” which was used for trapping octopuses in Japan, we proposed the term “tako-tsubo-like left ventricular dysfunction.” Our aim was to evaluate its clinical features and causes. Methods We studied 30 patients with tako-tsubo-like left ventricular dysfunction without significant coronary artery disease. We assessed its pathophysiologic mechanisms by coronary spasm provocation test, endomyocardial biopsy, measurement of virus titer, and measurement of circulating catecholamine levels. Results Patient age ranged from 55 to 83 years. Twenty-eight were women and 2 were men. Tako-tsubo-like left ventricular dysfunction was dramatically resolved on predischarge left ventriculogram at 11.3 ± 4.3 days. Acute coronary angiography revealed spontaneous multivessel coronary spasm in 3 patients. Among 14 patients, ergonovine or acetylcholine induced epicardial single coronary spasm in 4 patients and multivessel coronary spasm in 6 patients. Spontaneous microvascular spasm occurred at predischarge in 1 patient. An endomyocardial biopsy specimen in 3 patients and measurement of virus titer in 7 patients did not show evidence of acute myocarditis. Circulating norepinephrine was normal or slightly elevated in 6 patients. Conclusions We showed clinical features of a novel cardiac syndrome with tako-tsubo-like left ventricular dysfunction. Although the precise cause remains unclear, simultaneous multivessel coronary spasm at the epicardial artery or microvascular levels may contribute to the onset of tako-tsubo-like left ventricular dysfunction. (Am Heart J 2002;143:448-55.)