Provocation of Coronary Vasospastic Angina Using an Isoproterenol Head-up Tilt Test

Coronary Artery Spasm During Catheter Ablation Caused by the Intravenous Infusion of Isoproterenol

Radiofrequency ablation is an established treatment for atrial fibrillation (AF). However, coronary artery spasm (CAS) is a rare but a potentially lethal complication associated with this procedure. A 54-year-old man with paroxysmal AF underwent pulmonary vein isolation. The procedure was completed and AF could not be induced after burst pacing and the administration of isoproterenol. Suddenly, ST-segment elevation developed in the anterior leads and frequent premature ventricular contractions followed by non-sustained ventricular fibrillation. The diagnosis of CAS was made by urgent coronary angiography. We identified isoproterenol as a potential cause of CAS. Physicians should be aware of this potentially lethal side effect.

Isoproterenol Causing Coronary Vasospasm and ST Elevations During Tilt Table Testing

Syncope is a sudden but reversible brief loss of consciousness secondary to an acute reduction of cerebral perfusion. Reflex syncope denotes neurologically mediated syncope, which includes vasovagal, carotid sinus syndrome, and other situational syncope. The most frequent form of syncope is vasovagal, which is triggered by emotional stress or prolonged standing, and may be diagnosed with the tilt table test. A thorough investigation of syncope is necessary as serious cardiovascular disorders may also be a cause. A tilt table test is a widely used tool utilized by clinicians to diagnose vasovagal syncope and is sometimes augmented with isoproterenol, a β-sympathomimetic that acts on the heart. This report seeks to explain a case of a 48-year-old previously healthy woman who experienced inferior wall ST elevations during tilt table test supplemented with isoproterenol. There is reason to believe that the results of this patient's tilt table test were due to vasovagal syncope in conjunction with right coronary artery vasospasm.

Coronary Artery Spasm-Related Acute Coronary Syndrome in Patients With Coexisting Spasm of Angiographically Normal Coronary Artery and Fixed Narrowing of the Remaining Vessels

Fourteen patients with acute coronary syndrome are presented in this study. During angiography, hemodynamically significant coronary artery disease was demonstrated; however, it was not consistent with the electrocardiographic findings. The coronary artery spasm could be provoked in the rest of the angiographically normal coronary artery. Patient chest pain disappeared after administration of calcium channel blockers and/or isosorbide dinitrite. It is suggested that (1) both coronary artery spasm with no fixed stenosis and coronary atherosclerosis with fixed coronary stenosis can coexist in the same patient and cause symptoms, and (2) it is important to identify the predominant cause of symptoms, which then guides correct management.

Coronary spasm during cardiac electrophysiological study following isoproterenol infusion

Sudden cardiac death (SCD) remains the leading cause of death in industrialized world. The majority of SCD is caused by ventricular fibrillation associated with structural and/or ischemic heart disease. Ventricular fibrillation represents the final common pathway for SCD and, thus, is an attractive target for ablation. According to class I recommendation level of evidence A, an implantable cardioverter defibrillator (ICD) should be implanted for such patients [1]. Other than programmed electrical extrastimulus technique, isoproterenol infusion is commonly used in invasive cardiac electrophysiology labs for arrhythmia induction. We hereby report a rare case of transient coronary spasm during isoproterenol infusion for ventricular tachycardia induction testing.

Comparison of Clinical Characteristics and Prognosis in Taiwanese Patients With Coronary Vasospastic Angina Pectoris Without Significant Fixed Coronary Artery Disease Versus Patients With Significant Fixed Coronary Artery Disease and Either Stable Angina Pectoris or Acute Coronary Syndromes

BACKGROUND

Limited information is available comparing the clinical characteristics and prognosis for patients with coronary vasospastic angina in the absence of hemodynamically significant coronary artery disease (CAD) (defined as >50% stenosis) versus patients with significant fixed CAD presenting with either stable angina pectoris (SAP) or acute coronary syndromes (ACS).

METHODS

Patients who underwent cardiac catheterization for suspected ischemic heart disease between August 1999 and February 2003 were followed clinically. For patients without hemodynamically significant CAD, a provocation test for coronary vasospasm was undertaken using a step-wise dose of intracoronary ergonovine administration.

RESULTS

A total of 1134 patients were enrolled in the final analysis and stratified into 4 diagnostically distinct groups: control group (n = 239; mild CAD without coronary vasospasm); vasospasm group (n = 284; coronary vasospastic angina pectoris without hemodynamically significant CAD); SAP group (n = 110; hemodynamically significant CAD with SAP); ACS group (n = 501; hemodynamically significant CAD with ACS). Comparison of these 4 groups revealed that the ACS patients were more likely to be male, current smokers, and have hypercholesterolemia. In addition, this group had a significantly higher incidence of typical angina pectoris, 3-vessel CAD, and lower left ventricular ejection fraction. Between-group comparison revealed that vasospasm patients had a significantly higher incidence of early morning angina pectoris. Multivariate analysis showed that current smoking was the most independent risk factor associated with the diagnosis of coronary vasospastic angina pectoris in patients without hemodynamically significant CAD. During a median follow-up period of 49 months, recurrent angina pectoris was noted in patients from the control (n = 6; 3%), SAP (n = 9; 8%), vasospasm (n = 30, 11%), and ACS groups (n = 92; 18%); with nonfatal myocardial infarction identified during follow-up in the SAP (n = 5; 5%), vasospasm (n = 3; 1%), and ACS groups (n = 37; 7%). In addition, 29 and 3 cardiac deaths occurred in the ACS and SAP groups, respectively, whereas there were no such mortalities in the control and vasospasm groups.

CONCLUSIONS

Early morning angina pectoris and cigarette smoking were the most common clinical characteristics in patients with coronary vasospasm. These patients had an excellent prognosis despite the possibility of recurrences of vasospastic angina pectoris.

Coronary vasospasm-induced acute coronary syndrome complicated by life-threatening cardiac arrhythmias in patients without hemodynamically significant coronary artery disease

BACKGROUND

Coronary vasospasm-induced electrical and mechanical complications in patients with acute coronary syndrome and no hemodynamically significant coronary artery disease are rarely reported.

METHODS

A total of 733 consecutive patients with acute coronary syndrome admitted to our hospital who subsequently underwent coronary angiography at our institution were enrolled. Patients who had documented complete atrioventricular block or ventricular fibrillation, no evidence of hemodynamically significant coronary artery disease on coronary angiogram, and no other (non-coronary) cardiac abnormalities were included. Patients were followed for subsequent cardiac events and mortality.

RESULTS

Over a 6-year period at our institution, acute coronary syndrome complicated by life-threatening cardiac arrhythmias developed in six patients who had no hemodynamically significant coronary artery disease with corresponding intra-coronary ergonovine provocative coronary vasospasm. Acute myocardial infarction was diagnosed in five of these patients and variant angina pectoris in one. Complete atrioventricular block was the most common complication in these cases, followed by cardiogenic shock with or without right ventricular infarction, ventricular fibrillation, and severe sinus arrest. These complications were corrected with intravenous fluid, intravenous atropine or cardiac defibrillation. During a median follow-up period of 26 months, none of the patients expired or suffered nonfatal reinfarction. Two individuals who did not stop smoking during follow-up developed recurrent angina after self-discontinuation of calcium antagonists.

CONCLUSIONS

Coronary vasospasm can be a cause of life-threatening cardiac arrhythmias in patients with acute coronary syndrome and no hemodynamically significant coronary artery disease. Coronary angiography with/without intra-coronary ergonovine testing is necessary in acute coronary syndrome patients to identify the underlying pathology and establish appropriate treatment in these cases.

Clinical characteristics of patients with exercise-induced ST-segment elevation without prior myocardial infarction

BACKGROUND

Exercise-induced ST-segment elevation is a relatively uncommon problem and occurs more frequently in patients who have had a myocardial infarction. Data is limited on the characteristics of Taiwanese patients without prior myocardial infarction who develop exercise-induced ST-segment elevation.

METHODS AND RESULTS

Exercise-induced ST-segment elevation developed in 9 of 6,147 consecutive patients without myocardial infarction who underwent treadmill exercise testing at out institution over a 4-year period. The clinical and angiographic characteristics of these patients were studied. Angiographically normal coronary arteries with coronary vasospasm were found in 5 patients, hemodynamically significant coronary stenosis was found in 3 patients, and coexisting spasm in angiographically normal coronary arteries combined with hemodynamically significant coronary stenosis in the different vessel was found in 1 patient. During a median follow-up of 71 months, 2 patients with coronary vasospasm developed recurrent angina after self-discontinuation of calcium antagonists and 2 patients (1 with coronary vasospasm and 1 with hemodynamically significant coronary stenosis) died of cardiac causes before arrival at the emergency department.

CONCLUSION

Coronary vasospasm was a more common underlying pathology of exercise-induced ST-segment elevation in this Taiwanese cohort. Coronary angiography +/- intracoronary ergonovine provocation testing is necessary in these patients to identify the underlying pathology and appropriate treatment.