Autonomic changes associated with spontaneous coronary spasm in patients with variant angina

Meta-analysis on inflammation and autonomic nervous system of coronary heart disease combined with depression

OBJECTIVES

This meta-analysis aimed to explore the association between inflammatory factors, heart rate variability (HRV) and the coexistence of coronary heart disease (CHD) and depression.

DESIGN

Systematic review and meta-analysis. Complying with the Meta-analysis Of Observational Studies in Epidemiology statement.

DATA SOURCES

We searched PubMed, Web of Science and EMBASE for the data from the inception date to 16 March 2023.

ELIGIBILITY CRITERIA

We included cross-sectional and cohort studies with inclusion criteria: (1) patients with CHD; (2) depression measurement and (3) including inflammatory factors or cardiac biomarkers or HRV.

DATA EXTRACTION AND SYNTHESIS

Two authors searched the databases independently. The effect estimates and heterogeneity were synthesised by Review Manager V.5.3. Sensitivity analysis and publication bias were analysed by STATA software. The quantitative synthesis outcomes were presented by mean difference (MD) or standard MD (SMD) with 95% CI.

RESULTS

By searching the databases, we identified a total of 6750 articles. There were 22 articles left after selection, including 6344 participants. This meta-analysis indicated that patients with CHD with depression had higher levels of C reaction protein (CRP) (SMD 0.50, 95% CI (0.19 to 0.81), p=0.001), high-sensitivity C reactive protein (hs-CRP) (SMD 0.28, 95% CI (0.07 to 0.48), p=0.008), IL-6 (SMD 0.49, 95% CI (0.05 to 0.92), p=0.03) and a lower level of the mean RR interval and the SD of all RR intervals (SMD -0.64, 95% CI (-1.11 to -0.17), p=0.008), SD of the 5 min averages of all normal RR intervals (MD -12.77 ms, 95% CI (-21.20 to -4.33), p=0.003), overage of the SD of all normal RR intervals for each 5 min segment (MD -13.83 ms, 95% CI (-15.94 to -11.72), p<0.00001), root mean square of successive differences (MD: -8.02 ms, 95% CI (-13.62 to -2.43), p=0.005), proportion of adjacent cycles differing by >50 ms (pNN50) (SMD -0.86, 95% CI (-1.41 to -0.31), p=0.002), than those without depression.

CONCLUSIONS

This study underscores the association between elevated CRP, hs-CRP, IL-6 and lower HRV in patients with CHD with depression. It emphasises the importance of clinicians assessing CRP, hs-CRP, IL-6 and HRV in patients with CHD to potentially identify depressive conditions.

Capecitabine-induced-coronary-vasospasm leading to polymorphic ventricular tachycardia and cardiac arrest

Capecitabine, a pro-drug of 5-fluorouracil, is commonly used in the treatment of breast and colorectal cancer. Its side effects, including nausea, vomiting, diarrhea, fatigue, loss of appetite, and bone marrow suppression, are well recognized. However, coronary vasospasm represents a less commonly recognized but significant complication of fluoropyrimidine-based therapies such as capecitabine. Proposed mechanisms for this adverse effect complication include direct endothelium-independent vasoconstriction, activation of protein kinase C, and activation of the cyclooxygenase pathway. In this report, we present a case of capecitabine-induced coronary vasospasm leading to progressive, focal ST-elevations, myocardial ischemia, and subsequently polymorphic ventricular tachycardia. These events were captured on telemetry, in a male in his early 40s, diagnosed with stage IIIB sigmoid colon cancer. Notably, the patient had no pre-existing coronary artery disease or other cardiovascular risk factors. Upon diagnosis, the patient was initiated on a calcium channel blocker, verapamil, to mitigate further coronary vasospasm events. After thorough discussions that prioritized the patient's input and values, an implantable cardioverter-defibrillator was placed subcutaneously. Following discharge, the patient restarted capecitabine therapy along with verapamil prophylaxis and did not experience any subsequent shocks from his ICD as assessed during his outpatient follow-up visits. This case emphasizes the need to involve patients in decision-making processes, especially when managing unexpected and serious complications, to ensure treatments align with their quality of life and personal preferences.

Familial risk of vasospastic angina: a nationwide family study in Sweden

OBJECTIVES

Vasospastic angina (VSA) is a complex coronary vasomotor disorder associated with an increased risk of myocardial infarction and sudden death. Despite considerable advances in understanding VSA pathophysiology, the interplay between genetic and environmental factors remains elusive. Accordingly, we aimed to determine the familial VSA risk among first-degree relatives of affected individuals.

METHODS

A population-based multigenerational cohort study was conducted, including full-sibling pairs born to Swedish parents between 1932 and 2018. Register-based diagnoses were ascertained through linkage to the Swedish Multigeneration Register and National Patient Register. Incidence rate ratios (IRRs) and adjusted HRs were calculated for relatives of individuals with VSA compared with relatives of individuals without VSA.

RESULTS

The total study population included 5 764 770 individuals. Overall, 3461 (0.06%) individuals (median age at disease onset 59 years, IQR: 63-76) were diagnosed with VSA. Of these, 2236 (64.61%) were women. The incidence rate of VSA for individuals with an affected sibling was 0.31 (95% CI: 0.24 to 0.42) per 1000 person-years compared with 0.04 (95% CI: 0.04 to 0.04) per 1000 person-years for those without an affected sibling, yielding an IRR of 7.58 (95% CI: 5.71 to 10.07). The risk of VSA for siblings with an affected sibling was significantly increased in the fully adjusted model (HR: 2.56; 95% CI: 1.73 to 3.79). No increased risk of VSA was observed in spouses of affected individuals (HR: 0.63; 95% CI: 0.19 to 2.09).

CONCLUSIONS

In this nationwide family study, we identified high familial risk for VSA independent of shared environmental risk factors. Our findings indicate that VSA tends to cluster in families, emphasising the need to explore genetic and non-genetic factors that may contribute.

Mechanisms of Coronary Artery Spasm

Recent clinical trials have highlighted that percutaneous coronary intervention in patients with stable angina provides limited additional benefits on top of optimal medical therapy. This has led to much more attention being paid to coronary vasomotion abnormalities regardless of obstructive or non-obstructive arterial segments. Coronary vasomotion is regulated by multiple mechanisms that include the endothelium, vascular smooth muscle cells (VSMCs), myocardial metabolic demand, autonomic nervous system and inflammation. Over the years, several animal models have been developed to explore the central mechanism of coronary artery spasm. This review summarises the landmark studies on the mechanisms of coronary vasospasm demonstrating the central role of Rho-kinase as a molecular switch of VSMC hypercontraction and the important role of coronary adventitial inflammation for Rho-kinase upregulation in VSMCs.

Management of Coronary Artery Spasm

Calcium channel blockers (CCBs) are the first-line treatment for coronary artery spasm (CAS). When CAS-related angina symptoms are not well controlled by CCB therapy, long-acting nitrates or (where available) nicorandil can be added as second-line medications. In the case of CAS refractory to standard treatments, several other alternative drugs and interventions have been proposed, including the Rho-kinase inhibitor fasudil, anti-adrenergic drugs, neural therapies and percutaneous coronary interventions. In patients with syncope or cardiac arrest caused by CAS-related tachyarrhythmias, or even bradyarrhythmias, implantation of an ICD or pacemaker, respectively, should be considered according to the risk of recurrence and efficacy of vasodilator therapy.

Coronary Arterial Spasm During Pulsed Field Ablation to Treat Atrial Fibrillation

BACKGROUND

Pulsed field ablation (PFA) has a unique safety profile when used to treat atrial fibrillation, largely related to its preferentiality for myocardial tissue ablation, in particular, esophageal sparing. A pentaspline catheter was the first such PFA system studied clinically for atrial fibrillation ablation; in these initial regulatory trials, the catheter was used for pulmonary vein isolation and left atrial posterior wall ablation. Since its regulatory approval in Europe, in clinical practice, physicians have ablated beyond pulmonary vein isolation and left atrial posterior wall ablation to expanded lesion sets in closer proximity to coronary arteries. This is an unstudied important issue because preclinical and clinical data have raised the potential for coronary arterial spasm. Herein, we studied the vasospastic potential of PFA lesion sets, both remote from and adjacent to coronary arteries.

METHODS

During routine atrial fibrillation ablation using the pentaspline PFA catheter, coronary angiography was performed before, during, and after pulsed field applications. The lesion sets studied included: (1) those remote from the coronary arteries such as pulmonary vein isolation (n=25 patients) and left atrial posterior wall ablation (n=5), and (2) ablation of the cavotricuspid isthmus (n=20) that is situated adjacent to the right coronary artery.

RESULTS

During pulmonary vein isolation and left atrial posterior wall ablation, coronary spasm did not occur, but cavotricuspid isthmus ablation provoked severe subtotal vasospasm in 5 of 5 (100%) consecutive patients, and this was relieved by intracoronary nitroglycerin in 5.5±3.5 minutes. ST-segment elevation was not observed. However, no patient (0%, P=0.004) had severe spasm if first administered parenteral nitroglycerin, either intracoronary (n=5) or intravenous (n=10), before treatment.

CONCLUSIONS

Coronary vasospasm was not provoked during PFA at locations remote from coronary arteries, but when the energy is delivered adjacent to a coronary artery, PFA routinely provokes subclinical vasospasm. This phenomenon is attenuated by nitroglycerin, administered either post hoc to treat spasm or as prophylaxis.

Apolipoprotein (a)/Lipoprotein(a)-Induced Oxidative-Inflammatory α7-nAChR/p38 MAPK/IL-6/RhoA-GTP Signaling Axis and M1 Macrophage Polarization Modulate Inflammation-Associated Development of Coronary Artery Spasm

Objective. Apolipoprotein (a)/lipoprotein(a) (Lp(a)), a major carrier of oxidized phospholipids, and α7-nicotinic acetylcholine receptor (α7-nAChR) may play an important role in the development of coronary artery spasm (CAS). In CAS, the association between Lp(a) and the α7-nAChR-modulated inflammatory macrophage polarization and activation and smooth muscle cell dysfunction remains unknown. Methods. We investigated the relevance of Lp(a)/α7-nAChR signaling in patient monocyte-derived macrophages and human coronary artery smooth muscle cells (HCASMCs) using expression profile correlation analyses, fluorescence-assisted cell sorting flow cytometry, immunoblotting, quantitative real-time polymerase chain reaction, and clinicopathological analyses. Results. There are increased serum Lp(a) levels (3.98-fold, $p=0.011$ ) and macrophage population (3.30-fold, $p=0.013$ ) in patients with CAS compared with patients without CAS. Serum Lp(a) level was positively correlated with high-sensitivity C-reactive protein ( $r^2=0.48$ , $p<0.01$ ), IL-6 ( $r^2=0.38$ , $p=0.03$ ), and α7-nAChR ( $r^2=0.45$ , $p<0.01$ ) in patients with CAS, but not in patients without CAS. Compared with untreated or low-density lipoprotein- (LDL-) treated macrophages, Lp(a)-treated macrophages exhibited markedly enhanced α7-nAChR mRNA expression ( $p<0.01$ ) and activity ( $p<0.01$ ), in vitro and ex vivo. Lp(a) but not LDL preferentially induced CD80+ macrophage (M1) polarization and reduced the inducible nitric oxide synthase expression and the subsequent NO production. While shRNA-mediated loss of α7-nAChR function reduced the Lp(a)-induced CD80+ macrophage pool, both shRNA and anti-IL-6 receptor tocilizumab suppressed Lp(a)-upregulated α7-nAChR, p-p38 MAPK, IL-6, and RhoA-GTP protein expression levels in cultures of patient monocyte-derived macrophages and HCASMCs. Conclusions. Elevated Lp(a) levels upregulate α7-nAChR/IL-6/p38 MAPK signaling in macrophages of CAS patients and HCASMC, suggesting that Lp(a)-triggered inflammation mediates CAS through α7-nAChR/p38 MAPK/IL-6/RhoA-GTP signaling induction, macrophage M1 polarization, and HCASMC activation.

Myocardial infarction with nonobstructive coronary artery disease (MINOCA): a review of pathophysiology and management

PURPOSE OF REVIEW

Myocardial infarction with nonobstructive coronary artery disease (MINOCA) (≥ 50% stenosis) accounts for 5-8% of acute coronary syndrome (ACS) presentations. The demographic characteristics, risk factors, and management of patients with MINOCA differ from those with atherosclerotic ACS. The objective of this review is to provide a contemporary understanding of the epidemiology, pathophysiology, clinical presentation, and management of MINOCA.

RECENT FINDINGS

MINOCA is increasingly being recognized as an important and distinct cause of myocardial infarction among patients presenting with ACS. The predominant pathophysiologic mechanisms of MINOCA include both coronary (epicardial vasospasm, coronary microvascular disorder, spontaneous coronary artery dissection, coronary thrombus/embolism) and noncoronary (Takotsubo cardiomyopathy, myocarditis) pathologies. Coronary imaging with intravascular ultrasound and optical coherent tomography, coronary physiology testing, and cardiac magnetic resonance imaging offers important investigative modalities to facilitate diagnosis for appropriate management of MINOCA patients.

SUMMARY

MINOCA is an important cause of ACS observed in certain patients with unique challenges for diagnosis and management. A high index of suspicion and a comprehensive diagnostic evaluation are critical for early recognition and successful management.

Personalized Clinical Phenotyping through Systems Medicine and Artificial Intelligence

Personalized Medicine (PM) has shifted the traditional top-down approach to medicine based on the identification of single etiological factors to explain diseases, which was not suitable for explaining complex conditions. The concept of PM assumes several interpretations in the literature, with particular regards to Genetic and Genomic Medicine. Despite the fact that some disease-modifying genes affect disease expression and progression, many complex conditions cannot be understood through only this lens, especially when other lifestyle factors can play a crucial role (such as the environment, emotions, nutrition, etc.). Personalizing clinical phenotyping becomes a challenge when different pathophysiological mechanisms underlie the same manifestation. Brain disorders, cardiovascular and gastroenterological diseases can be paradigmatic examples. Experiences on the field of Fondazione Policlinico Gemelli in Rome (a research hospital recognized by the Italian Ministry of Health as national leader in "Personalized Medicine" and "Innovative Biomedical Technologies") could help understanding which techniques and tools are the most performing to develop potential clinical phenotypes personalization. The connection between practical experiences and scientific literature highlights how this potential can be reached towards Systems Medicine using Artificial Intelligence tools.

Renal sympathetic denervation in patients with vasospastic angina

BACKGROUND

Sympathetic overactivity has been linked to vasospastic angina (VSA), although the exact pathophysiology of VSA is poorly understood. The purpose of this study is to assess if renal sympathetic denervation (RDN) reduces cardiac sympathetic nerve activity with a subsequent beneficial effect on angina relief in patients with refractory VSA.

METHODS AND RESULTS

Cardiac sympathetic nerve activity was assessed prior to procedure and at 6 months post-procedure using iodine-123 labeled meta-iodobenzylguanidine (123I-MIBG) imaging. The Seattle Angina questionnaire (SAQ) was used to assess the degree to which the disease impacts quality of life. No significant change was observed in early HMR (pre-RDN: 2.74 [2.10 to 3.21] vs 6 months post-RDN: 2.57 [2.20 to 3.00]; P = 0.76), and late HMR (pre-RDN: 2.56 [2.18 to 3.20] vs 6 months post-RDN: 2.36 [2.13 to 3.22]; P = 0.22). Additionally, no change was seen in WR (P = 0.22). SAQ results revealed significant improvements in perceived physical limitation, angina frequency, and quality of life at 6 months (P < 0.05 for all).

CONCLUSION

RDN resulted in improvements in angina class and quality of life at 6 months in patients with refractory VSA. RDN, however, did not result in significant changes in cardiac sympathetic nerve activity as measured using 123I-MIBG. The latter observation should be considered with caution given the small sample size of this study. Larger studies are needed to assess this further.

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.

Recurrent ST Elevation Myocardial Infarction from Norepinephrine-induced Coronary Vasospasm

Myocardial infarction with no obstructive coronary atherosclerosis (MINOCA) is a distinct clinical syndrome characterized by evidence of myocardial infarction with normal or near-normal coronary arteries on angiography (stenosis severity < 50%). Coronary artery spasm, as seen in “variant angina,” usually occurs at a localized segment of an epicardial artery. Here, we present a case of a 58-year-old male who had norepinephrine-induced coronary vasospasm which resulted in ST elevation myocardial infarction on two consecutive admissions.

Acute Pancreatitis Masquerading as Inferior Wall Myocardial Infarction: A Review

A rare presentation of acute pancreatitis is with electrocardiographic (ECG) changes that mimic myocardial ischemia. We present a report of a patient that presented with hemodynamic instability and new ECG changes of ST segment elevations in contiguous leads II, III, and aVF mimicking an inferior wall myocardial infarction. Emergent coronary angiography showed no significant coronary obstruction, but it was followed by a left-sided hemiplegia with radiographic evidence of diffuse embolic stroke. The patient was later found to have an underlying diagnosis of pancreatitis. Additional history that later became available indicated a history of severe acute pancreatitis treated elsewhere a few months prior to the current admission. We present the first comprehensive review of the literature comprising 36 total cases with pancreatitis masquerading as acute myocardial infarction, with inferior wall STEMI pattern being the most frequent. We present this case to highlight the diagnostic dilemma posed by this masquerade of a high acuity myocardial infarction and to highlight alternative diagnoses to be considered in such clinical circumstances.

Coronary Artery Spasm as Related to Anxiety and Depression: A Nationwide Population-Based Study

OBJECTIVE

Anxiety and depression are risk factors for obstructive coronary artery disease (CAD), but their effects on coronary artery spasm (CAS) remain unestablished.

METHODS

Patient records in this population-based study were retrospectively collected from the Taiwan National Health Insurance Research Database. Using propensity score matching, we used 1:1:1 ratio stratification into a control group of 10,325 individuals without CAS or CAD, a CAS group comprising 10,473 patients, and a CAD group comprising 10,473 patients during 2000-2012.

RESULTS

The prevalence of CAS and CAD was 0.067% and 8.7%, respectively, in the general population. The prevalence of anxiety and depression diagnoses was significantly higher in patients with new-onset CAS than in those with new-onset CAD and controls without CAS/CAD, even after propensity score matching. Compared with CAD, anxiety and depression diagnoses conferred a higher risk of developing CAS (odds ratio [OR] = 2.29, 95% confidence interval [CI], 2.14-2.45, p < .001, and OR = 1.34, 95% CI, 1.08-1.66, p = .007, respectively). The association was even stronger when comparing CAS with the control group without CAD or CAS (OR = 5.20, 95% CI, 4.72-5.74, p < .001, and OR = 1.98, 95% CI, 1.50-2.62, p < .001, respectively). The increased risk of new-onset CAS as related to previous anxiety and depression diagnoses was comparable between males and females.

CONCLUSIONS

Compared with CAD or the general population, anxiety and depression diagnoses confer a higher risk of developing CAS. No sex differences are found for the association of anxiety and depression with CAS.

Heart rate recovery and blood pressure response during exercise testing in patients with microvascular angina

Background

Angina pectoris with a normal coronary angiogram, termed microvascular angina (MVA), is an important clinical entity; however, its causes remain unclear. Autonomic dysfunction is one of the possible causes. Therefore, this study aimed to investigate parasympathetic dysfunction assessed by heart rate recovery (HRR) and increased sympathetic activity assessed by exaggerated blood pressure (BP) response (EBPR) to exercise in MVA.

Methods

The study participants were consecutive patients with anginal chest pain who underwent both coronary angiography with an ergonovine provocation test and a treadmill exercise test between January 2008 and February 2015. Patients with significant coronary artery disease (coronary artery stenosis ≥50%) or significant coronary artery spasm (≥90%) were excluded. Based on the treadmill exercise test, patients were categorized into the microvascular angina (MVA) group (patients with uniform ST depression ≥1 mm) and the control group. HRR was defined as peak heart rate minus heart rate after a 1 min recovery; blunted HRR was defined as ≤12 beats/min. EBPR was defined as a peak exercise systolic BP ≥210 mmHg in men and ≥ 190 mmHg in women. These parameters were compared between patients with MVA and the controls.

Results

Among the 970 enrolled patients (mean age 53.1 years; female 59.0%), 191 (20.0%) were diagnosed with MVA. In baseline characteristics, the MVA group had older participants, female predominance, and a higher prevalence of hypertension. The MVA group showed significantly lower HRR 1 min (24.9 ± 15.9 vs. 31.3 ± 22.7, p <  0.001) compared with the control group. Moreover, the proportion of EBPR was significantly higher in the MVA group than in the control group (21.5% vs. 11.6%, p <  0.001). Multivariable logistic regression analysis showed that age (odds ratio (OR), 1.045; 95% confidence interval (CI), 1.026-1.064; p <  0.001), HRR 1 min (OR, 0.990; 95% CI, 0.982-0.999; p = 0.022), and EBPR (OR, 1.657; 95% CI, 1.074-2.554; p = 0.022) were independently associated with MVA.

Conclusion

HRR and EBPR were associated with MVA, which suggests a link between MVA and autonomic dysregulation.

Effect of diurnal variations in the QRS complex and T waves on the eligibility for subcutaneous implantable cardioverter-defibrillators

BACKGROUND

Subcutaneous implantable cardioverter-defibrillators (S-ICDs) are an established therapy for preventing sudden cardiac death. However, a considerable number of patients still undergo inappropriate shocks even after conventional preimplantation electrocardiographic (ECG) screening.

OBJECTIVE

This study aimed to elucidate the additional effect of diurnal variations in the QRS complex and T waves of 24-hour Holter screening on S-ICD eligibility.

METHODS

Patients with transvenous ICDs who did not need pacing were selected for the study. The ECG was recorded by placing the electrodes to simulate the 3 sensing vectors of the S-ICD, with the patient in the standing and supine positions (conventional), during exercise, and during 24-hour Holter screening. We investigated the additional discrimination of diurnal variations in patients ineligible for S-ICDs as well as characteristics of those patients.

RESULTS

Of the 86 patients (82% men; mean age 54±16 years) analyzed by all 3 screenings, 2 (2.3%) and 3 (3.4%) were considered ineligible by conventional and exercise screening, respectively. An additional 21 patients (24.4%) were found ineligible through Holter screening. A multivariate logistic regression analysis demonstrated that Brugada syndrome and an increased QRS duration per millisecond were associated with ineligibility (odds ratio 5.74; 95% confidence interval 1.74-20.2; P = .003 and odds ratio 1.04; 95% confidence interval 1.01-1.07; P = .007, respectively). T-wave oversensing was mostly observed during 0-6 AM, but no significant diurnal variations were observed in the incorrect QRS profiles.

CONCLUSION

The detection of diurnal variations through Holter monitoring in addition to conventional screening is expected to be useful for determining S-ICD eligibility.

Tako-Tsubo syndrome, spontaneous coronary dissection and microvascular disease: Sex-differences

Up to 50% of the patients undergoing coronary angiography present no epicardial disease. Most of these patients are women. Takotsubo cardiomyopathy, coronary microvascular dysfunction, and spontaneous coronary artery dissection are the most common syndromes that affect these patients. Their mechanisms are complex, with a interplay between neurohormonal factors and a number of other systems. The present review describes how changes in the estrogen state may lead to changes in vasomotor tone and endothelial dysfunction which result in coronary epicardial and microvascular spasm and coronary arterial wall instability in these three conditions. The sex-dependent differences in prevalence, pathogenesis, and prognosis are described.

Association between epicardial adipose tissue and coronary artery vasospasm during pulmonary vein isolation

Coronary artery vasospasms (CAVs) during pulmonary vein isolation have been reported, but the mechanism remains unclear. We experienced a rare case of CAVs caused by radiofrequency (RF) applications to sites with massive epicardial adipose tissue (EAT) attached. Because EAT contains ganglionated plexuses, RF application may have caused an autonomic nervous system imbalance, which thereby provoked severe CAVs.

Coronary Artery Spasm during Cryoballoon Ablation in a Patient with Atrial Fibrillation

The patient was a 63-year-old man with drug-resistant atrial fibrillation who developed coronary spasm during cryoballoon ablation (CBA). CBA was started from the left inferior pulmonary vein. ST elevations in II, III, and aVf, with reciprocal ST depressions in V2-5, occurred in association with chest pain just after balloon rewarming and deflation, and the patient's blood pressure fell to 50 mmHg. Coronary angiography revealed 90% diffuse stenosis from the orifice of segment 1 to segment 4 in the right coronary artery. The stenosis and ST elevations improved after the intracoronary injection of nitroglycerine. Using continuous peripheral intravenous coronary vasodilation, we electrically isolated the other pulmonary veins with CBA without incident.

Blunted heart rate recovery is associated with coronary artery spasm in patients with suspected vasospastic angina

Background

Autonomic nervous system activity has been shown to be altered in patients with vasospastic angina (VA). Heart rate recovery (HRR) is a simple, non-invasive measurement of autonomic nervous system dysfunction. We aimed to investigate whether HRR is related to VA, as established by an ergonovine test.

Methods

A total of 976 consecutive patients (47.5% male, mean age 55 years) without significant coronary artery disease who underwent both an ergonovine provocation test and a treadmill exercise test were enrolled. The relationship between VA and HRR was evaluated.

Results

A total of 30.7% (300/976) of patients were diagnosed with VA, as documented by the ergonovine provocation test. HRR was significantly reduced in patients with VA compared to patients without VA (24.6 ± 18.0 vs. 30.5 ± 22.2, p < 0.001), and HRR was lowest in patients with multi-vessel spasm (21.9 ± 17.3). The proportion of blunted HRR, which was defined as HRR less than 12 beats, was significantly higher in patients with VA than in those without coronary artery spasm (26.6% vs. 39.3%, p < 0.001). In multivariable regression analyses, age (odds ratio (OR) = 1.03; 95% confidence interval (CI): 1.01–1.04; p = 0.001), blunted HRR (OR = 1.71; 95% CI: 1.26–2.31; p < 0.001), current smoking status (OR = 2.11; 95% CI: 1.50–2.98; p < 0.001), and male gender (OR = 2.00; 95% CI: 1.43–2.78; p < 0.001) were significant independent predictors of VA presence.

Conclusion

Blunted HRR was an independent predictor of VA presence, which suggests a link between coronary artery spasm and autonomic dysregulation.

Acute Coronary Syndromes: The Way Forward From Mechanisms to Precision Treatment

Well into the 21st century, we still triage acute myocardial infarction on the basis of the presence or absence of ST-segment elevation, a century-old technology. Meanwhile, we have learned a great deal about the pathophysiology and mechanisms of acute coronary syndromes (ACS) at the clinical, pathological, cellular, and molecular levels. Contemporary imaging studies have shed new light on the mechanisms of ACS. This review discusses these advances and their implications for clinical management of the ACS for the future. Plaque rupture has dominated our thinking about ACS pathophysiology for decades. However, current evidence suggests that a sole focus on plaque rupture vastly oversimplifies this complex collection of diseases and obscures other mechanisms that may mandate different management strategies. We propose segmenting coronary artery thrombosis caused by plaque rupture into cases with or without signs of concomitant inflammation. This distinction may have substantial therapeutic implications as direct anti-inflammatory interventions for atherosclerosis emerge. Coronary artery thrombosis caused by plaque erosion may be on the rise in an era of intense lipid lowering. Identification of patients with of ACS resulting from erosion may permit a less invasive approach to management than the current standard of care. We also now recognize ACS that occur without apparent epicardial coronary artery thrombus or stenosis. Such events may arise from spasm, microvascular disease, or other pathways. Emerging management strategies may likewise apply selectively to this category of ACS. We advocate this more mechanistic approach to the categorization of ACS to provide a framework for future tailoring, triage, and therapy for patients in a more personalized and precise manner.

Renal Denervation Suppresses Coronary Hyperconstricting Responses After Drug-Eluting Stent Implantation in Pigs In Vivo Through the Kidney-Brain-Heart Axis

OBJECTIVE

Drug-eluting stent-induced coronary hyperconstricting responses remain an important issue. The adventitia harbors a variety of components that potently modulate vascular tone, including sympathetic nerve fibers (SNF) and vasa vasorum. Catheter-based renal denervation (RDN) inhibits sympathetic nerve activity. We, thus, examined whether RDN suppresses drug-eluting stent-induced coronary hyperconstricting responses, and if so, what mechanisms are involved.

APPROACH AND RESULTS

Protocol 1: pigs implanted with everolimus-eluting stents into the left coronary arteries underwent coronary angiography at 1 month after implantation for assessment of coronary vasomotion and adventitial SNF formation. Drug-eluting stent-induced coronary hyperconstricting responses were significantly enhanced associated with enhanced coronary adventitial SNF and vasa vasorum formation. Protocol 2: pigs implanted with everolimus-eluting stents were randomly assigned to the RDN or sham group. The RDN group underwent renal ablation. At 1 month, RDN significantly caused marked damage of the SNF at the renal arteries without any stenosis, thrombus, or dissections. Notably, RDN significantly upregulated the expression of α₂-adrenergic receptor-binding sites in the nucleus tractus solitarius, attenuated muscle sympathetic nerve activity, and decreased systolic blood pressure and plasma renin activity. In addition, RDN attenuated coronary hyperconstricting responses to intracoronary serotonin at the proximal and distal stent edges associated with decreases in SNF and vasa vasorum formation, inflammatory cell infiltration, and Rho-kinase expression/activation. Furthermore, there were significant positive correlations between SNF and vasa vasorum and between SNF and coronary vasoconstricting responses.

CONCLUSIONS

These results provide the first evidence that RDN ameliorates drug-eluting stent-induced coronary hyperconstricting responses in pigs in vivo through the kidney-brain-heart axis.

Patients with Primary Open-Angle Glaucoma May Develop Ischemic Heart Disease More Often than Those without Glaucoma: An 11-Year Population-Based Cohort Study

OBJECTIVES

To investigate whether patients with primary open angle glaucoma (POAG) have a higher proportion of ischemic heart disease (IHD) development.

DESIGN

A population-based retrospective cohort study, using the National Health Insurance Database (NHID) from 1st January, 2001, to 31st December, 2011, in Taiwan.

METHODS

3510 subjects with POAG were enrolled into the POAG group and 14040 subjects without glaucoma into the comparison group. The comparison group consisted of randomly selected individuals, matched with the POAG group based on age, gender, and index date (date of enrollment) at a ratio of 1:4. The participants of both groups should have no IHD before the index date, and they were followed until the end of 2011 to see whether they had new-onset IHD or not. Kaplan-Meier curves were used to compare the cumulative incidence of IHD between the two groups. Frailty model, a specialized form of Cox regression analysis, was used to estimate the crude and adjusted hazard ratio (HR) of IHD. Analyses were adjusted by age, gender, and systemic comorbidities (i.e. diabetes, hypertension, hyperlipidemia, atrial fibrillation and congestive heart failure).

RESULTS

The mean age of the cohort was 57.6±11.0 years. There were slightly more males than females (51.6% vs. 48.4%). A log-rank test comparing Kaplan-Meier curves of the two groups revealed a significantly higher cumulative incidence of IHD in the POAG group (p-value<0.001). In the univariate analysis by Frailty model, POAG patients had a significantly higher hazard of IHD (unadjusted HR = 2.32; 95% confidence interval 1.93 to 2.79). After adjustment, results remained significant (adjusted HR = 1.41; 95% confidence interval 1.16 to 1.72).

CONCLUSION

People with POAG may suffer from IHD more often than those without glaucoma.

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

The goals of this study were to determine the value of the isoproterenol (ISO) head-up tilt (HUT) test in detecting coronary vasospastic angina and to investigate the possible mechanism responsible for coronary artery spasm. The ISO + HUT test was performed in 16 patients with coronary artery spasm documented by the intracoronary ergonovine provocation test. Patients’ blood pressure and heart rate were measured at baseline, during the ISO + HUT (phase I), and during HUT after discontinuation of ISO (phase II). Patients were categorized as test-positive if they developed angina with ST-segment elevation during testing. Eight patients (50%) were test-positive (5 in phase I and 3 in phase II). Between the test-positive and test-negative groups, no significant differences were noted in the changes in blood pressure throughout the test. However, there were significant differences in the changes in heart rate from supine to 2 minutes after HUT under ISO infusion (-17 ±22 vs 11 ±25 beats/minute; p=0.035). In those patients with a positive result in the phase I stage, the heart rate decreased initially after tilt-up, and then significantly increased later (from 85 ±16 to 110 ±27 beats/minute; p=0.043), when coronary vasospasm occurred. In those patients with a positive result in the phase II stage, coronary vasospasm occurred immediately after HUT, when there was an insignificant transient increase in heart rate from the supine to the HUT position (from 85 ±12 to 92 ±11 beats/minute; p=0.109). The ISO + HUT test can provoke coronary vasospasm with ST-segment elevation in 50% of the patients with coronary artery spasm, when combined with an extensional protocol of HUT after discontinuation of ISO. This study suggests that the induction of coronary artery spasm during HUT testing is associated with a rapid elevation of sympathetic activity during augmented parasympathetic activity.

ESC Study Group of Sports Cardiology: recommendations for participation in leisure-time physical activity and competitive sports for patients with ischaemic heart disease

BACKGROUND

Evidence for the proper management of ischemic heart disease (IHD) in the general population is well established, but recommendations for physical activity and competitive sports in these patients are scarce. The aim of the present paper was to provide such recommendations to complement existing ESC and international guidelines on rehabilitation and primary/secondary prevention.

DESIGN AND METHODS

Due to the lack of studies in this field, the current recommendations are the result of consensus among experts. Sports are classified into low/moderate/high dynamic and low/moderate/high static, respectively.

RESULTS

Patients with a definitive IHD and higher probability of cardiac events are not eligible for competitive sports (CS) but for individually designed leisure time physical activity (LPA); patients with definitive IHD and lower probability of cardiac events as well as those with no IHD but with a positive exercise test and high risk profile (SCORE > 5%) are eligible for low/moderate static and low dynamic (IA-IIA) sports and individually designed LPA. Patients without IHD and a high risk profile+ a negative exercise-test and those with a low risk profile (SCORE < 5%) are allowed all LPA and competitive sports with a few exceptions.

CONCLUSIONS

Individually designed LPA is possible and encouraged in patients with and without established IHD. Competitive sports may be restricted for patients with IHD, depending on the probability of cardiac events and the demands of the sport according to the current classification.

Stress cardiomyopathy: Is it limited to Takotsubo syndrome? Problems of definition

In 2006, Takotsubo syndrome (TTC) was described as a distinct type of stress-induced cardiomyopathy (stress cardiomyopathy). However, when thinking about Takotsubo cardiomyopathy from the viewpoints of the AHA and ESC classifications, 2 possible problems may arise. The first potential problem is that a forecast of disease outcome is lacking in the ESC classification, whereas the AHA only states that 'outcome is favorable with appropriate medical therapy'. However, based on the literature data, one can make a general conclusion that occurrence of myocardial lesions in TTC (i.e., myocardial fibrosis and contraction-band necrosis) causes the same effects as in other diseases with similar levels of myocardial damage and should not be considered to have a lesser impact on mortality. To summarise, TTC can cause not only severe complications such as pulmonary oedema, cardiogenic shock, and dangerous ventricular arrhythmias, but also damage to the myocardium, which can result in the development of potentially fatal conditions even after the disappearance of LV apical ballooning. The second potential problem arises from the definition of TTC as a stress cardiomyopathy in the AHA classification. In fact, the main factors leading to TTC are stress and microvascular anginas, since, as has been already discussed, coronary spasm can cause myocardium stunning, resulting in persistent apical ballooning. Thus, based on this review, 3 distinct types of stress cardiomyopathies exist (variant angina, microvascular angina, and TTC), with poor prognosis. Adding these diseases to the classification of cardiomyopathies will facilitate diagnosis and preventive prolonged treatment, which should include intensive anti-stress therapy.

Acute Myocardial Infarction in Women: A Scientific Statement From the American Heart Association

Cardiovascular disease is the leading cause of mortality in American women. Since 1984, the annual cardiovascular disease mortality rate has remained greater for women than men; however, over the last decade, there have been marked reductions in cardiovascular disease mortality in women. The dramatic decline in mortality rates for women is attributed partly to an increase in awareness, a greater focus on women and cardiovascular disease risk, and the increased application of evidence-based treatments for established coronary heart disease. This is the first scientific statement from the American Heart Association on acute myocardial infarction in women. Sex-specific differences exist in the presentation, pathophysiological mechanisms, and outcomes in patients with acute myocardial infarction. This statement provides a comprehensive review of the current evidence of the clinical presentation, pathophysiology, treatment, and outcomes of women with acute myocardial infarction.

Autonomic Findings in Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy (TC) often occurs after emotional or physical stress. Norepinephrine levels are unusually high in the acute phase, suggesting a hyperadrenergic mechanism. Comparatively little is known about parasympathetic function in patients with TC. We sought to characterize autonomic function at rest and in response to physical and emotional stimuli in 10 women with a confirmed history of TC and 10 age-matched healthy women. Sympathetic and parasympathetic activity was assessed at rest and during baroreflex stimulation (Valsalva maneuver and tilt testing), cognitive stimulation (Stroop test), and emotional stimulation (event recall, patients). Ambulatory blood pressure monitoring and measurement of brachial artery flow-mediated vasodilation were also performed. TC women (tested an average of 37 months after the event) had excessive pressor responses to cognitive stress (Stroop test: p <0.001 vs baseline and p = 0.03 vs controls) and emotional arousal (recall of TC event: p = 0.03 vs baseline). Pressor responses to hemodynamic stimuli were also amplified (Valsalva overshoot: p <0.05) and prolonged (duration: p <0.01) in the TC women compared with controls. Plasma catecholamine levels did not differ between TC women and controls. Indexes of parasympathetic (vagal) modulation of heart rate induced by respiration and cardiovagal baroreflex gain were significantly decreased in the TC women versus controls. In conclusion, even long after the initial episode, women with previous episode of TC have excessive sympathetic responsiveness and reduced parasympathetic modulation of heart rate. Impaired baroreflex control may therefore play a role in TC.

Thoracic Sympathectomy for Severe Refractory Multivessel Coronary Artery Spasm

Coronary artery spasm is a rare but potentially fatal disease. Herein, we report a case of recurrent ST-segment myocardial infarctions and ventricular fibrillation complicating severe multivessel coronary artery spasm successfully treated with bilateral thoracic surgical sympathectomy.

Differing autonomic responses to dobutamine stress in the presence and absence of myocardial ischaemia

KEY POINTS

Dobutamine stress echocardiography is a validated tool for the non-invasive evaluation of myocardial ischaemia and enables the recording of heart rate variability in non-resting conditions. In this study we determined whether individuals with transient myocardial ischaemia had different autonomic responses to the stress of dobutamine infusion compared to non-ischaemic (normal) responders. Non-ischaemic responders had a residual predominance of parasympathetic over sympathetic activity. However, under conditions of myocardial ischaemia, there was a directionally opposite cardiac autonomic response with a residual increase of sympathetic over parasympathetic modulation. The sympathetic response to dobutamine stress is augmented as the burden of myocardial ischaemia is increased.

ABSTRACT

Cardiac autonomic dysfunction has prognostic significance in patients with coronary artery disease. This investigation aimed to assess changes in autonomic modulation induced by dobutamine stress in the presence and absence of myocardial ischaemia. In total, 314 individuals underwent dobutamine stress echocardiography to detect or exclude myocardial ischaemia. Simultaneous autonomic and haemodynamic data were obtained using a plethysmographic device. Total power spectral density and associated low-frequency (LF) and high-frequency (HF) power spectral components in absolute (ms(2) ) and normalised units (nu) were determined. Participants were categorised as non-ischaemic (NI) or ischaemic (IS) responders. There were no significant differences in LFnu or HFnu between groups at baseline. At peak stress, LFnu decreased from baseline in NI (43 ± 1.8 to 40 ± 1.8%), but increased from baseline in IS responders (39.5 ± 2 to 56 ± 2%, P < 0.05). In contrast, HFnu increased in NI patients (57 ± 1.8 to 60 ± 1.8%) but decreased in IS responders (60.5 ± 2 to 44 ± 2%, P < 0.05). Those with a high ischaemic burden [more than three ischaemic left ventricular (LV) segments] had a greater increase in LFnu (41 ± 4.8 to 65 ± 3.2% vs. 44.8 ± 3.8 to 57.7 ± 3.1%, P < 0.05) and greater decrease in HFnu (59 ± 4.8 to 35 ± 3.2% vs. 55.2 ± 3.8 to 42.3 ± 3.1%, P < 0.05) compared to patients with a low ischaemic burden (1-3 ischaemic LV segments) respectively, at peak stress. In the absence of myocardial ischaemia, dobutamine stress is associated with a residual predominance of parasympathetic over sympathetic activity. Under conditions of ischaemia, there is a directionally opposite autonomic response with a significant residual increase of sympathetic over parasympathetic modulation. This response is augmented as the burden of ischaemia is increased.

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.

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.

Negative chronotropic effects and coronary ischaemic abnormalities following thalidomide therapy

The severe teratogenic side effects of thalidomide led to its well-publicized withdrawal in the 1970s, but as it is cautiously being reintroduced into clinical use, new adverse effects are being described. A 65-year-old male with multiple myeloma received chemotherapy which included cyclophosphamide, thalidomide and dexamethasone. Whilst on this treatment he experienced severe chest pain leading to an acute hospital admission complicated by significant bradycardia with sinus pauses of 7 s, necessitating temporary right ventricular pacing. Despite correction of the bradycardia with temporary pacing, he experienced further episodes of chest pain, during which an ECG (with the pacemaker briefly switched off) showed ST elevation in the inferior leads along with runs of non-sustained ventricular tachycardia. Emergency coronary angiography demonstrated unobstructed coronary arteries. Due to ST elevation in the absence of flow-limiting coronary disease his presentation was presumed to be due to intermittent coronary artery spasm. He was started on sustained-release nifedipine without any beta-blockers and further thalidomide therapy was omitted. On this pharmacological therapy, over a period of 24 months, there were no further recurrences of any cardiac symptoms. To our knowledge there have been no previous reports of coronary artery spasm associated with the use of thalidomide. The precise mechanism remains undefined, with several plausible hypothetical pathways which we discuss. We discuss various mechanisms including autonomic, autocoid and paracrine modes of action that may underlie cardiac side effects of thalidomide. We report coronary spasm in addition to bradycardia as cardiac side effects that cardiologists and oncologists need to be alert to.

Coronary vasospasm induced by painful compression of the brachial artery following coronary angiography

We report the occurrence of coronary vasospasm following forceful compression of the brachial artery after coronary angiography.

A series of unfortunate events: prinzmetal angina culminating in transmural infarction in the setting of acute gastrointestinal hemorrhage

Prinzmetal angina or vasospastic angina is a clinical phenomenon that is often transient and self-resolving. Clinically it is associated with ST elevations on the electrocardiogram, and initially it may be difficult to differentiate from an acute myocardial infarction. The vasospasm induced in this setting occurs in normal or mildly to moderately diseased vessels and can be triggered by a number of etiologies including smoking, changes in autonomic activity, or drug ingestion. While the ischemia induced is usually transient, myocardial infarction and life-threatening arrhythmias can occur in 25% of cases. We present the case of a 65-year-old female where repetitive intermittent coronary vasospasm culminated in transmural infarction in the setting of gastrointestinal bleeding. This case highlights the mortality associated with prinzmetal angina and the importance of recognizing the underlying etiology.

Sudden cardiac arrest and syncope triggered by coronary spasm

BACKGROUND

Patients with coronary spasm generally have a good prognosis, although it can result in sudden cardiac arrest (SCA) and syncope. We hypothesized that the nature of coronary spasm triggering lethal arrhythmias may be different from that which induces angina-only.

METHODS

Clinical characteristics were examined in patients who had experienced SCA (n = 18) or syncope (n = 28) triggered by coronary spasm. These characteristics were compared to those of patients who had coronary spastic angina-only (n = 52).

RESULTS

SCA and syncope occurred frequently during daytime in 57% and 68%, respectively. Spontaneous ST-segment changes during daytime were recorded more often in patients with SCA (50%) and syncope (39%) than angina-only patients (4%, p < 0.01 for each). Nocturnal angina occurred less frequently in patients with SCA (33%) and syncope (32%) than angina-only patients (83%, p < 0.01 for each). Severe multivessel spasm, daytime ST-segment changes, and younger age were significant predictors of SCA. Daytime ST-segment changes and active smoking were related to syncope.

CONCLUSIONS

The circadian variance of coronary spasm triggering SCA or syncope may be different from that inducing typical coronary spastic angina. The coronary spasm should be evaluated for patients with aborted SCA or recurrent syncope of unknown cause, even though the patients have not experienced the typical nocturnal angina.

Disruption of coronary vasomotor function: the coronary spasm syndrome

Abnormal coronary vasoconstriction, or coronary spasm, can be the result of several factors, including local and neuroendocrine aberrations. It can manifest clinically as a coronary syndrome and plays an important role in the genesis of myocardial ischemia. Over the past half century, coronary angiography allowed the in vivo demonstration of spasm in patients who fit the initial clinical description of the condition as reported by Prinzmetal et al. Several clinical, basic, and more recently, genetic studies have provided insight into the pathogenesis, manifestations, and therapy of this condition. It is not uncommonly encountered in patients with coronary syndromes and absence of clearly pathologic lesions on angiography. Provocation tests utilizing pharmacologic and nonpharmacologic stimuli combined with imaging (echocardiography or coronary angiography) can help make the correct diagnosis. The use of calcium channel blockers and long-acting nitrates is currently considered standard of care and the overall prognosis appears to be good. The recent discovery of genetic abnormalities predisposing to abnormal spasm of the coronaries has stimulated interest in the development of targeted therapies for the management of this condition.

Combination of variant and microvascular angina

Prinzmetal's variant angina (VA) and cardiac syndrome X (CSX) are two distinct, usually easily recognizable, forms of angina syndromes, caused by epicardial spasm, usually responsible for transient transmural myocardial ischemia at rest and by coronary microvascular dysfunction (CMVD), usually responsible for effort induced subendocardial ischemia, respectively. In this article we report clinical evidence in three patients of the simultaneous occurrence of angina episodes typical of both VA and CSX, suggesting that common pathogenetic factors may be responsible for clinical manifestations both of functional macrovascular and microvascular coronary artery abnormalities in some angina patients.

Wavelet transform analysis of heart rate variability during dipyridamole-induced myocardial ischemia: relation to angiographic severity and echocardiographic dyssynergy

BACKGROUND

Analysis of heart rate variability (HRV) is a valuable noninvasive method for quantifying autonomic cardiac control in humans and has been utilized during dipyridamole echocardiographic test to differentiate positive from negative test results.

HYPOTHESIS

We aimed to evaluate, by means of HRV analysis, the influence of the angiographic severity of coronary artery disease on cardiac autonomic control during dipyridamole-induced myocardial ischemia.

METHODS

We analyzed RR interval variability changes during dipyridamole-induced myocardial ischemia in 31 selected patients (mean age 54 +/- 9 years) with available coronary angiography and positive dipyridamole echocardiographic test. Spectral components of HRV were assessed by means of wavelet transform analysis for the last 5 min before the beginning of the test (baseline) and for 5 min after the onset of ischemia-related events (peak dipyridamole effect).

RESULTS

Patients were divided into three groups according to the number of coronary diseased vessels (Group A, single-vessel disease; Group B, double-vessel disease; Group C, triple-vessel disease). No difference was detectable at baseline among the three groups. After dipyridamole, low-frequency power, a measure of sympathetic modulation of heart rate, increased and echocardiographic wall motion score index worsened in all groups (p < 0.001). The increase in low-frequency power was more evident in Group C patients than in the other two groups (p < 0.005). Furthermore, after dipyridamole, a direct correlation was found between low-frequency power and wall motion score index (r = 0.59; p < 0.001).

CONCLUSIONS

These data suggest that HRV analysis performed during dipyridamole echocardiographic test provides useful information to assess the severity of coronary artery disease.

Heart rate variability explored in the frequency domain: a tool to investigate the link between heart and behavior

The neural regulation of circulatory function is mainly effected through the interplay of the sympathetic and vagal outflows. This interaction can be explored by assessing cardiovascular rhythmicity with appropriate spectral methodologies. Spectral analysis of cardiovascular signal variability, and in particular of RR period (heart rate variability, HRV), is a widely used procedure to investigate autonomic cardiovascular control and/or target function impairment. The oscillatory pattern which characterizes the spectral profile of heart rate and arterial pressure short-term variability consists of two major components, at low (LF, 0.04-0.15Hz) and high (HF, synchronous with respiratory rate) frequency, respectively, related to vasomotor and respiratory activity. With this procedure the state of sympathovagal balance modulating sinus node pacemaker activity can be quantified in a variety of physiological and pathophysiological conditions. Changes in sympathovagal balance can be often detected in basal conditions, however a reduced responsiveness to an excitatory stimulus is the most common feature that characterizes numerous pathophysiological states. Moreover the attenuation of an oscillatory pattern or its impaired responsiveness to a given stimulus can also reflect an altered target function and thus can furnish interesting prognostic markers. The dynamic assessment of these autonomic changes may provide crucial diagnostic, therapeutic and prognostic information, not only in relation to cardiovascular, but also non-cardiovascular disease. As linear methodologies fail to provide significant information in conditions of extremely reduced variability (e.g. strenuous exercise, heart failure) and in presence of rapid and transients changes or coactivation of the two branches of autonomic nervous system, the development of new non-linear approaches seems to provide a new perspective in investigating neural control of cardiovascular system.

[Up-date of the diagnosis and treatment of vasospastic angina]

Vasospastic or Prinzmetal's variant angina as it is also known is a special type of ischemic heart disease characterized by spontaneous episodes of chest pain accompanied by transitory ST segment elevations during the episodes. These alterations are essential for its diagnosis and it is difficult to diagnose it in their absence. If clinical suspicion is high, it should be confirmed by coronary vasospasm provocation tests, since, on the contrary, there may be cases that are not diagnosed or considered to be other types of diseases. Furthermore, progression of this type of angina to a myocardial infarction due to coronary stenosis is a relatively uncommon event.

Coronary artery spasm as a cause of ST elevation and inappropriate implantable cardioverter defibrillator intervention

Coronary artery spasm can cause both brady- and tachyarrhythmia, through induction of AV block (usually linked to coronary spasm of the right coronary artery) or ventricular tachycardia/fibrillation linked to extensive myocardial ischemia. The electrocardiographic aspect of coronary artery spasm is an ST segment elevation. We describe the case of patient implanted with an implantable cardioverter defibrillator (ICD) for unexplained syncope which, during coronary artery spasm, received an inappropriate device firing due to ST segment elevation, leading to a double count of the QRS by the ICD.