Paroxysmal atrial fibrillation during intracoronary acetylcholine provocation test

Relation of Vasoreactivity in the Left and Right Coronary Arteries During Acetylcholine Spasm Provocation Testing

The diagnosis of vasospastic angina (VSA) according to Japanese guidelines involves an initial intracoronary acetylcholine (ACh) provocation test in the left coronary artery (LCA) followed by testing in the right coronary artery (RCA). However, global variations in test protocols often lead to the omission of ACh provocation in the RCA, potentially resulting in the underdiagnosis of VSA. This study assessed the validity of the LCA-only ACh provocation approach for the VSA diagnosis and whether vasoreactivity in the LCA aids in determining further provocation in the RCA. A total of 273 patients who underwent sequential intracoronary ACh provocation testing in the LCA and RCA were included. Patients with a positive ACh provocation test in the LCA were excluded. Relations between vasoreactivity in the LCA and ACh test outcomes (positivity and adverse events) in the RCA were evaluated. In patients with negative ACh test results in the LCA, subsequent ACh testing was positive in the RCA in 23 of 273 (8.4%) patients. In patients with minimal LCA vasoconstriction (<25%), only 3.0% had a positive ACh test in the RCA, whereas the ACh test in the RCA was positive in 13.5% of those with LCA constriction of 25% to 90% (p = 0.002). No major adverse events occurred during ACh testing in the RCA. In conclusion, for the VSA diagnosis, the omission of ACh provocation in the RCA may be clinically acceptable, particularly when vasoconstriction induced by ACh injection was minimal in the LCA. Further studies are needed to define ACh provocation protocols worldwide.

Drug-induced AF: Arrhythmogenic Mechanisms and Management Strategies

AF is a prevalent condition that is associated with various modifiable and unmodifiable risk factors. Drug-induced AF, despite being commonly under-recognised, can be relatively easy to manage. Numerous cardiovascular and non-cardiovascular agents, including catecholaminergic agents, adenosine, anti-tumour agents and others, have been reported to induce AF. However, the mechanisms underlying drug-induced AF are diverse and not fully understood. The complexity of clinical scenarios and insufficient knowledge regarding drug-induced AF have rendered the management of this condition complicated, and current treatment guidelines follow those for other types of AF. Here, we present a review of the epidemiology of drug-induced AF and highlight a range of drugs that can induce or exacerbate AF, along with their molecular and electrophysiological mechanisms. Given the inadequate evidence and lack of attention, further research is crucial to underscore the clinical significance of drug-induced AF, clarify the underlying mechanisms and develop effective treatment strategies for the condition.

Which Coronary Artery Should Be Preferred for Starting the Coronary Spasm Provocation Test?

BACKGROUND

The spasm provocation test (SPT) is a critical test for diagnosing vasospastic angina (VSA). However, the choice of vessel to be preferred for initiating the SPT-the right coronary artery (RCA) or the left coronary artery (LCA)-is unclear. This study aimed to assess SPT results including SPT-related complications while initiating the SPT in the RCA and LCA.

METHODS

We enrolled 225 patients who underwent coronary angiography and SPTs. The SPT was first performed in the RCA in 133 patients (RCA group) and the LCA in 92 patients (LCA group). We defined VSA as >90% narrowing of the coronary artery during the SPT, accompanied by chest pain and/or ST-T changes on the electrocardiogram. When coronary spasm occurs in two or more major coronary arteries, it is referred to as a multivessel spasm (MVS). SPT-related complications comprised atrial fibrillation, ventricular fibrillation, and unstable hemodynamics following catecholamine use. Analyses using propensity score matching (PSM) were performed in 120 patients.

RESULTS

No significant differences in the frequencies of VSA and complications were observed between the two groups (RCA: 79% and 19%, respectively; LCA: 85% and 22%, respectively). In both groups, spasms were most frequently provoked in the left anterior descending coronary artery (both p < 0.001) whereas spasms in the left circumflex coronary artery (LCX) were higher in the LCA group than in the RCA group (p = 0.015). Furthermore, no significant difference in the frequency of MVS was observed between both groups (RCA: 50%, LCA: 62%; p = 0.122). After PSM, no significant difference in the frequencies of VSA and complications were observed between the two groups (RCA: 82% and 15%, respectively; LCA: 88% and 18%, respectively). The frequencies of LCX spasms (RCA: 8%, LCA: 23%; p = 0.022) and MVS (RCA: 40%, LCA: 62%; p = 0.020) were higher in the LCA group than in the RCA group.

CONCLUSIONS

Although the diagnostic rate of VSA and frequency of SPT-related complications were similar in the two groups, the frequency of MVS was higher in the LCA group than in the RCA group because of the increase in the number of LCX spasms. A routine SPT may be started from the LCA.

Impact of preceding acetylcholine provocation testing on following coronary physiological assessment during an interventional diagnostic procedure

BACKGROUND

Intracoronary acetylcholine (ACh) provocation test and coronary physiological assessment are useful interventional diagnostic procedures for evaluating ischemia with no obstructive coronary arteries (INOCA). However, the appropriate sequential order of the diagnostic procedures has been a matter of debate. We investigated the impact of preceding ACh provocation on following coronary physiological assessment.

METHODS

Patients suspected of INOCA underwent invasive coronary physiological assessment using thermodilution method and were divided into two groups according to the implementation of ACh provocation test. The ACh group was further divided into the positive and negative ACh groups. In the ACh group, intracoronary ACh provocation was performed before the invasive coronary physiological assessment. The main interest of this study was to compare coronary physiological indices among the no ACh, negative ACh, and positive ACh groups.

RESULTS

Of 120 patients, the no ACh, and negative and positive ACh groups included 46 (38.3 %), 36 (30.0 %), and 38 (31.7 %), respectively. Fractional flow reserve was lower in the no ACh group than in the ACh group. Resting mean transit time was significantly longer in the positive ACh group, followed by the no ACh and negative ACh groups (1.22 ± 0.55 vs. 1.00 ± 0.46 vs. 0.74 ± 0.36 s, p < 0.001). Index of microcirculatory resistance and coronary flow reserve did not differ significantly among the three groups.

CONCLUSIONS

Preceding ACh provocation influenced following physiological assessment, particularly when ACh test was positive. Further studies are warranted to determine which interventional diagnostic procedure, ACh provocation or physiological assessment, should be preceded in the invasive evaluation of INOCA.

Implantable cardioverter-defibrillator therapy after resuscitation from cardiac arrest in vasospastic angina: A retrospective study

Patients with vasospastic angina (VSA) who are resuscitated from sudden cardiac arrest (SCA) are at a high risk of recurrent lethal arrhythmia and cardiovascular events. However, the benefit of the implantable cardioverter-defibrillator (ICD) therapy in this population has not been fully elucidated. The present study aimed to analyze the prognostic impact of ICD therapy on patients with VSA and SCA. A total of 280 patients who were resuscitated from SCA and received an ICD for secondary prophylaxis were included in the present multicenter registry. The patients were divided into two groups on the basis of the presence of VSA. The primary endpoint was a composite of all-cause death and appropriate ICD therapy (appropriate anti-tachycardia pacing and shock) for recurrent ventricular arrhythmias. Of 280 patients, 51 (18%) had VSA. Among those without VSA, ischemic cardiomyopathy was the main cause of SCA (38%), followed by non-ischemic cardiomyopathies (18%) and Brugada syndrome (7%). Twenty-three (8%) patients were dead and 72 (26%) received appropriate ICD therapy during a median follow-up period of 3.8 years. There was no significant difference in the incidence of the primary endpoint between patients with and without VSA (24% vs. 33%, p = 0.19). In a cohort of patients who received an ICD for secondary prophylaxis, long-term clinical outcomes were not different between those with VSA and those with other cardiac diseases after SCA, suggesting ICD therapy may be considered in patients with VSA and those with other etiologies who were resuscitated from SCA.

Safety and prognostic relevance of acetylcholine testing in patients with stable myocardial ischaemia or myocardial infarction and non-obstructive coronary arteries

BACKGROUND

Intracoronary provocation testing with acetylcholine (ACh) is crucial for the diagnosis of functional coronary alterations in patients with suspected myocardial ischaemia and non-obstructive coronary arteries.

AIMS

Our intention was to assess the safety and predictive value for major adverse cardiovascular and cerebrovascular events (MACCE) in patients presenting with ischaemia with non-obstructive coronary arteries (INOCA) or with myocardial infarction with non-obstructive coronary arteries (MINOCA).

METHODS

We prospectively enrolled consecutive INOCA or MINOCA patients undergoing intracoronary ACh provocation testing.

RESULTS

A total of 317 patients were enrolled: 174 (54.9%) with INOCA and 143 (45.1%) with MINOCA. Of these, 185 patients (58.4%) had a positive response to the ACh test. Complications during ACh provocative testing were all mild and transient and occurred in 29 (9.1%) patients, with no difference between patients with positive or negative responses to ACh testing, nor between INOCA and MINOCA patients. A history of paroxysmal atrial fibrillation, moderate/severe diastolic dysfunction and a higher QT dispersion at baseline electrocardiogram were independent predictors of complications. MACCE occurred in 30 patients (9.5%) during a median follow-up of 22 months. The incidence of MACCE was higher among patients with a positive ACh test (24 [13.0%] vs 6 [4.5%], p=0.017), and a positive ACh test was an independent predictor of MACCE.

CONCLUSIONS

ACh provocation testing is associated with a low risk of mild and transient complications, with a similar prevalence in both INOCA and MINOCA patients. Importantly, ACh provocation testing can help to identify patients at higher risk of future clinical events, suggesting a net clinical benefit derived from its use in this clinical setting.

Assessment of Vascular Dysfunction in Patients Without Obstructive Coronary Artery Disease: Why, How, and When

Ischemic heart disease secondary to coronary vascular dysfunction causes angina and impairs quality of life and prognosis. About one-half of patients with symptoms and signs of ischemia turn out not to have obstructive coronary artery disease, and coronary vascular dysfunction may be relevant. Adjunctive tests of coronary vasomotion include guidewire-based techniques with adenosine and reactivity testing, typically by intracoronary infusion of acetylcholine. The CorMicA (Coronary Microvascular Angina) trial provided evidence that routine management guided by an interventional diagnostic procedure and stratified therapy improves angina and quality of life in patients with angina but no obstructive coronary artery disease. In this paper, the COVADIS study group provide a comprehensive review of why, how, and when coronary vascular dysfunction should be assessed invasively. They discuss the rationale through a shared understanding of vascular pathophysiology and clinical evidence. They propose a consensus approach to how an interventional diagnostic procedure is performed with focus on practical aspects. Finally, the authors discuss the clinical scenarios in patients with stable and acute coronary syndromes in which measurement of coronary vascular function may be helpful for patient care.

Decreased Double Product at Rest in Patients With Severe Vasospasm

BACKGROUND

Autonomic nerve system and endothelial function play important roles in vasospastic angina. Elevated heart rate (HR), blood pressure (BP), and double product (DP) can increase endothelial-dependent coronary artery dilation and blood flow. However, the impact of HR, BP, and DP on occurrence and severity of VSA in the clinical setting is unclear.

METHOD

A total of 170 patients undergoing intracoronary acetylcholine (ACh) provocation test during hospitalisation was included. Resting HR, BP, and DP were measured at least four times, and their variabilities were evaluated by standard deviations (SD) and coefficient of variations (CVs). Angiographic coronary artery vasospasm was defined as total or subtotal occlusion induced by ACh provocation.

RESULTS

Mean±SD HR (65.7±9.1 vs 69.6±7.9 beats per minute; p=0.003), systolic BP (122.3±13.4 vs 127.7±14.6 mmHg; p=0.01), and DP (8,001±1,229 vs 8,903±1,495; p<0.001) were significantly lower in patients with a positive ACh test than the counterpart, whereas SD and CV of both HR and systolic BP were not significantly different between the two groups. Mean HR, BP, and DP progressively decreased with increase in the number of vessels with angiographic vasospasm. Multivariate analysis showed current smoking and lower DP as independent predictors of the greater number of vessels with provoked angiographic vasospasm.

CONCLUSIONS

Resting HR, BP, and DP were lower in patients with vasospastic angina, especially in those with severe vasospasm.

Relation between severity of myocardial bridge and vasospasm

BACKGROUND

Myocardial bridge (MB) has been reported to induce cardiac complications including coronary vasospasm. Although MB has some anatomical and morphological variations, the association of these variations with vasospasm is unclear. The aim of this study was to investigate the relation between morphological severity of MB and vasospasm induced by acetylcholine (ACh) provocation test.

METHODS

A total of 392 patients without coronary stent in the left anterior descending artery (LAD) undergoing intracoronary ACh provocation test were included. Angiographic coronary artery vasospasm was defined as total or subtotal occlusion induced by ACh provocation. MB was identified on coronary angiography as a milking effect. Total bridged length and maximum percent systolic compression of MB in the LAD were analyzed quantitatively.

RESULTS

MBs in the LAD were identified in 140 patients (36%), mostly in the mid segment. Patients with MB in the LAD had greater number of provoked vasospasm in the LAD and positive ACh provocation test compared to those without. The bridged length positively correlated with percent systolic compression of MB (r=0.37, p<0.001). In the receiver operating characteristic curve analysis, both bridged length and percent systolic compression of MB significantly predicted the provoked LAD spasm (AUC 0.74, p<0.001, and AUC 0.68, p<0.001). Multivariate regression analysis demonstrated these factors as independent predictors for provoked LAD spasm.

CONCLUSION

MB, especially morphologically severe MB, may induce greater coronary vasospasm.