Circumflex Coronary Artery Research Articles

Association between 82Rb positron emission tomography-derived regional myocardial blood flow, severity of angiographic coronary artery stenosis, and mortality in patients with chest pain

Impairment in global myocardial flow reserve (MFR) on rubidium-82 (82Rb) positron emission tomography (PET) stress testing predicts cardiovascular events; however, the relationship between regional coronary artery territory myocardial blood flow (MBF) and invasive coronary angiography is unknown. In this study, patients with acute chest pain who were referred for coronary angiography after abnormal PET stress testing were evaluated. Both global and regional coronary territory stress and rest MBF were derived using 82Rb PET. Coronary artery stenosis severity was assessed using quantitative coronary angiography (QCA) performed within 3 months of PET. A total of 189 patients were followed for a median of 4.1 years. The results showed a weak correlation between regional MFR impairment (<1.7) and stenosis severity in the left descending artery (r = −0.20, P = 0.005), left circumflex artery (r = −0.15, P = 0.042), and right coronary artery (r = −0.26, P < 0.001). In addition, a weak correlation was observed between global MFR and stenosis in any vessel, in both binary and continuous analyses. However, impairment in MFR within any territory was associated with increased all-cause mortality in both unadjusted and adjusted analyses. In conclusion, this is the first large-scale study to examine the relationship between regional coronary territory MBF, coronary artery stenosis severity as assessed using QCA, and mortality. Although coronary territory MFR demonstrated a weak correlation with coronary stenosis severity, impairment in per-territory MFR was significantly associated with increased all-cause mortality, suggesting that mechanisms such as diffuse atherosclerosis and/or microvascular disease may be contributing factors.

The effect of hydrostatic pressure on invasive coronary pressure measurements: Comparison with [15O]H2O-positron emission tomography flow data.

Fractional flow reserve (FFR) has emerged as the invasive gold standard for assessing vessel-specific ischemia. However, FFR measurements are influenced by the hydrostatic effect, which might adversely impact the assessment of ischemia. This study aimed to investigate the impact of hydrostatic pressure on FFR measurements by correcting for the height and comparing FFR with [15O]H2O positron emission tomography (PET)-derived relative flow reserve (RFR). The 206 patients were included in this analysis. Patients underwent coronary computed tomography angiography (CCTA), [15O]H2O PET, and invasive coronary angiography with routine FFR in every epicardial artery. Height differences between the aortic guiding catheter and distal pressure sensor were quantified on CCTA images. An FFR ≤ 0.80 was considered significant. The study found a reclassification in 7% of the coronary arteries. Notably, 11% of left anterior descending (LAD) arteries were reclassified from hemodynamically significant to nonsignificant. Conversely, 6% of left circumflex (Cx) arteries were reclassified from nonsignificant to significant. After correcting for the hydrostatic pressure effect, the correlation between FFR and PET-derived RFR increased significantly from r = 0.720 to r = 0.786 (p = 0.009). The average magnitude of correction was +0.05 FFR units in the LAD, -0.03 in the Cx, and -0.02 in the right coronary artery. Hydrostatic pressure has a small but clinically relevant influence on FFR measurements obtained with a pressure wire. Correcting for this hydrostatic error significantly enhances the correlation between FFR and PET-derived RFR.

Long-term efficacy of drug-coated balloon-only angioplasty for IgG4-related coronary artery disease: A case report

Abstract Background Although coronary artery involvement in patients with IgG4-related disease (IgG4-RD) is rare, emergency revascularisation is recommended for managing acute coronary syndrome. However, coronary aneurysm formation and stent migration after sirolimus-eluting stent implantation have been reported for this disease. Thus, new treatment modalities are warranted for the management of coronary artery disease in this vasculitis. Case summary A 70-year-old male who experienced progressive chest discomfort for 1 month underwent cardiac examination. Coronary computed tomography angiography (CCTA) revealed right coronary artery hypoplasia, coronary artery aneurysm with severely calcified stenosis in the proximal left anterior descending artery (LAD), and subtotal obstruction in the mid-LAD. The left circumflex artery (LCX) also had stenosis and dilated lesions. Additionally, diffuse perivascular soft tissue thickening was observed in the mid-LCX. Percutaneous coronary intervention was performed for the proximal- and mid-LAD lesions. Rotational atherectomy with low-pressure drug-coated balloon (DCB) dilation was considered for these lesions owing to suspicion of vasculitis. The patient was later diagnosed with Sjögren's syndrome and IgG4-RD overlap syndrome. Oral steroids and immunosuppressive drugs were initiated. In a follow-up at 7 and 26 months, late lumen enlargement was observed in the treated area of the LAD, without enlargement of the adjacent aneurysm. CCTA performed after 26 months revealed resolution of the diffuse perivascular soft tissue thickening in the mid-LCX. Discussion To our knowledge, this is the first case report demonstrating favourable outcomes for treatment of a coronary artery lesion attributed to IgG4-RD with DCB, leaving nothing implanted in the coronary artery tree.

Characterisation and distribution of human coronary artery innervation.

A detailed understanding of the sympathetic innervation of coronary arteries is relevant to facilitate the development of novel treatment approaches. This study aimed to quantitatively examine periarterial innervation in human epicardial coronary arteries. Coronary arteries with adjacent epicardial adipose tissue were excised along the left main coronary artery (LMCA), left anterior descending artery (LAD), left circumflex artery (LCx), and right coronary artery (RCA) from 28 body donors and examined histologically. Immunofluorescence staining was performed to characterise sympathetic nerve fibres. A total of 42,573 nerve fibres surrounding 100 coronary arteries (LMCA: n=21, LAD: n=27, LCx: n=26, RCA: n=26) were analysed. The nerve fibre diameter decreased along the vessel course (median [interquartile range]): (proximal 46 μm [31-73], middle 38 μm [26-58], distal 31 μm [22-46]; p<0.001), with the largest nerve fibre diameter along the LMCA (50 μm [31-81]), followed by the LAD (42 μm [27-72]; p<0.001). The total nerve fibre density was highest along the RCA (123 nerves/cm² [82-194]). Circumferentially, nerve density was higher in the myocardial tissue area of the coronary arteries (132 nerves/cm² [76-225]) than in the epicardial tissue area (101 nerves/cm² [61-173]; p<0.001). The median lumen-nerve distance was smallest around the LMCA (2.2 mm [1.2-4.1]), followed by the LAD (2.5 mm [1.1-4.5]; p=0.005). Human coronary arteries are highly innervated with sympathetic nerve fibres, with significant variation in the distribution and density. Understanding these patterns informs pathophysiological understanding and, potentially, the development of catheter-based approaches for cardiac autonomic modulation.

Frequency and Pattern of Anomalous Origin of Coronary Artery in Bangladeshi Population: Coronary Angiogram Based Single Center Study

Background: Anomalous origin of coronary artery (AOCA) has been traditionally described by coronary angiography or autopsy. However the actual prevalence of such abnormalities is unknown in general Bangladeshi population. Beside conventional coronary angiogram(CAG), CT CAG and Multi-detector computed tomography (MDCT) offers higher possibility to visualize AOCA non-invasively. The purpose of this study was to report the prevalence AOCA in Bangladeshi population by using conventional CAG. Methodology: This was a single center, cross sectional, observational study, done in department of Cardiology, BSMMU over 1 year period. Sample size was 1167. Samples were taken following inclusion and exclusion criteria. Descriptive statistical analysis was done by using SPSS v29.0 Results: 1.3% population had AOCA. Commonest (0.6%) was ‘absent Left main (LM) with separate origin of Left Anterior Descending (LAD) and Left Circumflex (LCX) artery. Second commonest (0.45%) was ‘Right Coronary Artery (RCA) arising from left sinus’. 0.17% had RCA highup origin, and 0.08% had RCA origin from posterior sinus. Discussion: Among AOCA, RCA origin from left sinus, is potentially dangerious, due to high risk of sudden cardiac death (SCD) and surgical complications. Other varities of AOCA are mostly benign, but it may cause difficulties in cannulation during coronary angiography and coronary artery bypass surgery. Conclusion: Although coronary artery anomalies are rare, they may cause difficulties during coronary interventions or cardiac surgery and may occasionally result in sudden cardiac death. So, optimum precaution to findout the AOCA is needed during conventional CAG, and if suspicion, CT CAG and MDCT should also be used. (Bangladesh Heart Journal 2024; 39(2): 117-120

Clinical and Angiographic Profile of Non-ST Elevation Myocardial Infarction Patients with Multivessel Disease: A Study in a Tertiary Care Hospital in Bangladesh

Background: Non-ST elevation myocardial infarction (NSTEMI) is a type of acute coronary syndrome without ST-segment elevation on electrocardiography. Many non-ST elevation myocardial infarction patients have multivessel disease, which leads to worse outcomes compared to single-vessel disease. Their clinical and angiographic profiles provide valuable insightf into the nature, severity, and treatment of this common cardiac condition. This study aimed to evaluate the clinical and angiographic profiles of non-ST elevation myocardial infarction patients with multivessel disease. Methods: This prospective study was conducted in the Department of Cardiology, National Heart Foundation Hospital and Research Institute, Dhaka, Bangladesh from September 2022 to August 2023. The study enrolled 270 consecutive patients with NSTEMI. Coronary angiography and electrocardiogram were used in assessing the disease condition. The data were analyzed using SPSS version 23.0. Results: The mean age of total participants was 54.31 ±10.54 years and most of them were male (77.8%). Majority of the patients had hypertension (68.1%), diabetes mellitus (59.3%), and dyslipidemia (58.5%). In the clinical assessment, 89.6% of patients had femoral access, 31.1% had a bifurcation lesion, 8.1% showed calcification, and 22.6% had a left main lesion. Stents were used in 41.9% of cases, with a mean total stent length of 55.8 ±26.9 mm. The mean left ventricular ejection fraction was 49.10 ±7.3%. Among the major culprit vessel involvements identified, 6% involved the left main (LM) artery, 56% involved the left anterior descending (LAD) artery, 34% involved the left circumflex (LCX) artery, and 39% involved the right coronary artery (RCA). Regarding the final angiographic findings among the total participants, double vessel disease (DVD) was observed in 40% of cases, while triple vessel disease was observed in 60% of cases. Conclusion: The increased prevalence of triple vessel disease among non-ST elevation myocardial infarction patients underscores the importance of heightened vigilance among healthcare providers and policymakers. Understanding the clinical and angiographic profiles of these patients is essential for effective management strategies.

Hybrid strategy of drug-eluting stent and drug-coated balloon in the treatment of de novo coronary artery disease: 1-year clinical outcomes.

The hybrid strategy of drug-eluting stent (DES) and drug-coated balloon (DCB) has been increasingly accepted for the treatment of de novo coronary artery disease. However, data regarding the clinical outcome of this practice in a Southeast Asian population are limited. We aimed to investigate the safety and clinical outcome of this hybrid strategy (DES and DCB) in the treatment of de novo coronary artery disease. The primary endpoint was target lesion failure (TLF) in the DES/DCB-treated segment at 12 months. TLF is defined as the composite of cardiac death, target vessel myocardial infarction (TVMI) and ischaemia-driven target lesion revascularisation (ID-TLR) in the DES- and/or DCB-treated segment. A total of 401 patients with 458 lesions were treated with the hybrid strategy at the National Heart Institute (IJN), Kuala Lumpur, Malaysia, from 1 July 2021 to 30 June 2022, were retrospectively enrolled in the study. A total of 38 patients (9.5%) were lost to subsequent follow-up, and the remaining 363 patients (90.5%) were included in the outcome analysis. Clinical outcomes at 1 year were analysed. In all, 219 lesions (47.8%) involved the left anterior descending artery, 146 lesions (31.9%) involved the right coronary artery, and 57 lesions (12.4%) involved the left circumflex artery. In all, 87 lesions (19%) were bifurcation lesions. A total of 8 patients (2.2%) had TLF, of whom 3 patients (0.83%) had TVMI, 3 patients (0.83%) had ID-TLR, and 2 patients (0.6%) experienced cardiac death. Four patients died of a non-cardiac cause at 1-year follow-up. A hybrid strategy of DES and DCB for the treatment of de novo coronary artery lesions appears to be feasible and clinically safe according to the 1-year outcomes.

Clinical and Angiographic Outcomes of Bilateral Internal Thoracic Artery Revascularization: In Situ vs Free Grafts

BackgroundBilateral internal thoracic artery (ITA) grafting is associated with improved long-term outcomes; however, the appropriate graft configuration remains controversial. We compared the long-term outcomes of different graft configurations. MethodsBetween 2009 and 2015, 1171 patients underwent isolated bilateral ITA grafting for left-sided complete revascularization at 4 Japanese cardiac surgery centers: underwent in situ left ITA to the left anterior descending artery plus in situ right ITA to the left circumflex artery (LR group, n = 278), in situ right ITA to the left anterior descending artery plus in situ left ITA to the left circumflex artery (RL group, n = 665), and in situ left ITA to the left anterior descending artery plus free right ITA to the left circumflex artery (free group, n = 228). Major adverse cardiovascular events (MACEs), including mortality, myocardial infarction and revascularization, and ITA patency, were compared. ResultsAmong the 3 groups, the free group showed significantly lower MACEs and overall mortality rates (P < .001). Nonfatal myocardial infarction and revascularization rates showed no marked differences among the groups. A weighted analysis revealed a decreased risk of MACEs and death in the free group. No marked difference was observed in the patency of the ITA anastomosed to the left anterior descending artery. Patency of the ITA grafted to the circumflex artery in the LR group was significantly lower relative to the other groups. Using a free right ITA grafted to the circumflex artery reduced the risk of graft failure. ConclusionsThe free right ITA configuration for left-sided revascularization might have better long-term outcomes and significantly better patency than other grafts.

Atypical Aslanger pattern in inferolateral myocardial infarction – A new variant to look out for?

We report a case of a 53-year-old male with inferolateral myocardial infarction, presenting an atypical Aslanger pattern on electrocardiogram (ECG). The ECG showed ST elevation in leads III, aVR, aVF, and posterior leads, with ST depression in II and V2-V6 with terminal positive T waves. Coronary angiography revealed total occlusion of the left circumflex artery (LCx) with significant stenosis of the left anterior descending (LAD) and right coronary artery (RCA). The LCx was successfully revascularized. This case highlights the importance of recognizing atypical Aslanger patterns, which may indicate multivessel coronary artery disease.

Case report: Woven-like coronary arteries in a patient with polycythemia vera

BackgroundWoven coronary artery (WCA) is a rare and underdiagnosed congenital anomaly that involves multiple thin and tortuous epicardial arterial conduits reassembling distally into a single lumen. Recanalized thrombus may present as woven-like coronary arteries, appearing similar to WCA on angiographic images.Case presentationA 58-year-old female patient with intermittent chest pain for 5 years and polycythaemia vera (PV) for 8 years. The left anterior descending artery was presented like WCA on coronary angiography and finally confirmed as recanalized thrombus by optical coherence tomography(OCT), which might have been caused by PV. Given the patient’s high thrombotic risk of PV and thrombotic changes in the left circumflex artery (LCX), we ultimately chose a conservative treatment without stenting.ConclusionsOCT would be needed for the diagnosis and differential diagnosis of woven-like coronary arteries. And physicians should take an appropriate treatment in a personalized way in patients with PV.

Cancer therapy-related cardiac dysfunction after radiation therapy for breast cancer: results from the BACCARAT cohort study

BackgroundRadiation therapy (RT) for breast cancer (BC) can result in subtle cardiac dysfunction that can occur early after treatment. In 2022, the European Society of Cardiology (ESC) published the first guidelines in cardio-oncology with a harmonized definition of cancer therapy-related cardiac dysfunction (CTRCD). The aim of this study was to evaluate CTRCD occurrence over 24 months of follow-up after RT in BC patients and to analyze the association with cardiac radiation exposure.MethodsThe prospective monocentric BACCARAT study included BC patients treated with RT without chemotherapy, aged 40–75 years, with conventional and 2D Speckle tracking echocardiography performed before RT, 6 and 24 months after RT. Based on ESC cardio-oncology guidelines, CTRCD and corresponding severity were defined with left ventricle ejection fraction and global longitudinal strain decrease, occurring at 6 or 24 months after RT. Dosimetry for whole heart, left ventricle (LV) and left coronary artery (left anterior descending and circumflex arteries (CX)) was considered to evaluate the association with CTRCD, based on logistic regressions (Odds Ratio – OR and 95% confidence interval – 95%CI). Youden index based on receiver operating characteristic curve analysis was used to identify the optimal threshold of dose-volume parameters for predicting CTRCD.ResultsThe study included 72 BC patients with a mean age of 58 ± 8.2 years. A total of 32 (44%) patients developed CTRCD during follow-up: 20 (28%) mild CTRCD, 7 (9%) moderate CTRCD, and 5 (7%) severe CTRCD. Cardiac radiation doses were generally higher among patients with CTRCD rather than non-CTRCD. Dose-response relationships were significant for mean CX dose (OR = 2.48, 95%CI (1.12–5.51), p = 0.02) and marginally significant for V2 of LV (OR = 1.03 95%CI (1.00-1.06), p = 0.05). V2 of LV ≥ 36% and mean CX dose ≥ 1.40 Gy thresholds were determined to be optimal for predicting CTRCD.ConclusionFor BC patients treated with RT without chemotherapy, CTRCD can be observed in an important proportion of the population over 24 months after treatment. Left ventricle and circumflex coronary artery exposure were found to be associated with CTRCD and could be used for the prediction of such cardiotoxicity. Further research remains needed to confirm these results.Trial RegistrationClinicalTrials.gov Identifier- NCT02605512.

Anomalous left circumflex artery origin in aortic root surgery

Anomalous left circumflex artery origin in aortic root surgery

The value of CT coronary angiography for a comprehensive assessment of left circumflex artery in Kawasaki disease: 9 years of experience from a tertiary center

Transthoracic echocardiography (TTE) has traditionally been the primary method for coronary imaging in children with Kawasaki disease (KD). We aimed to evaluate coronary artery lesions (CALs) of the left circumflex artery (LCx) in KD on computed tomography coronary angiography (CTCA). Over a 9-year period (November 2013-December 2022), 225 children with KD underwent radiation-optimized CTCA on a 128-slice dual-source platform. TTE was performed on the same day, or a day prior or after CTCA. On CTCA, LCx CALs were seen in 41/225 (18.2%) patients. However, TTE detected CALs in only one third of these patients [15/41 (36.6%)]. CTCA showed 47 LCx CALs in 41 patients-aneurysms in 39 patients (40 fusiform, 2 saccular; 7 giant aneurysms), stenoses in 3, and thrombosis in 2. Thromboses and stenoses were both missed on TTE. Proximal LCx aneurysms were seen in 39 patients-of these, 12 had distal extension. Six patients had distal LCx aneurysms without proximal involvement and 2 non-contiguous multiple aneurysms. Four (9.75%) patients had isolated LCx involvement. Based on CTCA findings, treatment protocols had to be modified in 3/41 (7.3%) patients. This study highlights anatomical findings of LCx involvement in KD. Isolated LCx CALs were noted in 4/41 (9.75%) patients. TTE alone proved inadequate for LCx assessment in children with KD. With abnormalities detected in 18.2% of cases, including those missed by TTE, CTCA emerges as an essential imaging modality. The findings have implications for treatment planning and follow-up strategies in children with KD. None.

Semaglutide Improves Myocardial Perfusion and Performance in a Large Animal Model of Coronary Artery Disease.

Coronary artery disease (CAD) is the leading cause of death worldwide. It imposes an enormous symptomatic burden on patients, leaving many with residual disease despite optimal procedural therapy, and up to 1/3 with debilitating angina amenable neither to procedures, nor to current pharmacologic options. Semaglutide, a glucagon-like peptide 1 agonist originally approved for management of diabetes, has garnered substantial attention for its capacity to attenuate cardiovascular risk. Although subgroup analyses in patients indicate promise, studies explicitly designed to isolate the impact of semaglutide on the sequelae of CAD, independently of comorbid diabetes or obesity, are lacking. Yorkshire swine (n=17) underwent placement of an ameroid constrictor around the left circumflex coronary artery to induce CAD. Oral semaglutide was initiated postoperatively at 1.5 mg and scaled up in 2 weeks to 3 mg in treatment animals (SEM, n=8) for a total of 5 weeks, while control animals (CON, n=9) received no drug. All then underwent myocardial harvest with acquisition of perfusion and functional data using microsphere injection and pressure-volume loop catheterization. Immunoblotting, immunohistochemistry, and immunofluorescence were performed on the most ischemic myocardial segments for mechanistic elucidation. SEM animals exhibited improved left ventricular ejection fraction, both at rest and during rapid myocardial pacing (both p<0.03), accompanied by increased perfusion to the most ischemic myocardial region at rest and during rapid pacing (both p<0.03); reduced perivascular and interstitial fibrosis (both p <0.03); and apoptosis (p=0.008). These changes were associated with increased activation of the endothelial-protective AMPK pathway (p=0.005), coupled with downstream increases in endothelial nitric oxide synthase (p=0.014). This study is the first to reveal the capacity of oral semaglutide to augment cardiac function in the chronically ischemic heart in a highly translational large animal model, likely through AMPK-mediated improvement in endothelial function and perfusion to the ischemic myocardium.

Imaging Challenge in Recurrent Spontaneous Coronary Artery Dissection (SCAD): A Case Report

Spontaneous Coronary Artery Dissection (SCAD) represents a significant cause of acute coronary syndrome (ACS) in patient populations with low-risk cardiovascular profiles and, therefore can be sometimes underdiagnosed. On the other hand, it often preserves the typical clinical presentation of ACS which makes coronary artery angiography (CAG) execution mandatory. A 62-year-old woman with a history of recurrent SCAD presented to the emergency department for a new episode of acute chest pain with troponin elevation. CAG revealed an ambiguous angiography image suggesting a sub-occlusive type 2 SCAD involving the distal segment of the left circumflex artery. The patient was managed conservatively due to the absence of ongoing ischemia or hemodynamic instability. At the seven-day follow-up, a computed tomography coronary angiography (CTCA) was performed to better assess SCAD and detect concomitant associated arteriopathies. Optimized medical therapy was prescribed at the discharge and at one-month follow-up, no recurrence of symptoms was referred.

Pericoronary adipose tissue for predicting long-term outcomes.

Pericoronary adipose tissue (PCAT) attenuation obtained by coronary computed tomography angiography (CCTA) has been associated with coronary inflammation and outcomes. Whether PCAT attenuation is predictive of major adverse cardiac events (MACE) during long-term follow-up is unknown. Symptomatic patients with coronary artery disease (CAD) who underwent CCTA were included, and clinical outcomes were evaluated. PCAT was measured at all lesions for all three major coronary arteries using semi-automated software. A comparison between patients with and without MACE was made on both a per-lesion and a per-patient level. The predictive value of PCAT attenuation for MACE was assessed in Cox regression models. In 483 patients (63.3 ± 8.5 years, 54.9% men), 1561 lesions were analysed over a median follow-up duration of 9.5 years. The mean PCAT attenuation was not significantly different between patients with and without MACE. At a per-patient level, the adjusted hazard ratio (HR) and 95% confidence interval (CI) for MACE were 0.970 (95% CI: 0.933-1.008, P = 0.121) when the average of all lesions per patient was analysed, 0.992 (95% CI: 0.961-1.024, P = 0.622) when only the most obstructive lesion was evaluated, and 0.981 (95% CI: 0.946-1.016, P = 0.285) when only the lesion with the highest PCAT attenuation per individual was evaluated. Adjusted HRs for vessel-specific PCAT attenuation in the right coronary artery, left anterior descending artery, and left circumflex artery were 0.957 (95% CI: 0.830-1.104, P = 0.548), 0.989 (95% CI: 0.954-1.025, P = 0.550), and 0.739 (95% CI: 0.293-1.865, P = 0.522), respectively, in predicting long-term MACE. In patients referred to CCTA for clinically suspected CAD, PCAT attenuation did not predict MACE during long-term follow-up.

Dressler - de Winter sign with acute inferoposterior STEMI: An ECG dilemma in artery localization

The Dressler-de Winter sign is an electrocardiogram (ECG) pattern characterized by upsloping ST-segment depression in leads V1-V6 followed by tall, hyperacute T waves, typically indicating an occlusion of the left anterior descending artery (LAD). We present a case involving an inferoposterior ST-segment elevation myocardial infarction (STEMI) with a variant of the de Winter sign, a concept of ST-segment continuum in the precordial leads. Despite initial ECG findings suggesting right coronary artery (RCA) or left circumflex artery (LCX) involvement, coronary angiography confirmed occlusion of the wrap-around LAD distal to the first septal (S1) and diagonal branch (D1) and revealed a left dominant system accompanied by a small non-dominant RCA. This case highlights the diagnostic complexity in accurately localizing the culprit artery in STEMI cases exhibiting the de Winter sign. Understanding such ECG variants is crucial for analyzing the mechanisms of acute ischemia and ensuring accurate assessment of the culprit vessel for effective revascularization.

Morphometry of left atrial appendage isthmus and mitral isthmus: implications for atrial fibrillation catheter ablation.

Radiofrequency catheter ablation (RFA) targets the left atrial appendage isthmus (LAA isthmus) and mitral isthmus for treatment of atrial fibrillation. However, proximity of left circumflex artery (LCxA) and great cardiac vein (GCV) in the isthmuses poses fatal risks during ablation. This study investigated relationships of LCxA and GCV across three lines in the LAA and mitral isthmus, using 15 human cadaveric hearts. Distances between the vessels and the endocardium, myocardium, and perivascular fat thickness were measured. The results showed that LCxA was mostly consistently located in lower atrial segments and GCV was in lower/upper atrial segments, with change of course mainly observed in the middle of the LAA. The LCxA was found as close as 3-5 mm from the lower border of the LAA isthmus in 80% of specimens, at a depth of 2-3 mm within the LAA isthmus, where 1 mm consisted of myocardium and the remainder was fat, which may not provide adequate protection due to the possibility of liquefaction of fat with heat application. The effective myocardial thickness was consistently 1 mm across all cases in both isthmuses. LCxA was 2 mm in second and third sections of LAA isthmus ("careful segment"). LCxA distances from left inferior pulmonary vein opening was 5 to 12 mm, occasionally dangerously close as <1 mm in 16% of cases. This study measured LCxA and GCV in the LAA and mitral isthmus across three lines for the first time in the Indian population, aiding surgeons in RFA planning.

Cardiac Substructure Radiation Dose and Associations With Tachyarrhythmia and Bradyarrhythmia After Lung Cancer Radiotherapy

BackgroundArrhythmias are common following radiotherapy for non–small cell lung cancer. ObjectivesThe aim of this study was to analyze the association of distinct arrhythmia classes with cardiac substructure radiotherapy dose. MethodsA retrospective analysis was conducted of 748 patients with locally advanced non–small cell lung cancer treated with radiotherapy. Cardiac substructure dose parameters were calculated. Receiver-operating characteristic curve analyses for predictors of Common Terminology Criteria for Adverse Events grade ≥3 atrial fibrillation (AF), atrial flutter, non-AF and non–atrial flutter supraventricular tachyarrhythmia (SVT), bradyarrhythmia, and ventricular tachyarrhythmia (VT) or asystole were calculated. Fine-Gray regression models were performed (with noncardiac death as a competing risk). ResultsOf 748 patients, 128 (17.1%) experienced at least 1 grade ≥3 arrhythmia, with a median time to first arrhythmia of 2.0 years (Q1-Q3: 0.9-4.2 years). The 2-year cumulative incidences of each arrhythmia group were 8.0% for AF, 2.7% for atrial flutter, 1.8% for other SVT, 1.4% for bradyarrhythmia, and 1.1% for VT or asystole. Adjusting for baseline cardiovascular risk, pulmonary vein (PV) volume receiving 5 Gy was associated with AF (subdistribution HR [sHR]: 1.04/mL; 95% CI: 1.01-1.08; P = 0.016), left circumflex coronary artery volume receiving 35 Gy with atrial flutter (sHR: 1.10/mL; 95% CI: 1.01-1.19; P = 0.028), PV volume receiving 55 Gy with SVT (sHR: 1.03 per 1%; 95% CI: 1.02-1.05; P < 0.001), right coronary artery volume receiving 25 Gy with bradyarrhythmia (sHR: 1.14/mL; 95% CI: 1.00-1.30; P = 0.042), and left main coronary artery volume receiving 5 Gy with VT or asystole (sHR: 2.45/mL; 95% CI: 1.21-4.97; P = 0.013). ConclusionsThis study revealed pathophysiologically distinct arrhythmia classes associated with radiotherapy dose to discrete cardiac substructures, including PV dose with AF and SVT, left circumflex coronary artery dose with atrial flutter, right coronary artery dose with bradyarrhythmia, and left main coronary artery dose with VT or asystole, guiding potential risk mitigation approaches.

Acute Inferior ST-elevation Myocardial Infarction Arising from Wrap-Around Left Anterior Descending Artery Occlusion

BACKGROUND: Acute myocardial infarction (AMI) remains a leading cause to global morbidity and mortality. Inferior MI predominantly stems from the right coronary artery (RCA) in more than 80% of instances, the left circumflex coronary artery (LCx) in fewer than 20% of cases, and infrequently from the left anterior descending artery (LAD) AIMS: This case report aims to highlight a rare occurrence of LAD occlusion initially manifested as inferior MI. CASE: A 56-year-old male presented with typical chest pain lasting for 6 hours. Vital signs were within normal range. Initial electrocardiogram (ECG) revealed ST-segment elevation in inferior leads (II, III, aVF). Laboratory tests indicated elevated troponin levels (&gt;25ng/mL). Coronary angiography identified the culprit lesion as the LAD, which wrapped around the apex. DISCUSSION: While ECG alterations are valuable in identifying thrombosed vessels during AMI, the presence of simultaneous ST elevation in both inferior and anterior leads can hinder clinicians' ability to determine the specific artery affected by the infarction. Our case, depicting a scenario where both the right and left coronary arteries are co-dominant, showed complete occlusion at the mid-distal wrap-around LAD, resulting in ST-elevation observed in both inferior and anterior leads. CONCLUSION: The existence of inferior ST-segment elevation alongside alterations in anterior leads could imply occlusion of the wrapped LAD.