Clinical and Genetic Features of Korean Inherited Arrhythmia Probands

Background and Objectives@#Inherited arrhythmia (IA) is a more common cause of sudden cardiac death in Asian population, but little is known about the genetic background of Asian IA probands. We aimed to investigate the clinical characteristics and analyze the genetic underpinnings of IA in a Korean cohort. @*Methods@#This study was conducted in a multicenter cohort of the Korean IA Registry from 2014 to 2017. Genetic testing was performed using a next-generation sequencing panel including 174 causative genes of cardiovascular disease. @*Results@#Among the 265 IA probands, idiopathic ventricular fibrillation (IVF) and Brugada Syndrome (BrS) was the most prevalent diseases (96 and 95 cases respectively), followed by long QT syndrome (LQTS, n=54). Two-hundred-sixteen probands underwent genetic testing, and 69 probands (31.9%) were detected with genetic variant, with yield of pathogenic or likely pathogenic variant as 6.4%. Left ventricular ejection fraction was significantly lower in genotype positive probands (54.7±11.3 vs. 59.3±9.2%, p=0.005). IVF probands showed highest yield of positive genotype (54.0%), followed by LQTS (23.8%), and BrS (19.5%). @*Conclusions@#There were significant differences in clinical characteristics and genetic yields among BrS, LQTS, and IVF. Genetic testing did not provide better yield for BrS and LQTS. On the other hand, in IVF, genetic testing using multiple gene panel might enable the molecular diagnosis of concealed genotype, which may alter future clinical diagnosis and management strategies.

Inherited arrhythmia syndrome predisposing to sudden cardiac death

Inherited arrhythmia (IA) is one of the main causes of sudden cardiac death (SCD) in young people, and is reported to be a more prevalent cause of SCD in Asia than in Western countries. IAs are a group of genetic disorders caused by mutations in genes encoding cardiac ion channels, leading to electrophysiological characteristics that often occur in the absence of structural abnormalities. Channelopathies, such as long QT syndrome and Brugada syndrome, carry a potential risk of life-threatening ventricular tachyarrhythmias that predispose to SCD, although early prediction and prevention of the risk remain challenging. Recent advances in genetic testing have facilitated risk stratification as well as a precise diagnosis for IA, despite ongoing debates about the implications. Herein, we provide epidemiological data, a pathophysiological overview, and the current clinical approach to IAs related to SCD. In addition, we review the general issues arising from genetic testing for IAs.

Inherited arrhythmia syndrome predisposing to sudden cardiac death

Inherited arrhythmia (IA) is one of the main causes of sudden cardiac death (SCD) in young people, and is reported to be a more prevalent cause of SCD in Asia than in Western countries. IAs are a group of genetic disorders caused by mutations in genes encoding cardiac ion channels, leading to electrophysiological characteristics that often occur in the absence of structural abnormalities. Channelopathies, such as long QT syndrome and Brugada syndrome, carry a potential risk of life-threatening ventricular tachyarrhythmias that predispose to SCD, although early prediction and prevention of the risk remain challenging. Recent advances in genetic testing have facilitated risk stratification as well as a precise diagnosis for IA, despite ongoing debates about the implications. Herein, we provide epidemiological data, a pathophysiological overview, and the current clinical approach to IAs related to SCD. In addition, we review the general issues arising from genetic testing for IAs.

Impact of carotid atherosclerosis in CHA2DS2-VASc-based risk score on predicting ischemic stroke in patients with atrial fibrillation

Background/Aims@#Vascular disease is an established risk factor for stroke in patients with atrial fibrillation (AF), which is included in CHA2DS2-VASc score. However, the role of carotid atherosclerosis remains to be determined. @*Methods@#Three hundred-ten patients with AF who underwent carotid sonography were enrolled. @*Results@#During a median follow-up of 31 months, 18 events (5.8%) of stroke were identified. Patients with stroke had higher carotid intima-media thickness (CIMT) (1.16 ± 0.33 mm vs. 0.98 ± 0.25 mm, p = 0.017). CIMT was significantly increased according to the CHA2DS2-VASc score (p < 0.001) and it was correlated with left ventricular mass index and early diastolic mitral annular velocity (e’), a ratio of early transmitral flow velocity to e’ (E/e’) and pulmonary artery systolic pressure (all p < 0.05). Cox regression using multivariate models showed that carotid plaque was associated with the risk of stroke (hazard ratio, 3.748; 95% confidence interval [CI], 1.107 to 12.688; p = 0.034). C-statistics increased from 0.648 (95% CI, 0.538 to 0.757) to 0.716 (95% CI, 0.628 to 0.804) in the CHA2DS2-VASc score model after the addition of CIMT and carotid plaque as a vascular component (p = 0.013). @*Conclusions@#Increased CIMT and presence of carotid plaque are associated with a high risk of ischemic stroke, and CIMT is related to myocardial remodeling and diastolic dysfunction, suggesting that carotid atherosclerosis can improve risk prediction of stroke in patients with AF, when included under vascular disease in the CHA2DS2-VASc scoring system.

Three-Dimensional Angiography-Guided Percutaneous Transluminal Angioplasty for Distal Aorta and Bi-Iliac Chronic Total Occlusion

Percutaneous recanalization of chronic total occlusions (CTOs) in peripheral arteries, especially TASC D classification including the distal aorta and both iliac arteries is still technically challenging. The conventional technique using standard guidewires and catheters guided by computed tomography and angiography can achieve a limited initial success, depending on lesion characteristics and operator's experience. A special imaging technique using 3-dimensional rotational angiography and spatio-temporal reconstruction with endoview for a better examination of the proximal stump, exact obstruction location, and distal stump direction in a stumpless lesion can be indispensable for successful intervention. We report a successful revascularization case of stumpless distal aorta and bi-iliac CTO guided by this specialized imaging technique.

Spontaneous Partial Regression of Coronary Artery Fistula Following Optimal Medical Therapy in a Patient Who Had Combined Significant Coronary Artery Spasm

Coronary artery fistulas (CAFs) are one of the most rare cardiac anomalies. Some patients with CAF may suffer from ischemic chest pain that originates from combined significant coronary artery spasm (CAS). Spontaneous regression of CAF has been reported in a few cases, almost all of which were infants. We report an adult patient who presented with ischemic chest pain due to multiple coronary arteries to pulmonary artery fistulas and combined significant CAS induced by intracoronary acetylcholine provocation test. Spontaneous regression of one of the fistulas was observed at 2-year angiography follow-up.

Unusual Polymorphic Ventricular Tachycardia Originating from the Pulmonary Artery

We report a case about a 27-year-old healthy young male who developed syncope during exercise, which was subsequently identified to be attributable to non-sustained polymorphic ventricular tachycardia (VT). Occurrence of polymorphic VT was neither related to a prolonged QT interval nor a fixed short coupling interval. Standard examinations including echocardiography, coronary angiography, isoproterenol infusion study, and cardiac MRI showed no structural heart disease. On the electrophysiology study, activation mapping revealed that a discrete potential preceded the premature ventricular complex (PVC) triggered polymorphic VT, which was recorded just above the pulmonary valve. After radiofrequency ablation at this area, PVC and polymorphic VT disappeared and did not recur after a 2 month follow up.

Unusual Polymorphic Ventricular Tachycardia Originating from the Pulmonary Artery

We report a case about a 27-year-old healthy young male who developed syncope during exercise, which was subsequently identified to be attributable to non-sustained polymorphic ventricular tachycardia (VT). Occurrence of polymorphic VT was neither related to a prolonged QT interval nor a fixed short coupling interval. Standard examinations including echocardiography, coronary angiography, isoproterenol infusion study, and cardiac MRI showed no structural heart disease. On the electrophysiology study, activation mapping revealed that a discrete potential preceded the premature ventricular complex (PVC) triggered polymorphic VT, which was recorded just above the pulmonary valve. After radiofrequency ablation at this area, PVC and polymorphic VT disappeared and did not recur after a 2 month follow up.

A Case of Successful Bare Metal Stenting for Aortic Coarctation in an Adult

Aortic coarctation is a correctable hypertensive disease. For safety reasons and due to the invasiveness of surgical techniques, percutaneous interventions have become drastically more popular in recent times. In elderly patients with aortic coarctation who are at risk of an aortic wall aneurysm and rupture, covered stents are preferred but in younger patients, bare metal stenting may be sufficient for long-term safety. Herein we present a 47-year-old typical aortic coarctation patient who was successfully treated with a bare metal stent.

Two Different Successful Angioplasty Methods in Patients with Stenotic Coronary Artery Ectasia / 전남의대학술지

There is no current guideline for percutaneous coronary angioplasty in stenotic ectatic coronary arteries because of the heterogeneity of the coronary artery morphology. We report two successful angioplasty cases in coronary artery ectasia with different clinical scenarios. One case showed atherosclerotic stenosis in the ectatic portion of the right coronary artery that was aggravated after a coronary artery bypass graft. In this case, balloon angioplasty alone without stenting showed acceptable results at the 6-month follow-up coronary angiography. In the other case, we used a peripheral artery balloon and stent for stenosis in the ectatic portion of a large coronary artery. Six-month follow-up coronary angiography showed excellent patency of the previously implanted peripheral stent.

Two Different Successful Angioplasty Methods in Patients with Stenotic Coronary Artery Ectasia / 전남의대학술지

There is no current guideline for percutaneous coronary angioplasty in stenotic ectatic coronary arteries because of the heterogeneity of the coronary artery morphology. We report two successful angioplasty cases in coronary artery ectasia with different clinical scenarios. One case showed atherosclerotic stenosis in the ectatic portion of the right coronary artery that was aggravated after a coronary artery bypass graft. In this case, balloon angioplasty alone without stenting showed acceptable results at the 6-month follow-up coronary angiography. In the other case, we used a peripheral artery balloon and stent for stenosis in the ectatic portion of a large coronary artery. Six-month follow-up coronary angiography showed excellent patency of the previously implanted peripheral stent.