Hyungdon Kook

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.

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

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.

Characteristics and Outcomes of Atrial Tachycardia Originating from the Sinus Venosus during Catheter Ablation of Atrial Fibrillation.

Background and Objectives The sinus venosus (SV) is not a well known source of atrial tachycardia (AT), but it can harbor AT during catheter ablation of atrial fibrillation (AF). Subjects and Methods A total of 1223 patients who underwent catheter ablation for AF were reviewed. Electrophysiological and electrocardiographic characteristics and outcomes after catheter ablation of AT originating from the SV were investigated. Results Ten patients (0.82%) demonstrated AT from the SV (7 males, 53.9±16.0 years, 6 persistent) during ablation of AF. The mean cycle length was 281±73 ms. After pulmonary vein isolation and left atrial ablation, AF converted to AT from the SV during right atrial ablation in 2 patients, by rapid atrial pacing after AF termination in 7 patients, and during isoproterenol infusion in 1 patient. Positive P-waves in inferior leads were shown in most patients (90%). The activation sequence of AT was from proximal to distal in the superior vena cava and high to low in the right atrium, which was similar to that of AT from crista terminalis. Fragmented double potentials were recorded during sinus, and a second discrete potential preceded the onset of P wave by 80±37 ms during AT. Using 4.4±2.7 radiofrequency focal applications, ATs were terminated and became no longer inducible in all. After ablation procedure, two patients showed transient right phrenic nerve palsy. After 19.9±14.8 months, all but 1 patient were free of atrial tachyarrhythmia without complications. Conclusion The AT which develops during AF ablation is rarely originated from SV, and its electrophysiologic characteristics may be helpful in guiding effective focal ablation.

Trends and Outcomes of Transcatheter Aortic Valve Implantation (TAVI) in Korea: the Results of the First Cohort of Korean TAVI Registry

Background and Objectives There has been no nation-wide data on the outcomes of transcatheter aortic valve implantation (TAVI) after commercialization of TAVI in Korea. We report clinical features and outcomes of the first cohort of TAVI performed from Jun 2015 to Jun 2017 in Korea. Methods The first cohort of Korean-TAVI (K-TAVI) registry includes 576 consecutive patients with severe symptomatic aortic stenosis who underwent TAVI from 17 Korean hospitals for 2 years. Results Most of TAVI procedures were performed for septuagenarians and octogenarians (90.8%) through transfemoral approach (98.3%). The rate of device success was 92.5% and permanent pacemaker was implanted in 5.6%. In successive years, incidences of paravalvular leakage (PVL) and major bleeding declined. Society of Thoracic Surgeons (STS) score was 5.2 (3.0 to 9.0) and 34.7% of patients had high surgical risk (STS ≥8). One-year all-cause death occurred in 8.9% and was significantly lower in low to intermediate risk one than in high risk (5.4% vs. 15.5%, p<0.001). The independent predictors of 1-year mortality were age (hazard ratio [HR], 1.087; 95% confidence interval [CI], 1.036–1.141; p=0.001), moderate or severe PVL (HR, 4.631; 95% CI, 1.624–13.203; p=0.004) and end-stage renal disease (HR, 5.785; 95% CI, 2.717–12.316; p<0.001). Conclusions K-TAVI registry showed favorable 1-year outcomes with decreasing complication rate over time in real-world Korean patients. Two-thirds of patients were low to intermediate surgical risk and showed a significantly lower mortality than the high-risk patients, suggesting the promising future on the expanded indications of TAVI.

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.

Non-Vitamin K antagonist oral anticoagulants versus warfarin for the prevention of spontaneous echo-contrast and thrombus in patients with atrial fibrillation or flutter undergoing cardioversion: A trans-esophageal echocardiography study

Spontaneous echo-contrast (SEC) and thrombus observed in trans-esophageal echocardiography (TEE) is known as a strong surrogate marker for future risk of ischemic stroke in patients with atrial fibrillation (AF) or atrial flutter (AFL). The efficacy of non-vitamin K antagonist oral anticoagulants (NOAC) compared to warfarin to prevent SEC or thrombus in patients with AF or AFL is currently unknown. AF or AFL patients who underwent direct current cardioversion (DCCV) and pre-DCCV TEE evaluation from January 2014 to October 2016 in a single center were analyzed. The prevalence of SEC and thrombus were compared between patients who received NOAC and those who took warfarin. NOAC included direct thrombin inhibitor and factor Xa inhibitors. Among 1,050 patients who were considered for DCCV, 424 patients anticoagulated with warfarin or NOAC underwent TEE prior to DCCV. Eighty patients who were anticoagulated for less than 21 days were excluded. Finally, 344 patients were included for the analysis (180 warfarin users vs. 164 NOAC users). No significant difference in the prevalence of SEC (44.4% vs. 43.9%; p = 0.919), dense SEC (13.9% vs. 15.2%; p = 0.722), or thrombus (2.2% vs. 4.3%; p = 0.281) was observed between the warfarin group and the NOAC group. In multivariate analysis, there was no association between NOAC and risk of SEC (odds ratio [OR]: 1.4, 95% CI: 0.796–2.297, p = 0.265) or thrombus (OR: 3.4, 95% CI: 0.726–16.039, p = 0.120). In conclusion, effectiveness of NOAC is comparable to warfarin in preventing SEC and thrombus in patients with AF or AFL undergoing DCCV. However, numerical increase in the prevalence of thrombus in NOAC group warrants further evaluation.

Successful Transcatheter Aortic Valve Replacement for Severe Aortic Regurgitation after CARVAR Operation

A 79-year-old female patient had severe AR after a Comprehensive Aortic Root and VAlve Repair (CARVAR) operation presenting with worsening dyspnea (Supplementary Video 1). CARVAR operation is a valve sparing surgical technique for aortic diseases, consisting of annular and sinotubular junction (STJ) reduction with leaflet correction.2) For reduction and correction of aortic structures, specially designed outer strip ring is used in CARVAR procedure. However, this novel technique which had been criticized for safety issues comparing with the conventional valve replacement surgery was banned in South Korea since 2013.3) Due to high surgical risk (Society of Thoracic Surgeons predicted risk of mortality score 14.756%) and frailty of the patient (clinical frailty scale of 6), heart team decided to proceed with the TAVR procedure. In preprocedural device selection, the perimeter of the annulus was 71.9 mm and the perimeter driven diameter was 22.9 mm in multi-slice computed tomography (CT) images. The diameter of STJ with outer ring was measured as 27 mm. We thought that 2 possible anchoring points were annulus and STJ with outer ring. Therefore, a 26 or 29 mm transcatheter heart valve seemed to be possible according to the conventional annular valve sizing because perimeter or diameter was on the gray zone. Considering TAVI for AR with no calcification at annulus, larger one would be better. In addition, considering the possibility that the upper part of the transcatheter heart valve is anchored to the 27 mm-sized CARVAR ring located in the STJ instead of annulus, a transcatheter heart valve of 29 or 31 mm is considered to be appropriate. Finally, we chose a 29 mm EvolutTM R valve instead of a larger sized transcatheter heart valve due to possible risk of device deformation by outer strip ring. Despite the absence of any calcification at the annulus and leaflets (Figure 1), a 29 mm CoreValve® EvolutTM R valve (Medtronic, Minneapolis, MN, USA) was successfully implanted at a slightly lower location than the usual position utilizing an outer ring used in CARVAR surgery as the landing zone (Figure 2, Supplementary Videos 2 and 3). Upper part between outflow and waist of 29 mm EvolutTM R valve was seated at the outer strip ring.

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 operators 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.