Demonstration of differential ventricular overdrive pacing during long RP' supraventricular tachycardia.

We described the differential ventricular overdrive pacing during long RP' supraventricular tachycardia and discussed about its response leading to the dianosis.

Complete atrioventricular block following internal electrical cardioversion during atrial fibrillation ablation.

BACKGROUND: Complete atrioventricular block (C-AVB) following internal electrical cardioversion (IEC) during atrial fibrillation (AF) ablation has not been fully investigated. We aimed to determine the prevalence and predictors of C-AVB following IEC during AF ablation. METHODS: C-AVB (non-conducted sinus impulse after IEC) and ventricular pause (VP) (the interval between IEC and the QRS complex) following the first attempt of IEC, and baseline electrocardiographic parameters were investigated in patients who underwent first-time AF ablation. RESULTS: We investigated the first attempt of IEC in 124 patients (mean age:70 ± 11 years, 81 men, 99 non-paroxysmal AF). AF was terminated in 109/124 (88%) patients, with a VP of 1590 [1014-2208] (maximum, 8780) ms. Transient C-AVB following IEC occurred in 14/109 (13%) patients. The VP was longer in patients with transient C-AVB than in those without transient C-AVB (2418 [1693-4425] vs. 1530 [876-2083] ms, p = 0.002). In multivariate analysis, the left atrial diameter (Odds ratio [OR]:1.21; 95% confidence interval (95%CI):1.06-1.39; p = 0.005) and preexisting intraventricular conduction abnormality (OR:9.22; 95%CI:1.60-53.3; p = 0.013) were predictors of transient C-AVB following IEC. CONCLUSION: Left atrial diameter and preexisting intraventricular conduction abnormalities were predictors of transient C-AVB following IEC during AF ablation.

Revisiting exit block after entrance block: Investigation of ablation index-guided pulmonary vein isolation.

INTRODUCTION: Unidirectional block, left atrium to pulmonary vein (LA-PV) entrance block without PV-LA exit block, has not been fully investigated in the setting of ablation index (AI)-guided pulmonary vein (PV) isolation (PVI). The aim of this study was to investigate unidirectional blocks during AI-guided PVI. METHODS: After achieving entrance block, exit block was evaluated by pacing from the catheter placed in the PV. Local PV musculature capture without conduction to the LA was necessary to prove exit block. RESULTS: In total, 441 PVs (including nine left common PVs) from 113 consecutive patients (mean age: 71 ± 12 years, 77 men, 61 paroxysmal atrial fibrillation cases) who underwent initial AI-guided PVI for atrial fibrillation were studied. Entrance block was achieved in all PVs. of the 247/441 (56%) PVs showing local PV musculature capture, 5/247 (2.0%) showed unidirectional blocks. Three of the five PVs (left superior and inferior PVs in one patient; right superior PV in another patient) showed LA-PV reconnection, requiring additional ablation to achieve bidirectional block during the procedure. Two of the five PVs (left superior and inferior PVs in one patient) showed LA-PV reconnection, and thereafter, LA-PV conduction became blocked again spontaneously, leading to bidirectional block without further ablation during the procedure. CONCLUSION: AI-guided PVI presented a low prevalence of unidirectional block (2%), using entrance block alone as the endpoint of PVI could therefore be justified.

Atrial activation sequence changes during ventricular overdrive pacing: What is the mechanism?

We describe atrial activation sequence changes during ventricular overdrive pacing in a patient with a concealed left-sided accessory pathway and discuss its potential mechanism.

True Brugada syndrome ECG or Brugada phenocopy ECG? Can the ECG itself tell us the diagnosis?

We described a type 1 Brugada electrocardiogram and discussed about the potential diagnostic electrocardiographic indicators to differentiate true Brugada syndrome and Brugada phenocopy.

Electrocardiographic features of paradoxical ventriculophasic response.

BACKGROUND: Paradoxical ventriculophasic response (P-VR), a rare entity, has not been fully investigated. This study sought to compare the electrocardiographic features of P-VR and typical ventriculophasic response (T-VR). METHODS: The 12­lead electrocardiogram (ECG) data recorded before implantation of a cardiac implantable electronic device were analyzed in patients with greater than second-degree atrioventricular block (AVB). P-VR or T-VR was defined as present if the PP interval interposing a QRS complex was prolonged or shortened, respectively, by >3% compared with the preceding PP interval without a QRS complex when a QRS complex occurred within a span of 60% of the preceding PP interval. RESULTS: Of 95 patients (age 80 ± 9 years; 49 men) with heart block, 1868 instances (an instance was defined as a set of PP intervals without a QRS complex and the subsequent PP interval interposing a QRS complex) from 214 ECGs were analyzed: 894 instances from 122 ECGs in 64 patients with complete AVB (cAVB) and 974 instances from 92 ECGs in 43 patients with 2:1 AVB (12 showed both cAVB and 2:1 AVB). P-VR was observed in 48 patients (51%). The position of the interposed QRS complex relative to the preceding PP interval was earlier in P-VR than in T-VR. The PP interval was shorter in P-VR than in T-VR. CONCLUSION: P-VR was present in >50% of patients and was affected by the position of the interposed QRS complex and the PP interval.

Regularly irregular atrial rhythm after superior vena cava isolation: Another manifestation of sinoatrial node injury?

The present case described an unusual clinical manifestation of the sinoatrial node (or sinoatrial junction) injury during superior vena cava isolation.

Validation of the correlation between angiosome-based target arterial path, mid-term limb-based patency, and the global limb anatomical staging system.

This study aimed to validate the correlation between the Global Limb Anatomical Staging System (GLASS) and limb-based patency (LBP) and angiosome-based target arterial path (TAP) and to detect the predictors of LBP loss. After the publication of the Global Vascular Guidelines in 2019, the evaluation of GLASS and identification of TAP have been recommended. However, there are few reports regarding GLASS. Eighty-three patients with chronic limb-threatening ischemia (CLTI) and tissue loss from 2016 to 2020 were evaluated. The correlation between GLASS and LBP and successful revascularization of angiosome-based TAP was analyzed. We also investigated the predictors of LBP loss. The number of patients in each GLASS stage was as follows: GLASS I, 6 patients; GLASS II, 15 patients; GLASS III, 62 patients. At 6 months, the Kaplan-Meier estimate of LBP was 66.7% in GLASS I, 41.6% in GLASS II, and 16.4% in GLASS III, respectively (p = 0.034). The rate of successful revascularization of angiosome-based TAP was 100% in GLASS I, 86.7% in GLASS II, and 46.8% in GLASS III, respectively (p = 0.002). Multivariate analysis showed that the Wound, Ischemia, and foot Infection (WIfI) stage [hazard ratio (HR) 1.58; 95% confidence interval (CI) 1.07-2.33; p = 0.021] and GLASS infrapopliteal (IP) grade (HR 1.96; 95% CI 1.31-2.95; p = 0.001) were the independent predictors of LBP loss. The GLASS stage was significantly correlated with successful revascularization of angiosome-based TAP and mid-term LBP. The WIfI stage and GLASS IP grade were the independent predictors of loss of LBP.

What is the attributing electrocardiographic phenomenon underlying a concomitant 2:1 and Wenckebach atrio-ventricular block?

We herein describe the case of a spontaneously observed bidirectional block (both entrance and exit block) at the sino-atrial junction. This bidirectional block at the sino-atrial junction associated with the failure of conduction to the ventricle revealed the Wenckebach periodicity of the atrio-ventricular conduction.

A 2:1 atrioventricular block presenting paradoxical ventriculophasic response.

Ventriculophasic response (VR) is defined as the shortening of the sinus cycle length in the setting of greater than second-degree atrioventricular (AV) block. Typically, the PP intervals interposing a QRS complex are shorter than those without a QRS complex. Paradoxical VR is a rare clinical entity. We report about an 80-year-old man presenting with a 2:1 AV block, in whom typical and paradoxical VRs were observed.

Feasibility of tissue characterization of coronary plaques using 320-detector row computed tomography: comparison with integrated backscatter intravascular ultrasound.

Recently, a new generation of multi-detector row computed tomography (CT) with 320-detector rows (DR) has become available in the clinical settings. The purpose of the present study was to determine the cutoff values of Hounsfield unit (HU) for discrimination of plaque components by comparing HU of coronary plaques with integrated backscatter intravascular ultrasound (IB-IVUS) serving as a gold standard. Seventy-seven coronary atherosclerotic lesions in 77 patients with angina were visualized by both 320-DR CT (Aquilion One, Toshiba, Japan) and IB-IVUS at the same site. To determine the thresholds for discrimination of plaque components, we compared HU with IB values as a gold standard. Optimal thresholds were determined from receiver operating characteristic (ROC) curves analysis. The HU values of lipid pool (n = 115), fibrosis (n = 93), vessel lumen and calcification (n = 73) were 28 ± 19 HU (range -18 to 69 HU), 98 ± 31 HU (44 to 195 HU), 357 ± 65 HU (227 to 534 HU) and 998 ± 236 HU (366 to 1,489 HU), respectively. The thresholds of 56 HU, 210 HU and 490 HU were the most reliable predictors of lipid pool, fibrosis, vessel lumen and calcification, respectively. Lipid volume measured by 320-DR CT was correlated with that measured by IB-IVUS (r = 0.63, p < 0.05), whereas fibrous volume measured by 320-DR CT was not. Lipid volume measured by 320-DR CT was correlated with that measured by IB-IVUS, whereas fibrous volume was not correlated with that measured by IB-IVUS because manual exclusion of the outside of vessel hindered rigorous discrimination between fibrosis and extravascular components.