Pause-Dependent Paroxysmal Episode of Third-Degree Atrioventricular Block Triggered by Premature Atrial Contraction.

BACKGROUND Paroxysmal third-degree atrioventricular block (AVB) can exhibit a vast array of symptoms, but commonly, paroxysmal AVB leads to presyncope, syncope, or possibly sudden cardiac death. We present a rare case of pause-dependent paroxysmal AVB that was triggered by a premature atrial contraction. CASE REPORT A 65-year-old man with frequent episodes of presyncope and syncope for 3 weeks was admitted to our hospital for further diagnosis. A resting 12-lead electrocardiogram showed an incomplete right bundle branch block, and a 24-h Holter recording showed multiple episodes of third-degree AVB. Intracardiac tracing revealed that the block site was distal, at the infra-His-Purkinje system. CONCLUSIONS This case highlights a rare case of pause-dependent paroxysmal AVB that was triggered by a premature atrial contraction. This type of AVB is an abrupt, unexpected, repetitive block of atrial impulses as they propagate to the ventricles. It is relatively rare, and due to its transient nature, it is often under recognized and can lead to sudden cardiac death.

Treatment of accidental puncture of the left subclavian artery and ongoing haemorrhage with vascular stenting.

A man in his 60s was admitted for radiofrequency catheter ablation (RFCA) as a treatment for atrial fibrillation. A decapolar catheter (Synaptic Medical, Beijing, China) was inserted into the coronary sinus via the left subclavian vein. Two hours after RFCA, the patient presented new symptoms of cough, mild haemoptysis, mild dyspnoea and mild chest discomfort. Contrast-enhanced CT showed a mediastinal haematoma with contrast medium extravasation at the interlobular fissure outside the parietal pleura and mild-moderate pericardial effusion. Active left subclavian artery bleeding, rather than venous bleeding due to superior vena cava perforation, was finally diagnosed. Ongoing haemorrhage conservative treatment with red cell concentrate and intravenous fluid (normal saline) replacement may lead to compression of the mediastinum, and a covered stent was used to treat this iatrogenic complication.

Metabolomics and Biomarkers for Paroxysmal and Persistent Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most common type of arrhythmia worldwide and is associated with serious complications. This study investigated the metabolic biomarkers associated with AF and the differences in metabolomics and associated metabolic biomarkers between paroxysmal AF (AFPA) and persistent AF. METHODS AND RESULTS: Plasma samples were prospectively collected from patients with AF and patients in sinus rhythm with negative coronary angiography. The patients were divided into 3 groups: AFPA, persistent AF, and sinus rhythm (N=54). Metabolomics (n=36) using ultra-high-performance liquid chromatography mass spectrometry was used to detect differential metabolites that were validated in a new cohort (n=18). The validated metabolites from the validation phase were further analyzed by receiver operating characteristic. Among the 36 differential metabolites detected by omics assay, 4 were successfully validated with area under the curve >0.8 (P<0.05). Bioinformatics analysis confirmed the enrichment pathways of unsaturated fatty acid biosynthesis, glyoxylate and dicarboxylate metabolism, and carbon metabolism. Arachidonic acid was a potential biomarker of AFPA, glycolic acid and L-serine were biomarkers of AFPA and persistent AF, and palmitelaidic acid was a biomarker of AFPA. CONCLUSIONS: In this metabolomics study, we detected 36 differential metabolites in AF, and 4 were validated with high sensitivity and specificity. These differential metabolites are potential biomarkers for diagnosis and monitoring of disease course. This study therefore provides new insights into the precision diagnosis and management of AF.

The underrecognized and neglected compact atrioventricular nodal potential: clinical significance for preventing atrioventricular block during so-called slow pathway radiofrequency ablation.

BACKGROUND: The radiofrequency (RF) ablation target may be located at the compact atrioventricular node (AVN) region during so-called slow pathway (SP) RF ablation, potentially leading to transient or permanent atrioventricular block (AVB). However, related data are rare. METHODS: Among 715 index consecutive patients who underwent RF ablation for atrioventricular nodal re-entry tachycardia, 17 patients subsequently experienced transient or permanent AVB and were included in this retrospective observational study. RESULTS: Among the 17 patients, two patients (11.8%) developed transient first-degree AVB, four patients (23.5%) developed transient second-degree AVB, seven patients (41.2%) developed transient third-degree AVB, and four patients (23.5%) developed permanent third-degree AVB. During baseline sinus rhythm before the start of RF ablation, no His-bundle potential was recorded from the RF ablation catheter. During the so-called SP RF ablation that led to transient or permanent AVB, junctional rhythm with ventriculoatrial (VA) conduction block followed by subsequent AVB was observed in 14 of 17 patients (82.4%), and a low-amplitude, low-frequency hump-shaped atrial potential was recorded before the start of RF ablation in 7 of the 17 patients (41.2%). Direct AVB occurred in 3 of the 17 patients (17.6%), and a low-amplitude, low-frequency hump-shaped atrial potential was recorded before the start of RF ablation in all 3 patients. CONCLUSIONS: The low-amplitude, low-frequency hump-shaped atrial potential recorded at the so-called SP region may reflect the electrogram of compact AVN activation, and RF ablation to this site heralds impending AVB even when a His-bundle potential is not recorded.

Monitoring Spike Potential and Abrupt Impedance Rise with Concomitant Temperature/Contact Force Change for Timely Detection of the Occurrence of "Silent" or "Nonaudible" Steam Pop.

Aim: Steam pop (SP) during radiofrequency catheter ablation (RFCA) for pulmonary vein isolation (PVI) may cause cardiac perforation, which may require drainage and emergent thoracotomy or even lead to death. Data investigating the timely detection of the occurrence of "silent" or "nonaudible" SP events are limited. Methods and Results: A total of 516 consecutive atrial fibrillation (AF) patients who underwent index PVI were included in this retrospective observational study. The duration, power, impedance, temperature, and contact force (CF) of RFCA were continually monitored and recorded throughout the procedure. A total of 15 (2.9%) audible SP events occurred in 14 patients; 2 of the patients developed pericardial tamponade, 1 patient underwent drainage, and 1 patient underwent emergent thoracotomy. The time from RFCA initiation to the occurrence of audible SP was 19.4 ± 6.9 s. Abrupt temperature change occurred in 13 (86.7%) of the 15 SP events, of which 8 (53.3%) exhibited an abrupt temperature rise of 2.3 ± 1.0°C, 5 (33.3%) exhibited an abrupt temperature drop of 2.3 ± 1.3°C, and 2 (13.3%) exhibited no discernible temperature change. Conclusions: In conclusion, simultaneously recorded spike potentials and abrupt impedance rise with concomitant temperature and/or CF change could be a feasible method for the timely detection of the occurrence of audible, "silent," or "nonaudible" SP events, particularly in regions where the risk of perforation may be of concern.

Electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias with acute successful ablation at the left ventricular basal inferoseptum recess near the mitral annulus.

PURPOSE: We sought to clarify the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs), including idiopathic ventricular tachycardia (VT) and premature ventricular contractions (PVCs), with acute successful radiofrequency catheter ablation (RFCA) at the left ventricular basal inferoseptum recess near the mitral annulus (LV-BIS-MA). METHODS: Twenty-five patients with acute successful RFCA at the LV-BIS-MA were included in this study. RESULTS: The S-wave amplitudes on lead III during VAs were 1.54 ± 0.38 mV, significantly larger than those on lead II (0.55 ± 0.19 mV) and aVF (1.04 ± 0.31 mV) (P < 0.01). Precordial R/S > 1 transition before lead V2 and S-waves in lead V6 was recorded in 100% and 48.0% of patients, respectively. The earliest bipolar activation preceded the QRS onset by 32.3 ± 11.5 ms. Pace mapping demonstrated perfect QRS morphology matching in only 56.0% of patients. The RFCA start-to-effect time was 10.2 ± 5.8 seconds (s) in 21 patients (84.0%). In the remaining 4 patients (16.0%), the mean duration of successful RFCA was not well determined due to the infrequent presence of clinical VAs during ablation. The trans-septal approach was utilized in all 25 cases. Intra-cardiac echocardiography (ICE) showed that the ablation catheter tip was underneath the anterior leaflet of the mitral valve via the reversed C-curve technique. Early (within 3 days) and late (1 year) recurrence rates were 4.0% (one patient) and 12.0% (three patients), respectively. No complications during RFCA or at the 1-year follow-up. CONCLUSIONS: LV-BIS-MA VAs are a subgroup of idiopathic VAs with distinctive ECG and EP features. RFCA via a trans-septal approach using a reversed C-curve technique is effective for better identification and targeting of the areas of VAs origin, and ICE showed that the ablation catheter tip was underneath the anterior leaflet of the mitral valve.

Electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias with acute successful ablation at the superior portion of the mitral annulus.

BACKGROUND: We sought to identify the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs), including idiopathic ventricular tachycardia (VT) and premature ventricular contractions (PVCs), with acute successful radiofrequency catheter ablation (RFCA) at the superior portion of the mitral annulus (SP-MA). METHODS AND RESULTS: Among 437 consecutive patients who presented with VAs for RFCA, twenty-six patients with acute successful RFCA at the SP-MA were included in this study. The ratio of the amplitude of the first positive peak (if present) versus the nadir in the unipolar electrogram (EGM) was 0.00-0.03 (0.00) at the acute successful RFCA site. The time interval between the QRS onset and the maximum descending slope (D-Max) in the unipolar EGM (QRS-Uni) was 18.8 ± 13.6 ms. With bipolar mapping, the ventricular QRS (V-QRS) interval was 3.75-17.3 (11) ms, 6 (23.1%) patients showed the earliest V-QRS interval of 0 ms, and the other 20 patients (76.9%) showed a V-QRS interval of 10-54 ms. The RFCA start-to-effect time was 14.1 ± 7.2 s in 23 patients (88.5%). In the remaining 3 patients (11.5%), the mean duration of successful RFCA was not well defined due to the infrequent nature of clinical VAs during RFCA. Early (within 3 days) and late (1-year) recurrence rates were 23.1% (6 patients) and 26.9% (7 patients), respectively. VAs disappeared 3 days later due to delayed RFCA efficacy in 2 patients (7.7%). No complications occurred during the RFCA procedure or the one-year follow-up. CONCLUSIONS: SP-MA VAs are a rare but distinct subgroup of VAs. Bipolar and unipolar EGM features can help to determine the optimal RFCA site, and the QRS-Uni interval may serve as a marker that could be used to guide RFCA.

Current trends in optimal medical therapy after PCI and its influence on clinical outcomes in China.

BACKGROUND: Limited data were available on the current trends in optimal medical therapy (OMT) after PCI and its influence on clinical outcomes in China. We aimed to evaluate the utilization and impact of OMT on the main adverse cardiovascular and cerebrovascular events (MACCEs) in post-PCI patients and analyzed the factors predictive of OMT after discharge. METHODS: We collected data from 3812 individuals from 2016.10 to 2017.09 at TEDA International Cardiovascular Hospital. They were classified into an OMT group and a non-OMT group according to their OMT status, which was defined as the combination of dual antiplatelet therapy, statins, ß-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers after PCI. Multivariable Cox regression models were developed to assess the association between OMT and MACCEs, defined as all-cause mortality, nonfatal myocardial infarction, stroke, and target vessel revascularization. A logistic regression model was established to analyze the factors predictive of OMT. RESULTS: Our results revealed that the proportion of patients receiving OMT and its component drugs decreased over time. A total of 36.0% of patients were still adherent to OMT at the end of follow-up. Binary logistic regression analysis revealed that baseline OMT (P < 0.001, OR = 52.868) was the strongest predictor of OMT after PCI. The Cox hazard model suggested that smoking after PCI was associated with the 1-year risk of MACCE (P = 0.001, HR = 2.060, 95% CI 1.346-3.151), while OMT (P = 0.001, HR = 0.486, 95% CI 0.312-0.756) was an independent protective factor against postoperative MACCEs. CONCLUSIONS: There was still a gap between OMT utilization after PCI and the recommendations in the evidence-based guidelines. Sociodemographic and clinical factors influence the application of OMT. The management of OMT and smoking cessation after PCI should be emphasized.

Intraprocedural Conversion Efficacy of Intravenous Nifekalant Administration for Persistent Atrial Fibrillation after Pulmonary Vein Isolation.

The aim of this study was to prospectively assess the efficacy, safety, and predictive effect of intravenous nifekalant administration for persistent atrial fibrillation (PerAF) after pulmonary vein isolation (PVI) with second-generation cryoballoon ablation (CBA) on 1-year atrial tachyarrhythmia (ATa) -free survival by examining the pharmacological conversion rate.One hundred and two drug-refractory, consecutive PerAF patients undergoing PVI were enrolled in this prospective observational study. After PVI, nifekalant (50 mg) was given followed by 30 minutes of observation and no further intervention. PerAF was successfully converted to sinus rhythm (SR) in 60 patients (58.8%) after a median time of 7.75 (4.13-12) minutes (group N). In the remaining 42 patients (41.2%) (group C), PerAF was successfully converted to SR by external electrical cardioversion. Nonsustained ventricular tachycardia occurred in 1 patient in group N. The left atrial volume (LAV) in group C was larger than that in group N (128.2 ± 28.2 versus 111.8 ± 24.5 mL, P = 0.002). Phrenic nerve injury occurred in 4 of 102 patients (3.9%). No other complications occurred during the procedure or within the 1-year follow-up period. At the 1-year follow-up, after a 3-month blanking period (BP), ATa-free survival during 1-year follow-up in group C was significantly lower than that in group N (50.0% versus 71.7%, P = 0.026), and the overall ATa-free survival rate was 62.7%. Two patients in group C and 4 patients in group N underwent a second procedure with radiofrequency catheter ablation. Multivariate Cox regression analysis demonstrated that unsuccessful conversion to SR (P = 0.025), ATa relapse during the BP (P = 0.000), and larger LAV (P = 0.016) were independent predictors of ATa recurrence at the 1-year follow-up.In conclusion, at the 1-year follow-up, the ATa-free survival rate after PVI with CBA for PerAF patients was 62.7%, and successful conversion to SR with nifekalant could serve as a clinical predictor of reduced ATa recurrence.

A single-loop macroreentrant biatrial flutter identified by the Rhythmia mapping system.

We herein present a rare case of perimitral annulus (MA) counterclockwise single-loop macro-reentrant biatrial flutter utilizing Bachmann's bundle (BB), the atrial septum and the coronary sinus (CS) ostium as the critical components of the reentrant circuit, even though the left atrial anterior line was blocked. By acknowledging the interatrial conduction via the BB and the CS identified by the ultrahigh-resolution mapping result, we could understand the atrial flutter mechanism and successfully treat the patient.

The V1-V3 transition index as a novel electrocardiographic criterion for differentiating left from right ventricular outflow tract ventricular arrhythmias.

PURPOSE: The aim of this study was to develop a new electrocardiographic criterion for differentiating the origin of outflow tract ventricular arrhythmias (OT-VAs) with precordial transition in lead V3. METHODS: A total of 147 consecutive patients with OT-VAs displaying precordial transition in lead V3 who underwent successful catheter ablation in the right ventricular outflow tract (RVOT) (n = 118) or left ventricular outflow tract (LVOT) (n = 29) were included in this study. The V1-V3 transition index was defined as the sum of S-wave amplitude in lead V1 and V2 during premature ventricular contractions (PVCs) divided by the S-wave amplitude during sinus rhythm (SR), respectively, minus the sum of R-wave amplitude in lead V1, V2, and V3 during PVCs divided by the R-wave amplitude during SR, respectively, i.e., [(SPVC/SSR)V1 + (SPVC/SSR)V2] - [(RPVC/RSR) V1 + (RPVC/RSR)V2 + (RPVC/RSR)V3]. RESULTS: The V1-V3 transition index was significantly higher for RVOT origins than for LVOT origins (1.25 ± 2.48 vs. - 3.94 ± 3.11; P < 0.001). Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.931 for the V1-V3 transition index, and a cutoff value of > - 1.60 predicted a RVOT origin with a 93% sensitivity and 86% specificity. With respect to AUC and accuracy, the V1-V3 transition index was superior to any previously proposed ECG indices for differentiating left from right OT-VAs. In 37 prospective cases, the new index was able to predict the site of a RVOT origin with 95% accuracy (35 of 37 cases). CONCLUSIONS: The V1-V3 transition index is a useful novel ECG criterion for distinguishing left from right OT-VAs with precordial transition in lead V3.