Expert consensus document on automated diagnosis of the electrocardiogram: The task force on automated diagnosis of the electrocardiogram in Japan part 3: Inappropriate internal processing in the automatic diagnosis of electrocardiograms and its problems.

Computer diagnosis of electrocardiograms is widely used to provide useful information in clinical practice and medical checkups. However, it is common for users to be confused by the inappropriate diagnosis. We illustrate some examples of inappropriate automatic diagnoses and discuss the actual situation of inappropriate automatic processing and its problems.

Late life-threatening arrhythmia in patients with Brugada syndrome: Results from long-term follow-up in a large Japanese cohort.

INTRODUCTION: Most patients with Brugada syndrome (BrS) are first diagnosed in their 40s, with sudden cardiac death (SCD) often occurring in their 50s. Ventricular fibrillation (VF) may occur in some patients with BrS despite having been asymptomatic for a long period. This study aimed to assess the incidence and risk factors for late life-threatening arrhythmias in patients with BrS. METHODS: Patients with BrS (n = 523; mean age, 51 ± 13 years; male, n = 497) were enrolled. The risk of late life-threatening arrhythmia was investigated in 225 patients who had experienced no cardiac events (CEs: SCD or ventricular tachyarrhythmia) for at least 10 years after study enrollment. The incidence of CEs during the follow-up period was examined. RESULTS: During the follow-up of the 523 patients, 59 (11%) experienced CEs. The annual incidences of CEs were 2.87%, 0.77%, and 0.09% from study enrollment to 3, 3-10, and after 10 years, respectively. Among 225 patients who had experienced no CEs for at least 10 years after enrollment, four patients (1.8%) subsequently experienced CEs. Kaplan-Meier analysis revealed significant differences in the incidence of late CEs between patients with and without a history of symptoms (p = .032). The positive and negative predictive values of late CEs for the programmed electrical stimulation (PES) test were 2.9% and 100%, respectively. CONCLUSION: Our results suggest that patients with BrS who are asymptomatic and have no ventricular tachycardia/VF inducibility by PES are at extremely low risk of experiencing late life-threatening arrhythmias.

Relationship between coronary blood flow and improvement of cardiac function after catheter ablation for persistent atrial fibrillation.

BACKGROUND: The relationship between coronary blood flow during atrial fibrillation (AF) and improvement of cardiac function after catheter ablation (CA) for persistent AF (PeAF) is not prominent; this study was conducted to evaluate this relationship. METHODS: This was a retrospective case-control study. Eighty-five patients with PeAF (resting heart rate < 100 bpm) and heart failure with reduced ejection fraction (left ventricular ejection fraction (LVEF) < 40%) who had undergone coronary angiography within 1 week before CA were included. All patients could maintain a sinus rhythm for > 6 months after CA. The primary outcome was improvement of cardiac function with an LVEF cutoff value of > 50% during sinus rhythm 6 months after CA. RESULTS: In the LVEF improvement group (N = 57), patients were younger, with a higher baseline diastolic blood pressure and lower baseline brain natriuretic peptide level than the no LVEF improvement group (N = 28). Heart rate at baseline and 6 months after CA and AF duration did not differ between the two groups. Thrombolysis in myocardial infarction frame count parameters was significantly higher in the LVEF improvement (P < 0.001) than in the no LVEF improvement group. Multivariate logistic regression analysis revealed mean thrombolysis in myocardial infarction frame count as an independent factor for LVEF improvement (odds ratio, 1.72 (95% confidence interval 1.17-2.54); P = 0.006). CONCLUSION: Coronary blood flow in patients with PeAF is strongly associated with improved left ventricular systolic function after the restoration of sinus rhythm by CA for PeAF and heart failure with reduced ejection fraction.

Expert consensus document on automated diagnosis of the electrocardiogram: The task force on automated diagnosis of the electrocardiogram in Japan: Part 2: Current status of inappropriate automated diagnosis is widely used electrocardiographs in Japan.

It is important to objectively grasp the current status of automated electrocardiogram (ECG) diagnosis. This report aimed to analyze and evaluate ECG records that our members have encountered as an inappropriate diagnosis in real-world clinical practices.

Expert consensus document on automated diagnosis of the electrocardiogram: The task force on automated diagnosis of the electrocardiogram in Japan. Part 1: Nomenclature for diagnosis and abnormal findings.

As these terms should accurately represent the abnormal findings and conditions as much as possible, we propose to unify these terms into terminologies that are not confusing and easy to understand for everyone.

Long-term prognosis in patients with non-type 1 Brugada electrocardiogram: Results from a large Japanese cohort of idiopathic ventricular fibrillation.

BACKGROUND: Brugada syndrome (BrS) is diagnosed in patients with ST-segment elevation with spontaneous, drug-induced, or fever-induced type 1 morphology. Prognosis in type 2 or 3 Brugada electrocardiogram (Br-ECG) patients remains unknown. The purpose of this study is to evaluate long-term prognosis in non-type 1 Br-ECG patients in a large Japanese cohort of idiopathic ventricular fibrillation (The Japan Idiopathic Ventricular Fibrillation Study [J-IVFS]). METHODS: From 567 patients with Br-ECG in J-IVFS, a total of 28 consecutive non-type 1 patients who underwent programmed electrical stimulation (PES) (median age: 58 years, all male, previous sustained ventricular tachyarrhythmias [VTs] 1, syncope 11, asymptomatic 16) were enrolled. Cardiac events (CEs: sudden cardiac death or sustained VT/ventricular fibrillation) during the follow-up period were examined. RESULTS: During a median follow-up of 136 months, four patients (14%) had CEs. None of patients with PES- have experienced CEs. There was no statistically significant clinical risk factor for the development of CEs. Using the Kaplan-Meier method, the event-free rate significantly decreased in a group with all 3 risk factors (symptom, wide QRS complex in lead V2 , and positive PES) (p = .01). CONCLUSIONS: Our study revealed long-term prognosis in patients with non-type 1 Br-ECG. The combination analysis of these risk factors may be useful for the risk stratification of CEs in non-type 1 Br-ECG patients. The present study suggests that the patients with all these parameters showed high risk for CEs and need to be carefully followed.

Risk stratification in asymptomatic patients with Brugada syndrome: Utility of multiple risk factor combination rather than programmed electrical stimulation.

BACKGROUND: The prognostic value of programmed electrical stimulation (PES) in Brugada syndrome (BrS) remains controversial. Asymptomatic BrS patients generally have a better prognosis than those with symptoms. The purpose of this study was to evaluate the value of nonaggressive PES with up to two extra stimuli and predict clinical factors for risk stratification in asymptomatic BrS patients. METHODS: The study enrolled 193 consecutive asymptomatic BrS patients with type 1 ECG (mean age: 50 ± 13 years, 180 males) who underwent PES using a nonaggressive uniform protocol. Cardiac events (CEs: sudden cardiac death or ventricular tachyarrhythmia) during the follow-up period were examined. RESULTS: During a mean follow-up of 101 ± 48 months, seven asymptomatic patients (3.6%) had a CE. The incidence of CEs was not different between patients with and without inducible ventricular tachyarrhythmia by PES (p = .51). The clinical significance of risk factor combinations, including spontaneous type 1 ECG, family history of sudden cardiac death, QRS duration in lead V2 , and presence of J wave, was evaluated. Using the Kaplan-Meier method according to the number of risk factors, the prevalence of CE in patients with three or four risk factors was determined to be significantly higher than in those with one risk factor (p = .02 and p = .004, respectively). CONCLUSIONS: The present study suggests that inducibility of ventricular tachyarrhythmia does not predict future CEs in asymptomatic BrS patients. Combination analysis of the other four clinical risk parameters may be effective for risk assessment.

The coronary artery calcium score correlates with left atrial low-voltage area: Sex differences.

INTRODUCTION: In patients with coronary artery disease, a high coronary artery calcium score (CACS) correlates with atrial fibrillation (AF); however, the association between left atrial (LA) remodeling progression and coronary arteriosclerosis is unclear. This study aimed to evaluate the relationship between LA remodeling progression and the CACS. METHODS: This retrospective study enrolled 148 patients with AF (paroxysmal AF, n = 94) who underwent catheter ablation. Voltage mapping for the left atrium and coronary computed tomography for CACS calculations were performed. The ratio of the LA low-voltage area (LA-LVA), defined by values less than 0.5 mV divided by the total LA surface without pulmonary veins, was calculated. Patients with LA-LVA (<0.5 mV) >5% and ≤5% were classified as the LVA (n = 30) and non-LVA (n = 118) groups, respectively. Patient characteristics and CACS values were compared between the two groups. RESULTS: LA volume, age, CHA2 DS2 VASc score, and percentage of female patients were significantly higher, and the estimated glomerular filtration rate was lower in the LVA group than in the non-LVA group. The CACS was significantly higher in the LVA group (248.4 vs. 13.2; p = .001). Multivariate analysis identified the LA volume index and CACS as independent predictors of LA-LVA (<0.5 mV) greater than 5%. The areas under the receiver operating characteristic curves for predicting LA-LVA (<0.5 mV) greater than 5% with CACS were 0.695 in the entire population, 0.782 in men, and 0.587 in women. CONCLUSION: Progression of LA remodeling and coronary artery calcification may occur in parallel. A high CACS may indicate advanced LA remodeling, especially in men.

Quality of life improvements by durable pulmonary vein isolation in patients with atrial fibrillation.

INTRODUCTION: Successful pulmonary vein isolation (PVI) can improve the quality of life (QOL) of patients with atrial fibrillation (AF). However, the role of durable PVI for such QOL improvement is not known. The aim of this study was to clarify the effectiveness of durable PVI in improving the QOL of patients with AF. METHODS AND RESULTS: We assessed 119 patients who underwent PVI (age 66.4 ± 9.6 years, 104 paroxysmal AF). A scheduled electrophysiological study was performed 6 months after the first PVI session-regardless of recurrence of AF-to assess the durability of PVI and to identify and re-isolate reconnected pulmonary veins. QOL scores were evaluated by an AF-specific QOL questionnaire and checked at baseline, 6 months, and 1 year after the first session. In patients without AF recurrence (nonrecurrence group, n = 93), the scores at 6 months improved compared with those at baseline; conversely, the scores did not improve in patients with AF recurrence (n = 26). Nevertheless, the scores at 1 year improved compared with those at 6 months in both groups. Within the nonrecurrence group, the score difference between 6 months and baseline was higher in the durable PVI group (n = 58) than that in the nondurable PVI group (n = 35). CONCLUSIONS: The QOL of AF patients improved by the resumption of sinus rhythm following PVI. Patients with durable PVI had increased QOL scores compared with those with nondurable PVI. The durability of PVI may achieve further improvements in the QOL of patients with AF.

Comparison of touch-up ablation rate and pulmonary vein isolation durability between hot balloon and cryoballoon.

INTRODUCTION: This study aimed to compare touch-up ablation (TUA) rates and pulmonary vein isolation (PVI) durability of hot balloon ablation (HBA) and cryoballoon ablation (CBA) in paroxysmal atrial fibrillation (PAF) patients. METHODS: In total, 137 PAF patients were enrolled in the study. Among them, 59 underwent two HBA procedures at 6-month intervals and 78 patients underwent two CBA sessions, both regardless of atrial fibrillation recurrence. Propensity score matching was performed to estimate similar patient characteristics between the HBA and CBA groups. RESULTS: Each group comprised of 46 matched patients for comparison. The TUA rate at the first session was higher for HBA (49 of 184 PVs) than for CBA (20 PVs) (P = .01), with the highest incidence at the left superior pulmonary vein (LSPV). The rates of PVI durability at the second session performed 7 months later were similar between HBA (168 of 184 PVs) and CBA (162 PVs) groups. The PVI durability rate at the TUA sites of the first session was higher for HBA than for CBA (41 of 49 PVs vs 10 PVs, respectively; P = .01). Fifty percent of the patients underwent HBA at 73°C for the LSPV. HBA performed at 73°C yielded a lower TUA rate than that at 70°C (16 of 23 PVs vs 7 of 23 PVs; P = .008). CONCLUSIONS: While PVI durability was similar between HBA and CBA, the TUA rate was higher for HBA than for CBA, especially on the LSPV. For LSPV, HBA at a balloon temperature of 73°C may reduce the TUA rate.

Recurrent ischemic stroke in patients with atrial fibrillation ablation and prior stroke: A study based on etiological classification.

BACKGROUND: Different subtypes of ischemic stroke may have different risk factors, clinical features, and prognoses. This study investigated the incidence and mode of stroke recurrence in patients with a history of stroke who underwent atrial fibrillation (AF) ablation. METHODS: Of 825 patients who underwent AF ablation from 2006 to 2016, 77 patients (9.3%, median age 69 years) with a prior ischemic stroke were identified. Patients were classified as those with prior cardioembolic (CE) stroke (n = 55) and those with prior non-CE stroke (n = 22). The incidence and pattern of stroke recurrence were investigated. RESULTS: The incidence of asymptomatic AF (54.5% vs 22.7%; P = .011) and left atrial volume (135.8 mL vs 109.3 mL; P = .024) was greater in the CE group than in the non-CE group. Anticoagulation treatment was discontinued at an average of 28.1 months following the initial ablation in 34 (44.2%) patients. None of the patients developed CE stroke during a median 4.1-year follow-up. In the non-CE group, 2 patients experienced recurrent non-CE stroke (lacunar infarction in 1 and atherosclerotic stroke in 1); however, AF was not observed at the onset of recurrent ischemic stroke. CONCLUSIONS: In patients with a history of stroke who underwent catheter ablation for AF, the incidence of recurrent stroke was 0.54/100 patient-years. The previous stroke in these patients may not have been due to AF in some cases; therefore, a large-scale prospective study is warranted to identify the appro priate antithrombotic therapy for the prevention of potentially recurrent stroke.

Catheter ablation for monomorphic ventricular tachycardia in Brugada syndrome patients: detailed characteristics and long-term follow-up.

PURPOSE: Brugada syndrome (BrS) is a risk of sudden cardiac death due to polymorphic ventricular tachycardia and ventricular fibrillation with unusual monomorphic ventricular tachycardia (MVT). Detailed characteristics of MVT and long-term outcome of catheter ablation are still unknown. This study is aimed to identify the detailed characteristics and long-term follow-up of catheter ablation in BrS patients. METHODS: We evaluated 188 patients who were diagnosed with BrS from March 1999 to March 2018. Of those, patients who developed MVT and underwent catheter ablation were included. We identified eight MVTs in seven BrS patients. RESULTS: Three of them already had implantable cardioverter-defibrillator, and MVTs were terminated by cardioversion or anti-tachycardia pacing. Four patients presented with MVT originating from the right ventricular outflow tract, one patient had MVT arising from the LV septum, one patient had MVT arising from the tricuspid annulus, and one patient had bundle branch reentry ventricular tachycardia. All MVTs were successfully treated by catheter ablation in the acute phase, and seven of eight (87.5%) were free from ventricular tachyarrhythmia during the long-term follow-up (median, 7.2 years). CONCLUSIONS: All MVT cases were successfully treated by catheter ablation. We observed high ventricular arrhythmia free rate following catheter ablation during the long-term follow-up period. BrS patients who developed MVT should consider catheter ablation.

Characteristics of Marshall bundle-related atrial tachycardias using an ultrahigh-resolution mapping system.

PURPOSE: Marshall bundle (MB)-related atrial tachycardias (ATs) have already been described; however, their characteristics using an ultrahigh-resolution mapping system are not yet well known. The purpose of this study was to clarify the characteristics of MB-related ATs with ultrahigh-resolution mapping. METHODS: In 28 patients who underwent an electrophysiological study for ATs using an ultrahigh-resolution mapping system, precise circuits of 37 ATs were detected. Among those ATs, five were diagnosed as MB-related ATs that had epicardial connections among the reentrant circuits (mean age 76.6 ± 3.7 years, one male patient). We analyzed the characteristics of those MB-related ATs with ultrahigh-resolution mapping. RESULTS: The mean cycle length was 260 ± 60 ms, and the total acquired electrograms were 12,962 ± 2616 points. Two ATs were perimitral ATs, two rotated around the left pulmonary vein (PV), and one rotated around the left inferior PV. All ATs had a centrifugal activation pattern: 5 o'clock on the mitral annulus in four ATs and the upper ridge in one. Tiny potentials, which indicated epicardial potentials covering the cycle length, were detected in four of five ATs. The local activation times covered over 95% of the tachycardia cycle length on the endocardial side only in all ATs. All ATs were terminated during a radiofrequency ablation from the endocardial side of the Marshall bundle. CONCLUSIONS: The ultrahigh-resolution mapping system demonstrated an activation map of MB-related ATs with a centrifugal pattern. Macroreentrant tachycardias with a centrifugal activation pattern should be considered as possible MB-related ATs.

The Horizon and History of Asia Pacific Heart Rhythm Society.

The Asia Pacific Heart Rhythm Society (APHRS) has grown very rapidly and efficiently after its founding in 2008. The success of our organization and rapid growth was due to the enthusiastic support by pioneer electrophysiologists and efforts by many physicians to cure heart rhythm disorders. With the experience of preceding arrhythmia symposia of inter-cities or international basis in the region, the organization could quickly grow to become APHRS. The mission of APHRS is to promote basic research and improve clinical practice, optimize care of patients with heart rhythm disorders, and to train and encourage young physicians to actively participate and promote the activity of our society.

Characteristics of ventricular intracardiac electrograms of ventricular tachycardias originating from the epicardia in patients with an implantable cardioverter defibrillator.

INTRODUCTION: While characteristic waveforms of 12-lead electrocardiograms have been reported to predict the epicardial origin of ventricular tachycardia (VT), it has not been fully examined whether ventricular intracardiac electrograms (VEGMs) recorded from the implantable cardioverter defibrillator (ICD) via telemetry can determine the origin of VT or not. The aim of this study was to investigate the VEGM characteristics of VT originating from the epicardia. METHOD AND RESULTS: Intracardiac VEGMs of the induced VTs, with detected sites of origin during the VT study, were recorded in 15 (23 VTs) of the 46 patients. The characteristics of the 23 VTs were evaluated using far-field and near-field VEGMs recorded via telemetry. Five of 23 VTs were found to be focused on the epicardial site (epi group) and 18 VTs were focused on the endocardium (endo group). VTs of the epi group had longer VEGM duration in far-field EGM than those of the endo group (epi group: 240 ± 49 ms vs endo group: 153 ± 45 ms; P = 0.002) and the duration from the onset to the peak of VEGM was also longer than that of the endo group (epi group: 153 ± 53 ms vs endo group: 63 ± 28 ms; P < 0.001). There was no difference in the V wave duration in tip-ring EGM between both groups (epi group: 122 ± 52 ms vs endo group: 98 ± 6 ms; P = 0.377). CONCLUSION: Evaluation of intracardiac VEGM before VT ablation may be helpful to predict the epicardial origin of VT in patients with an ICD.

The relationship between obstructive sleep apnea and recurrence of atrial fibrillation after pulmonary vein isolation using a contact force-sensing catheter.

PURPOSE: Our aim was to elucidate the relationship between obstructive sleep apnea (OSA) and atrial fibrillation (AF) recurrence after repeated pulmonary vein isolation (PVI). METHODS: We conducted a non-randomized observational study, with the data prospectively collected. One hundred patients (paroxysmal AF, n = 89) underwent PVI using a contact force-sensing catheter. All patients underwent an electrophysiological study and additional ablation for left atrium-pulmonary vein (PV) reconnection and non-PV foci, 6 months after the first treatment session, regardless of AF recurrence. Those with an apnea-hypopnea index ≥ 15 were diagnosed with OSA. Continuous positive air pressure (CPAP) therapy was initiated after the second treatment session, based on results of a sleep study. For analysis, patients were classified into the non-OSA (n = 66), treated OSA (OSA patients undergoing CPAP; n = 11), and untreated OSA (n = 23) groups, and between-group differences evaluated. RESULTS: After the first session, AF recurrence was observed in 18.2% (12/66) and 14.7% (5/34) of patients without and with OSA, respectively (P = 0.678). After the second procedure, the rate of AF recurrence was 12.1% (8/66) in the non-OSA group, 9.1% (1/11) in the treated OSA group, and 8.7% (2/23) in the untreated OSA group (log-rank P = 0.944). CONCLUSIONS: The rate of AF recurrence might not be greater in patients with untreated OSA than in those without OSA and those with treated OSA after repeated PVI, using a contact force-sensing catheter, for patients with paroxysmal or short-term persistent AF.

Ventricular Fibrillation Induced by Coronary Vasospasm in a Patient with Early Repolarization and Hyperthyroidism.

Vasospastic angina (VSA) has been recognized as a cause of ventricular fibrillation (VF) degenerating into sudden cardiac death. We experienced a case of VSA with hyperthyroidism in which VF was provoked with an augmented J-wave amplitude in the inferior leads. The patient underwent insertion of an implantable cardioverter-defibrillator for the secondary prevention of VF in addition to taking Ca-channel antagonists. He has shown no recurrence of fatal arrhythmia or anginal attack for a follow-up period of one year.