Showing papers by "Hui Nam Pak published in 2015"

Why Is Left Atrial Appendage Morphology Related to Strokes? An Analysis of the Flow Velocity and Orifice Size of the Left Atrial Appendage

Abstract: Why Is Left Atrial Appendage Morphology Related to Strokes?Background A specific morphology of left atrial appendage (LAA) has been reported to be related to stroke in nonvalvular atrial fibrillation (AF) patients. However, the mechanism is not completely understood. This study evaluated whether a specific LAA morphology was related to stroke, and whether it was related to the change of flow velocity and size of LAA in AF patients. Methods The morphology, size, and flow velocity of LAA were evaluated in AF patients with ischemic strokes (stroke, n = 160) and age-matched AF patients without ischemic strokes (control, n = 200). Results Compared with control, the stroke group had a larger LA dimension (4.5 ± 0.7 vs. 4.2 ± 0.6 cm, P < 0.001), larger LAA orifice area (5.3 ± 2.1 vs. 4.1 ± 1.7 cm2, P < 0.001), and slower LAA flow velocity (37 ± 19 vs. 51 ± 20 cm/s, P < 0.001). The stroke group had the chicken wing type less frequently than the control (34% vs. 50%, P = 0.003). After an adjustment for multiple potential confounding factors, the chicken wing type LAA had a decreased stroke risk (odds ratio 0.34, 95% confidence interval 0.14–0.84, P = 0.020). Patients with a chicken wing LAA had a smaller LAA orifice area (4.4 ± 1.6 vs. 4.9 ± 2.2 cm2, P = 0.013) and higher LAA velocity (55 ± 19 vs. 41 ± 20 cm/s, P < 0.001) than those with non-chicken wing LAA. Conclusion A chicken wing type of LAA was related to the less incidence of stroke. Our results suggest that the relationship between a specific LAA morphology and stroke might be partially explained by the change of the size and flow velocity of LAA.

Korean Atrial Fibrillation (AF) Network: Genetic Variants for AF Do Not Predict Ablation Success

Abstract: Background Genomewide association studies have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between top susceptibility loci and AF recurrence after ablation have not been examined in Asian populations. We examined whether the top single nucleotide polymorphisms (SNPs) at chromosomes 4q25 ( PITX2 ), 16q22 ( ZFHX3 ), and 1q21 ( KCNN3 ) were associated with AF in a Korean population and whether these SNPs were associated with clinical outcomes after catheter ablation for AF. Methods and Results We determined the association between 4 SNPs and AF in 1068 AF patients who underwent catheter ablation (74.6% male, aged 57.5±10.9 years, 67.9% paroxysmal AF) and 1068 age‐ and sex‐matched controls. The SNPs at the PITX2 and ZFHX3 loci, but not the KCNN3 locus, were significantly associated with AF ( PITX2 /rs6843082_G: odds ratio 3.41, 95% CI 2.55 to 4.55, P =1.32×10−16; PITX2 /rs2200733_T: odds ratio 2.05, 95% CI 1.66 to 2.53, P =2.20×10−11; ZFHX3 /rs2106261_A: odds ratio 2.33, 95% CI 1.87 to 2.91, P =3.75×10−14; KCNN3 /rs13376333_T: odds ratio 1.74, 95% CI 0.93 to 3.25, P =0.085). Among those patients who underwent catheter ablation for AF, none of the top AF‐associated SNPs were associated with long‐term clinical recurrence of AF after catheter ablation. Conclusions SNPs at the PITX2 and ZFHX3 loci were strongly associated with AF in Korean patients. In contrast to prior reports, none of the 4 top AF‐susceptibility SNPs predicted clinical recurrence after catheter ablation.

Linear ablation in addition to circumferential pulmonary vein isolation (Dallas lesion set) does not improve clinical outcome in patients with paroxysmal atrial fibrillation: a prospective randomized study

Abstract: Aims Although the concept of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) was derived from maze surgery, it is unclear if linear ablation in addition to circumferential pulmonary vein isolation (CPVI) reduces the recurrence rate in patients with paroxysmal AF. Therefore, we compared clinical outcomes of CPVI with additional linear ablations (Dallas lesion set) and CPVI in a prospective randomized controlled study among patients with paroxysmal AF. Methods and results This study enrolled 100 paroxysmal AF patients (male 75.0%, 56.4 ± 11.6 years old) who underwent RFCA and were randomly assigned to the CPVI group ( n = 50) or the catheter Dallas lesion group (CPVI, posterior box lesion, and anterior linear ablation, n = 50). The catheter Dallas lesion group required longer procedure (190.3 ± 46.3 vs. 161.1 ± 30.3 min, P < 0.001) and ablation times (5345.4 ± 1676.4 vs. 4027.2 ± 878.0 s, P < 0.001) than the CPVI group. Complete bidirectional conduction block rate was 68.0% in the catheter Dallas lesion group and 100% in the CPVI group. Procedure-related complication rates were not significantly different between the catheter Dallas lesion (0%) and CPVI groups (4%, P = 0.157). During the 16.3 ± 4.0 months of follow-up, the clinical recurrence rates were not significantly different between the two groups (16.0% in the catheter Dallas lesion group vs. 12.0% in the CPVI group, P = 0.564), regardless of complete bidirectional conduction block achievement after linear ablation. Conclusion Linear ablation in addition to CPVI (catheter Dallas lesion) did not improve clinical outcomes of RFCA in paroxysmal AF patients and required longer procedure times.

Low Left Atrial Compliance Contributes to the Clinical Recurrence of Atrial Fibrillation after Catheter Ablation in Patients with Structurally and Functionally Normal Heart.

Abstract: Stiff left atrial (LA) syndrome was initially reported in post-cardiac surgery patients and known to be associated with low LA compliance. We investigated the physiological and clinical implications of LA compliance by estimating LA pulse pressure (LApp) among patients with atrial fibrillation (AF) and structurally and functionally normal heart. Among 1038 consecutive patients with LA pressure measurements before AF ablation, we included 334 patients with structurally and functionally normal heart (81.7% male, 54.1±10.6 years, 77.0% paroxysmal AF) after excluding those with hypertension, diabetes, and previous ablation or cardiac surgery. We measured LApp (peak-nadir LA pressure) at the beginning of the ablation procedure and compared the values with clinical parameters and the AF recurrence rate. AF patients with normal heart were younger and more frequently male and had paroxysmal AF, a lower body mass index, and a lower LApp compared to others (all p<0.05). Based on the median value, the low LA compliance group (LApp≥13 mmHg) had a smaller LA volume index and lower LA voltage (all p<0.05) compared to the high LA compliance group. During a mean follow-up of 16.7±11.8 months, low LA compliance was independently associated with two fold-higher risk of clinical AF recurrence (HR:2.202; 95%CI:1.077-4.503; p = 0.031). Low LA compliance, as determined by an elevated LApp, was associated with a smaller LA volume index and lower LA voltage and independently associated with higher clinical recurrence after catheter ablation in AF patients with structurally and functionally normal heart.

Comparison of two different doses of single bolus steroid injection to prevent atrial fibrillation recurrence after radiofrequency catheter ablation.

Abstract: Purpose Steroids may play a role in preventing the early recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). However, optimal doses and route of steroid delivery have not yet been determined. This study evaluated the effect of two different doses of a single bolus injection of steroids on AF recurrence after RFCA.

Combined ECG, Echocardiographic, and Biomarker Criteria for Diagnosing Acute Myocardial Infarction in Out-of-Hospital Cardiac Arrest Patients.

Abstract: Purpose Acute coronary lesions commonly trigger out-of-hospital cardiac arrest (OHCA). However, the prevalence of coronary artery disease (CAD) in Asian patients with OHCA and whether electrocardiogram (ECG) and other findings might predict acute myocardial infarction (AMI) have not been fully elucidated. Materials and methods Of 284 consecutive resuscitated OHCA patients seen between January 2006 and July 2013, we enrolled 135 patients who had undergone coronary evaluation. ECGs, echocardiography, and biomarkers were compared between patients with or without CAD. Results We included 135 consecutive patients aged 54 years (interquartile range 45-65) with sustained return of spontaneous circulation after OHCA between 2006 and 2012. Sixty six (45%) patients had CAD. The initial rhythm was shockable and non-shockable in 110 (81%) and 25 (19%) patients, respectively. ST-segment elevation predicted CAD with 42% sensitivity, 87% specificity, and 65% accuracy. ST elevation and/or regional wall motion abnormality (RWMA) showed 68% sensitivity, 52% specificity, and 70% accuracy in the prediction of CAD. Finally, a combination of ST elevation and/or RWMA and/or troponin T elevation predicted CAD with 94% sensitivity, 17% specificity, and 55% accuracy. Conclusion In patients with OHCA without obvious non-cardiac causes, selection for coronary angiogram based on the combined criterion could detect 94% of CADs. However, compared with ECG only criteria, the combined criterion failed to improve diagnostic accuracy with a lower specificity.

Fibrillation Number Based on Wavelength and Critical Mass in Patients Who Underwent Radiofrequency Catheter Ablation for Atrial Fibrillation

Abstract: The heart characteristic length, the inverse of conduction velocity (CV), and the inverse of the refractory period are known to determine vulnerability to cardiac fibrillation (fibrillation number, FibN) in in silico or ex vivo models. The purpose of this study was to validate the accuracy of FibN through in silico atrial modeling and to evaluate its clinical application in patients with atrial fibrillation (AF) who had undergone radiofrequency catheter ablation. We compared the maintenance duration of AF at various FibNAF values using in silico bidomain atrial modeling. Among 60 patients (72% male, $54\pm 13$ years old, 82% with paroxysmal AF) who underwent circumferential pulmonary vein isolation (CPVI) for AF rhythm control, we examined the relationship between FibN AF and postprocedural AF inducibility or induction pacing cycle length (iPCL). Clinical FibNAF was calculated using left atrium (LA) dimension (echocardiogram), the inverse of CV, and the inverse of the atrial effective refractory periods measured at proximal and distal coronary sinus. In silico simulation found a positive correlation between AF maintenance duration and FibNAF ( $R = 0.90$ , $p ). After clinical CPVI, FibNAF ( $0.296\pm 0.038$ versus $0.192\pm 0.028$ , $p ) was significantly higher in patients with postprocedural AF inducibility ( $n = 41$ ) than in those without ( $n = 19$ ). Among 41 patients with postprocedural AF inducibility, FibNAF ( $P = 0.935$ , $p ) had excellent correlations with induction pacing cycle length. FibNAF, based on LA mass and wavelength, correlates well with AF maintenance in computational modeling and clinical AF inducibility after CPVI.

Prognostic Implications of Right and Left Atrial Enlargement after Radiofrequency Catheter Ablation in Patients with Nonvalvular Atrial Fibrillation

Abstract: Background and Objectives The prognostic role of the right atrium (RA) compared with that of the left atrium (LA) is unclear in patients with atrial fibrillation (AF). We assessed structural changes in both atria and determined their association with recurrence of AF after radiofrequency catheter ablation (RFCA).

The ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em) predicts improvement in left ventricular systolic and diastolic function 1 year after catheter ablation for atrial fibrillation.

Abstract: Aims Successful rhythm control after atrial fibrillation catheter ablation is known to induce left atrial reverse remodelling and improve left ventricular (LV) function. We explored the clinical factors affecting LV systolic and diastolic function 1-year after catheter ablation for atrial fibrillation. Methods and results We compared pre-procedural and 1-year follow-up echocardiograms in 521 patients with atrial fibrillation who underwent catheter ablation. Left ventricular systolic function was estimated by the ejection fraction (EF); diastolic function was estimated by the ratio of early transmitral flow velocity ( E ) to early mitral annular velocity ( E m). (i) Catheter ablation of atrial fibrillation significantly reduced left atrium volume index ( P < 0.001) and improved LV EF both in patients with recurrent atrial fibrillation ( n = 133, P = 0.008) and those without recurrence ( n = 388, P < 0.001). (ii) Follow-up EF was significantly improved in patients with baseline E / E m < 15 ( n = 454, P < 0.001), whereas E / E m was significantly reduced in patients with pre-procedural E / E m ≥ 15 ( n = 67, P = 0.008). (iii) Baseline E / E m < 15 ( β = −3.854, 95% CI −5.99 to −1.72, P < 0.001), baseline EF <50% ( β = 10.586, 95% CI 7.55 to 13.63, P < 0.001), and female ( β = −1.726, 95% CI −3.36 to −0.10, P = 0.038) were independently associated with improved EF. Baseline E / E m ≥ 15 ( β = 4.896, 95% CI 3.45 to 6.34, P < 0.001) and younger age ( β = −0.066, 95% CI −0.11 to −0.02, P = 0.003) were independent factors associated with improved E / E m. Conclusion Pre-procedural E / E m predicted improvement in LV systolic and diastolic functions 1 year after catheter ablation for atrial fibrillation. Low baseline E / E m was independently associated with improved EF, while high E / E m predicted improvement in LV diastolic function.

Prognostic Implications of Right and Left Atrial Enlargement after Radiofrequency Catheter Ablation in Patients with Nonvalvular Atrial Fibrillation

Abstract: Background and Objectives The prognostic role of the right atrium (RA) compared with that of the left atrium (LA) is unclear in patients with atrial fibrillation (AF). We assessed structural changes in both atria and determined their association with recurrence of AF after radiofrequency catheter ablation (RFCA).

Cardiovascular Events of Electrical Cardioversion Under Optimal Anticoagulation in Atrial Fibrillation: The Multicenter Analysis.

Abstract: PURPOSE Electric cardioversion has been successfully used in terminating symptomatic atrial fibrillation (AF). Nevertheless, largescale study about the acute cardiovascular events following electrical cardioversion of AF is lacking. This study was performed to evaluate the incidence, risk factors, and clinical consequences of acute cardiovascular events following electrical cardioversion of AF. MATERIALS AND METHODS The study enrolled 1100 AF patients (mean age 60±11 years) who received cardioversion at four tertiary hospitals. Hospitalizations for stroke/transient ischemic attack, major bleedings, and arrhythmic events during 30 days post electric cardioversion were assessed. RESULTS The mean duration of anticoagulation before cardioversion was 95.8±51.6 days. The mean International Normalized Ratio at the time of cardioversion was 2.4±0.9. The antiarrhythmic drugs at the time of cardioversion were class I (45%), amiodarone (40%), beta-blocker (53%), calcium-channel blocker (21%), and other medication (11%). The success rate of terminating AF via cardioversion was 87% (n=947). Following cardioversion, 5 strokes and 5 major bleedings occurred. The history of stroke/transient ischemic attack (OR 6.23, 95% CI 1.69-22.90) and heart failure (OR 6.40, 95% CI 1.77-23.14) were among predictors of thromboembolic or bleeding events. Eight patients were hospitalized for bradyarrhythmia. These patients were more likely to have had a lower heart rate prior to the procedure (p=0.045). Consequently, 3 of these patients were implanted with a permanent pacemaker. CONCLUSION Cardioversion appears as a safe procedure with a reasonably acceptable cardiovascular event rate. However, to prevent the cardiovascular events, several risk factors should be considered before cardioversion.

Deletion of the Serotonin Receptor Type 3A in Mice Leads to Sudden Cardiac Death During Pregnancy

Abstract: BACKGROUND The serotonin receptor type 3 (Htr3) blocker is associated with QT prolongation and torsades de pointes. However, little is known about effects of Htr3 on the heart arrhythmia. METHODS AND RESULTS An electrophysiological study Involving knock-out (KO) female mice lacking functional Htr3a (Htr3a(-/-)) and their wild-type littermates during non-pregancy (NP) and late pregnancy (LP) was performed. Htr3a mRNA was present in the wild-type, but not in the Htr3a(-/-)mouse hearts. Serotonin and tryptophan hydroxylase 1 (Tph1), a rate-limiting enzyme of serotonin synthesis in hearts, is increased during pregnancy. The heart weight and size were increased in the pregnant mice regardless of a mutation. The QTc intervals were prolonged after pregnancy in both the wild (NP: 171.2±16.8 vs. LP: 247.7±14.3 ms; P<0.001) and Htr3a(-/-)mice (NP: 187.9±18.7 vs. LP: 275.6±11.0 ms, P<0.001). Compared with wild-type LP mice, Htr3a(-/-)LP mice had increased spontaneous ventricle tarchycardia (VT; 56% vs. 0%, P=0.002), VT inducibility (66% vs. 25%, P=0.002) and mortality (56% vs. 0%, P=0.002). Pharmacologic administration of serotonin and Htr3 agonists (m-CPBG) decreased the QT interval in wild mice, but not in Htr3a(-/-)mice. CONCLUSIONS Htr3a is present in mouse hearts. Serotonin and Tph1 were increased during pregnancy. The deletion of Htr3a was related to fatal arrhythmias and sudden cardiac death during pregnancy, and its activation reversed the QT prolongation.

Left Atrial Volume Index Predicts Recurrence of Stroke in Patients with Nonsustained Atrial Tachycardia.

Abstract: Background Nonsustained atrial tachycardia (NSAT) is known to appear more frequently in patients with paroxysmal atrial fibrillation (AF). Enlarged left atrium (LA) is considered to be an independent risk factor for newly diagnosed AF. Methods We investigated the risk factors for predicting the stroke recurrence in NSAT patients. In total, 252 patients (114 women, mean 70 ± 11 years) with acute ischemic stroke and documented NSAT in 24-hour Holter monitoring were enrolled and followed. All patients underwent echo–Doppler evaluations. Results During a mean follow-up period of 35 ± 31 months, the stroke recurrence rate was 11.1% (28 of 252). The patients with recurrence (n = 28) had higher left atrium volume index (LAVI, P P = .028) compared with those without recurrence (n = 224). On the Kaplan–Meier survival analysis, stroke recurrence rate was significantly higher in patients with enlarged LA (LAVI >28 mm3/m2; P P Conclusions In patients with acute ischemic stroke and NSAT, enlarged LA predicts an increased risk of stroke recurrence. This study supports the necessity of prolonged rhythm monitoring in stroke patients with NSAT and enlarged LA to detect undiagnosed AF and consequently considering anticoagulation therapy.

Deletion of the Serotonin Receptor Type 3A in Mice Leads to Sudden Cardiac Death During Pregnancy

Abstract: BACKGROUND The serotonin receptor type 3 (Htr3) blocker is associated with QT prolongation and torsades de pointes. However, little is known about effects of Htr3 on the heart arrhythmia. METHODS AND RESULTS An electrophysiological study Involving knock-out (KO) female mice lacking functional Htr3a (Htr3a(-/-)) and their wild-type littermates during non-pregancy (NP) and late pregnancy (LP) was performed. Htr3a mRNA was present in the wild-type, but not in the Htr3a(-/-)mouse hearts. Serotonin and tryptophan hydroxylase 1 (Tph1), a rate-limiting enzyme of serotonin synthesis in hearts, is increased during pregnancy. The heart weight and size were increased in the pregnant mice regardless of a mutation. The QTc intervals were prolonged after pregnancy in both the wild (NP: 171.2±16.8 vs. LP: 247.7±14.3 ms; P<0.001) and Htr3a(-/-)mice (NP: 187.9±18.7 vs. LP: 275.6±11.0 ms, P<0.001). Compared with wild-type LP mice, Htr3a(-/-)LP mice had increased spontaneous ventricle tarchycardia (VT; 56% vs. 0%, P=0.002), VT inducibility (66% vs. 25%, P=0.002) and mortality (56% vs. 0%, P=0.002). Pharmacologic administration of serotonin and Htr3 agonists (m-CPBG) decreased the QT interval in wild mice, but not in Htr3a(-/-)mice. CONCLUSIONS Htr3a is present in mouse hearts. Serotonin and Tph1 were increased during pregnancy. The deletion of Htr3a was related to fatal arrhythmias and sudden cardiac death during pregnancy, and its activation reversed the QT prolongation.

Catheter Ablation of Atrial Fibrillation Raises the Plasma Level of NGF-β Which Is Associated with Sympathetic Nerve Activity.

Abstract: Purpose The expression of nerve growth factor-β (NGF-β) is related to cardiac nerve sprouting and sympathetic hyper innervation. We investigated the changes of plasma levels of NGF-β and the relationship to follow-up heart rate variability (HRV) after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF).

eNOS3 Genetic Polymorphism Is Related to Post-Ablation Early Recurrence of Atrial Fibrillation.

Abstract: PURPOSE Previous studies have demonstrated an association between eNOS polymorphisms and atrial fibrillation (AF). We sought to determine whether eNOS polymorphisms are associated with AF recurrence after a radiofrequency catheter ablation (RFCA). MATERIALS AND METHODS A total of 500 consecutive patients (56±11 years, 77% male) with paroxysmal (68%) or persistent (32%) AF who underwent RFCA and 500 age, gender-matched controls were genotyped for the eNOS3 single nucleotide polymorphism (rs1799983). AF recurrence was monitored according to 2012 ACC/AHA/ESC guidelines. RESULTS The frequencies of the rs1799983 variant alleles (T) in the case and control group were not significantly different (OR 1.05, 95% CI 0.75-1.46, p=0.798). AF patients with rs1799983 variants were more likely to have coronary artery disease or stroke than those without genetic variant at this gene (31.0% vs. 17.3%, p=0.004). During mean 17 months follow-up, early recurrence of AF (ERAF; within 3 months) and clinical recurrence (CR) of AF were 31.8% and 24.8%, respectively. The rs1799983 variant was associated with higher risk of ERAF (OR 1.71, 95% CI 1.06-2.79, p=0.028), but not with CR. ERAF occurred earlier (11±16 days) in variant group than those without variant allele (20±25 days, p=0.016). A multiple logistic regression analysis showed that presence of the rs1799983 variant (OR 1.75, 95% CI 1.07-2.86, p=0.026) and persistent AF were independent predictors for ERAF after AF ablation. CONCLUSION The rs1799983 variant of the eNOS3 gene was associated with ERAF, but not with CR, after RFCA. eNOS3 gene variants may have a potential role for stratification of post-ablation management.

Predictors of Sick Sinus Syndrome in Patients after Successful Radiofrequency Catheter Ablation of Atrial Flutter

Abstract: Purpose The identification of sick sinus syndrome (SSS) in patients with atrial flutter (AFL) is difficult before the termination of AFL. This study investigated the patient characteristics used in predicting a high risk of SSS after AFL ablation. Materials and methods Out of 339 consecutive patients who had undergone radiofrequency ablation for AFL from 1991 to 2012, 27 (8%) had SSS (SSS group). We compared the clinical characteristics of patients with and without SSS (n=312, no-SSS group). Results The SSS group was more likely to have a lower body mass index (SSS: 22.5±3.2; no-SSS: 24.0±3.0 kg/m²; p=0.02), a history of atrial septal defects (ASD; SSS: 19%; no-SSS: 6%; p=0.01), a history of coronary artery bypass graft surgery (CABG; SSS: 11%; no-SSS: 2%; p=0.002), and a longer flutter cycle length (CL; SSS: 262.3±39.2; no-SSS: 243.0±40; p=0.02) than the no-SSS group. In multivariate analysis, a history of ASD [odds ratio (OR) 3.7, 95% confidence interval (CI) 1.2-11.4, p=0.02] and CABG (7.1, 95% CI 1.5-32.8, p=0.01) as well as longer flutter CL (1.1, 95% CI 1.0-1.2, p=0.04) were independent risk factors for SSS. Conclusion A history of ASD and CABG as well as longer flutter CL increased the risk of SSS after AFL ablation. While half of the patients with SSS after AFL ablation experienced transient SSS, heart failure was associated with irreversible SSS.

Watch out for the WATCHMAN.

Abstract: A 55-year-old man underwent percutaneous left atrial appendage (LAA) occlusion for recurrent bleeding during anticoagulation for atrial fibrillation. He had a history of myocardial infarction, ischaemic cardiomyopathy, hypertension, and …

Conduit Puncture for Electrophysiological Procedures in Patients with Fontan Circulation

Abstract: Background: Electrophysiological procedures are challenging in pa- tients who have undergone lateral tunnel or extracardiac conduit Fontan operation because the caval veins are not connected to the cardiac atria and ventricles. This study describes our experience in managing a series of patients with Fontan circulation requiring cath- eter ablation for arrhythmias. Methods: This study included eight consecutive patients with Fontan circulation who underwent catheter ablation or pacemaker implan- tation via Fontan conduit puncture (median age (interquartile range), 21.5 (16.0-25.8) years; 5 men). Lateral tunnel and extracardiac con- duit were equally distributed among the eight patients. A standard technique for conduit puncture and subsequent electrophysiologic procedure was used. The time taken for conduit puncture was com- pared for different types of conduits. Results: The median age of patients in this series was 21.5 years (interquartile range: 16.0-25.8 years). Fontan conduit puncture via right femoral vein under intracardiac echocardiographic guidance was successfully performed without complications in seven of the eight patients. Conduit puncture failed in one patient with extracardiac conduit made of the pericardium due to interruption of both femoral veins. In three patients with Fontan conduit made of pericardium, a Bronckenbrough transseptal needle or a radiofrequency transseptal needle with a snare was used. In four patients with Fontan conduit made of Gore-tex, a radiofrequency transseptal needle with a snare, and percutaneous transluminal angioplasty balloon were used. Fontan conduit puncture time was significantly longer in patients with conduit made of Gore-tex (median time, 91 min; interquartile range, 59.8-130.5 min) than in patients with conduit made of the pericardium (median time, 11.5 min; interquartile range, 10.0-18.3 min), respectively (p=0.020). Conclusions: Conduit puncture is feasible and safe in patients with lateral tunnel and extracardiac Fontan circulation. Puncture of the Gore-tex conduit is more difficult and time consuming than punc- ture of the pericardium conduit.

Blunted rate-dependent left atrial pressure response during isoproterenol infusion in atrial fibrillation patients with impaired left ventricular diastolic function: a comparison to pacing.

Abstract: Aims A heart rate (HR)-dependent haemodynamic linkage between peak left atrial (LA) pressure during sinus rhythm (LAPpeak) and estimated left ventricular (LV) filling pressure (E/Em) has not yet been explored. We hypothesized that rate-dependent LAPpeak response differs depending on E/Em in patients with atrial fibrillation (AF). Methods and results A total of 331 patients (68.0% male, 59.8 ± 10.8 years old) undergoing radiofrequency catheter ablation (RFCA) for AF were included, and their LAPpeak in sinus rhythm was recorded at the beginning of the procedure and at the HRs of 90, 100, 110, and 120 b.p.m. during right atrial pacing and isoproterenol (ISO-stress) infusion. We compared LAPpeak changes between patients with E/Em ≥ 15 ( n = 58) and those with <15 ( n = 273). (i) The patterns of pacing rate-dependent LAPpeak increase were similar in both the E/Em < 15 ( P < 0.001) and E/Em ≥ 15 groups ( P = 0.002). (ii) The ISO-stress reduced LAPpeak in patients with E/Em < 15 ( P = 0.015), but not in those with E/Em ≥ 15 ( P = 0.582). (iii) Paradoxical ISO-stress LAP elevation in patients with E/Em ≥ 15 was independently associated with 1-year follow-up E/Em reduction ( B = −4.07, 95% CI −5.41 to −2.72, P < 0.001). Coexistence of E/Em ≥ 15 and ISO-stress LAP elevation increased specificity in predicting 1-year follow-up E/Em reduction after AF ablation than E/Em alone. Conclusion Isoproterenol LAPpeak reduction was blunted in patients with impaired LV diastolic function estimated by E/Em ≥ 15. The improvement of LV diastolic dysfunction 1 year after AF ablation was independently associated with both paradoxical ISO-stress LAP elevation and E/Em ≥ 15 at the time of procedure. Clinicaltrials.gov NCT02138695.

Usefulness of a crista catheter for 3-dimensional electroanatomical mapping of complex right atrial tachyarrhythmias

Abstract: Right atrial (RA) tachyarrhythmias are not rare in patients with congenital heart disease and a history of cardiac surgery. This study investigated the usefulness of a crista catheter for 3-dimensional electroanatomical mapping of RA tachyarrhythmias. We consecutively included 35 patients (age, 43.2 ± 15.6 years; 15 men) who underwent an electrophysiological study with 3-dimensional electroanatomical mapping for RA tachycardia or flutter. In 13 patients with atrial flutter, we recorded and compared the electrical sequence in the anterior and posterior portions of the RA lateral wall. We used a crista catheter as a mapping catheter for 3-dimensional mapping in 12 patients (crista group), a lasso catheter in 12 patients (lasso group), and an ablation catheter in 11 patients (ablation group). We compared the 3-dimensional mapping points, time, and speed (mapping points per minute) among the groups. Atrial flutter was confirmed as cavotricuspid isthmus-dependent in all patients whose two atrial electrical sequences were the same direction and as atypical (including scar-related and dual-loop) in all patients whose sequences were in the opposite direction. Mapping speed in the crista group was significantly faster than in the lasso and ablation groups: median (interquartile range) 44.0 (35.5–69.4) points/min, 23.7 (17.8–29.8) points/min, and 8.2 (4.8–11.0) points/min, respectively (p = 0.001). A crista catheter is useful for high-density 3-dimensional electroanatomical mapping of complex RA tachyarrhythmias. Comparison of the electrical sequences in the anterior and posterior portions of the RA lateral wall is helpful for differentiating between cavotricuspid isthmus-dependent and atypical atrial flutter.

Combined Algorithm Using a Poor Increase in Inferior P-Wave Amplitude During Sympathetic Stimulation and Sinus Node Recovery Time for the Diagnosis of Sick Sinus Syndrome.

Abstract: BACKGROUND This study sought to evaluate whether a poor increase in inferior P-wave amplitude during sympathetic stimulation might be a helpful diagnostic tool for sick sinus syndrome (SSS). METHODS AND RESULTS Three-dimensional electroanatomic mapping of the right atrium, inferior P-wave amplitude and conventional corrected sinus node recovery time (CSNRT) were compared in 112 consecutive atrial fibrillation (AF) patients with (n=21) and without SSS (n=91). The significant cranial shift of earliest activation site (EAS) (the distance from the superior vena cava to the EAS: 11.1 vs. 5.9 mm, P 550 ms showed a sensitivity of 50% and specificity of 84% for diagnosing SSS, poor increases of P-waves amplitude in lead aVF ( 550 ms and poor increase of P-waves amplitude in lead aVF showed more improved diagnostic accuracy (sensitivity 89%, specificity 75%). CONCLUSIONS A combined algorithm using inferior P-wave amplitude showed improved performance for the diagnosis of SSS compared with CSNRT >550 ms alone.

Mitochondrial DNA 4977bp deletion mutation in peripheral blood reflects atrial remodeling in patients with non-valvular atrial fibrillation

Abstract: Purpose Recently, mitochondrial DNA 4977bp deletion (mtDNA4977-mut), a somatic mutation related to oxidative stress, has been shown to be associated with atrial fibrillation (AF). We hypothesized that patient age, as well as electroanatomical characteristics of fibrillating left atrial (LA), vary depending on the presence of mtDNA4977-mut in peripheral blood among patients with non-valvular AF.

Elimination Of Triggers Without An Additional Substrate Modification Is Not Sufficient In Patients With Persistent Atrial Fibrillation.

Abstract: Atrial fibrillation (AF) is a multifactorial disease with complex pathophysiology. Although restoring sinus rhythm delays the progression of atrial remodeling, non-pharmacologic intervention, such as radiofrequency catheter ablation (RFCA), should be done based on the background pathophysiology of the disease. While circumferential pulmonary vein isolation (CPVI) has been known to be the cornerstone of AF catheter ablation, a clinical recurrence rate after CPVI is high in patients with persistent AF (PeAF). Step-wise linear ablation, complex fractionate atrial electrogram (CFAE)-guided ablation, rotor ablation, ganglionate plexus ablation, and left atrial appendage isolation may improve the ablation success rate after CPVI. But, there are still substantial AF recurrences after such liberal atrial substrate ablation, and current ablation techniques regarding substrate modification still have limitations. Therefore, more understanding about AF pathophysiology and early precise intervention may improve clinical outcome of AF management. Keeping in mind "more touch, more scar," operators should generate most efficient substrate modification to achieve better long-term clinical outcome.