Increase in heart rate-dependent left atrial pressure is associated with symptoms in patients with paroxysmal atrial fibrillation.

BACKGROUND: It remains unclear why some patients with the same heart rate during an atrial fibrillation (AF) have subjective symptoms, whereas others do not. We assessed the hypothesis that different responses of arterial and left atrial blood pressures to rapid stimulation may be associated with the symptoms of AF. METHODS: A total of 110 patients who underwent catheter ablation for paroxysmal AF were retrospectively studied. Asymptomatic AF was defined as a European Heart Rhythm Association score of Ⅰ for AF-related symptoms. The left atrial pressure (LAP) was measured during sinus rhythm (SR), in 10 pacing per minute (ppm) increments from 100 ppm to the Wenckebach block rate in high right atrial pacing. RESULTS: Asymptomatic AF was observed in 19/110 patients (17%). Patients with symptomatic AF showed higher E/e' ratio and gradual LAP increase that was dependent on the pacing rate. Patients with asymptomatic AF had decreased LAP at 100 ppm compared that at SR, and thereafter, LAP gradually increased depending on the pacing rate. The rate of LAP change compared to that at SR was significantly lower in patients with asymptomatic AF than that in patients with symptomatic AF. The rate of LAP change was independently associated with AF symptoms. CONCLUSION: Patients with asymptomatic AF showed lower E/e' ratio and decreased LAP at 100 ppm to rapid stimulation, followed by a steady increase in LAP afterwards. Factors other than left ventricular diastolic dysfunction may be involved in AF symptoms.

Incidence and Characteristics of Coronary Artery Spasms Related to Atrial Fibrillation Ablation Procedures　- Large-Scale Multicenter Analysis.

BACKGROUND: Coronary artery spasms (CASs), which can cause angina attacks and sudden death, have been recently reported during catheter ablation. The aim of the present study was to report the incidence, characteristics, and prognosis of CASs related to atrial fibrillation (AF) ablation procedures.Methods and Results:The AF ablation records of 22,232 patients treated in 15 Japanese hospitals were reviewed. CASs associated with AF ablation occurred in 42 of 22,232 patients (0.19%). CASs occurred during ablation energy applications in 21 patients (50%). CASs also occurred before ablation in 9 patients (21%) and after ablation in 12 patients (29%). The initial change in the electrocardiogram was ST-segment elevation in the inferior leads in 33 patients (79%). Emergency coronary angiography revealed coronary artery stenosis and occlusions, which were relieved by nitrate administration. No air bubbles were observed. A comparison of the incidence of CASs during pulmonary vein isolation between the different ablation energy sources revealed a significantly higher incidence with cryoballoon ablation (11/3,288; 0.34%) than with radiofrequency catheter, hot balloon, or laser balloon ablation (8/18,596 [0.04%], 0/237 [0%], and 0/111 [0%], respectively; P<0.001). CASs most often occurred during ablation of the left superior pulmonary vein. All patients recovered without sequelae. CONCLUSIONS: CASs related to AF ablation are rare, but should be considered as a dangerous complication that can occur anytime during the periprocedural period.

Predictors for reduced flow velocity in left atrial appendage during sinus rhythm in patients with atrial fibrillation.

Discontinuation of anticoagulation therapy after catheter ablation (CA) for atrial fibrillation (AF) remains controversial. While decreased left atrial appendage flow velocity (LAAFV) during AF leads to left atrial appendage thrombus and embolic events, some AF patients show decreased LAAFV even during sinus rhythm (SR). We studied 392 patients (256 males, 68 ± 10 years) who exhibited SR during transesophageal echocardiography (TEE) before CA for AF. Clinical factors, transthoracic echocardiography, and blood samples were obtained before TEE. Reduced LAAFV was defined as < 35 cm/s of LAAFV. Reduced LAAFV was observed in 72/392 patients (18%). Reduced LAAFV was significantly associated with high prevalence of non-paroxysmal AF, elevated brain natriuretic peptide (BNP), prior heart failure, high CHADS2 score, high CHA2DS2-VASc score, no beta blocker administration, increased left atrial volume index (LAVI), elevated E/e' ratio, reduced left ventricular ejection fraction and high prevalence of left ventricular hypertrophy. On multivariate analysis, BNP (P = 0.0005, OR 1.045 for each 10 pg/ml increase in BNP, 95% CI 1.018-1.073) and LAVI (P = 0.0045, OR 1.044 for each 1 increase in LAVI, 95% CI 1.013-1.077) were associated with decreased LAAFV. The elevated BNP levels and large LAVI predict decreased LAAFV during SR in patients with AF.

Is the abnormal conduction zone of the left atrium a precursor to a low voltage area in patients with atrial fibrillation?

BACKGROUND: The abnormal conduction zone (ACZ) in the left atrium (LA) has attracted attention as an arrhythmia source in atrial fibrillation (AF). We investigated the hypothesis that the ACZ is related to the low voltage area (LVA) or the LA anatomical contact areas (CoAs) with other organs. METHODS AND RESULTS: We studied 100 patients (49 non-paroxysmal AF, 66 males, and 67.9 ± 9.9 years) who received catheter ablation for AF. High-density LA mapping during high right atrial pacing was constructed. Isochronal activation maps were created at 5-ms interval setting, and the ACZ was identified on the activation map by locating a site with isochronal crowding of ≥3 isochrones, which are calculated as ≤27 cm/s. The LVA was defined as the following; mild ( < 1.3 mV), moderate (<1.0 mV), and severe LVA (<0.5 mV). The CoAs (ascending aorta-anterior LA, descending aorta-posterior LA, and vertebrae-posterior LA) were assessed using computed tomography. The ACZ was linearly distributed, and observed in 95 patients (95%). The ACZ was most frequently observed in the anterior wall region (77%). A longer ACZ was significantly associated with a larger LA size and a prevalence of non-PAF. The 51.2 ± 36.2% of ACZ overlapped with mild LVA, 32.9 ± 32.8% of ACZ with moderate LVA, and 14.6 ± 22.0% of ACZ with severe LVA. In contrast, only 25.6 ± 28.0% of ACZ matched with the CoAs. CONCLUSION: The ACZ reflects LA electrical remodeling and may be a precursor finding of the low voltage zone and not the LA CoAs in patients with atrial fibrillation.

Evaluation of an Integrated Device Diagnostics Algorithm to Risk Stratify Heart Failure Patients　- Results From the SCAN-HF Study.

BACKGROUND: Integrated device diagnostics, Triage-HF, is useful in risk stratifying patients with heart failure (HF), but its performance for Japanese patients remains unknown. This is a prospective study of Japanese patients treated with a cardiac resynchronization therapy defibrillator (CRT-D), with a Medtronic OptiVol 2.0 feature.Methods and Results:A total of 320 CRT-D patients were enrolled from 2013 to 2017. All received HF treatment in the prior 12 months. Following enrollment, they were followed every 6 months for 48 months (mean, 22 months). Triage-HF-stratified patients at low, medium and high risk statuses at every 30-day period, and HF-related hospitalization occurring for the subsequent 30 days, were evaluated and repeated. The primary endpoint was to assess Triage-HF performance in predicting HF-related hospitalization risk. All device data were available for 279 of 320 patients (NYHA class II or III in 93%; mean left ventricular ejection fraction, 31%). During a total of 5,977 patient-month follow-ups, 89 HF-related hospitalization occurred in 72 patients. The unadjusted event numbers for Low, Medium and High statuses were 19 (0.7%), 42 (1.6%) and 28 (4.1%), respectively. Relative risk of Medium to Low status was 2.18 (95% CI 1.23-3.85) and 5.78 (95% CI 3.34-10.01) for High to Low status. Common contributing factors among the diagnostics included low activity, OptiVol threshold crossing, and elevated night heart rate. CONCLUSIONS: Triage-HF effectively stratified Japanese patients at risk of HF-related hospitalization.

Predictors of movable type left atrial appendage thrombi in patients with atrial fibrillation.

Left atrial appendage thrombi (LAAT) are the main cause of thromboembolic events. Especially, movable type LAAT is high-risk for thromboembolic events. We aimed to investigate the predictors of the movable type LAAT in patients with atrial fibrillation (AF). We retrospectively studied 827 consecutive patients who underwent transthoracic echocardiography (TEE) prior to cardioversion or catheter ablation for AF. Sixty-nine patients who underwent cardiac surgery or significant valvular disease were excluded. The remaining 758 patients (age 67.6 ± 9.3, 535 males) were included in this study. Clinical data were evaluated at the time of TEE. The LAAT were classified into movable and fixed type LAAT by three independent observers who did not know clinical data. LAAT were detected in 57 (11 with movable and 46 with fixed type) of 758 patients (7.5%). Patients with movable type LAAT had an elevated E/e' ratio, lower left ventricular ejection fraction (LVEF), larger left atrial volume index, elevated C-reactive protein, higher prevalence of non-paroxysmal AF, patients taking warfarin (73% vs. 21%, P < 0.0001), and structural heart disease than control group (fixed type LAAT and without LAAT). On multivariate analysis, E/e' ratio, LVEF, and taking warfarin were significantly associated with movable type LAAT. The rate of movable type LAAT was the highest (7 of 49 patients, 14.3%) in patients with elevated E/e' ratio (> 12.7) and decrease LVEF (< 44%). E/e' ratio and LVEF could predict movable type LAAT in patients with AF. High-risk patients might need powerful antithrombotic therapy or taking early TEE.

Left Ventricular Inflow Velocity Pattern in Patients With Symptomatic Premature Ventricular Contraction.

BACKGROUND: Because premature ventricular contractions (PVCs) are one of the most common arrhythmias, but with unclear causative mechanisms, we studied the hemodynamic features that can cause symptomatic PVCs.Methods and Results:We studied 109 patients (48 males, age 60±19 years) with frequent monomorphic PVCs and no structural heart disease. The left ventricular inflow diastolic filling velocity was recorded by transthoracic echocardiography (TTE) at the time of PVCs in all patients. We assessed the PVC E wave flow (E wave velocity×duration at PVC). A total of 38 patients (35%) had PVC-related symptoms (19 palpitations, 12 pulse deficit, 6 shortness of breath, 6 malaise, 1 syncope). These patients showed reduced PVC E wave flow (9.3±6.0 vs. 14.6±6.5 cm, P<0.0001), and reduced PVC stroke volume (20.5±10.8 vs. 29.9±17.2 mL, P=0.0030). In the multivariate analysis, only reduced PVC E wave flow was independently associated with PVC-related symptoms (P=0.00349, odds ratio: 1.134029, each 1.0 cm increase in PVC E wave flow, 95% confidence interval: 1.040726-1.247544). CONCLUSIONS: Decreased E wave flow at the time of PVC was independently related with PVC-related symptoms in patients with PVCs. The LV contraction at the time of inadequate filling might be a cause of PVC-related symptoms.

The association between left atrial stiffness and low-voltage areas of left atrium in patients with atrial fibrillation.

The low-voltage areas of left atrium (LA-LVA) have recently been of significant focus. However, very few studies have focused on the association between LA function and LA-LVA, and the mechanism of appearance of LA-LVA remains unclear. We investigated the marker for the existence of LA-LVA using automated 3-D mapping system. We studied 92 patients (75 males, 68 ± 9 years, 47 non-paroxysmal AF) who received CA for AF and 40 control patients without AF. Echocardiography was performed before the CA, and high-density voltage mapping during sinus rhythm after pulmonary isolation was performed in AF patients. LA-LVA was defined as < 0.5 mV, and LA stiffness index (LASI) was defined as the ratio of E/e' to LA peak strain. LA-LVA (LVA burden > 10%) was detected in 19/92 AF patients (21%). Patients with LA-LVA were associated with higher LASI (1.64 ± 1.70 vs. 0.61 ± 0.46, p < 0.0001), larger LA volume, non-paroxysmal AF, higher brain natriuretic peptide, structural heart disease, and older age. On multivariate analysis, LASI, LA volume, and age were independently associated with the existence of LA-LVA. Of these markers, the highest area under curve was obtained with LASI. The rate of high LASI (≥ 0.552) was highest in AF patients with LA-LVA. Moreover, the existence of LVA in anterior LA wall was associated with higher LASI. High LA stiffness index was associated with the presence of LA-LVA. The LA-LVA might be attributed to LA functional remodeling rather than LA anatomical remodeling.

A novel protocol for initial heparin administration during catheter ablation for atrial fibrillation in patients taking direct oral anticoagulants.

Thromboembolism and bleeding complications remain a major limitation of the catheter ablation (CA) for atrial fibrillation (AF). This study aimed to evaluate the association between achieving target activated clotting time (ACT) and clinical factors, and to develop an appropriate protocol for early achievement of target ACT in patients with direct oral anticoagulants (DOACs). At the initiation cohort, 190 patients (127 males, age 68 ± 9) taking DOACs who underwent CA for AF were studied. All patients underwent transthoracic echocardiography/transesophageal echocardiography/blood sampling before the CA. The ACTs were measured before heparin administration (pre-ACT) and in 30 min (30-min ACT) after initial heparin administration (100 U/kg +3000 U). At the validation cohort, the indicator obtained from the first study was reassessed in the subsequent 138 patients (94 males, age 68 ± 10). At the initiation cohort, 30-min ACT reached the target ACT in 79/190 patients (42%). Univariate analysis showed that longer pre-ACT, elevated aPTT, higher PT-INR, antiplatelet medication, and dabigatran were associated with achieving the target 30-min ACT. On multivariate analysis, only longer pre-ACT was independently associated with achieving the target 30-min ACT (P = 0.0396, the optimal cutoff value; 130 s). As a novel protocol, we added 2000 U of initial heparin dose (total 100 U/kg +5000 U) in patients with low pre-ACT (< 130); then, the achievement rate to target 30-min ACT improved from 41.6 to 80.5% without increasing bleeding complications. Our novel protocol of initial heparin administration based on pre-ACT is useful for an appropriate systemic anticoagulation in patients taking DOACs during the CA for AF.

Predictors of Left Atrial Thrombi and Spontaneous Echocardiographic Contrast in the Acute Phase After Cardioembolic Stroke in Patients With Atrial Fibrillation.

INTRODUCTION: The underlying mechanism of the residual left atrial thrombus (LAT)/spontaneous echo contrast (SEC) after the onset of cardioembolic stroke (CES) is unknown. This study aims to investigate the utility of CHADS2 and CHA2DS2-VASc scores for predicting LAT/SEC, and to investigate the risk factors of residual LAT/SEC after CES onset. METHODS: This retrospective study included 124 patients who were admitted with the acute phase of CES at our center. The clinical, echocardiographic variables, the CHADS2/CHA2DS2-VASc scores, and National Institutes of Health Stroke Scale score were retrospectively assessed on admission. RESULTS: Of 124 patients, LAT or SEC was detected in 39 patients (31.5%, 17 LAT and 38 SEC). Univariate analysis showed that the LAT/SEC group had a higher prevalence of nonparoxysmal atrial fibrillation (AF), left ventricular (LV) hypertrophy, hypertension, the rate of anticoagulation before admission, higher National Institutes of Health Stroke Scale score, larger left atrial diameter, and elevated E wave. In contrast, the CHADS2 and CHA2DS2-VASc scores were not associated with LAT/SEC. LAT/SEC was associated with nonparoxysmal AF and LV hypertrophy on multivariate analysis. Moreover, all patients were divided into 4 groups based on the combination between non-paroxysmal AF and LV hypertrophy. The rate of LAT/SEC was the highest (87.5%) in patients with nonparoxysmal AF and LV hypertrophy. CONCLUSIONS: Nonparoxysmal atrial fibrillation and left ventricular hypertrophy were associated with residual left atrial thrombus/spontaneous echo contrast in the acute phase after cardioembolic stroke that was independent of the CHADS2 and CHA2DS2-VASc scores.

Left atrial ejection force predicts the outcome after catheter ablation for paroxysmal atrial fibrillation.

INTRODUCTION: Left atrium (LA) systolic dysfunction is observed in the early stages of atrial fibrillation (AF) prior to LA anatomical change. We investigated whether LA systolic dysfunction predicts recurrent AF after catheter ablation (CA) in patients with paroxysmal AF. METHODS AND RESULTS: We studied 106 patients who underwent CA for paroxysmal AF. LA systolic function was assessed with the LA emptying volume = Maximum LA volume (LAVmax ) - Minimum LA volume (LAVmin ), LA emptying fraction = [(LAVmax - LAVmin )/LAVmax ] × 100, and LA ejection force calculated with Manning's method [LA ejection force = (0.5 × ρ × mitral valve area × A2 )], where ρ is the blood density and A is the late-diastolic mitral inflow velocity. Recurrent AF was detected in 35/106 (33%) during 14.6 ± 9.1 months. Univariate analysis revealed reduced LA ejection force, decreased LA emptying fraction, larger LA diameter, and elevated brain natriuretic peptide as significant variables. On multivariate analysis, reduced LA ejection force and larger LA diameter were independently associated with recurrent AF. Moreover, patients with reduced LA ejection force and larger LA diameter had a higher risk of recurrent AF than preserved LA ejection force (log-rank P = 0.0004). CONCLUSIONS: Reduced LA ejection force and larger LA diameter were associated with poor outcome after CA for paroxysmal AF, and could be a new index to predict recurrent AF.

Left atrial pressure pattern without a-wave in sinus rhythm after cardioversion affects the outcomes after catheter ablation for atrial fibrillation.

The a-wave in left atrial pressure (LAP) is often not observed after cardioversion (CV). We hypothesized that repeated atrial fibrillation (AF) occurs in patients who do not show a-wave pattern after CV. We investigated the impact of "LAP pattern without a-wave" on the outcome after catheter ablation (CA) for AF. We studied 100 patients (64 males, age 66 ± 8 years, 42 with non-paroxysmal AF) who underwent CA for AF. Sustained- or induced-AF were terminated with internal CV, and LAP was measured during sinus rhythm (SR) after CV. LAP pattern without a-wave was defined as absence of a-wave (the "a-wave" was defined as a protruding part by 0.2 mmHg or more from the baseline) in LAP wave form. AF was terminated with CV in all patients. Recurrent AF was detected in 35/100 (35%) during the follow-up period (13.1 ± 7.8 month). Univariate analysis revealed higher prevalence of LAP pattern without a-wave (71 vs. 17%, P < 0.0001), larger left atrial volume, elevated E wave, and decreased deceleration time as significant variables. On multivariate analysis, LAP pattern without a-wave was only independently associated with recurrent AF (P = 0.0014, OR 9.865, 95% CI 2.327-54.861). Moreover, patients with LAP pattern without a-wave had a higher risk of recurrent AF than patients with a-wave (25/36 patients, 69 vs. 10/64 patients, 16%, log-rank P < 0.0001). Left atrial pressure pattern without a-wave in sinus rhythm after cardioversion could predict recurrence after catheter ablation for AF.

Interatrial septal motion as a novel index to predict left atrial pressure.

We investigated whether the interatrial septal (IAS) motion of each heartbeat which is observed by transesophageal echocardiography reflects left atrial pressure (LAP) in patients with atrial fibrillation (AF). We studied 100 patients (70 males, age 67 ± 9 years) who underwent catheter ablation for AF. The amplitude of IAS motion was measured using M-mode and averaged for five cardiac cycles. Left and right atrial pressures, the left to right atrial pressure gradient were directly measured during the catheter ablation. In patients with sinus rhythm during measurement, elevated mean LAP, larger maximum left to right atrial pressure gradient, and greater left atrial emptying fraction were associated with IAS motion. The optimal cut-off value of the IAS motion for predicting high LAP (mean LAP > 15 mmHg) was 8.5 mm (sensitivity 100%, specificity 70.1%) in patients with sinus rhythm during pressure measurement. In addition, all patients were divided into 6 groups based on rhythm during measurement and cutoff value of IAS motion. In patients with sinus rhythm during measurement, low IAS motion group had a highest prevalence of elevated LAP compared with high IAS motion group (64 vs. 0%, P < 0.0001). The amplitude of interatrial septal motion during sinus rhythm reflects left atrial pressure in patients with atrial fibrillation. Interatrial septal motion could be a new index to predict elevated left atrial pressure.

Differences in amiodarone efficacy in relation to ejection fraction and basal rhythm in patients with implantable cardioverter defibrillators.

BACKGROUND: Atrial fibrillation (AF) and ventricular arrhythmias (VAs) are associated with increased morbidity and mortality. However, data are lacking concerning the association of AF and VAs. This study aimed to clarify the association between AF and VAs and to investigate the effect of amiodarone on the incidence of VAs in patients with implantable cardioverter defibrillators (ICDs). METHODS AND RESULTS: We enrolled 612 patients who had ICDs or who underwent cardiac resynchronization therapy with a defibrillator (CRT-D) and classified them into two groups (sinus rhythm [SR] group, n = 427; AF group, n = 185) according to their basal rhythm at enrollment. Patients with paroxysmal AF were grouped into the AF group. The incidence of VAs, i.e., ventricular tachycardia (VT) and ventricular fibrillation (VF), was significantly lower in the AF group than in the SR group (0.54 vs 0.95 episodes/person/year, P = 0.032). Furthermore, amiodarone use was significantly higher in the AF group than in the SR group (P = 0.003). Non-use of amiodarone was associated with a significant increase in the occurrence of VT/VF in the two groups. This beneficial suppressive effect of amiodarone on the incidence of VT/VF was present in the AF group regardless of left ventricular ejection fraction (LVEF). However, this effect of amiodarone was present only in patients with LVEF ≥ 40% in the SR group. CONCLUSIONS: Amiodarone was negatively associated with VT/VF occurrence and was frequently used in ICD/CRT-D patients with AF. VT/VF was controlled by amiodarone in all cases in the AF group but only in patients with an LVEF ≥ 40% in the SR group.

The Impact of Transforming Growth Factor-ß1 Level on Outcome After Catheter Ablation in Patients With Atrial Fibrillation.

INTRODUCTION: Transforming growth factor-ß1 (TGF-ß1 ) is an important factor that induces atrial fibrosis and atrial fibrillation (AF). The purpose of this study was to evaluate the association between TGF-ß1 level and clinical factors before catheter ablation (CA), and to investigate the impact of TGF-ß1 level on the outcome after CA for AF. METHODS AND RESULTS: This prospective study included 151 patients (persistent AF group: n = 59, paroxysmal AF [PAF] group: n = 54, and control group: n = 38). All patients who underwent CA for AF were followed up for 12 months. The PAF group had the highest TGF-ß1 levels in all patients. An early recurrence of AF (ERAF: defined as episodes of atrial tachyarrhythmia within a 3-month blanking period) was detected in 60 patients (53%). Recurrent AF after the blanking period was detected in 36 patients (32%). On multivariate analysis, low TGF-ß1 level was the only independent factor associated with recurrent AF. Moreover, the AF recurrence ratio was higher in the low TGF-ß1 group (< 12.56 ng/mL) than in the high TGF-ß1 group (16 of 29 patients, 55% vs. 20 of 84 patients, 24%, P = 0.002 by log-rank test). CONCLUSIONS: PAF was associated with a higher TGF-ß1 level. Moreover, lower TGF-ß1 level in AF patients could be a cause of recurrent AF after CA.

Efficacy of Intensive Radiofrequency Energy Delivery to the Localized Dense Scar Area in Post-Infarction Ventricular Tachycardia Ablation　- A Comparative Study With Standard Strategy Targeting the Infarcted Border Zone.

BACKGROUND: Several reports have demonstrated the importance of severely low voltage areas as arrhythmogenic substrates of ventricular tachycardia (VT). However, a comparative study of dense scar-targeted and infarcted border zone-targeted strategies has not been reported.Methods and Results:We divided 109 consecutive patients with VT post-infarction from 6 centers into 2 groups according to the ablation strategy used: dense scar-targeted ablation (DS ablation, 48%) or border zone-targeted ablation (BZ ablation, 52%). During DS ablation, we attempted to identify VT isthmuses in the dense scar areas (≤0.6 mV) using detailed pace mapping, and linear ablation lesions were applied mainly to those areas. During BZ ablation, linear ablation of standard low voltage areas (0.5-1.5 mV) was performed along with good pace map sites of the clinical VT. Acute success was defined as complete success (no VTs inducible) or partial success (clinical VT was noninducible). The acute complete success rate was significantly higher for DS ablation than for BZ ablation (62% vs. 42%, P=0.043). During a median follow-up of 37 months, the VT-free survival rate was significantly higher for DS ablation than for BZ ablation (80% vs. 58% at 48 months; log-rank P=0.038). CONCLUSIONS: DS ablation may be a more effective therapy for post-infarction VT than BZ ablation in terms of the acute complete success rate and long-term follow-up.

The Impact of Elevated Left Atrial Pressure in Sinus Rhythm After Cardioversion on Outcomes After Catheter Ablation for Atrial Fibrillation.

INTRODUCTION: Some patients with atrial fibrillation (AF) exhibit elevated left atrial pressure (LAP) in sinus rhythm (SR). The aim of the study was to investigate whether LAP changes between SR and AF are associated with outcomes after catheter ablation (CA) for AF. METHODS AND RESULTS: We retrospectively studied 110 patients (70 men, 66 ± 8 years, 37 with non-paroxysmal AF) who underwent CA of AF. In all patients, AF was induced by programmed stimulation and then terminated with cardioversion during CA. LAP was measured in SR and AF. The LAPSR-AF was defined as the difference between mean LAP in SR and mean LAP in AF (mean LAPSR - mean LAPAF ). Recurrence of AF after CA was detected in 37/110 patients (33.6%) during the follow-up period (13 ± 5 months). Univariate analysis revealed higher LAPSR-AF , larger left atrial diameter, and persistent AF (PeAF) as significant variables. On multivariate analysis, higher LAPSR-AF and PeAF were independently associated with recurrence of AF after CA. All patients were divided into the non-elevated LAPSR-AF group (LAPSR-AF <0 mmHg) or the elevated LAPSR-AF group (LAPSR-AF ≥0 mmHg) using the optimal cut-off value of LAPSR-AF . During a mean follow-up period of 13 ± 5 months, the AF recurrence ratio was higher in the elevated LAPSR-AF group than in the non-elevated LAPSR-AF group (20/42 patients, 48% vs. 17/68 patients, 25%, log-rank, P = 0.0306). CONCLUSION: Elevated LAP after cardioversion is associated with poor outcome after CA of AF. Sustained pressure overload of the LA in SR could be a cause of the recurrent AF.

The Effects of Shock from Defibrillation Threshold Testing on Cardiac Systolic and Diastolic Function.

BACKGROUND: Inappropriate implantable cardioverter defibrillator (ICD) shocks are associated with increased overall mortality. However, it remains unclear whether shocks from defibrillation threshold (DFT) testing directly impair cardiac function. METHODS: DFT testing was performed in 34 patients who underwent ICD/cardiac resynchronization therapy with a defibrillator implantation/generator exchange. Heart rate and cardiac function, including left ventricular (LV) systolic pressure, LV end-diastolic pressure, peak positive and negative dp/dt ( + dp/dt and -dp/dt, respectively) of LV pressure, and the tau index, were assessed with a Mikro-Cath™ diagnostic pressure catheter (CD Leycom, Zoetermeer, the Netherlands). These parameters were measured before and 1 minute, 3 minutes, 5 minutes, 10 minutes, and 15 minutes after DFT testing. RESULTS: Peak positive dp/dt increased over baseline at each interval (976 ± 229 mm Hg/s vs 1,039 ± 258, 1,049 ± 245, 1,042 ± 247, 1,037 ± 259, and 1,034 ± 254 mm Hg/s, respectively; P < 0.01). Furthermore, peak negative dp/dt (-1,140 ± 397 mm Hg/s vs -1,185 ± 447, 1,193 ± 435, -1,195 ± 434, -1,189 ± 449, and -1,186 ± 459 mm Hg/s, respectively; P < 0.01) and the tau index (65.1 ± 18.5 vs 62.5 ± 16.8*, 62.4 ± 15.9(**) , 63.0 ± 16.8*, and 62.8 ± 18.7*, respectively; *P < 0.05, (**) P < 0.01) decreased compared to those at baseline at each interval. CONCLUSION: Shock after DFT testing improved LV systolic and diastolic function immediately, especially in patients with preserved LV ejection fraction.

The impact of left atrial pressure on filtered P-wave duration in patients with atrial fibrillation.

The cause of prolonged filtered P-wave duration (FPD) remains unclear in atrial fibrillation (AF) patients with normal left atrial size. We investigated whether FPD is associated with left atrial pressure (LAP) in AF patients without prominent LA enlargement. This study included 80 patients (48 men, age 65 ± 9 years, 25 persistent AF) with non-valvular AF who underwent catheter ablation (CA) for AF. LAP was measured in sinus rhythm during CA and signal-averaged electrocardiogram was recorded after CA. We retrospectively assessed the clinical and echocardiographic variables. Prolonged FPD was defined as FPD > 120 ms. Prolonged FPD (FPD > 120 ms) was detected in 23/80 patients (29 %). According to univariate analysis, higher mean LAP (14.9 ± 4.4 vs. 10.8 ± 3.5 mmHg, p < 0.0001), higher prevalence of persistent arrhythmia, higher BNP, larger LAD, higher E wave, and lower LVEF were associated with Prolonged FPD. According to multivariate analysis, higher mean LAP was the only factor associated with Prolonged FPD (p = 0.0058, OR 1.256 for each 1 mmHg increase in mean LAP, 95 % CI 1.068-1.476). Moreover, a significant correlation was observed between FPD and mean LAP (r = 0.503, p < 0.0001). Prolonged FPD is associated with high LAP in AF patients without prominent left atrial enlargement. Pressure overload of the left atria might cause slowing of atrial electrical activation.

Does Left Atrial Appendage Morphology Influence Left Atrial Appendage Flow Velocity?

BACKGROUND: The shape of the left atrial appendage (LAA) might affect thrombus formation. The chicken wing-type LAA (CW) has been reported as unlikely to influence stroke events in atrial fibrillation (AF) patients, so we investigated whether LAA shapes could influence LAA function. METHODS AND RESULTS: We studied 102 patients (64 men, age 65±9 years) who underwent transthoracic echocardiography, transesophageal echocardiography (TEE), and cardiac computed tomography prior to catheter ablation (CA) for AF. LAA morphology were classified into 2 types: (1) CW: LAA with a bend in its shape and (2) non-CW type (NCW): LAA without any bends. All patients were classified into these groups using a cutoff value of LAA flow velocity (LAAFV). Patients with LAAFV <35 cm/s were classified as the low LAAFV group (Low FV, n=37). The patients with LAAFV >35 cm/s were classified as normal LAAFV group (Normal FV, n=65). The NCW type was detected in 25/102 patients (25%). In multivariate analysis, the patients with Low FV were associated with NCW type (P=0.0429, odds ratio [OR] 9.664, 95% confidence interval [CI] 1.075-86.900) and higher B-type natriuretic peptide (BNP) (P=0.0350, OR 1.012 for each 1 pg/ml increase in BNP, 95% CI 1.001-1.022). CONCLUSIONS: The NCW-type LAA and higher BNP were associated with lower LAAFV. One reason for the frequent cardiogenic stroke in patients with the NCW-type LAA may be the lower LAAFV.