Activated clotting time on the day of atrial fibrillation ablation for minimally interrupted and uninterrupted direct oral anticoagulation therapy: Sequential changes, differences among direct oral anticoagulants, and ablation safety outcomes.

BACKGROUND: Activated clotting time (ACT)-guided heparinization is used during atrial fibrillation (AF) ablation. Differences in sensitivity to ACT assays have been identified among different direct oral anticoagulants (DOACs). OBJECTIVE: We aimed to examine ACT just before ablation (pre-ACT) for different ablation start times (9:00, 11:00, 13:00, or 15:00) and ablation safety outcomes in minimally interrupted (min-Int) and uninterrupted (Unint) DOAC regimens and examine differences in pre-ACT values among four DOACs. METHODS: Consecutive patients were randomized into the min-Int (n = 307) or Unint (n = 277) groups. DOACs examined were apixaban, dabigatran, edoxaban, and rivaroxaban. RESULTS: No sequential changes in pre-ACT values were observed for each DOAC used and for all four DOACs combined in the min-Int and Unint groups. There was no meaningful difference in pre-ACT at each ablation start time between the groups. Clinically significant differences in overall pre-ACT were not obtained between the groups (138 ± 24 vs 142 ± 23 seconds). The pre-ACT (baseline) value for dabigatran was on average 29 seconds higher than that for the other three DOACs. The min-Int and Unint groups showed similar thromboembolic (0% vs 0%) and bleeding event rates (major, 1% vs 0%; all, 3.5% vs 2.5%). CONCLUSION: The pre-ACT did not show a sequential change in the min-Int and Unint groups. No notable differences in the time-dependent change in pre-ACT between the groups were observed. Variations in baseline ACT suggest the need for moderate adjustment of ACT for adequate modification of heparin dose for the other three DOACs. Both regimens provided similar acceptable AF ablation safety outcomes.

Effects of Oral Anticoagulants on Patients With Atrial Fibrillation Aged 90 Years and Older: Comparison Among Direct Oral Anticoagulant, Warfarin Anticoagulant, and Nonanticoagulation.

This study aimed to investigate the effects of anticoagulants on ultra-aged patients with nonvalvular atrial fibrillation (AF). We retrospectively studied 320 consecutive patients with AF (median age, 91 years; range 90-100.1 years). Patients were categorized as follows: patients taking direct oral anticoagulant (DOAC group, n = 93), those taking warfarin (warfarin group, n = 147), and those not taking oral anticoagulants (non-OAC group, n = 80). During the follow-up periods (median 3.00 years; first and fourth quantiles, 1.13 and 4.56 years, respectively), in thromboembolic events, the DOAC, warfarin, and non-OAC groups showed the lowest (0%, 0/93; 0%/year), intermediate (4.7%, 7/149; 1.43%/year), and highest (5%, 4/80; 2.65%/year) incidence rates, respectively. In major bleeding events, the DOAC, warfarin, and non-OAC groups showed the highest (9.67%, 9/96; 5.00%/year), intermediate (8.1%, 12/149; 2.46%/year), and lowest (0%, 0/80; 0%/year) incidence rates, respectively. These differences in the relationships of the 3 groups were statistically significant. Confounding factors did not affect these results. Bruises associated with impairment of motor function with aging caused major bleeding in approximately 60% of major bleeding cases. The Cox proportional hazards model revealed that warfarin decreased mortality, whereas antiplatelet drugs increased mortality. In conclusion, DOACs had considerably high incidence of major bleeding events, whereas absence of OAC treatment was associated with substantially high thromboembolic events. Warfarin showed acceptable incidence ratios of both events. At present, warfarin is thus believed to be adequate for ultra-aged (≥90 years) patients with nonvalvular AF. Avoidance of bruises was important to prevent major bleeding events. Antiplatelet drugs were suggested not to be adequate for these patients.

Adjunctive left anterior line ablation induced left atrial dysfunction and dyssynchrony in atrial fibrillation ablation.

We evaluated the effects of adjunctive left anterior line (LAL) ablation on LA dyssynchrony and function using real-time three-dimensional echocardiography (3DE) in connection with thromboembolic complications and tachyarrhythmia recurrence in patients with persistent atrial fibrillation (AF). We randomly and prospectively assigned consecutive persistent AF patients to the LAL (n = 52, 65 ± 7 years) and control groups (n = 50, 64 ± 10 years). In the LAL group, extensive encircling pulmonary vein isolation (EEPVI), roof line ablation, and LAL ablation regardless of the extent of the low-voltage area (LVA) were performed. The control group underwent EEPVI and roof line ablation. After ablation, 3DE demonstrated LA dyssynchrony in 23 (46%) and 4 patients (8%, P < 0.001) of the LAL and control groups, respectively. Baseline LA LVAs were relatively small in most patients and there were no significant differences in extent of LVA between control and LAL groups or between patients with and without dyssynchrony. During the follow-up periods (771 ± 121 days), patients with LA dyssynchrony in the LAL group did not show significant differences in symptomatic thromboembolic events (0%) and atrial tachyarrhythmia recurrence (39%) from patients without LA dyssynchrony in the LAL (0% and 30%) and control groups (0% and 32%, respectively). LA ejection fraction and active emptying fraction were lower by 9% on average in the LAL group than in the control group (P < 0.0001). Similarly, in the LAL group, LA ejection fraction, active emptying fraction, and expansion index were significantly lower by approximately 7%, 8%, and 15%, respectively, in LA with dyssynchrony than those in LA without dyssynchrony. In conclusion, LA dyssynchrony and LA hypofunction were induced by LAL ablation in patients with persistent AF and relatively mild LVA. LAL ablation with or without LA dyssynchrony is thought not to affect thromboembolic complications or atrial tachyarrhythmia recurrence.

Differences in activated clotting time and initial heparin dosage during atrial fibrillation ablation for patients with edoxaban compared with warfarin.

BACKGROUND: Different target activated clotting times (ACTs) during atrial fibrillation (AF) ablation have been proposed. Moreover, relationships between initial bolus dose of heparin at the start of AF ablation in patients receiving edoxaban anticoagulation therapy and ACT are unclear. METHODS: Patients who received anticoagulation with uninterrupted warfarin (control; n = 120) or interrupted edoxaban (n = 120) on the morning of day of ablation were studied. An initial dose of 100 U/kg heparin was administered as a reliable control for warfarin. Initial heparin doses of 120, 130, 140, or 150 U/kg were randomly administered to the edoxaban group. RESULTS: Edoxaban group showed shorter baseline ACT before the procedure (130 ± 16 seconds) than the warfarin group (152 ± 26 seconds, P < 0.0001). In the warfarin group, 100 U/kg heparin showed 361 ± 48 seconds 15-minute ACT. In the edoxaban group, an increase in initial dose induced prolongation of 15-minute ACT (i.e., 15-minute ACTs of 293 ± 56, 306 ± 39, 311 ± 45, and 319 ± 45 seconds for 120, 130, 140, and 150 U/kg initial doses, respectively). The total heparin required during the procedure was higher in the edoxaban group than in the warfarin group (109 ± 37 vs. 77 ± 21 U/kg/h, P < 0.0001). The 120-150 U/kg dose of heparin in edoxaban group did not cause thromboembolic or major bleeding complications. CONCLUSION: Edoxaban interrupted on the day of ablation showed a shorter baseline ACT than uninterrupted warfarin. Edoxaban required a higher initial heparin dose to achieve a similar 15-minute ACT to warfarin. These results are useful for determining the initial heparin dose required to achieve variable target ACTs.

Safety and Efficacy of Underdosing Non-vitamin K Antagonist Oral Anticoagulants in Patients Undergoing Catheter Ablation for Atrial Fibrillation.

BACKGROUND: Some patients with atrial fibrillation (AF) received underdoses of non-vitamin K antagonist oral anticoagulants (NOACs) in the real world. Underdosing is defined as administration of a dose lower than the manufacturer recommended dose. OBJECTIVES: To identify the efficacy and safety of underdosing NOACs as perioperative anticoagulation for atrial fibrillation ablation. METHODS: We retrospectively analyzed patients who received rivaroxaban or dabigatran etexilate according to dosage: adjusted low dosage (reduced by disturbed renal function; n = 30), underdosage (n = 307), or standard dosage (n = 683). Non-vitamin K antagonist oral anticoagulants and dosing decisions were at the discretion of treating cardiologists. RESULTS: Patients who received underdosed NOACs were older, more often female, and had lower body weight and lower renal function than those who received standard dosages. Activated clotting time at baseline in patients who received adjusted low dosage or underdosages was slightly longer than that in patients receiving standard dosages (156 ± 23, 151 ± 224, and 147 ± 24 seconds, respectively). Meaningful differences were not observed in other coagulation parameters. Adjusted low-, under-, and standard-dosing regimens did not differ in perioperative thromboembolic complications (0/30, 0.0%; 1/307, 0.3%; and 0/683, 0%, respectively) or major (0/30, 0.0%; 2/307, 0.6%; 3/683, 0.4%) and minor (1/30, 3.3%; 13/307, 4.2%; 25/683, 3.6%) bleeding episodes. When comparisons were performed for each NOAC, similar results were observed. CONCLUSIONS: With consideration of patient condition, age, sex, body weight, body mass index, and renal function, underdosing NOACs was effective and safe as a perioperative anticoagulation therapy for atrial fibrillation ablation. The therapeutic range of NOACs is potentially wider than manufacturer recommendations.

Adaptive-servo ventilation combined with deep sedation is an effective strategy during pulmonary vein isolation.

AIMS: Pulmonary vein isolation (PVI) by catheter ablation for atrial fibrillation (AF) requires suppression of patient restlessness by sufficient sedation in addition to maintaining stable respiration. We applied adaptive-servo ventilation (ASV) and examined the effects of ASV combined with deep propofol sedation on PVI using a NavX. METHODS AND RESULTS: We analysed 75 paroxysmal AF (PAF) patients (62 ± 11 years; 53 men and 22 women) who underwent PVI for treatment of PAF using an ASV system combined with deep sedation (ASV group). Control patients included 75 consecutive PAF patients (62 ± 11 years; 51 men and 24 women) who underwent PVI just before introduction of the ASV system. Deep sedation was defined as a Ramsay sedation score of 6. The ASV group had a lower frequency of restless body movements compared with the control group during PVI (1.5 ± 0.7 vs. 7.8 ± 1.4 times, P < 0.01). The frequency of respiratory compensation and EnGuide alignment of catheter position by the NavX was lower in the ASV (4.2 ± 3.3 and 8.8 ± 7.1 times) than control group (7.1 ± 5.1 and 15.2 ± 10.0 times, P < 0.05 and <0.01, respectively). Consequently, significantly lower total electrical energy supply (48.7 ± 6.0 KJ) was required in the ASV than control group (64.5 ± 24.9 KJ, P < 0.01). Further, significantly shorter fluoroscopy and procedural times were observed in the ASV (28 ± 5 and 109 ± 25 min) than the control group (33 ± 6 and 141 ± 38 min, respectively, P < 0.01) and the AF recurrence rate was significantly lower in the ASV than the control group (12 vs. 25%, P < 0.01). CONCLUSION: ASV combined with deep sedation is an effective strategy during PVI using the NavX in patients with PAF.

Radiofrequency catheter ablation of the accessory pathway adversely affected the left ventricular outflow tract pressure gradient in a patient with hypertrophic obstructive cardiomyopathy.

Although hypertrophic cardiomyopathy (HCM) with an accessory pathway is encountered in clinical practice, there is little evidence of a coherent strategy for ablation of the accessory pathway in patients with HCM. We present the case of a 61-year-old man who had type B Wolff-Parkinson-White (WPW) syndrome with hypertrophic obstructive cardiomyopathy (HOCM). Due to paroxysmal atrial fibrillation, he underwent radiofrequency catheter ablation of the accessory pathway located in the right postero-lateral wall to prevent secondary symptomatic events. His LV dyssynchrony improved after the procedure, but the degree of the LV outflow tract (LVOT) pressure gradient was increased. To stabilize the LVOT pressure gradient, he needed additional medications. This case shows that patients with HOCM should be carefully evaluated before making a decision concerning ablation of the accessory pathway.

Sufficient pulmonary vein image quality of non-enhanced multi-detector row computed tomography for pulmonary vein isolation by catheter ablation.

AIMS: We evaluated the quality of non-enhanced multi-detector row computed tomography (MDCT) images of the pulmonary vein (PV) and the clinical results of catheter ablation to isolate the PV for treatment of atrial fibrillation (AF) without the use of contrast medium in patients with chronic kidney disease (CKD). METHODS AND RESULTS: We compared PV images quantitatively and qualitatively between non-enhanced and enhanced images (n = 50). Procedural parameters and clinical outcomes were compared between catheter ablation for AF referring solely to non-enhanced MDCT in CKD patients (n = 20) and using enhanced MDCT images integrated with electroanatomic mapping in non-CKD patients (n = 30). In gross anatomy, complete agreement was obtained between non-enhanced and enhanced MDCT images. Bland-Altman plots and cumulative coefficient variation showed good agreement in PV diameter determination between non-enhanced and enhanced MDCT images. There were no statistically significant differences in procedural or fluoroscopic times between PV isolation only referring to non-enhanced MDCT images and that using enhanced MDCT images integrated with electroanatomic mapping. Similarly, the ablation success rate and AF-free status at 3 months after PV isolation did not differ between PV isolation referring only to non-enhanced MDCT images and that using an electroanatomic integration system. No complications occurred in PV isolation with or without enhanced MDCT. CONCLUSIONS: Non-enhanced MDCT provides adequate PV image quality both quantitatively and qualitatively. The present study suggests that catheter ablation referring solely to non-enhanced MDCT images for AF could be performed with clinically acceptable results. These findings warrant further studies involving a much larger number of patients to confirm the present results.

Efficacy of an Adjunctive Electrophysiological Test-Guided Left Atrial Posterior Wall Isolation in Persistent Atrial Fibrillation Without a Left Atrial Low-Voltage Area.

BACKGROUND: Electrical remodeling precedes structural remodeling. In adjunctive left atrial (LA) low-voltage area (LVA) ablation to pulmonary vein isolation of atrial fibrillation (AF), LA areas without LVA have not been targeted for ablation. We studied the effect of adjunctive LA posterior wall isolation (PWI) on persistent AF without LA-LVA according to electrophysiological testing (EP test). METHODS: We examined consecutive patients with persistent AF with (n=33) and without (n=111) LA-LVA. Patients without LA-LVA were randomly assigned to EP test-guided (n=57) and control (n=54) groups. In the EP test-guided group, an adjunctive PWI was performed in those with positive results (PWI subgroup; n=24), but not in those with negative results (n=33). The criteria for positive EP tests were an effective refractory period ≤180 ms, effective refractory period>20 ms shorter than the other sites, and/or induction of AF/atrial tachycardia (AT) during measurements. LVA ablation was performed in the patients with LA-LVA. RESULTS: During the follow-up period (62±33 weeks), the EP test-guided group had significantly lower recurrence rates (19%,11/57 versus 41%, 22/54, P=0.012) and higher Kaplan-Meier AF/AT-free survival curve rates than the control group (P=0.01). No significant differences in the recurrence and AF/AT-free survival curve rates between the PWI (positive EP test) and non-PWI (negative EP test) subgroups were observed. Therefore, PWI for positive EP tests reduced the AF/AT recurrence in the EP test-guided group. A stepwise Cox proportional hazard analyses identified EP test-guided ablation as a factor reducing the recurrence rate. The recurrence rates in the LA-LVA ablation group and EP test-guided group were similar. CONCLUSIONS: This pilot study proposed that an EP test-guided adjunctive PWI of persistent AF without LA-LVA potentially reduced AF/AT recurrences. The results suggest that there is an AF substrate in the LA with altered electrophysiological function even when there is no LA-LVA. Graphic Abstract: A graphic abstract is available for this article.

Correlation of the peak oxygen consumption and ventilatory aerobic threshold by cardiopulmonary exercise testing with atrial fibrillation recurrences after ablation in patients with paroxysmal atrial fibrillation.

BACKGROUND: The cardiopulmonary function is hypothesized to be associated with atrial fibrillation/atrial tachyarrhythmia (AF/AT) recurrence after AF ablation. PURPOSE: To clarify the relationship between the cardiopulmonary function after successful ablation and AF/AT recurrence. METHODS: We examined 31 patients with paroxysmal AF who underwent AF ablation. Cardiopulmonary exercise testing (CPET) was performed at 1month after the ablation. A continuously increasing loading method on a bicycle ergometer was employed for the CPET. RESULTS: No adverse events, including AF/AT recurrence, occurred during the CPET. Among 31 patients, AT/AF recurrence was observed in seven (23%). The ventilatory anaerobic threshold (VAT) and peak oxygen consumption (VO2) were significantly higher in patients without AF/AT recurrence than in those with AT/AF recurrences (peak VO2 23.6 ± 5.7 vs 17.2 ± 4.1 mL/kg/min; VAT, 16.7 ± 2.8 vs 13.8 ± 2.7 mL/min/kg). The areas under the receiver operating characteristic curve for the peak VO2 and VAT were 0.786 (P < .01) and 0.789(P < .01), respectively. Both indices had a sensitivity of 70%-80% and specificity of 70%-80% for predicting AT/AF recurrence. Similar results were obtained for the percent values of the predicted peak VO2 and VAT. CONCLUSIONS: The present pilot study found that CPET can be performed safely at approximately 1 month after AF ablation. The peak VO2 and VAT were significantly associated with AT/AF recurrence. The peak VO2 and VAT were thought to provide helpful information regarding AT/AF recurrence.

Association of elevated plasma B-type natriuretic peptide levels with paroxysmal atrial fibrillation in patients with nonobstructive hypertrophic cardiomyopathy.

OBJECTIVES: To investigate the relationship between the plasma B-type natriuretic peptide (BNP) level and the occurrence of atrial fibrillation (AF) in nonobstructive hypertrophic cardiomyopathy (HCM) patients. METHODS: Patients (n=97) were classified into chronic AF (CAF; n=14), paroxysmal AF (PAF; n=18) and normal sinus rhythm (NSR; n=65) groups. The plasma BNP values were analyzed with logarithmic transformation. RESULTS: The PAF group showed significantly higher plasma BNP levels than the NSR group [mean (range; -l SD and +1 SD); 248.3 (143.5, 429.5) vs. 78.2 (27.9, 218.8 ng/L), p<0.0001]. The CAF group also showed significantly higher plasma BNP levels than the NSR group [291.1 (161.4, 524.8 ng/L), p<0.0001]. Multivariate analysis with other clinical factors selected association of PAF as one of the factors that increased the plasma BNP level. CONCLUSIONS: The present study indicated that plasma BNP level is clinically useful for identification of nonobstructive HCM patients who have a risk of PAF.

Higher incidence and serum levels of minor cardiac biomarker elevation in sirolimus-eluting stent (Cypher) than bare metal stent implantations.

OBJECTIVES: Minor cardiac biomarker elevation after percutaneous coronary intervention has long-term prognostic significance. The sirolimus-eluting stent (Cypher) has been reported to require high postinflation pressure for optimal implantation. We examined the incidence of minor cardiac biomarker elevation induced by Cypher implantation. METHODS: We measured the serum concentration of cardiac troponin-I (cTnI) 24 h after stenting and those of creatine kinase isoenzyme MB and creatine kinase before, immediately after, and 6, 12 and 24 h after implantation in patients who underwent Cypher stent (CS group; n=53) or bare metal stent (BMS group; n=57) implantation. RESULTS: No significant difference in clinical background was observed between the two groups. When a cutoff cTnI value of 0.50 ng/ml was used, the CS group showed a significantly higher incidence of cTnI elevation (35.8%, 19/53) than the BMS group (14.0%, 8/57) (P<0.05). Similarly, the incidence of cTnI > or = 0.03 ng/ml tended to be higher in the CS group (88.7%, 47/53) than in the BMS group (73.7%, 42/57: 0.05

A rapid and precise method for measuring plasma apoE-rich HDL using polyethylene glycol and cation-exchange chromatography: a pilot study on the clinical significance of apoE-rich HDL measurements.

BACKGROUND: High-density lipoprotein (HDL) containing apolipoprotein E (apoE-rich HDL) represents only a small portion of plasma HDL. Reliable methods for determining and isolating apoE-rich HDL have not been well studied. METHODS: We established a novel analytical method for apoE-rich HDL using polyethylene glycol and a cation-exchange column (PEG-column method). Furthermore, we examined biochemical correlates of apoE-rich HDL-cholesterol (HDL-C) in 36 patients who underwent coronary computed tomographic angiography. RESULTS: Our PEG-column method demonstrated high reproducibility (coefficient of variation <3.52%) and linearity up to 15mg/dl for apoE-rich HDL-C concentrations. Isolated apoE-rich HDL exhibited a larger diameter (14.8nm) than apoE-poor HDL (10.8nm) and contained both apoE and apoA-I. ApoE-rich HDL-C concentrations correlated significantly with triglycerides (rs=-0.646), LDL size (rs=0.472), adiponectin (rs=0.476), and other lipoprotein components. No significant correlation was obtained with the coronary calcium score. Multiple regression analysis revealed that plasma triglycerides and adiponectin concentrations remained significant independent predictors of apoE-rich (adjusted R2=0.486) but not apoE-poor HDL-C. CONCLUSIONS: The PEG-column method demonstrated, to various degrees, significant correlations between HDL subfractions and several lipid-related biomarkers involved in an atherogenic lipoprotein profile. Our separation technique for apoE-rich HDL is useful to clarify the role of apoE-rich HDL in atherosclerosis.

Adjunctive interpulmonary isthmus ablation has no added effects on atrial fibrillation recurrence.

OBJECTIVE: Data on the efficacy of adjunctive interpulmonary isthmus ablation following completion of extensive encircling pulmonary vein isolation (EEPVI) on atrial fibrillation (AF) recurrence have still been insufficient. We aimed to compare the AF recurrence between EEPVI with and without adjunctive interpulmonary isthmus ablation. METHODS: We enrolled 200 consecutive patients with paroxysmal AF (first session) who underwent EEPVI with double-Lasso technique. Patients were prospectively randomised into two groups: EEPVI with (group 1) and without (group 2) adjunctive interpulmonary isthmus ablation. RESULTS: No differences were found in patients' clinical and echocardiographic backgrounds, including arrhythmia status, between the two groups. No differences were also observed in complications (two groin haematoma in both groups). All patients in both groups reached the EEPVI endpoint. The AF recurrence rate between groups 1 (32/100, 32%) and 2 (33/100, 33%; p=1.0) was quite similar during the follow-up period (45±5 months; 36-54 months). The two groups showed identical Kaplan-Meier AF-free curves (p=0.460; NS). Similar pulmonary vein (PV) reconnection incidence was observed in both groups during the second session. Durable isolation between the superior and inferior PVs was confirmed in 88% (21/27) of patients in group 1, indicating that interpulmonary isthmus ablation maintained a non-conducting state in a considerable number of patients. Nevertheless, AF recurrence was identical between the two groups. CONCLUSION: The results of our study showed similar AF recurrence rates between the two groups, indicating that adjunctive interpulmonary isthmus ablation with EEPVI has no obvious effects on AF recurrence.

Coronary pressure measurement to identify the lesion requiring percutaneous coronary intervention in equivocal tandem lesions.

OBJECTIVES: No reliable methods are available for determining application of percutaneous coronary intervention for treatment of equivocal tandem lesions. We investigated whether coronary pressure measurement is useful for determining the lesion that requires percutaneous coronary intervention in tandem lesions. METHODS: We measured coronary pressure in 72 consecutive patients with tandem lesions. Myocardial fractional flow reserve (FFRmyo) was obtained as the ratio of coronary pressure distal to the lesion/aortic pressure under maximal hyperemia. If the FFRmyo across the tandem lesions was >or=0.75, we deferred percutaneous coronary intervention for the lesion. When the tandem lesions showed FFRmyo<0.75, percutaneous coronary intervention was performed on the lesion that showed angiographically higher stenosis. When FFRmyo was <0.75 after one-lesion percutaneous coronary intervention, this intervention was carried out on the remaining lesion. RESULTS: We deferred percutaneous coronary intervention for 26 patients (36.1%), and performed percutaneous coronary intervention in 46 patients (63.8%). We performed percutaneous coronary intervention for one lesion in 19 patients (26.4%) and for both lesions in 27 patients (37.5%). Among patients in whom percutaneous coronary intervention was deferred, only two patients (7.7%) required target lesion revascularization during the follow-up period. This rate was not higher than that in the 46 patients who underwent percutaneous coronary intervention for one or two lesions (six patients, 13.0%). Similarly, the target lesion revascularization in lesions with initially deferred percutaneous coronary intervention (5.6%, 4/71 lesions) was not higher than that in lesions with percutaneous coronary intervention (15.1%, 11/73 lesions). Major cardiac events, cardiac death and acute myocardial infarction, did not occur in patients with deferred percutaneous coronary intervention and in those with percutaneous coronary intervention during the follow-up period. CONCLUSION: Our results clearly showed that coronary pressure measurement was clinically useful for identifying equivocal tandem lesions requiring percutaneous coronary intervention.

Nicorandil reduces the incidence of minor cardiac marker elevation after coronary stenting.

BACKGROUND: Minor cardiac marker elevation after percutaneous coronary intervention has long-term prognostic significance. We examined whether nicorandil, a nicotinamide-nitrate ester, reduces the incidence of minor cardiac marker elevation after coronary stenting. METHODS: Patients (n=192) undergoing coronary stenting were randomly assigned to receive nicorandil (nicorandil group, n=91) or vehicle (control group, n=101). Nicorandil (2 mug/kg/min, intravenously) was administered immediately after the patients were transferred into the catheterization laboratory and continued for 6 h. We measured the serum concentrations of creatine kinase isoenzyme MB (CK-MB) before, immediately after, and 6, 12, and 24 h after the procedure, and those of cardiac troponin T (cTnT) 24 h after the procedure. RESULTS: There was no significant difference in clinical background between the 2 groups. The nicorandil group showed a significantly lower incidence of CK-MB elevation (>1x upper limit of control range, 20 IU/l) than the control group (8.8% vs 21.8%, p<0.05). The levels of serum CK-MB in the nicorandil group were significantly lower than those in the control group (13.4+/-5.7 vs 16.5+/-9.7 IU/l, p<0.01). Similarly, the nicorandil group showed a significantly lower incidence of cTnT elevation [>1x (0.1 ng/ml) or >2x (0.2 ng/ml)] upper limit of control range than the control group (14.3% vs 26.7%, p<0.05, or 7.7% vs 17.8%, p<0.05). Serum cTnT levels were also significantly lower in the nicorandil group than in the control group (0.05+/-0.10 vs 0.15+/-0.36 ng/ml, p<0.05). CONCLUSIONS: The results demonstrated that nicorandil reduces minor cardiac marker elevation after coronary stenting.

Changes in escape rhythms several years after radiofrequency ablation of the atrioventricular junction combined with pacemaker implantation.

OBJECTIVE: Escape rhythm is thought to play a considerable role in protection against adverse outcome due to pacemaker malfunction. We studied the escape rhythms in 32 patients with supraventricular tachyarrhythmia refractory to medical therapy who underwent radiofrequency ablation of the atrioventricular junction combined with implantation of a pacemaker. METHODS AND RESULTS: We performed the escape rhythm analysis immediately and 2.6 +/- 1.9 years after the radiofrequency ablation by decreasing the pacing rate. In the initial study, escape rhythms (41 +/- 8 beats/min) were documented in 20 patients (63%). Non-cardiac death occurred in 3 patients with escape rhythm, and cardiac death occurred in I patient without escape rhythm. In the follow-up study, escape rhythms were detected in 22 of 28 patients (79%). Escape rhythm had developed in 6 (55%) of 11 patients who were without escape rhythm initially, while escape rhythm disappeared in 1 of 17 (5.9%) patients who had escape rhythm initially. The changes in escape rhythm were not related to QRS width of the intrinsic beat. There was no correlation between the number of radiofrequency applications or the ratio between atrial and ventricular electrocardiogram voltages of radiofrequency applications and the development of escape rhythms. CONCLUSIONS: The present long-term follow-up study demonstrated that the emergence of an escape rhythm increased several years after ablation, but was unrelated to procedural factors. There are, however, certain patients in whom the disappearance of escape rhythms occur. The evaluation of escape rhythms is thus necessary to determine the risk associated with pacemaker failure.

Adequate Initial Heparin Dosage for Atrial Fibrillation Ablation in Patients Receiving Non-Vitamin K Antagonist Oral Anticoagulants.

BACKGROUND AND OBJECTIVE: During atrial fibrillation ablation, heparin is required and is guided by the activated clotting time (ACT). Differences in the ACT before ablation and adequate initial heparin dosing in patients receiving non-vitamin K antagonist oral anticoagulants (NOACs) were examined. METHODS: Patients who received warfarin (control, N = 90), dabigatran etexilate (N = 90), rivaroxaban (N = 90) and apixaban (N = 90) were studied. A 100 U/kg dose of heparin was administered as a reliable control dose for warfarin, and the remaining patients were randomly administered 110, 120 or 130 U/kg of heparin in each NOAC group, followed by a continuous heparin infusion. RESULTS: Periprocedural thromboembolic and major bleeding were not observed. Minor bleeding occurred rarely without significant differences among the groups examined. Baseline ACTs were longer in the warfarin (152 ± 16 s) and dabigatran (153 ± 13 s) groups than in the rivaroxaban (134 ± 13 s) and apixaban (133 ± 20 s) groups. The initial bolus heparin dosages required to produce an ACT 15 min after the initial bolus that was identical to the control (333 ± 32 s) were 120 U/kg (318 ± 29 s) and 130 U/kg (339 ± 43 s) for dabigatran, 130 U/kg (314 ± 31 s) for rivaroxaban and 130 U/kg (317 ± 39 s) for apixaban. The NOAC groups required significantly larger doses of total heparin than the warfarin group. CONCLUSION: The baseline ACTs differed among the three NOAC groups. The results of the comparison with warfarin (the control) indicated that dosages of 120 or 130 U/kg for dabigatran, and 130 U/kg for rivaroxaban and apixaban, were adequate initial heparin dosages.

Significant correlation of recruitable coronary collateral blood flow determined by coronary wedge pressure with ST-segment elevation during coronary occlusion.

OBJECTIVES: Quantitative assessment of coronary collateral blood flow can be archived by measuring coronary pressure. We studied the relationships between recruitable coronary collateral blood flow and electrocardiographic changes during percutaneous coronary intervention (PCI). METHODS: We measured coronary pressure during coronary occlusion with PCI in 119 patients with left anterior descending coronary artery stenosis. During balloon inflation, the electrocardiogram was continuously recorded. The ST-segment elevation in the most elevated lead was defined as MaxST and the sum of the maximal ST elevation in leads V2-V4 was defined as sumST. Fractional collateral flow (Qc/Q(N)) was calculated as the coronary wedge pressure divided by the mean aortic pressure. Myocardial ischemia was defined as an ST-segment shift >0.1 mV in any of the V2, V3 or V4 leads. RESULTS: A significant relationship between Qc/Q(N) and MaxST was observed (r=-0.455, P<0.0001). Similarly, Qc/Q(N) was significantly correlated with sumST (r=-0.477, P<0.0001). The receiver operating characteristic curve showed that a cut-off value of 0.27 for Qc/Q(N), with sensitivity of 71.4% and specificity of 76.2%, was an indicator of electrophysiologically sufficient recruitable coronary collateral blood flow for prevention of ischemia during coronary obstruction. Qc/Q(N) values during the first, second, third and fourth inflation were not significantly different. CONCLUSIONS: Qc/Q(N) could be clinically useful for determining whether there is electrophysiologically sufficient recruitable coronary collateral blood flow for prevention of ischemia during coronary obstruction. Repeat transient coronary occlusion during PCI did not lead to increased collateral blood flow.

Usefulness of dabigatran etexilate as periprocedural anticoagulation therapy for atrial fibrillation ablation.

BACKGROUND: The usefulness of dabigatran etexilate for the prevention of stroke in patients with atrial fibrillation (AF) has been reported. OBJECTIVES: In this study the efficacy and safety of dabigatran etexilate for anticoagulation for AF ablation were examined. METHOD: Patients were divided into three groups: Group 1, interrupted warfarin bridged by heparin between pre- and post-ablation; Group 2, continuous warfarin therapy; and Group 3, dabigatran etexilate therapy. Anticoagulation therapy with warfarin or dabigatran etexilate was performed from 30 days before to at least 90 days after AF ablation. Dabigatran etexilate was administered at 110 or 150 mg twice daily, depending on renal function and age. RESULTS: Patients' clinical characteristics, associated disorders, echocardiographic parameters and arrhythmia status were not different among the three groups. Procedural parameters such as procedural time and radiofrequency energy supply were also not different among the three groups. The dabigatran etexilate group and the warfarin groups had no embolic complications (stroke, cerebral transient ischaemic attack, deep venous thrombosis or pulmonary embolism). No pericardial tamponade was observed in the dabigatran etexilate group, while two patients in each of Group 1 (2/194, 1.0 %) and Group 2 (2/203, 0.98 %) developed cardiac tamponade, though the differences were not significant. Pericardial effusion and groin haematoma were observed in one patient each (1/105, 0.9 %) in the dabigatran etexilate group, and the incidences were not different from the warfarin group (Group 1: 4/194, 2.1 % and 2/194, 1.0 %; Group 2: 3/203, 1.5 % and 2/203, 1.0 %, respectively). As a whole, the safety outcomes did not differ among the three groups. CONCLUSION: Dabigatran etexilate is an effective and safe anticoagulation therapy for AF ablation. Thus, dabigatran etexilate appears to be useful as an alternative anticoagulant therapy to warfarin for AF ablation.