Systolic blood pressure visit-to-visit variability and outcomes in Asian patients with atrial fibrillation.

We aimed to assess the association between SBP-VVV and outcomes in Asian patients with atrial fibrillation (AF). AF patients in the COOL-AF registry with SBP measured at baseline, and at least two other visits were studied. We defined SBP-VVV using the standard deviation (SD) of average SBP. Patients were categorized according to the quartiles of SBP SD. The associations between SBP-VVV and outcomes were assessed in the adjusted Cox model. We studied 3172 patients (mean age 67.7 years; 41.8% female), with the prevalence of hypertension being 69%. Warfarin was used in 69% of patients, whereas 7% received non-vitamin K antagonist oral anticoagulants. The minimum and maximum SD of average SBP in the study population was 0.58 and 56.38 mmHg respectively. The cutoff of SD of average SBP for each quartile in our study were 9.09, 12.15, and 16.21 mmHg. The rates of all-cause mortality, ischemic stroke or systemic embolization (SSE), major bleeding, and intracranial hemorrhage (ICH) were 3.10, 1.42, 2.09, and 0.64 per 100 person-years, respectively. Compared with the first quartile, patients in the fourth quartile had a significantly higher risk of mortality (adjusted HR 1.60, 95%CI 1.13-2.25), bleeding (aHR 1.92, 95%CI 1.25-2.96) and ICH (aHR 3.51, 95%CI 1.40-8.76). The risk of SSE was not significantly different among the quartiles. SBP-VVV had a significant impact on the long-term outcomes of Asian patients with AF, particularly mortality and bleeding. Adequate SBP control and maintaining SBP stability over time may improve outcomes for AF patients.

Net clinical benefit of oral anticoagulants in Asian patients with atrial fibrillation based on a CHA2DS2-VASc score.

BACKGROUND: This study was conducted to assess the net clinical benefit (NCB) for oral anticoagulant (OAC) in atrial fibrillation (AF) patients according to the CHA2DS2-VASc score. METHODS: Patients with AF were prospectively recruited in the COOL AF Thailand registry from 2014 to 2017. The incidence rate of thromboembolic (TE) events and major bleeding (MB) was calculated. Cox proportional hazards model was used to compare the TE and MB rate in patients with and without OACs in CHA2DS2-VASc score of 0-1 and ≥ 2, respectively. The survival analysis was performed based on CHA2DS2-VASc score. The NCB of OACs was defined as the TE rate prevented minus the MB rate increased multiplied by a weighting factor. RESULTS: A total of 3,402 AF patients were recruited. An average age of patients was 67.38 ± 11.27 years. Compared to non-anticoagulated patients, the Kaplan Meier curve showed anticoagulated patients with CHA2DS2-VASc score of 2 or more had the lower thromboembolic events with statistical significance (p = 0.043) and the higher MB events with statistical significance (p = 0.018). In overall AF patients, there were positive NCB in warfarin patients with CHA2DS2-VASc score of 3 or more while there were positive NCB in DOACs patients regardless of CHA2DS2-VASc score. Females with CHA2DS2-VASc score of 3 or more had a positive NCB regardless of OACs type. Good anticoagulation control (TTR ≥65%) improved an NCB in males with CHA2DS2-VASc score of 3 or more. CONCLUSIONS: AF patients with CHA2DS2-VASc score of 3 or more regardless warfarin or DOACs had a positive NCB. The NCB of OACs was more positive for DOACs compared to warfarin and for females compared to males.

Efficacy and safety outcomes of patients with atrial fibrillation compared between warfarin and non-vitamin K antagonist oral anticoagulants based on SAMe-TT2R2 score.

OBJECTIVES: This study aimed to investigate the efficacy and safety outcomes of patients with atrial fibrillation (AF) compared between those taking warfarin and non-vitamin K antagonist oral anticoagulants (NOACs) based on SAMe-TT2R2 score. METHODS: AF patients using warfarin or NOACs were enrolled from Thailand's COOL-AF registry. A low SAMe-TT2R2 score was defined as a score of 0-2. The efficacy outcomes were all-cause death, ischemic stroke (IS), transient ischemic attack (TIA), and/or systemic embolization (SE). The safety outcome was major bleeding (MB). The secondary outcome was a combination of cardiovascular (CV) death, IS/TIA/SE, or MB. Cox proportional hazards model was used to compare the event rate between the AF patients taking warfarin and NOACs according to SAMe-TT2R2 score. RESULTS: A total of 2568 AF patients taking oral anticoagulants were enrolled. Warfarin and NOACs were used in 2340 (91.1%) and 228 (8.9%) patients, respectively. Among overall patients, 305 patients taking warfarin (13.0%) and 21 patients taking NOACs (9.2%) had the efficacy outcome, while 155 patients taking warfarin (6.6%) and 11 patients taking NOACs (4.8%) had the safety outcome. After adjustment for confounders, overall patients taking warfarin had significantly more secondary outcome than those taking NOACs (11.4% vs. 7.5%, respectively; adjusted hazard ratio: 1.74, 95% confidence interval: 1.01-2.99; p = 0.045) regardless of SAMe-TT2R2 score. CONCLUSIONS: AF patients taking warfarin had a significantly higher CV death or IS/TIA/SE or MB compared to those taking NOACs regardless of SAMe-TT2R2 score. The results of this study do not support the use of SAMe-TT2R2 score to guide OAC selection.

Impact of Achieving Blood Pressure Targets and High Time in Therapeutic Range on Clinical Outcomes in Patients With Atrial Fibrillation Adherent to the Atrial Fibrillation Better Care Pathway: A Report From the COOL-AF Registry.

Background We aimed to determine the effect of integrating Atrial Fibrillation Better Care pathway compliance in relation to achievement of systolic blood pressure (SBP) targets and good control of time in therapeutic range (TTR) on clinical outcomes in patients with atrial fibrillation. Methods and Results We prospectively enrolled patients with nonvalvular atrial fibrillation  from 27 hospitals in Thailand. All clinical outcomes were recorded. Main outcomes were the composite of all-cause death or ischemic stroke/systemic embolism (SSE), as well as secondary outcomes of all-cause death, SSE, major bleeding, intracranial hemorrhage, and heart failure. An SBP of 120 to 140 mm Hg was considered good blood pressure control. Target TTR was a TTR ≥65%. A total of 3405 patients were studied (mean age 67.8 years, 41.8% female). Full ABC pathway compliance was evident in 42.7%. For blood pressure control, 41.9% had SBP within target, whereas 35.9% of those on warfarin had TTR within target. The incidence rates of all-cause death/SSE, all-cause death, SSE, major bleeding, intracranial hemorrhage, and heart failure were 5.29, 4.21, 1.51, 2.25, 0.78, and 2.84 per 100 person-years respectively. Adjusted hazard ratios and 95% CI of Atrial Fibrillation Better Care pathway compliance for all-cause death/SSE, all-cause death, and heart failure were 0.76 (0.62-0.94), 0.79 (0.62-0.99), and 0.69 (0.51-0.94), respectively, compared with noncompliance. Patients with Atrial Fibrillation Better Care compliance and SBP within target had a better outcome or TTR within target had better outcomes. Conclusions In COOL-AF (Cohort of Antithrombotic Use and Optimal International Normalized Ratio Level in Patients With Non-Valvular Atrial Fibrillation in Thailand), a multicenter nationwide prospective cohort of patients with atrial fibrillation, achieving SBP within target and TTR ≥ 65% has added value to Atrial Fibrillation Better Care pathway compliance in the reduction of adverse clinical outcomes in patients with atrial fibrillation.

Revised HAS-BLED score for bleeding prediction in atrial fibrillation patients with oral anticoagulants.

Background: There were several limitations to the original HAS-BLED (oHAS-BLED) score in patients with atrial fibrillation (AF). This trial studied the revised HAS-BLED (rHAS-BLED) score for predicting bleeding events in anticoagulated AF patients. Methods: This study retrospectively recruited anticoagulated AF patients in the Central Chest Institute of Thailand between 2014 and 2021. The rHAS-BLED score was oHAS-BLED using the estimated glomerular filtration rate of <60 ml/min/1.73 m2 for abnormal renal function, SAMe-TT2R2 score of ≥3 for labile INR, and adding clinically relevant nonmajor bleeding (CRNMB) into bleeding history. The outcome was major bleeding (MB) and/or CRNMB at 1-year follow-up visit. The outcome between both groups was compared by using the chi-square test or Fisher's exact test. Receiver-operating characteristics curve was used to analyze the discrimination performances of both scores and the results were illustrated by using c-statistics. Results: A total of 256 anticoagulated AF patients were enrolled. The average age was 73.6 ± 10.1 years. The average oHAS-BLED and rHAS-BLED scores were 1.7 ± 0.9 and 2.6 ± 1.2, respectively. Twenty patients in rHAS-BLED ≥3 (15.9%) and 9 patients in rHAS-BLED <3 (6.9%) experienced MB and/or CRNMB. The rHAS-BLED score of ≥3 increased the bleeding risk with statistical significance (OR 2.54, 95% CI 1.11-5.81, p = .04). The discriminative performance of the rHAS-BLED score was illustrated with c-statistics of 0.61 (95% CI 0.50-0.71). Conclusions: The rHAS-BLED score could predict bleeding events in anticoagulated AF patients. However, a larger study is needed to confirm these results in the future.

The Rate of Clinical Outcomes in Atrial Fibrillation according to Antithrombotic Strategy: The COOL-AF Registry.

Background: Ischemic stroke/transient ischemic attack (TIA), major bleeding, and death are common outcomes in atrial fibrillation (AF) patients, so appropriate antithrombotic therapy is crucial. The objective of this study was to investigate the rate of ischemic stroke/TIA, major bleeding, and death compared among AF patients who received oral anticoagulant (OAC) alone, antiplatelet alone, or OAC plus antiplatelet. Methods: Prospective data from the COOL-AF Registry (Thailand's largest multicenter nationwide AF registry) were analyzed. Clinical, laboratory, and medication data were collected at baseline and during follow-up. Clinical outcomes, including ischemic stroke/TIA, major bleeding, and death, were collected. Results: There were 3,148 patients included. Mean age was 68.1 ± 10.8 years and 1,826 (57.7%) were male. AF was paroxysmal in 998 (31.7%), persistent in 603 (19.2%), and permanent in 1,547 (49.1%). The mean follow-up duration was 25.7 ± 10.6 months. The median rates of ischemic stroke/TIA, major bleeding, and death were 1.49 (1.21-1.81), 2.29 (1.94-2.68), and 3.89 (3.43-4.40) per 100 person-years. Antiplatelet alone, OAC plus antiplatelet, and OAC alone were used in 582 (18.5%), 308 (9.8%), and 2,258 (71.7%) patients, respectively. Antiplatelet alone significantly increased the risk of ischemic stroke/TIA and death compared to OAC alone. OAC plus antiplatelet significantly increased the risk of death compared to OAC alone. Conclusions: Antiplatelet was used in 890 (28.3%) AF, of whom 582 (18.5%) received antiplatelet alone, and 308 (9.8%) received antiplatelet and OAC. OAC plus antiplatelet significantly increased the risk of death without additional stroke prevention benefit. Antiplatelet alone should not be used in patients with AF.

Safety and efficacy of non-vitamin K antagonist oral anticoagulants compared with well-controlled warfarin in Thai patients with atrial fibrillation.

Background: In trials of patients with atrial fibrillation (AF), non-vitamin K antagonist oral anticoagulants (NOACs) were not inferior to warfarin for thromboembolic and bleeding events. However, there are scant data comparing the efficacy and safety of NOACs in patients with AF with that of well-controlled warfarin treatment in such patients. Objectives: To compare total bleeding and thromboembolic events in patients with AF who received NOACs, with the same events in those who received well-controlled warfarin treatment. Methods: We used retrospective data from patients with AF who received NOACs or well-controlled warfarin at the Central Chest Institute of Thailand from January 2017 to December 2019. The primary outcome was total bleeding or thromboembolic events or both. The secondary outcome was all-cause mortality, total bleeding events including major or minor bleeding, and thromboembolic events including ischemic stroke or systemic embolization. Results: We included data from 180 patients with AF, 90 who received NOACs and 90 who received well-controlled warfarin. The average time in the therapeutic range for those who received warfarin was 84.9% ± 9.8%. The patients who received well-controlled warfarin had more frequent thromboembolic or total bleeding events or both than those who received NOACs (odds ratio [OR] 3.17; 95% confidence interval [CI] 2.27-4.07; P = 0.01). There were more minor bleeding events in those who received well-controlled warfarin (OR 3.75; 95% CI 2.79-4.71; P = 0.01). However, there was no significant difference in thromboembolic events, major bleeding, or all-cause mortality between the 2 groups. Conclusions: Thai patients with AF who received NOACs had less thromboembolic or total bleeding events than those who received well-controlled warfarin treatment.

Efficacy of R2CHA2DS2-VA score for predicting thromboembolism in Thai patients with non-valvular atrial fibrillation.

BACKGROUND: There is no data specific to the addition of renal dysfunction and age 50-64 years as risk parameters to the CHA2DS2-VA score, which is known as the R2CHA2DS2-VA score, among NVAF patients. Accordingly, the aim of this study was to validate the R2CHA2DS2-VA score for predicting thromboembolism in Thai NVAF patients. METHODS: Thai NVAF patients were prospectively enrolled in a nationwide multicenter registry from 27 hospitals during 2014-2020. Each component of the CHA2DS2-VA and R2CHA2DS2-VA scores was scored and recorded. The main outcomes were thromboembolism, including ischemic stroke, transient ischemic attack (TIA), and/or systemic embolism. The annual incidence rate of thromboembolism among patients in each R2CHA2DS2-VA and CHA2DS2-VA risk score category is shown as hazard ratio (HR) and 95% confidence interval (95% CI). The performance of the R2CHA2DS2-VA and CHA2DS2-VA scores was demonstrated using c-statistics. Net reclassification index was calculated. Calibration plat was used to assess agreement between observed probabilities and predicted probabilities of both scoring system. RESULTS: A total of 3402 patients were enrolled during 2014-2020. The average age of patients was 67.38 ± 11.27 years. Of those, 46.9% had renal disease, 30.7% had a history of heart failure, and 17.1% had previous stroke or TIA. The average R2CHA2DS2-VA and CHA2DS2-VA scores were 3.92 ± 1.92 and 2.98 ± 1.43, respectively. Annual thromboembolic risk increased with incremental increase in R2CHA2DS2-VA and CHA2DS2-VA scores. Oral anticoagulants had benefit in stroke prevention in NVAF patients with an R2CHA2DS2-VA score of 2 or more (adjusted HR: 0.630, 95% CI 0.413-0.962, p = 0.032). The c-statistics were 0.630 (95% CI 0.61-0.65) and 0.627 (95% CI 0.61-0.64), for R2CHA2DS2-VA and CHA2DS2-VA scores respectively. NRI was 2.2%. The slope and R2 of the calibration plot were 0.73 and 0.905 for R2CHA2DS2-VA and 0.70 and 0.846 for CHA2DS2-VA score respectively. CONCLUSIONS: R2CHA2DS2-VA score was found to be at least as good as CHA2DS2-VA score for predicting thromboembolism in Thai patients with NVAF. Similar to CHA2DS2-VA score, thromboembolism increased with incremental increase in R2CHA2DS2-VA score.

Influence of gender on the clinical outcomes of Asian non-valvular atrial fibrillation patients: insights from the prospective multicentre COOL-AF registry.

OBJECTIVE: To determine the effect of gender on clinical outcomes of Asian non-valvular atrial fibrillation patients. DESIGN: This is a cohort study. SETTING: 27 university and regional hospitals in Thailand. PARTICIPANTS: Patients with non-valvular atrial fibrillation. PRIMARY AND SECONDARY OUTCOMES MEASURES: The clinical outcomes were ischaemic stroke/transient ischaemic attack (TIA), major bleeding, intracerebral haemorrhage (ICH), heart failure and death. Follow-up data were recorded every 6 months until 3 years. Differences in clinical outcomes between males and females were determined. Multivariate analysis was performed to assess the effect of gender on clinical outcomes. Survival analysis and log-rank test were performed to determine the time-dependent effect of clinical outcomes, and the difference between males and females. Effect of oral anticoagulant (OAC) on outcomes and net clinical benefit of OAC was assessed. The analysis was performed both for the whole dataset and propensity score matching with multiple imputation. RESULTS: A total of 3402 patients (mean age: 67.4±11.3 years; 58.2% male) were included. Average follow-up duration 25.7±10.6 months (7192.6 persons-year). Rate of ischaemic stroke/TIA, major bleeding, ICH, heart failure and death were 1.43 (1.17-1.74), 2.11 (1.79-2.48), 0.70 (0.52-0.92), 3.03 (2.64-3.46) and 3.77 (3.33-4.25) per 100 person-years. Females had increased risk for ischaemic stroke/TIA and heart failure and males had increased risk for major bleeding and ICH. Ischaemic stroke/TIA risk in females and major bleeding and ICH risk in males remained even after correction for age, comorbid conditions and anticoagulation treatment. OAC reduced the risk of ischaemic stroke/TIA in males and females, and markedly increased the risk of major bleeding and ICH in males. CONCLUSIONS: Females had a higher risk of ischaemic stroke/TIA and heart failure, and a lower risk of major bleeding and ICH compared with males. OAC reduced risk of ischaemic stroke/TIA in females, and markedly increased risk of major bleeding and ICH in males.

Peguero-Lo Presti criteria modified by body surface area for the electrocardiographic diagnosis of left ventricular hypertrophy in Thai patients.

Background: Several electrocardiographic (ECG) criteria are used to diagnose left ventricular hypertrophy (LVH); however, they have low sensitivity. Objective: To assess the sensitivity of LVH diagnosis using Peguero-Lo Presti criteria modified by body surface area (BSA). Methods: This study used retrospective data from 9,438 patients who attended the Central Chest Institute of Thailand from January 2017 to December 2017 with available echocardiography, and who were categorized into those with and without LVH to determine diagnostic accuracy. We randomly selected 317 patients after excluding others based on various conditions. The left ventricular mass of the 317 patients was estimated using echocardiography. Peguero-Lo Presti criteria were modified by dividing original criteria by BSA. The accuracy of the modified criteria was compared with that of the original Peguero-Lo Presti, Sokolow-Lyon, and Cornell voltage criteria. A McNemar test was used to determine the agreement of all ECG criteria examined with LV mass index. The area under a receiver operating characteristic curve (AUC) was used to assess the performance of the criteria. Results: LVH was diagnosed in 164 of the 317 patients using echocardiography. The sensitivity of modified Peguero-Lo Presti criteria was 50.6% (95% confidence interval [CI] 42.7% to 58.5%), and specificity was 88.2% (95% CI 82.0% to 92.9%), with an AUC of 0.67 (95% CI 0.61-0.73). Conclusions: Peguero-Lo Presti criteria modified by dividing them by BSA can improve sensitivity with acceptable specificity for the diagnosis of LVH compared with other ECG criteria examined, at least in selected Thai patients. The modified Peguero-Lo Presti criteria have accuracy similar to that for the original criteria.

Optimal INR level in patients with atrial fibrillation with EHRA type 2 valvular heart disease receiving warfarin.

BACKGROUND: To date, there has been no study that compares the efficacy and safety of warfarin in atrial fibrillation (AF) patients with Evaluated Heartvalves, Rheumatic or Artificial (EHRA) type 2 valvular heart disease (VHD). This study was conducted to determine the optimal INR in these patients. METHODS: This retrospective study enrolled AF patients with EHRA type 2 VHD receiving warfarin in Central Chest Institute of Thailand between January 2016 and December 2018. The incidence density of thromboembolic or bleeding events was calculated. The International normalized ratio (INR) was classified into six groups (less than 1.50, 1.50 to 1.99, 2.00 to 2.49, 2.50 to 2.99, 3.00 to 3.49, and 3.50 or more). The optimal INR level was defined as the lowest incidence density of thromboembolic events and bleeding complications. RESULTS: A total of 200 AF patients with EHRA type 2 VHD receiving warfarin were enrolled, contributing to 289 patient-years of observation period. There were 13 thromboembolic events (4.5 per 100 patient-years) and 16 bleeding events (5.5 per 100 patient-years). The incidence density of thromboembolic events was significantly increased in the INR level below 2.00 (P = .03), while the INR level of 3.50 or more was significantly increased in the incidence density of major bleeding events (P = .03). Total bleeding and minor bleeding were increased significantly in INR level of 2.50 or more (P = .04). CONCLUSIONS: The INR of 2.00 to 2.49 was appeared to be associated with the lowest incidence density of thromboembolic and bleeding events in these patients.

Use of simplified HAS-BLED score in patients with atrial fibrillation receiving warfarin.

BACKGROUND: Oral anticoagulant drugs are proven to prevent thromboembolism in patients with atrial fibrillation (AF). To date, HAS-BLED score is used to assess bleeding risk. This study was conducted to compare simplified HAS-BLED (sHAS-BLED) with conventional HAS-BLED (cHAS-BLED) scores. METHODS: This retrospective study recruited patients with AF receiving warfarin among July 2013 to December 2018 in Central Chest Institute of Thailand. The cHAS-BLED score used the time in therapeutic range less than 70% as labile INR, whereas sHAS-BLED score used SAMe-TT2R2 score of 3 or more as a substitute for labile INR. A paired Student's t test was used to compare sHAS-BLED and cHAS-BLED. The Pearson's correlation was used to assess the correlation of sHAS-BLED to cHAS-BLED scores. The Bland-Altman plot was used to confirm the agreement of individual sHAS-BLED to cHAS-BLED score. RESULTS: A total of 126 AF patients were enrolled. The average age, SAMe-TT2R2 score, and cHAS-BLED score were 70.52 ± 10.37 years, 3.53 ± 1.03, and 2.03 ± 0.95, respectively. The sHAS-BLED score was not statistically significantly different compared with cHAS-BLED score (P = .08). The sHAS-BLED and cHAS-BLED scores had a very strong correlation with a correlation coefficient of .86 (P < .01). The Bland-Altman plot was performed to confirm the agreement of individual sHAS-BLED to cHAS-BLED scores. CONCLUSIONS: The sHAS-BLED was not statistically significantly different compared with cHAS-BLED and can be used in clinical practice. However, larger clinical trial will be needed to prove whether sHAS-BLED can predict bleeding risk in the future.

Risk profiles and pattern of antithrombotic use in patients with non-valvular atrial fibrillation in Thailand: a multicenter study.

BACKGROUND: Anticoagulation therapy is a standard treatment for stroke prevention in patients with non-valvular atrial fibrillation (NVAF) that have risk factors for stroke. However, anticoagulant increases the risk of bleeding, especially in Asians. We aimed to investigate the risk profiles and pattern of antithrombotic use in patients with NVAF in Thailand, and to study the reasons for not using warfarin in this patient population. METHODS: A nationwide multicenter registry of patients with NVAF was created that included data from 24 hospitals located across Thailand. Demographic data, atrial fibrillation-related data, comorbid conditions, use of antithrombotic drugs, and reasons for not using warfarin were collected. Data were recorded in a case record form and then transferred into a web-based system. RESULTS: A total of 3218 patients were included. Average age was 67.3 ± 11.3 years, and 58.2% were male. Average CHADS2, CHA2DS2-VASc, and HAS-BLED score was 1.8 ± 1.3, 3.0 ± 1.7, and 1.5 ± 1.0, respectively. Antiplatelet was used in 26.5% of patients, whereas anticoagulant was used in 75.3%. The main reasons for not using warfarin in those with CHA2DS2-VASc ≥2 included already taking antiplatelet (26.6%), patient preference (23.1%), and using non-vitamin K antagonist oral anticoagulants (NOACs) (22.7%). Anticoagulant was used in 32.3% of CHA2DS2-VASc 0, 56.8% of CHA2DS2-VASc 1, and 81.6% of CHA2DS2-VASc ≥2. The use of NOACs increased from 1.9% in 2014 to 25.6% in 2017. CONCLUSIONS: Anticoagulation therapy was prescribed in 75.3% of patients with NVAF. Among those receiving anticoagulant, 90.9% used warfarin and 9.1% used NOACs. The use of NOACs increased over time.

Determining the Site of Accessory Pathways in Orthodromic Reciprocating Tachycardia by Using the Response to Right Ventricular Pacing.

BACKGROUND: Postpacing interval (PPI) after right ventricular (RV) pacing entrainment minus tachycardia cycle length (TCL) with a correction for atrioventricular (AV) node delay (corrected PPI-TCL) was useful to differentiate atrioventricular node reentrant tachycardia (AVNRT) from orthodromic reciprocating tachycardia (ORT). However, the value of corrected PPI-TCL in determining the site of the accessory pathway (AP) in ORT has not been investigated. The purpose of this study was to assess whether the corrected PPI-TCL is useful in differentiating ORT using a left-sided AP from a right-sided AP. METHODS: We studied 52 patients with ORT using a left-sided AP and 13 patients with a right-sided AP. The PPI was measured upon cessation of the RV pacing at a cycle length 10-40 ms shorter than the TCL. The corrected PPI-TCL was calculated from the subtraction of the increment in AV nodal conduction time of the first PPI from the PPI-TCL. RESULTS: The mean corrected PPI-TCL was 83 ± 20 ms in patients with ORT using a left-sided AP and 27 ± 19 ms in patients with a right-sided AP (P ≤ 0.001). All patients with ORT using a left-sided AP except three patients with left septal AP and none of the patients with ORT using a right-sided AP had a corrected PPI-TCL > 55 ms. CONCLUSIONS: The corrected PPI-TCL after the RV pacing entrainment is useful to guide differentiating ORT using a left-sided AP from a right-sided AP.

Optimal INR level in Thai atrial fibrillation patients who were receiving warfarin for stroke prevention in Thailand.

OBJECTIVE: To determine the optimal International Normalized Ratio (INR) level in Thai atrialfibrillation (AF) patients who received warfarin. MATERIAL AND METHOD: This retrospective study enrolled 230 AF patients that received warfarin in Siriraj Hospital between January 1, 2005 andDecember 31, 2009 and collected the INR level at the time of the event, the numbers of ischemic stroke, and bleeding events. The incidence density of ischemic stroke or bleeding events was calculated by dividing the number of ischemic stroke or bleeding event in each INR level with the summation of the time that each patient stayed in each INR group. The patients with a prosthetic valve were excluded. The INR range was classified into six groups (less than 1.5, 1.5 to 1.9, 2.0 to 2.4, 2.5 to 2.9, 3.0 to 3.4, and greater than 3.4). The optimal INR level was defined as the lowest incidence density of ischemic stroke and bleeding complications. RESULTS: Two hundred thirty AF patients (the mean age 68 ± 12 years) were enrolled, contributing to 737.54 patient-years of observation period. Of the 230 patients, nine patients experienced 12 ischemic events (1.6 per 100 patient-years) and 54 patients experienced 57 bleeding events (7.7 per 100 patient-years). The percentage of patient-time spent within INR 2 to 3, INR less than 2, and INR more than 3 were 40.75, 46.22, and 13.03%, respectively. The INR level more than 3.4 increased both major and minor bleeding events (p = 0.001). The INR level of 3.0 to 3.4 increased the minor bleeding events (p = 0.03). The INR level less than 1.5 increased incidence of ischemic stroke (p = 0.03). The overall event rate was lowest in the INR range from 1.5 to 2.9, which is significantly different from that of lNR more than 2.9 (p < 0.0001), but trend lower than INR less than 1.5 without being statistically significant (p = 0.198). CONCLUSION: An INR of 1.5-2.9 appeared to be associated with the lowest incidence rate of bleeding or ischemic stroke in a cohort of Thai AFpatients receiving warfarin therapy for stroke prevention.