The anticoagulation one year after ablation of atrial fibrillation in patients with atrial fibrillation (ALONE-AF) trial: Study protocol.

Background: The ideal long-term antithrombotic strategy for patients after successful catheter-based atrial fibrillation (AF) ablation is still uncertain. Presently, practices vary, and the advantages of oral anticoagulation (OAC) for the post-ablation population are not clearly established. To date, no randomized trials have addressed this therapeutic question. This study aimed to evaluate whether no OAC therapy is superior to apixaban in reducing the risk of stroke, systemic embolism, or major bleeding among patients without apparent recurrent atrial arrhythmias for at least 1 year after their AF ablation procedure. Methods: The ALONE-AF trial is a prospective, multicenter, open-label, randomized study with blinded outcome assessment. Patients with AF who have at least one non-gender stroke risk factor (as determined by the CHA2DS2-VASc score) and no documented recurrences of atrial arrhythmia for at least 12 months post-ablation will be randomly assigned to apixaban 5 mg b.i.d. or no OAC therapy. The primary endpoint is a composite outcome of stroke, systemic embolism, and major bleeding. Key secondary outcomes include clinically relevant non-major bleeding, all-cause mortality, myocardial infarction, transient ischemic attack, quality of life, and frailty analysis. Participants will be followed for a period of 2 years. The estimated total sample size is 840 subjects, with 420 subjects in each arm. Conclusion: The ALONE-AF trial aims to provide robust evidence for the optimal anticoagulation strategy for patients with stroke risk factors following successful AF ablation.

Net clinical benefit of oral anticoagulants in Korean atrial fibrillation patients with low to intermediate stroke risk: A report from the Clinical Survey on Stroke Prevention in patients with Atrial Fibrillation (CS-SPAF).

Background: The balance of stroke risk reduction and potential bleeding risk associated with antithrombotic treatment (ATT) remains unclear in atrial fibrillation (AF) at non-gender CHA2DS2-VASc scores 0-1. A net clinical benefit (NCB) analysis of ATT may guide stroke prevention strategies in AF with non-gender CHA2DS2-VASc scores 0-1. Methods: This multi-center cohort study evaluated the clinical outcomes of treatment with a single antiplatelet (SAPT), vitamin K antagonist (VKA), and non-VKA oral anticoagulant (NOAC) in non-gender CHA2DS2-VASc score 0-1 and further stratified by biomarker-based ABCD score (Age [≥60 years], B-type natriuretic peptide [BNP] or N-terminal pro-BNP [≥300 pg/mL], creatinine clearance [<50 mL/min], and dimension of the left atrium [≥45 mm]). The primary outcome was the NCB of ATT, including composite thrombotic events (ischemic stroke, systemic embolism, and myocardial infarction) and major bleeding events. Results: We included 2465 patients (age 56.2 ± 9.5 years; female 27.0%) followed-up for 4.0 ± 2.8 years, of whom 661 (26.8%) were treated with SAPT; 423 (17.2%) with VKA; and 1040 (42.2%) with NOAC. With detailed risk stratification using the ABCD score, NOAC showed a significant positive NCB compared with the other ATTs (SAPT vs. NOAC, NCB 2.01, 95% confidence interval [CI] 0.37-4.66; VKA vs. NOAC, NCB 2.38, 95% CI 0.56-5.40) in ABCD score ≥1. ATT failed to show a positive NCB in patients with truly low stroke risk (ABCD score = 0). Conclusions: In the Korean AF cohort at non-gender CHA2DS2-VASc scores 0-1, NOAC showed significant NCB advantages over VKA or SAPT with ABCD score ≥1.

Standard-Intensity Versus Low-Intensity Anticoagulation with Warfarin in Asian Patients with Atrial Fibrillation: A Multi-Center, Randomized Controlled Trial.

Anticoagulation with warfarin in Asian patients with atrial fibrillation (AF) often has been decreased as an international normalized ratio (INR) of prothrombin time 1.6-2.6 due to fear of bleeding, although universal criteria recommend an INR of 2.0-3.0. In this randomized, open-label trial, low-intensity anticoagulation (INR 1.6-2.6) was compared with standard-intensity anticoagulation (INR 2.0-3.0) with warfarin. A total 616 patients with AF and at least 1 risk factor for stroke were randomized to low-intensity anticoagulation (n = 308) and standard-intensity anticoagulation (n = 308) groups. The intention-to-treat analysis was performed to determine differences. The baseline characteristics of the two groups were comparable. New-onset stroke occurred in 2 patients (0.44% per year) in the low-intensity group and 5 patients (1.05% per year) in the standard-intensity group (HR 0.42, 95% CI 0.08-2.15). Major bleeding occurred in 4 patients (0.89% per year) in the low-intensity group and 5 patients (1.06% per year) in the standard-intensity group (HR 0.84, 95% CI 0.22-3.11). The rate of the net clinical outcome (composite of stroke, systemic embolism, major bleeding, and death) was 1.33% per year in the low-intensity group compared with 2.12% per year in the standard-intensity group (HR 0.63, 95% CI 0.23-1.72). In Asian patients with AF, clinical outcomes were not different between low-intensity and standard-intensity anticoagulation with warfarin.

Validation of Biomarker-Based ABCD Score in Atrial Fibrillation Patients with a Non-Gender CHA2DS2-VASc Score 0-1: A Korean Multi-Center Cohort.

PURPOSE: Atrial fibrillation (AF) patients with low to intermediate risk, defined as non-gender CHA2DS2-VASc score of 0-1, are still at risk of stroke. This study verified the usefulness of ABCD score [age (≥60 years), B-type natriuretic peptide (BNP) or N-terminal pro-BNP (≥300 pg/mL), creatinine clearance (<50 mL/min/1.73 m²), and dimension of the left atrium (≥45 mm)] for stroke risk stratification in non-gender CHA2DS2-VASc score 0-1. MATERIALS AND METHODS: This multi-center cohort study retrospectively analyzed AF patients with non-gender CHA2DS2-VASc score 0-1. The primary endpoint was the incidence of stroke with or without antithrombotic therapy (ATT). An ABCD score was validated. RESULTS: Overall, 2694 patients [56.3±9.5 years; female, 726 (26.9%)] were followed-up for 4.0±2.8 years. The overall stroke rate was 0.84/100 person-years (P-Y), stratified as follows: 0.46/100 P-Y for an ABCD score of 0; 1.02/100 P-Y for an ABCD score ≥1. The ABCD score was superior to non-gender CHA2DS2-VASc score in the stroke risk stratification (C-index=0.618, p=0.015; net reclassification improvement=0.576, p=0.040; integrated differential improvement=0.033, p=0.066). ATT was prescribed in 2353 patients (86.5%), and the stroke rate was significantly lower in patients receiving non-vitamin K antagonist oral anticoagulant (NOAC) therapy and an ABCD score ≥1 than in those without ATT (0.44/100 P-Y vs. 1.55/100 P-Y; hazard ratio=0.26, 95% confidence interval 0.11-0.63, p=0.003). CONCLUSION: The biomarker-based ABCD score demonstrated improved stroke risk stratification in AF patients with non-gender CHA2DS2-VASc score 0-1. Furthermore, NOAC with an ABCD score ≥1 was associated with significantly lower stroke rate in AF patients with non-gender CHA2DS2-VASc score 0-1.

Clinical Implications of Heart Rate Control in Heart Failure With Atrial Fibrillation: Multi-Center Prospective Observation Registry (CODE-AF Registry).

Background: Atrial fibrillation (AF) is treated by heart rate (HR) control. However, the optimal HR target in AF patients with heart failure (HF) remains unclear. To evaluate the clinical implication of the resting HR in AF patients with HF accompanied by preserved, mid-range, or reduced ejection fraction (HFpEF, HFmrEF, or HFrEF, respectively). Methods: Echocardiographic data from June 2016 to April 2020 in a prospective, multicenter, observational registry from 11,104 patients were analyzed. The follow-up duration was 2.2 years. The main outcome was composite of death and hospitalization. We categorized patients according to the HF type and resting HR: ≤ 60 bpm, 61-80 bpm, 81-110 bpm, and >110 bpm. Results: A total of 1,421 patients were enrolled in the study: 582 in the HFpEF group, 506 in the HFmrEF group, and 333 in the HFrEF group. The patients had a mean age of 69 ± 11 years and consisted of 872 (61.4%) men. Primary endpoint rates among HFpEF patients with 60 < HR ≤ 110 bpm were lower than those with HR ≤ 60 bpm (61-80 bpm group: hazard ratio, 0.66; 95% CI, 0.46-0.94; p = 0.021; 81-110 bpm group: hazard ratio, 0.60; 95% CI, 0.40-0.90; p = 0.013). Especially, HFpEF patients with HR 81-110 bpm had a lower incidence of hospitalization caused by HF aggravation than those with other HR strata (HR ≤ 80bpm strata or HR >110 bpm strata). In HFmrEF and HFrEF patients, the survival rates did not differ significantly among patients in the three groups with HR ≤ 110 bpm. Moreover, the event rates increased significantly in HFmrEF patients with HR >110 bpm (hazard ratio, 1.91; 95% CI, 1.16-3.14, p = 0.011). Conclusion: In patients with AF and HFpEF, the resting HR has U-shaped associations with the overall primary endpoint. A lower or higher resting HR is associated with increased cardiovascular outcomes, especially in patients with HFpEF and AF.

Screening for Atrial Fibrillation Using a Single Lead ECG Monitoring Device.

Atrial fibrillation (AF) is the most common arrhythmia which needs management for stroke prevention. Therefore, it has emphasized the importance of screening for general population to detect AF earlier. We conducted screening for AF in the Chonbuk region in South Korea. Participants who were older than 50 years were enrolled. The screening test used a single lead electrocardiography (ECG) (KardiaBand, AliveCor, CA, USA). Diagnosis of AF was confirmed by electrophysiologists, if the single lead ECG demonstrated AF of more than 30 seconds. We analyzed the prevalence of AF and the characteristics of newly detected AF patients. A total of 2728 participants, 145 (5.3%) participants had already been diagnosed with AF before. The number of screening positive was 55. Among them, 40 participants were confirmed for AF. Male gender and age older than 70 years were the independent risk factors for AF among the screening positive participants. Most of newly detected AF patients were at high risk for stroke which had more than 2 points on the CHA2DS2-VASc score. We followed up with those patients and encouraged them to visit the hospital. As a result, 31 (77.5%) patients started to manage AF. The additional 1.2% of AF was detected by a screening test with a single lead ECG monitor device. Considering most participants of newly detected AF by screening were at high risk for stroke, it was thought that AF was still undertreated. Therefore, screening tests with simple mobile device might be useful for early detection of AF.

Factors Related to Major Bleeding After Ticagrelor Therapy: Results from the TICO Trial.

Background There is a lack of data on factors that are related to clinically relevant bleeding after ticagrelor treatment. We investigated the clinical and procedural factors related to major bleeding in patients with acute coronary syndrome treated with ticagrelor after coronary stent implantation. Methods and Results From the TICO (Ticagrelor Monotherapy After 3 Months in Patients Treated With New Generation Sirolimus-Eluting Stent for Acute Coronary Syndrome) randomized trial, a total of 2660 patients were included for the present study. Patients with major bleeding, defined by TIMI (Thrombolysis in Myocardial Infarction) major or Bleeding Academic Research Consortium type 3 or 5, were compared with those without major bleeding. On the basis of multivariable and receiver operating characteristic curve analyses, weight ≤65 kg, hemoglobin ≤12 g/dL, and estimated glomerular filtration rate <60 mL/min per 1.73 m2 were associated with an increased risk of major bleeding. In contrast, 3-month aspirin therapy with continued ticagrelor (versus 12-month aspirin and ticagrelor) was associated with a decreased risk of major bleeding. The lower risk of a net adverse clinical event (a composite of TIMI major bleeding and major adverse cardiac and cerebrovascular events) in patients treated with 3-month aspirin therapy reported from the TICO trial remained valid in patients with any of these risk factors (hazard ratio, 0.59; 95% CI, 0.39-0.90; Pinteraction=0.74). Conclusions Low body weight, anemia, and chronic kidney disease were risk factors for major bleeding after ticagrelor therapy. Early aspirin discontinuation had a net clinical benefit among patients with a bleeding risk. Registration URL: https://www.clinicaltrials.gov/. Unique Identifier: NCT02494895.

Introduction of Wearable Device in Cardiovascular Field for Monitoring Arrhythmia.

There has been increasing adoption of wearable smart devices in health care field and they enable non-invasive continuous monitoring of various cardiac parameters. Lots of studies have demonstrated that ambulatory monitoring devices were able to provide data for reliable diagnostics for arrhythmia. Distinguishing features of wearables such as ubiquitous continuous monitoring make it a convincing alternative to traditional diagnostic devices. Additionally, this revolutionary technology does not only enhance the diagnostic utility of wearable devices, but has also facilitated remote health care using IOT (internet of things) capability. In this review, the authors aim to present the state of current technologic development of smart wearables for detection of arrhythmia and comment on future perspectives with reviewing recent studies focused on clinical utility.

Protective Effect of Cilostazol Against Restraint Stress Induced Heart Failure in Post-Myocardial Infarction Rat Model.

Cilostazol, a phosphodiesterase III inhibitor, has antiplatelet and vasodilatory effects. It also has pleiotrophic effects including reduction of oxygen free radicals, positive chronotropic effect and inhibition of intracellular Ca2+ associated catecholamine secretion. The study was aimed to examine, in vivo, the effects of cilostazol treatments on myocardial function, myocardial remodeling, and neurohormonal status in myocardial infarction (MI) with restrained stress rat model. Male Sprague Dawley rats, subjected to coronary artery ligation to induce myocardial infarction (MI), received either a standard rat chow alone (control, n=5) or combined with cilostazol (cilostazol, n=5; 5 mg/kg×5 weeks). They were exposed to repeated restraint stress (2 h×2 times/day) for 10 days beginning 1 week after surgery. Left ventricular ejection fraction (LVEF), LV mass by heart weight/body weight ratio and level of tissue brain natriuretic peptide (BNP) expression by immunoblotting were determined. Plasma epinephrine and norepinephrine levels were also measured. Mean LVEF was higher in the cilostazol group than in the control group (66.9±14.3 vs 47.0±17.1, p<0.05) at 5 weeks after MI. However, LV mass and tissue BNP expression were significantly lower in the cilostazol than in the control group (p<0.05). Plasma epinephrine and norepinephrine levels were also lower in the cilostazol group compared with the control (p<0.05). Cilostazol preserves left ventricular systolic function and attenuates stress induced remodeling in postinfarct rats. Its beneficial effects were associated with reduced plasma catecholamine levels during postinfarct remodeling.

Ondansetron blocks wild-type and p.F503L variant small-conductance Ca2+-activated K+ channels.

Apamin-sensitive small-conductance Ca2+-activated K+ (SK) current ( IKAS) is encoded by Ca2+-activated K+ channel subfamily N ( KCNN) genes. IKAS importantly contributes to cardiac repolarization in conditions associated with reduced repolarization reserve. To test the hypothesis that IKAS inhibition contributes to drug-induced long QT syndrome (diLQTS), we screened for KCNN variants among patients with diLQTS, determined the properties of heterologously expressed wild-type (WT) and variant KCNN channels, and determined if the 5-HT3 receptor antagonist ondansetron blocks IKAS. We searched 2,306,335 records in the Indiana Network for Patient Care and found 11 patients with diLQTS who had DNA available in the Indiana Biobank. DNA sequencing discovered a heterozygous KCNN2 variant (p.F503L) in a 52-yr-old woman presenting with corrected QT interval prolongation at baseline (473 ms) and further corrected QT interval lengthening (601 ms) after oral administration of ondansetron. That patient was also heterozygous for the p.S38G and p.P2835S variants of the QT-controlling genes KCNE1 and ankyrin 2, respectively. Patch-clamp experiments revealed that the p.F503L KCNN2 variant heterologously expressed in human embryonic kidney (HEK)-293 cells augmented Ca2+ sensitivity, increasing IKAS density. The fraction of total F503L-KCNN2 protein retained in the membrane was higher than that of WT KCNN2 protein. Ondansetron at nanomolar concentrations inhibited WT and p.F503L SK2 channels expressed in HEK-293 cells as well as native SK channels in ventricular cardiomyocytes. Ondansetron-induced IKAS inhibition was also demonstrated in Langendorff-perfused murine hearts. In conclusion, the heterozygous p.F503L KCNN2 variant increases Ca2+ sensitivity and IKAS density in transfected HEK-293 cells. Ondansetron at therapeutic (i.e., nanomolar) concentrations is a potent IKAS blocker. NEW & NOTEWORTHY We showed that ondansetron, a 5-HT3 receptor antagonist, blocks small-conductance Ca2+-activated K+ (SK) current. Ondansetron may be useful in controlling arrhythmias in which increased SK current is a likely contributor. However, its SK-blocking effects may also facilitate the development of drug-induced long QT syndrome.

Comparison of the Infarct Size between the Loading of Ticagrelor and Clopidogrel in Patients with Acute Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention.

BACKGROUND AND OBJECTIVES: Ticagrelor is considered a potent antiplatelet agent compared to clopidogrel. However, there are no studies regarding the effect of ticagrelor loading on infarct size in patients with ST-segment elevation myocardial infarction (STEMI) in a primary percutaneous coronary intervention (PCI) setting. SUBJECTS AND METHODS: In this single-center, randomized, open-label study, 188 patients who underwent primary PCI for STEMI were enrolled (92 patients in the clopidogrel group and 96 in the ticagrelor group) and compared the infarct size by technetium-99m (Tc-99m) tetrofosmin single-photon emission computed tomography (SPECT) and serial cardiac biomarker levels between the groups. SPECT was performed at a median of 2 days after PCI. RESULTS: Baseline clinical and procedural characteristics were similar between the groups. Infarct size on SPECT, was similar between the 2 groups (28.1%±34.5% vs. 32.8%±29.2%; p=0.169). At all time-points after PCI (8, 24, and 48 hours), the peak levels of creatine kinase-myocardial band (CK-MB) and troponin T were lower in the clopidogrel group. The clopidogrel group showed lower cumulative troponin T levels than the ticagrelor group (12.59±10.66 vs. 17.67±19.51 ng/mL; p=0.029). CONCLUSION: Ticagrelor loading before primary PCI was not associated with reduced myocardial infarct size during the first 48 hours, compared to clopidogrel loading.

Correlations between High Platelet Reactivity, Extent of Coronary Artery Disease, and Periprocedural Myonecrosis in Patients with Acute Coronary Syndrome.

The purpose of the present study was to evaluate the correlations between high platelet reactivity (HPR) and the extent of coronary atherosclerosis and periprocedural myonecrosis in patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI). A total of 485 patients who underwent PCI for ACS was studied. HPR was defined as ≥230 platelet reactivity units (PRU) in point-of-care P2Y12 tested by the VerifyNow assay. The incidence of multi-vessel disease (MVD) was higher in patients with HPR than those with no HPR (56.2% vs 45.8%, p=0.023). PRU values progressively increased with the number of diseased coronary arteries (1-vessel disease 221.8±86.7; 2-vessel disease 239.3±90.1; 3-vessel disease 243.4±84.5; p=0.038 by ANOVA). Multivariate analysis revealed that HPR was independently associated with MVD (Odds ratio 1.48, 95% confidence interval 1.01-2.25, p=0.048). Patients with periprocedural myonecrosis showed significantly higher PRU values compared with those without myonecrosis (258.6±94.5 vs. 228.5±85.6, p=0.013). Multivariate analysis revealed that HPR was an independent predictor for periprocedural myonecrosis as defined as any creatine kinase-myocardial band isoenzyme elevation or troponin T elevation. In conclusion, HPR is associated with MVD and periprocedural myonecrosis in patients with ACS and PCI. Thus, platelet reactivity after treatment with clopidogrel might be associated not only with blood clot formation but also with increased coronary atherosclerotic burden.

Carotid Atherosclerosis and Electrocardiographic Left Ventricular Hypertrophy in the General Population: The Namwon Study.

This study aimed to investigate the relationship between carotid atherosclerosis and left ventricular hypertrophy on electrocardiogram (ECG-LVH) on adults living in the community. A total of 9,266 adults who participated in the Namwon Study were included in this analysis. Carotid atherosclerosis, including intima-media thickness (IMT) and plaques, were assessed using high-resolution B-mode ultrasound. ECG-LVH was determined using the Sokolow-Lyon voltage (SokV) and Cornell voltage (CorV) criteria. The prevalence of ECG-LVH was 12.7% using the SokV criteria and 9.7% using the CorV criteria. After full adjustment, compared to the lowest quartile of common carotid artery IMT (CCA-IMT), the odds ratios and 95% confidence intervals for ECG-LVH of the carotid IMT quartiles 2, 3, and 4 increased linearly as follows: 1.54 (1.24-1.90), 1.62 (1.31-2.02), and 1.91 (1.54-2.38), respectively, for the SokV criteria (p<0.001); and 1.33 (1.05-1.68), 1.41 (1.11-1.78), and 1.48 (1.16-1.88), respectively, for the CorV criteria (p=0.003). Positive associations between the carotid bulb IMT (CB-IMT) quartiles and the ECG-LVH were also observed, although the magnitudes of association between CB-IMT and ECG-LVH were slightly lower than those of CCA-IMT. However, no significant association between carotid plaques and ECG-LVH as defined by the SokV or CorV criteria was found. The present study demonstrated that increased carotid IMT, but not carotid plaques, is significantly associated with LVH defined by various ECG criteria in a large population.

Arrhythmogenic calmodulin mutations impede activation of small-conductance calcium-activated potassium current.

BACKGROUND: Apamin-sensitive small-conductance calcium-activated potassium (SK) channels are gated by intracellular Ca(2+) through a constitutive interaction with calmodulin. OBJECTIVE: We hypothesize that arrhythmogenic human calmodulin mutations impede activation of SK channels. METHODS: We studied 5 previously published calmodulin mutations (N54I, N98S, D96V, D130G, and F90L). Plasmids encoding either wild-type or mutant calmodulin were transiently transfected into human embryonic kidney 293 cells that stably express subtype 2 of SK protein channels (SK2 cells). Whole-cell voltage-clamp recording was used to determine apamin-sensitive current densities. We also performed optical mapping studies in normal murine hearts to determine the effects of apamin in hearts with (n=7) or without (n=3) pretreatment with sea anemone toxin. RESULTS: SK2 cells transfected with wild-type calmodulin exhibited an apamin-sensitive current density of 33.6 pA/pF (31.4-36.5 pA/pF) (median and confidence interval 25th-75th percentile), which was significantly higher than that observed for cells transfected with N54I (17.0 pA/pF [14.0-27.7 pA/pF]; P = .016), F90L (22.6 pA/pF [20.3-24.3 pA/pF]; P = .011), D96V (13.0 pA/pF [10.9-15.8 pA/pF]; P = .003), N98S (13.7 pA/pF [8.8-20.4 pA/pF]; P = .005), and D130G (17.6 pA/pF [13.8-24.6 pA/pF]; P = .003). The decrease in SK2 current densities was not associated with a decrease in membrane protein expression or intracellular distribution of the channel protein. Apamin increased the ventricular action potential duration at 80% repolarization (from 79.6 ms [63.4-93.3 ms] to 121.8 ms [97.9-127.2 ms]; P = .010) in hearts pretreated with anemone toxin but not in control hearts. CONCLUSION: Human arrhythmogenic calmodulin mutations impede the activation of SK2 channels in human embryonic kidney 293 cells.

Small-Conductance Calcium-Activated Potassium Current Is Activated During Hypokalemia and Masks Short-Term Cardiac Memory Induced by Ventricular Pacing.

BACKGROUND: Hypokalemia increases the vulnerability to ventricular fibrillation. We hypothesize that the apamin-sensitive small-conductance calcium-activated potassium current (IKAS) is activated during hypokalemia and that IKAS blockade is proarrhythmic. METHODS AND RESULTS: Optical mapping was performed in 23 Langendorff-perfused rabbit ventricles with atrioventricular block and either right or left ventricular pacing during normokalemia or hypokalemia. Apamin prolonged the action potential duration (APD) measured to 80% repolarization (APD80) by 26 milliseconds (95% confidence interval [CI], 14-37) during normokalemia and by 54 milliseconds (95% CI, 40-68) during hypokalemia (P=0.01) at a 1000-millisecond pacing cycle length. In hypokalemic ventricles, apamin increased the maximal slope of APD restitution, the pacing cycle length threshold of APD alternans, the pacing cycle length for wave-break induction, and the area of spatially discordant APD alternans. Apamin significantly facilitated the induction of sustained ventricular fibrillation (from 3 of 9 hearts to 9 of 9 hearts; P=0.009). Short-term cardiac memory was assessed by the slope of APD80 versus activation time. The slope increased from 0.01 (95% CI, -0.09 to 0.12) at baseline to 0.34 (95% CI, 0.23-0.44) after apamin (P<0.001) during right ventricular pacing and from 0.07 (95% CI, -0.05 to 0.20) to 0.54 (95% CI, 0.06-1.03) after apamin infusion (P=0.045) during left ventricular pacing. Patch-clamp studies confirmed increased IKAS in isolated rabbit ventricular myocytes during hypokalemia (P=0.038). CONCLUSIONS: Hypokalemia activates IKAS to shorten APD and maintain repolarization reserve at late activation sites during ventricular pacing. IKAS blockade prominently lengthens the APD at late activation sites and facilitates ventricular fibrillation induction.

Effect of High Dose Rosuvastatin Loading before Percutaneous Coronary Intervention on Contrast-Induced Nephropathy.

BACKGROUND AND OBJECTIVES: Contrast-induced nephropathy (CIN) is associated with increased morbidity and mortality. This observational, non-randomized study evaluated the effect of rosuvastatin loading before percutaneous coronary intervention (PCI) on the incidence of CIN in patients with acute coronary syndrome (ACS). SUBJECTS AND METHODS: A total of 824 patients who underwent PCI for ACS were studied (408 patients in the statin group=40 mg rosuvastatin loading before PCI; 416 patients of control group=no statin pretreatment). Serum creatinine concentrations were measured before and 24 and 48 hours after PCI. The primary endpoint was development of CIN defined as an increase in serum creatinine concentration of ≥0.5 mg/dL or ≥25% above baseline within 72 hours after PCI. RESULTS: The incidence of CIN was significantly lower in the statin group than that in the control group (18.8% vs. 13.5%, p=0.040). The maximum percent changes in serum creatinine and estimated glomerular filtration rate in the statin group within 48 hours were significantly lower than those in the control group (5.84±22.59% vs. 2.43±24.49%, p=0.038; -11.44±14.00 vs. -9.51±13.89, p=0.048, respectively). The effect of rosuvastatin on preventing CIN was greater in the subgroups of patients with diabetes, high-dose contrast medium, multivessel stents, high baseline C-reactive protein, and myocardial infarction. A multivariate analysis revealed that rosuvastatin loading was independently associated with a decreased risk for CIN (odds ratio, 0.64; 95% confidence interval, 0.43-0.95, p=0.026). CONCLUSION: High-dose rosuvastatin loading before PCI was associated with a significantly lower incidence of CIN in patients with ACS.

Effect of High Dose Rosuvastatin Loading before Primary Percutaneous Coronary Intervention on Infarct Size in Patients with ST-Segment Elevation Myocardial Infarction.

BACKGROUND AND OBJECTIVES: High dose rosuvastatin loading before percutaneous coronary interventions (PCI) reduces the myocardial damage and the incidence of adverse cardiac events in patients with stable angina and acute coronary syndrome. However, no studies are present yet about rosuvastatin loading in patients with ST-segment elevation myocardial infarction (STEMI) in a primary PCI setting. SUBJECTS AND METHODS: A total of 475 patients who underwent primary PCI for STEMI were studied. The study population was divided into two groups with 208 patients in the statin group=40 mg rosuvastatin loading before primary PCI and 267 patients in the control group=no statin pretreatment. At median 3 days after PCI a single-photon emission computed tomography (SPECT) was performed with technetium 99m tetrofosmin For this study were compared infarct size, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count and the myocardial blush grade (MBG) between the both groups. RESULTS: Baseline clinical and procedural characteristics were similar between the groups. Infarct size, as assessed by SPECT, was significantly smaller (19.0±15.9% vs. 22.9±16.5%, p=0.009) in the statin group than in the control group. Patients of the statin group showed a lower corrected TIMI frame count (28.2±19.3 vs. 32.6±21.4, p=0.020), and higher MBG (2.49±0.76 vs. 2.23±0.96, p=0.001) than the patients of the control group. The multivariate analysis revealed that rosuvastatin loading {odds ratio (OR) 0.61}, pain to balloon time (OR 2.05), anterior myocardial infarction (OR 3.89) and final the MBG (OR 2.93) were independent predictors of a large infarct size. CONCLUSION: A high dose rosuvastatin loading before the primary PCI reduced the infarct size by microvascular myocardial perfusion improvement.