Statement from the Asia Summit: Current state of arrhythmia care in Asia.

On May 27, 2022, the Asia Pacific Heart Rhythm Society and the Heart Rhythm Society convened a meeting of leaders from different professional societies of healthcare providers committed to arrhythmia care from the Asia Pacific region. The overriding goals of the meeting were to discuss clinical and health policy issues that face each country for providing care for patients with electrophysiologic issues, share experiences and best practices, and discuss potential future solutions. Participants were asked to address a series of questions in preparation for the meeting. The format of the meeting was a series of individual country reports presented by the leaders from each of the professional societies followed by open discussion. The recorded presentations from the Asia Summit can be accessed at https://www.heartrhythm365.org/URL/asiasummit-22. Three major themes arose from the discussion. First, the major clinical problems faced by different countries vary. Although atrial fibrillation is common throughout the region, the most important issues also include more general issues such as hypertension, rheumatic heart disease, tobacco abuse, and management of potentially life-threatening problems such as sudden cardiac arrest or profound bradycardia. Second, there is significant variability in the access to advanced arrhythmia care throughout the region due to differences in workforce availability, resources, drug availability, and national health policies. Third, collaboration in the area already occurs between individual countries, but no systematic regional method for working together is present.

Ventricular pacing dependency after transcatheter aortic valve replacement: a prospective cohort.

Background: Atrioventricular conduction disturbance occurs in a significant number of patients undergoing transcatheter aortic valve replacement (TAVR). However, not all cases are ventricular pacing-dependent. Thus, we aimed to study the incidence, predictors, and outcomes of new ventricular pacing dependency (VpDep) after TAVR. Methods: We prospectively analyzed 130 consecutive transfemoral TAVR cases performed in Ramathibodi Hospital between 2015 and 2020. Three patients with prior ventricular pacing-dependent on cardiac implantable electronic devices (CIEDs) were excluded. The endpoints were VpDep at 1 month and all-cause mortality at the follow-up period end in 2021. The effects of variables on VpDep and all-cause mortality were evaluated using multivariate binary logistic regression and Cox regression analyses, respectively. First-degree atrioventricular block (AVB) was considered severe when the PR interval was >300 ms. Results: Of the 127 patients [mean age, 81.8 years; 62.2% females; 67.7% balloon-expandable (BE) device], 7 patients (5.5%) had CIEDs implanted before TAVR that were not ventricular pacing-dependent. TAVR was successfully performed in 126 (99.2%) patients. Periprocedural stroke, cardiac tamponade, and major bleeding occurred in 2 (1.6%), 4 (3.1%), and 4 (3.1%) patients, respectively. The VpDep incidence at 1 month was 7.9% (n=10) among all patients and 34.5% among those with CIEDs (n=29). VpDep was more likely to occur in patients with pre-existing right bundle branch block (RBBB) [odds ratio (OR), 21.38; 95% confidence interval (CI): 3.28-139.33; P=0.001] and severe 1st degree or Mobitz I AVB (OR, 14.79; 95% CI: 1.65-132.74; P=0.016). After a mean follow-up of 25.8 months [standard deviation (SD), 21.2 months], death from any cause occurred in 18 patients (14.2%). However, VpDep was not associated with an increased mortality. Conclusions: In this real-world cohort, pre-existing conduction abnormalities were significantly associated with a higher risk of VpDep. Mortality was similar between patients with and without VpDep.

Effect of ElectroMagnetic interference from SmartPHone on cardiac ImplaNtable electronic device (EMI-PHONE study).

Background: Smartphone can emit two types of electromagnetic waves, static field and dynamic field. Evidence showed the interference from phones to cardiac implantable electronic devices (CIEDs). The smartphones and CIEDs are reportedly better designed to reduce electromagnetic interference (EMI). Methods: 80 consecutive subjects with CIEDs were recruited and tested for EMI. Subject was tested with three different smartphones (Nokia 3310, Iphone 7, and Samsung 9S). Phone was attached to chest wall at 0 cm at generator site, at atrial lead level, and at ventricular lead level. During the tests, real-time interrogations were performed to detect any EMI from smartphone in standby mode, and during calling-in and out for 30 s. After the tests, post-test interrogations were performed to detect any parameter change. Adverse events including pacemaker inhibition, false ICD shock, CIEDs device malfunction, and urgent electrophysiologist consultations were recorded. Results: 80 subjects (mean age 70.5-year-old, 50% male) recruited in the study, all completed the testing protocol. The most common type of CIEDs tested was pacemaker (N = 56, 70%), followed by ICD (N = 16, 20%), and CRT (N = 8, 10%). Most patients (N = 62, 77.5%) had more than one lead implanted. The mean year of implantation was 5.2±2.8 (devices were implanted from 2008 to 2019). Of all the tests performed, there was no EMI or adverse events observed. Conclusion: Current generation of smartphones has no EMI effect on CIEDs in our study and can be used safely with less concern about adverse events including pacemaker inhibition, inappropriate ICD shock, and CIEDs device malfunction.

Outcome disparities in patients with atrial fibrillation based on insurance plan and educational attainment: a nationwide, multicenter and prospective cohort trial.

BACKGROUND: Atrial fibrillation (AF) is a complex disease. The management of AF requires continuous patient engagement and integrative healthcare. OBJECTIVES: To explore the association between adverse AF-related clinical outcomes and the following two sociodemographic factors: educational attainment and insurance plan. DESIGN: A nationwide, prospective, multicenter, cohort trial. SETTING: National registry of 3402 patients with non-valvular AF in Thailand. PARTICIPANTS: All patients enrolled in the registry, except those with missing information on educational attainment or insurance plan. Finally, data from 3026 patients (mean age 67 years, SD 11.3; 59% male sex) were analysed. PRIMARY OUTCOMES: Incidences of all-cause mortality, ischaemic stroke and major bleeding during the 36-month follow-up period. Survival analysis was performed using restricted mean survival time (RMST) and adjusted for multiple covariates. The levels of the educational attainment were as follows: no formal education, elementary (grade 1-6), secondary (grade 7-12) and higher education (tertiary education). RESULTS: The educational attainment of the majority of patients was elementary (N=1739, 57.4%). The predominant health insurance plans were the Civil Servant Medical Benefit Scheme (N=1397, 46.2%) and the Universal Coverage Scheme (N=1333, 44.1%). After 36 months of follow-up, 248 patients died (8.2%), 95 had ischaemic stroke (3.1%) and 136 had major bleeding (4.5%). Patients without formal education died 1.78 months earlier (adjusted RMST difference -1.78; 95% CI, -3.25 to -0.30; p=0.02) and developed ischaemic stroke 1.04 months sooner (adjusted RMST difference -1.04; 95% CI, -2.03 to -0.04; p=0.04) than those attained a level of higher education. There were no significant differences in RMSTs for all three clinical outcomes when considering the type of health insurance plan. CONCLUSION: Educational attainment was independently associated with all-cause mortality and ischaemic stroke in patients with AF, but adverse clinical outcomes were not related to the types of health insurance in Thailand. TRIAL REGISTRATION NUMBER: Thai Clinical Trial Registration; Study ID: TCTR20160113002.

Transvenous Lead Extraction (TLE) Procedure: Experience from a Tertiary Care Center in Thailand.

BACKGROUND: Transvenous Lead Extraction (TLE) is a standard treatment for some late Cardiac Implantable Electronics Device (CIED) complications. The outcome of transvenous lead extraction procedure in Thailand is not robust. METHODS: A Single-center retrospective cohort of TLE procedures performed at Ramathibodi hospital between January 2008 and December 2020 was studied. RESULTS: There were 157 leads from 105 patients who underwent lead removal procedure during the specified period. Data analysis was performed from 79 TLE patients due to incomplete data and lead explant procedure of the excluded subjects. Mean patients' age was 57.7 ± 18.7 years, with 70.9% male. There were 82 pacemaker leads, 35 ICD leads, and 5 CS leads (mean number of leads were 1.54 ± 0.66 per patient), with mean implanted duration of 87.8 ± 68.2 months. Main indication for TLE was infection-related, which accounted for 67.1% of the cases. Overall clinical success rate was 97.5%. Mean operative time was 163.8 ± 69.5 min. Major complications occurred in 4 patients (5.1%) with one in-hospital mortality from severe sepsis. CONCLUSION: TLE using laser sheath and rotating mechanical sheath for transvenous lead extraction is effective and safe, even outside high-volume center.

Mortality risk and temporal patterns of atrial fibrillation in the nationwide registry.

AIMS: Persistent and permanent atrial fibrillation (AF) often occurs in the presence of multiple comorbidities and is linked to adverse outcomes. It is unclear whether the sustained pattern of AF itself is prognostic or if it is confounded by underlying comorbidities. Here, we tested the association between the temporal patterns of AF and the risks of ischemic stroke and all-cause mortality. METHODS AND RESULTS: In a prospective multicenter cohort, 3046 non-valvular AF patients were consecutively enrolled and followed for adverse outcomes of all-cause mortality and ischemic stroke. The risks of both outcomes were adjusted for underlying comorbidities, and compared between the patterns of AF. At baseline, the patients were classified as paroxysmal (N = 963, 31.6%), persistent (N = 604, 19.8%), and permanent AF (N = 1479, 45.6%) according to the standard definition. Anticoagulants were administered in 75% of all patients and 83% of those with CHA2DS2-VASc score ≥2 in males or ≥3 in females. During a mean follow up of 26 (SD 10.5) months, all-cause mortality occurred less in paroxysmal AF (2.5 per 100 patient-years) than in persistent AF (4.4 per 100 patient-years; adjusted hazard ratio [HR] 0.66, 95% CI, 0.46-0.96; P = .029) and permanent AF (4.1 per 100 patient-years; adjusted HR 0.71, 95% CI, 0.52-0.98; P = .036). The risk of ischemic stroke was similar across all patterns of AF. CONCLUSIONS: In this multicenter cohort of AF patients, persistent and permanent AF was associated with higher all-cause mortality than paroxysmal AF, independent of baseline comorbidities. CLINICAL TRIAL REGISTRATION: Thai Clinical Trial Registration; Study ID: TCTR20160113002 (http://www.thaiclinicaltrials.org/show/TCTR20160113002).

Adherence to Anticoagulant Guideline for Atrial Fibrillation Improves Outcomes in Asian Population: The COOL-AF Registry.

Background and Purpose- Guideline adherent oral anticoagulant (OAC) management of patients with nonvalvular atrial fibrillation has been associated with improved outcomes, but limited data are available from Asia. We aimed to investigate outcomes in patients who received guideline compliant management compared with those who were OAC undertreated or overtreated, in a large nationwide multicenter cohort of patients with nonvalvular atrial fibrillation in Thailand. Methods- Patients with nonvalvular atrial fibrillation were prospectively enrolled from 27 hospitals-all of which are data contributors to the COOL-AF Registry (Cohort of Antithrombotic Use and Optimal INR Level in Patients With Non-Valvular Atrial Fibrillation in Thailand). Patients were categorized as follows: (1) guideline adherence group when OAC was given in high-risk or intermediate-risk, but not in low-risk patients; (2) undertreatment group when OAC was not given in the high-risk or intermediate-risk groups; and (3) overtreatment group when OAC was given in the low-risk group or when OAC was given in combination with antiplatelets without indication. Results- A total of 3327 patients who had follow-up clinical outcome data were included. The mean age of patients was 67.4 years and 58.1% were male. The numbers of patients in the guideline adherence group, undertreatment group, and overtreatment group were 2267 (68.1%), 624 (18.8%), and 436 (13.1%) patients, respectively. The overall rate of ischemic stroke, major bleeding, all bleeding, and death was 3.0%, 4.4%, 15.1%, and 7.8%, respectively. Undertreated patients had a higher risk of ischemic stroke and death compared with guideline adherent patients, and overtreated patients had a higher risk of bleeding and death compared with OAC guideline-managed patients. Conclusions- Adherence to OAC management guidelines is associated with improved clinical outcomes in Asian nonvalvular atrial fibrillation patients. Undertreatment or overtreatment was found to be associated with increased risk of adverse outcomes compared with guideline-adherent management.

SAMe-TT2R2 score for prediction of suboptimal time in therapeutic range in a Thai population with atrial fibrillation.

INTRODUCTION: International normalised ratio (INR) control is an important factor in patients with non-valvular atrial fibrillation (NVAF) being treated with warfarin. INR control was previously reported to be poorer among Asians compared to Westerners. We aimed to validate the SAMe-TT2R2 score for prediction of suboptimal INR control (defined as time in therapeutic range [TTR] < 65% in the Thai population) and to investigate TTR among Thai NVAF patients being treated with warfarin. METHODS: INR data from patients enrolled in a multicentre NVAF registry was analysed. Clinical and laboratory data was prospectively collected. TTR was calculated using the Rosendaal method. Baseline data was compared between patients with and without suboptimal INR control. Univariate and multivariate analyses were performed to identify variables independently associated with suboptimal INR control. RESULTS: A total of 1,669 patients from 22 centres located across Thailand were included. The average age was 69.1 ± 10.7 years, and 921 (55.2%) were male. The mean TTR was 50.5% ± 27.5%; 1,125 (67.4%) had TTR < 65%. Univariate analysis showed hypertension, diabetes mellitus, heart failure, renal disease and SAMe-TT2R2 score to be significantly different between patients with and without optimal TTR. The SAMe-TT2R2 score was the only factor that remained statistically significant in multivariate analysis. The C-statistic for the SAMe-TT2R2 score in the prediction of suboptimal TTR was 0.54. CONCLUSION: SAMe-TT2R2 score was the only independent predictor of suboptimal TTR in NVAF patients being treated with warfarin. However, due to the low C-statistic, the score may have limited discriminative power.

CHA2DS2-VASc scores predict mortality after hospitalization for atrial fibrillation.

OBJECTIVE: The outcome of patients hospitalized for atrial fibrillation (AF) is relatively poor. We sought to determine the mortality rate and predictors of mortality following hospitalization for AF and to evaluate whether the CHA2DS2-VASc score was a predictor of mortality. METHODS: We examined the national database of Thailand residents who registered for government provided health insurance in 2005 and reviewed patient records from 2005 to 2010 to determine all-cause mortality. A total of 8981 patients (mean age, 65 years; 42% male) were admitted to the hospital with a diagnosis of AF. Data on demographics and comorbidities were retrieved from the database. The CHA2DS2-VASc score was calculated for each patient. RESULTS: The hospitalization rate for AF was 15.5 per 100,000 person-years. The two most common comorbidities were hypertension (N=1638, 18.2%) and diabetes (N=1349, 15.0%). The average CHA2DS2-VASc score for all patients was 1.8. By the 72-month follow-up (average 46 months), 3948 patients (44.0%) had died. The CHA2DS2-VASc score was directly related to the mortality rate (P log-rank <0.0001). Multivariate analysis showed that a CHA2DS2-VASc score ≥ 6 (hazard ratio [HR] 2.2, 95% confidence interval [CI], 1.4-3.7, P=0.002) and the presence of chronic kidney disease (HR 2.0, 95% CI 1.7-2.4, P<0.0001) were the strongest predictors of death. CONCLUSION: The outcome after hospitalization for AF is relatively poor. The CHA2DS2-VASc score is an independent prognostic marker of poor outcomes following hospitalization for AF.

Fragmented QRS as a Predictor of Appropriate Implantable Cardioverter-defibrillator Therapy.

BACKGROUND: Fragmented QRS (fQRS) has been shown to be a marker of local myocardial conduction abnormalities and a predictor of cardiac events in selected populations. We hypothesized that the presence of a fQRS might predict arrhythmic events in patients who received an implantable cardioverter-defibrillator (ICD), regardless of the indications for implantation. METHODS AND RESULTS: A cohort of 107 consecutive patients (mean age, 53 years; 82% male) who underwent an ICD implantation was studied. We defined fQRS, on a routine 12-lead ECG, as the presence of an additional R wave or notching in the nadir of the S wave in 2 consecutive leads corresponding to a major coronary artery territory. In the presence of bundle branch block, more than 2 notches in the R or S waves in 2 consecutive leads were required to characterize fQRS. Patients were followed for 21.3±23 months for appropriate ICD therapy (antitachycardia pacing and/or shock). ICDs were implanted predominantly in patients with ischemic cardiomyopathy (N=45, 42.1%), followed by Brugada syndrome (N=26, 24.3%). fQRS presented in 42 patients (39.3%). During follow-up, patients with fQRS received more appropriate ICD therapy than those without fQRS (45.2% vs. 10.8%, P<0.0001). After adjustment for covariates, fQRS remained an independent predictor for appropriate ICD therapy (hazard ratio=5.32, 95% confidence interval=2.11-13.37, P<0.0001). CONCLUSION: The presence of fQRS appeared to be directly associated with appropriate ICD therapy.

Correlation of echocardiographic left atrial abnormality with myocardial ischemia during myocardial perfusion assessment in the presence of known left ventricular hypertrophy.

Left atrial (LA) abnormality, an easily quantifiable parameter of left ventricular (LV) diastolic dysfunction, has been associated with cardiovascular risk similar to that of LV hypertrophy. The correlation between LV hypertrophy and LA abnormality among patients undergoing myocardial perfusion (MP) study has not been described. We prospectively studied 78 consecutive patients with LV hypertrophy who underwent MP study after screening for electrocardiographic and echocardiographic LA abnormality over a 6-month period. Of those, 48 had a positive MP imaging result, and 30 did not. LA size (p = 0.002) and P-wave duration (p = 0.017) were significantly increased in the former. The differential change in LA size (no defect = 35 ± 4, mild = 36 ± 5, moderate = 38 ± 5, severe = 44 ± 5 mm; p <0.0001) and P-wave duration (no defect = 107 ± 14, mild = 110 ± 17, moderate = 113 ± 15, severe = 127 ± 22 ms; p = 0.003) was greatest when the MP study defect exceeded moderate severity. In conclusion, the presence of LA abnormality could assist during MP study interpretation among patients with LV hypertrophy when such markers appear to be correlated with the severity of the MP study defect.

Correlation of echocardiographic left atrial abnormality with myocardial ischemia during myocardial perfusion assessment in patients with left bundle branch block.

Left atrial (LA) abnormality, an easily quantifiable parameter of left ventricular (LV) diastolic dysfunction, has been associated with cardiovascular risk. Because during myocardial perfusion study (MPS), the abnormal LV activation pattern in patients with left bundle branch block (LBBB) frequently induces perfusion defects, a clinical correlate of early myocardial ischemia such as LA enlargement could alleviate some of these inherent challenges. We prospectively studied 144 consecutive patients with LBBB who underwent MPS after screening for electrocardiographic and echocardiographic LA enlargement over a 6-month period. Of those, 114 had a positive MPS result. We found that LA size (p <0.0001) and P-wave duration (p = 0.001) were significantly increased in patients as the severity of the defects increased on MPS, whereas LV ejection fraction was decrementally reduced (p = 0.001). Importantly, LA size (≥43.5 mm; sensitivity 70%, specificity 89%) and P-wave duration (≥135 milliseconds; sensitivity 63%, specificity 90%) were greatest when the MPS defect was severe. In conclusion, the presence of LA enlargement appears significantly correlated with myocardial ischemia among patients with LBBB and could therefore assist during MPS interpretation among patients in whom MPS interpretation could be challenging.

Association of statin therapy with ventricular arrhythmias among patients with acute coronary syndrome.

BACKGROUND: In addition to lowering cholesterol, statins stabilise atherosclerotic plaques and can potentially reduce the incidence of ventricular arrhythmias. We tested the hypothesis that prior statin therapy is associated with a lower incidence of inhospital ventricular arrhythmias among patients with acute coronary syndrome (ACS). METHODS: The study population consisted of 2007 patients (mean age 64 years, 67.5% male) enrolled in the Thai Registry of Acute Coronary Syndrome, a prospective, multicentre, nationwide, observational study of patients with ACS. Patients were categorised as either statin users or non-users according to their reports of statin use before enrolment at their initial presentation. The primary endpoint was inhospital ventricular arrhythmias. The secondary endpoint was a composite endpoint of inhospital ventricular arrhythmias or inhospital cardiac death. A propensity-adjusted multivariate model was developed to assess the effects of statin use on the primary and secondary endpoints. RESULTS: During a mean hospital stay of 7 days, a total of 96 patients (4.8%) died; 82 (4.1%) of the deaths were due to cardiac causes. The primary and secondary endpoints were reached in 163 patients (8.1%) and 194 patients (9.7%), respectively. A total of 525 patients (26.2%) had used statins prior to hospitalisation. After adjusting for the propensity scores and other relevant covariates, statin use was associated with lower risks of the primary (adjusted OR 0.505, 95% CI 0.276 to 0.923) and secondary endpoints (adjusted OR 0.498, 95% CI 0.276 to 0.897). CONCLUSIONS: The use of statins is associated with a reduced incidence of ventricular arrhythmias among patients with ACS.

Usefulness of diastolic time measured on electrocardiogram to improve sensitivity and specificity of exercise tolerance tests.

The current exercise tolerance test (ETT) criteria predominantly assess changes in ST-segment deviation (i.e., a systolic component of the cardiac cycle). Because diastolic dysfunction precedes that of systolic dysfunction during myocardial ischemia and most coronary flow is diastolic, the addition of electrocardiographic markers of diastolic time might improve the ETT sensitivity and specificity for detecting significant coronary artery disease. Among consecutive patients who had an ETT and subsequently underwent coronary angiography, we evaluated the diastolic time by assessing the TP and TQ segments and TP/RR and TQ/RR ratios in each ETT stage. Coronary artery disease was defined angiographically as significant (≥70% lumen occlusion), intermediate (>50% but <70% lumen occlusion), or nonsignificant (≤50% lumen occlusion). Of the 48 study patients, hypertension and hyperlipidemia appeared highly prevalent. TP, TQ, TP/RR, and TQ/RR correlated significantly with RR and changed with each ETT stage. Although TP and TQ were not significantly associated with significant coronary artery disease, TP/RR and TQ/RR proved to be, particularly beyond stage 2. When TQ/RR of ≤0.39 and TP/RR of ≤0.13 were used, their individual sensitivities and specificities were reasonably comparable to that of traditional ETT criteria (79% sensitivity and 44% specificity at our institution). Adding TQ/RR of ≤0.39 and/or TP/RR of ≤0.13 to existing ETT criteria improved its sensitivity to 100% and specificity to 86%. In conclusion, the addition of diastolic time indexes of TP/RR and TQ/RR significantly improved the overall ETT diagnostic value above the guideline-oriented, perhaps "traditional," criteria for the diagnosis of myocardial ischemia. Such parameters should be widely investigated further for clinical accuracy and compatibility.

Electrocardiographic detection of emphysema.

Emphysema of any pathogenesis (nearly always chronic obstructive pulmonary disease) verticalizes the frontal P-wave axis >60° in adults, which, as a single criterion, has screened for obstructive pulmonary disease. In patients with emphysema, the QRS was of a significantly shorter duration than that in matched control patients. We investigated whether combining these 2 criteria would better detect or screen for emphysema. From consecutive unselected daily electrocardiograms with sinus rhythm, 50 were selected with a P-wave axis of >60°. An equal control group from the same electrocardiogram continuum with a P-wave axis of ≤60° was matched for age and gender. The QRS durations were those measured by the electrocardiographic computer and manually verified individually. The charts were then reviewed for the diagnosis of chronic obstructive pulmonary disease and/or pulmonary emphysema according to the pulmonary function test and chest radiographic findings, respectively. The patients and controls were well matched demographically. Those with a vertical P axis had a strikingly greater incidence of emphysema than did the controls (86% vs 4%, respectively). The sensitivity of a P axis >60° was 96% and the specificity was 87%. The mean QRS duration with emphysema was significantly shorter (78 ± 8 vs 89 ± 6 ms, p <0.01). The combination of QRS duration <75 ms in conjunction with a P axis of >60° achieved a specificity of 100%, although the sensitivity decreased to 33%. We have reported multiple other cutpoints for each and for the combination. In conclusion, a P axis >60° can be used alone with very high sensitivity and specificity to detect emphysema. The verticality of the P axis is usually immediately visible in the limb leads; therefore, this could be a rapid screening test for emphysema. The specificity was increased when combined with a shortened QRS duration, at the cost of the sensitivity.

Feasibility, efficacy, and safety of radiofrequency catheter ablation for cardiac arrhythmias: a twelve-year experience in Thailand.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is widely accepted as a curative treatment for many types of cardiac arrhythmias. MATERIAL AND METHOD: The authors retrospectively reviewed 1,193 cases (mean age 45, 41% male) performed in the electrophysiology laboratory at Ramathibodi Hospital from 1996 to 2007. Success rate, recurrence rate and complications were analyzed. RESULTS: Ablations of atrioventricular nodal reentrant tachycardia (AVNRT, 428 cases, 35.9%) and atrioventricular reentrant tachycardia (AVRT, 346 cases, 29%) were the most common procedures. The overall success rate and recurrence rate of RFCA were 88.8% and 6.1% respectively. Complications occurred in 50 patients (4.2%) with 1 death (0.08%). RFCA of AVNRT or AVRT rather than other arrhythmias (Odd ratio 11.46, 95% confidence interval 8.14-16.15, p < 0.001) and adult rather than pediatric patients (Odd ratio for age 1.007, 95% confidence interval 1.003-1.011, p < 0.001) were independent predictors for successful RFCA. CONCLUSION: RFCA of cardiac arrhythmia in our institution is safe and effective.

Is the presence of mitral annular calcification associated with poor left atrial function?

INTRODUCTION: Mitral annular calcification (MAC) is characterized by calcium and lipid deposition in the annular fibrosa of the mitral valve. MAC is associated with cardiovascular events but little is known of its association with left atrial (LA) function. METHODS: We prospectively obtained 12-lead electrocardiograms (ECGs) and transthoracic echocardiograms (TTE) on patients scheduled for nonemergent echocardiographic assessment at a tertiary care hospital. MAC was graded as 0 = none, 1 = mild, 2 = moderate, 3 = severe. LA linear and volume measurements (stroke volume, LA passive emptying fraction, LA active emptying fraction and LA kinetic energy) were done specifically in addition to commonly measured TTE parameters. RESULTS: From the 124 considered for the study, 72 patients remained (aged 68+/-18 years; 44% male) after excluding those with poor ECG tracings and/or poor TTE images. Eighteen patients had MAC; mild MAC = 14, moderate MAC = 3, severe MAC = 1. When patients with MAC were compared to those without MAC, no significant difference was noted, except for LA linear dimension index (2.1+/-0.4 vs. 1.9+/-0.3 cm/m(2); P = 0.03). For those with mild and moderate MAC, a trend was noted toward lower LA function with increasing MAC severity. In addition, significant differences were noted between those with and without interatrial conduction delay, where those with such delay had significantly impaired LA stroke volume (9.8+/-3 vs. 19.93+/-4 ml; P < 0.0001), LA active emptying fraction (18.83+/-8 vs. 65.71+/-9%; P < 0.0001) and LA total/reservoir fraction (39.54+/-6 vs. 75.1+/-6%; P < 0.0001). CONCLUSIONS: MAC is associated with increase in LA linear dimension on TTE and may be equally represented with lower overall LA function. Further study in a much larger cohort is warranted to delineate these and other potential associations of MAC.

Prospective assessment of cardiovascular events in patients with partial and advanced interatrial conduction delay: a preliminary observation.

INTRODUCTION: Major adverse cardiovascular events (MACE) have been investigated with partial interatrial block (IAB; P wave > or = 110 ms) but not with advanced IAB. METHODS: Twenty-four advanced IAB and 34 partial IAB patients were followed for 24 months for MACE, change in renal function and death. RESULTS: Three patients with advanced IAB had myocardial infarction compared to none with partial IAB (p = 0.03). However, overall MACE was not significantly different between groups with an overall low event rate. There was also no difference between change in mean blood urea nitrogen levels and calculated glomerular filtration rates over time. CONCLUSION: In a preliminary 24-month period, when compared to patients with partial IAB, those with the uncommon, advanced form of IAB do not appear to be overly at increased risk for MACE. However, larger prospective studies are needed to confirm these results in order to appraise other cardiovascular risk factors.

The association of atrial tachyarrhythmias with isolated atrial amyloid disease: preliminary observations in autopsied heart specimens.

OBJECTIVE: Isolated atrial amyloidosis (IAA) is associated with atrial tachyarrhythmias. However, only a few studies have appraised atrial tachyarrhythmias and atrial depolarization abnormalities in connection with high-grade IAA. We conducted a collaborative retrospective study to assess this association. METHODS: One hundred consecutive autopsied hearts were studied histologically for IAA. To increase the specificity for atrial depolarization abnormalities in this preliminary study, we excluded those specimens with intermediate amyloid involvement, i.e. IAA grades 1 and 2 (grade 0 = absent or trivial deposits; grade 1 = small deposits; grade 2 = moderate deposits; grade 3 = dense, large deposits). We then screened for baseline, premortem electrocardiograms (ECGs) to assess rhythm. In those with sinus rhythm, the P wave axis, duration, dispersion and terminal force in V1 were determined under magnification. RESULTS: Of the 27 premortem ECGs corresponding to the autopsy specimens with grades 3 (sample) or 0 (controls) IAA, 9 showed sinus rhythm, 13 showed atrial fibrillation, 1 showed atrial flutter and 4 were uninterpretable. Fourteen autopsied hearts (52%) were positive for grade 3 IAA. Ten of those had atrial tachyarrhythmias (9 atrial fibrillation and 1 atrial flutter) compared to 4 of the 13 hearts with grade 0 IAA (72 vs. 31%, respectively; p = 0.03). Although there was excellent interobserver agreement using intraclass correlation coefficients, there were no significant differences in P wave measurements among the small number of patients with sinus rhythm for grade 3 versus grade 0 IAA. CONCLUSION: In a collaborative, preliminary, pilot assessment of autopsied hearts for which premortem ECGs were necessarily screened retrospectively, significantly more hearts with high-grade IAA were associated with atrial tachyarrhythmias compared to those with low-grade IAA. A larger study with an appropriately matched autopsy control group is needed to confirm these and previous observations.

Formulaic quantification of echocardiographic left atrial volume.

INTRODUCTION: The association between increasing severity in abnormal atrial depolarization and left atrial (LA) volume derived by transthoracic echocardiogram (TTE) has been described through the following regression formula: LA end-systolic volume index (LAVI [milliliter]) = 8.0 + 0.2 (P-wave duration [millisecond]) (r = 0.47; P = .0002). However, prospective assessment of this formula has not been validated among inpatients outside the institution where it was first derived. METHODS: We prospectively obtained 12-lead electrocardiograms (ECGs) and TTEs on consecutive inpatients who were scheduled for nonemergent echocardiographic assessment. P waves were assessed independently to the nearest 10 milliseconds for application of the formula with a Bland-Altman plot. P-wave durations were obtained specifically from lead II and also from the any lead that yielded the widest measurement. RESULTS: After excluding those with poor ECG tracing and TTE images, 72 patients were studied. We found a strong formulaic correlation with LAVI by TTE when maximal P-wave measurements were obtained from any ECG lead (r = 0.67; P < .0001) and more so, when restricted only to lead II (r = 0.89; P < .0001). Correlation was strongest when there was no or minimal difference between P-wave measurements in lead II and all other leads (r = 0.84; P < .0001 for no difference vs r = 0.67; P < .0001 for 60-millisecond difference). The Bland-Altman plot showed good agreement of LAVI assessment using the formulaic estimation when compared to TTE measurements derived by Simpson's rule (coefficient of reproducibility for 2 SD equivalent to 8.8% for lead II and 11.4% for any lead). CONCLUSION: There is good agreement and correlation between formulaic estimation and that of TTE for LAVI among inpatients. Such quantification of LA size not only serves as an indirect asset that could perhaps supplement TTE measurements in certain circumstances but also can facilitate risk stratification of patients.