Sirin Apiyasawat

CHA2DS2-VASc scores predict mortality after hospitalization for atrial fibrillation

OBJECTIVEnThe 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.nnnMETHODSnWe 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.nnnRESULTSnThe 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.nnnCONCLUSIONnThe 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.

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/m2; 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.

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.

Fragmented QRS on 12-lead EKG is an independent predictor for myocardial scar: a cardiovascular magnetic resonance imaging study

Background Fragmented QRS (fQRS) is a common EKG findings in general population. It has emerged as the independent predictor for cardiac events and all-cause mortality in patients with known coronary artery disease. However, none of the study evaluated the role of fQRS in patients without Q-wave on EKG. We aimed to evaluate whether fQRS is the predictor of cardiac function and myocardial scar in patients without Q-wave using cardiac MRI as the imaging tool. Methods 250 patients who underwent stress cardiac MRI were included. The 12-lead EKG was analyzed by two independent observers. Fragmented QRS was defined as the presence of an additional R wave (R’) or notching in the nadir of R or S wave, or the presence of more than 1 R’ .P atients whom EKG showed Q-wave were excluded. Cardiac MRI was performed under 1.5T magnetic resonance scanner (Philips Achieva release 3.2). Resting left ventricular systolic function and mass was acquired with steady-state free precession sequence in short-axis view. All patients were given either Gadopentetate dimeglumine or Gadobenate demeglumine (total 0.2 mmol/kg) for late gadolinium enhancement sequence. Images were analyzed by 2 observers using Extended MR WorkSpace release 2.6. Impaired cardiac function was defined as left ventricular ejection fraction less than 50%. Myocardial scar was defined as hyper-enhanced area within left ventricular myocardium. Statistical analysis was done by SPSS. Results

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 64u2005years, 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 7u2005days, 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.

Formulaic quantification of echocardiographic left atrial volume

INTRODUCTIONnThe 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.nnnMETHODSnWe 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.nnnRESULTSnAfter 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 Simpsons rule (coefficient of reproducibility for 2 SD equivalent to 8.8% for lead II and 11.4% for any lead).nnnCONCLUSIONnThere 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.

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.