Factors Associated with Ischemic Stroke on Therapeutic Anticoagulation in Patients with Nonvalvular Atrial Fibrillation

PURPOSE: In this study, we investigated the stroke mechanism and the factors associated with ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF) who were on optimal oral anticoagulation with warfarin. MATERIALS AND METHODS: This was a multicenter case-control study. The cases were consecutive patients with NVAF who developed cerebral infarction or transient ischemic attack (TIA) while on warfarin therapy with an international normalized ratio (INR) > or =2 between January 2007 and December 2011. The controls were patients with NVAF without ischemic stroke who were on warfarin therapy for more than 1 year with a mean INR > or =2 during the same time period. We also determined etiologic mechanisms of stroke in cases. RESULTS: Among 3569 consecutive patients with cerebral infarction or TIA who had NVAF, 55 (1.5%) patients had INR > or =2 at admission. The most common stroke mechanism was cardioembolism (76.0%). Multivariate analysis demonstrated that smoking and history of previous ischemic stroke were independently associated with cases. High CHADS2 score (> or =3) or CHA2DS2-VASc score (> or =5), in particular, with previous ischemic stroke along with > or =1 point of other components of CHADS2 score or > or =3 points of other components of CHA2DS2-VASc score was a significant predictor for development of ischemic stroke. CONCLUSION: NVAF patients with high CHADS2/CHA2DS2-VASc scores and a previous ischemic stroke or smoking history are at high risk of stroke despite optimal warfarin treatment. Some other measures to reduce the risk of stroke would be necessary in those specific groups of patients.

Factors Associated with Ischemic Stroke on Therapeutic Anticoagulation in Patients with Nonvalvular Atrial Fibrillation

PURPOSE: In this study, we investigated the stroke mechanism and the factors associated with ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF) who were on optimal oral anticoagulation with warfarin. MATERIALS AND METHODS: This was a multicenter case-control study. The cases were consecutive patients with NVAF who developed cerebral infarction or transient ischemic attack (TIA) while on warfarin therapy with an international normalized ratio (INR) > or =2 between January 2007 and December 2011. The controls were patients with NVAF without ischemic stroke who were on warfarin therapy for more than 1 year with a mean INR > or =2 during the same time period. We also determined etiologic mechanisms of stroke in cases. RESULTS: Among 3569 consecutive patients with cerebral infarction or TIA who had NVAF, 55 (1.5%) patients had INR > or =2 at admission. The most common stroke mechanism was cardioembolism (76.0%). Multivariate analysis demonstrated that smoking and history of previous ischemic stroke were independently associated with cases. High CHADS2 score (> or =3) or CHA2DS2-VASc score (> or =5), in particular, with previous ischemic stroke along with > or =1 point of other components of CHADS2 score or > or =3 points of other components of CHA2DS2-VASc score was a significant predictor for development of ischemic stroke. CONCLUSION: NVAF patients with high CHADS2/CHA2DS2-VASc scores and a previous ischemic stroke or smoking history are at high risk of stroke despite optimal warfarin treatment. Some other measures to reduce the risk of stroke would be necessary in those specific groups of patients.

A case of recurrent lead fracture and complete dislocation after permanent pacemaker implantation / 대한내과학회지

With the increased use of implantable cardiac devices, the incidence of hardware problems has also increased. Some of the hardware problems might be induced by patient factors. We experienced recurrent pacemaker lead fracture and dislocation after permanent pacemaker implantation. The patient was a bus driver who used his left arm vigorously when he turned the steering wheel. After a new lead was inserted via an axillary vein approach and the patient changed his occupation, no more lead problems have occurred. When a recurrent hardware problem with an implantable pacemaker or defibrillator occurs, patient factors related to anatomy or behavior must be considered.

Initiation and Maintenance Mechanism of Atrial Fibrillation Assessed by 3-Dimensional Non-Contact Mapping System

BACKGROUND AND OBJECTIVES: We undertook this study to assess the initiation and maintenance mechanisms of atrial fibrillation (AF) and their relationships with the anatomical structures of the left atrium (LA) and pulmonary veins (PVs). SUBJECTS AND METHODS: Thirty-seven patients (33 men, mean age 50, range 25-68 years) with paroxysmal AF (n=29) and persistent AF (n=8) who underwent mapping of the LA and PV using 3D non-contact endocardial mapping system (EnSite 3000) were enrolled. The multielectrode array and ablation catheter were positioned in the LA via the double transseptal approach. Atrial premature beats (APBs) which triggered initiation of AF that lasted longer than 1 min were mapped and the activation sequence was analyzed on isopotential color maps. Wave front dynamics and the relationship with the underlying structures were assessed. RESULTS: More than half, 56.4%, of APBs from PV were related to the initiation of AF, but not related to the maintenance of AF. A quarter, 25.6%, of APBs from PV not only initiated AF, but also maintained AF without continuous triggering. Mixed type and indeterminate type of AF was 5.0% and 12.8%, respectively. During AF, the mean number of wavelets was 1.45 (maximum 3 in 76.5%). Anatomical structures showing slow conduction and wavebreaks were mostly located at the septopulmonary bundle (86.5%) and the posterior roof of the LA between the left superior PV and right superior PV (54.1%). CONCLUSION: Focal repetitive activity from PV played an important role in both the initiation and maintenance of AF. Specific anatomical structures such as septopulmonary bundle or posterior roof of the LA were related to the heterogeneous conduction delay and spontaneous wavebreak, which was also important in the maintenance of AF.

Carotid Artery Intima-Media Thickness in Patients with Hypertension with Left Ventricular Hypertrophy

BACKGROUND AND PURPOSE: Left ventricular hypertrophy (LVH) and increased common carotid artery intimamedia thickness (IMT) are known target organ damages of hypertension. However, the relation between LVH and carotid artery IMT is not well defined in Korea. Thus, the purpose of this study is to evaluate the association of common carotid artery IMT and luminal diameter (LD) with LVH (LV mass) in patients with hypertension. METHOD: LV mass was measured by echocardiography and IMT and LD of right and left common carotid artery were measured by high resolution ultrasound in non-hypertensive subjects (n=24), patients with known hypertension without LVH (n=22) and hypertension with LVH (n=22). Data obtained were adjusted statistically for age. RESULTS: Mean IMT (in mm) were 0.51+/-0.12 in non-hypertension group, 0.61+/-0.09 in hypertension without LVH group and 0.73+/-0.13 in hypertension with LVH group (age adjusted p<0.0001 by ANCOVA). Mean systolic and diastolic IMT/LD ratios were 0.077+/-0.015 and 0.089+/-0.018 in non-hypertensive group, 0.052+/-0.015 and 0.09+/-0.014 in hypertension without LVH group, and 0.085+/-0.015 and 0.104+/-0.022 in hypertension with LVH group (p=0.063 for systolic ratio and 0.137 for diastolic ratio). CONCLUSION: These findings suggest that there is a significant correlation between carotid artery intima-media thickness and LVH in hypertensio.

Structural and Functional Changes of Heart after Cardioversion of Atrial Fibrillation

BACKGROUND AND OBJECTIVES: Chronic atrial fibrillation (AF) causes atrial enlargement and impairs cardiac function. It is known that restoration of sinus rhythm reduces left atrial size and improves left ventricular ejection fraction (EF). However, it's unclear whether the restoration of sinus rhythm is more beneficial than controlling the ventricular rate. This study was designed to compare the effects of two treatment strategies on structural and functional changes of the heart in patients with AF. SUBJECTS AND METHODS: Thirty-seven AF patients who initially cardioverted to sinus rhythm were studied. At 6 months after cardioversion, 17 patients (Group I) maintained normal sinus rhythm (NSR) and 20 (Group II) experienced AF recurrence. Initial and follow-up echocardiography were evaluated in each patient and compared between the two groups. RESULTS: Baseline clinical and echocardiographic findings were similar between the two groups except that the left atrial length was longer in Group II than in Group I. Compared to baseline, left atrial dimension (LAD) and left ventricular mass index (LVMI) measured by M-mode were significantly reduced in group I at follow-up (p<0.05); however, these changes were not observed in group II. The reduction of LAD and LVMI was observed only in patients with less than 50% EF and/or dilated left atrium at baseline (p<0.05). CONCLUSION: In patients with AF, maintenance of NSR after cardioversion significantly reduces LAD and LVMI, especially in cases of left ventricular dysfunction or dilated left atrium. Even after adjustment of baseline LAD, LVMI and EF, maintenance of NSR remains the independent factor that reduces LAD at follow-up (p=0.001).

Brugada syndrome : Right bundle branch block, ST segment elevation and sudden cardiac death / 대한내과학회지

No abstract available.

Coronary Blood Flow Velocity and Coronary Flow Reserve in Normal Left anterior Descending Coronary Arteries

BACKGROUND: Recently, assessment of left anterior descending (LAD) coronary flow by transthorasic Doppler echocardiography (TTDE) has been emerged as a useful tool in evaluation of microcirculatory function of coronary circulation. The measuring site of coronary flow by TTDE is distal LAD. But it was not fully investigated whether the distal flow velocity is identical to that of proximal segment. The purpose of this study is to compare coronary blood flow velocity and coronary flow reserve (CFR) in normal LAD according to its level. METHOD: 9 patients (1 male, 8 females; mean age 52.8+/-11.1years) were included for this study. Coronary flow velocity was measured with intracoronary Doppler guide wire at the proximal (before first diagonal branch), mid (after second diagonal branch), and distal segments of LAD at baseline and after intracoronary bolus injection of 18 microgram adenosine. Baseline and hyperemic average peak velocity (APV) and CFR were compared between segment. RESULTS: Baseline and hyperemic APV appears to be diminished from proximal (24.6+/-3.5 cm/sec, 55.8+/-10.7 cm/sec) to distal (21.7+/-6.9 cm/sec, 49.7+/-17.2 cm/sec) LAD without statistical significance. But, CFR showed no significant difference in each segments (proximal, mid, and distal segment; 2.3+/-0.26, 2.3+/-0.32, 2.3+/-0.48, p=0.95). As the increment of peak systolic velocity (PSV) from baseline to hyperemic state was larger than that of peak diastolic velocity (PDV), diastolic to peak systolic velocity ratio (DSVR) was decreased significantly by hyperemic state in proximal and distal segment (baseline; 2.1+/-0.8, 2.1+/-0.5 vs hyperemia; 1.8+/-0.6, 1.7+/-0.3, p<0.05). CONCLUSION: Coronary blood flow velocity appears to be decreased from proximal to distal segment of normal LAD without statistical significance. There were no differences in CFR between proximal, mid and distal segment of normal LAD.

Diagnostic Value of QT and JT Dispersion in Exercise ECG

BACKGROUND: QT dispersion(QTD : QTmax-QTmin) or JT dispersion(JTD:JTmax-JT-min)in 12 leads ECG has been known to reflect regional variations in ventricular repolarization and has been reported to bel one of the marker of regional myocardial ischemia. To evaluate the significance of QTD or JTD of exercise ECG in diagnosis of coronary artery disease, we studied 106 patients(mean age, 56.9 years old, male 63) who were referred for the evaluation of chest pain on exertion. METHOD: Treadmill exercise stress test with modified Bruce protocol and coronary angiography were performed in 106 patients with chest pain on exertion. ST-segment depression by >1.0 mm 0.08 second after J-point during or after exercise in exercise test and >50% stanosis of epicardial artery in coronary angiogram were defined as positive. Of 106 patients, 41 had positive exercise ECG and positive coronary angiogram(true positive, TP), 20 had positive exercise ECG and negative coronary angiogram(false positive, FT), 20 had negative exercise ECG and positive coronary angiogram(faalse negative, FN), and 23 had negative exercise ECG and negative coronary angiogram(true negative, Tn). QT and JT interval in 12 leads were measured at baseline and peakexercise and were corrected for heart rate using Bazett's formula. QTD and JTD were measured by calculation the difference between the maximum QT and mininum QT and that between maximum JT and minumum JT. RESULTS: QTD at baseline for TP(72.8ms)was prolonged compared to Tn(52.2ms,P<0.01), but was not different from that for FT(70.2 ms). At peak exercise, QTD for TP(81.3 msec) was significantly prolonged(p<0.01), while QTD for FP(71.2 msec) was not different from that for TN(56.8 msec). JTD at baseline(78.4 msec) and at peak exercise(88.2 msec) for TP were significantly prolonged compared to those for TN(55.2msec and 55.1msec p<0.01,p<0.01, respectively), but those for FP were not porlonged(77.0msec and 79.0msec, respectively). QTD and JTD at peak exercise were more markedly prolonged in patients with sever stenosis of coronary artery(p=0.053 and p<0.05, repectively) and multivessels diseases(p<0.01, 0<0.05) than those with less severe disease and single vessel disease. Patients with left anterior descending artery lesion had greater QTD and JTD at peak exercise than those with other vessels lesion(p<0.01). In addition to standard criteria with ST segment displacement in exercise EGC, inclusion of exercise induced QTD of more than 60msec increased the sensitivity of exercise ECG from 66.7% to 83.3%, and JTD of more than 70msec increased the specificity from 52% to 76.0%. CONCLUSION: Measurement of QT dispersion and JT dispersion of exercise ECG may be useful method to identify the severity of coronary artery disease and to improve diagnostic accuracy of exercise ECG in coronary artery disease.

Coronary Angiographic Findings and Risk Factors in Acute Myocardial Infarction Patients before after Age 50

BACKGROUND: A number of studies in western countries have shown that coronary artery disease(CAD) and younger patients with acute myocardial infarction(AMI) is less extensive but more. closely related to cigarette smoking. However, there are some similarities between the characteristics of the CAD and the risk factors analyzed by age subsets in patients with AMI in Korea. METHODS: Pre-discharge coronary angiograms and risk factors in 194 patients with first AMI(male/female : 154/40,79.4%/20.6%) were analyzed. A comparison was made between the lesion characteristics of the infarct related artery(IRA) and the CAD risk factors. Those under 49 years old (Group I, n=54, male/female : 50/4 : 92.6%/7.4%) and those over 50 years old ( Group II, n=140, male/female : 104/36 : 74.3%/25.7%). RESULTS: There are 54 and 140 patients in groups I and II respectively. 92% of group I and 74.1% of group II were male (p<0.01). At the time of study, more group I patients were smoking cigarettes and drinking alcohol(over 3 times per week 22.6% vs 11.5%, p<0.01) and insignificant stenosis was more common in group I than in group II. In both groups, the most common IRA was the left anterior descending artery and concurrently the anterior wall was the most common morphological type of coronary stenosis of IRA was concentric irregular in group I(27.7%) and eccentric smooth in groupII(31.5%). Although group I had the larger minimal cross sectional area of coronary stenosis(0.97+/-1.16mm2 and 0.54+/-0.80mm2, respectively, p<0.05, reference diameters 2.71+/-0.60mm and 2.66+/-0.67mm, respectively),the coronary lesion was shorter in group I patients(3.39+/-4.06cm and 5.49+/-6.13cm respecitively, p=0.03). CONCLUSION: These findings reveal that coronary atherosclerotic lesions of IRA in patients with AMI in the younger age group are less severe. However, they are more closely related to cigarette smoking and alcohol intake, than cases in the older age group.

Coronary Angiographic Findings and Risk Factors in Acute Myocardial Infarction Patients before after Age 50

BACKGROUND: A number of studies in western countries have shown that coronary artery disease(CAD) and younger patients with acute myocardial infarction(AMI) is less extensive but more. closely related to cigarette smoking. However, there are some similarities between the characteristics of the CAD and the risk factors analyzed by age subsets in patients with AMI in Korea. METHODS: Pre-discharge coronary angiograms and risk factors in 194 patients with first AMI(male/female : 154/40,79.4%/20.6%) were analyzed. A comparison was made between the lesion characteristics of the infarct related artery(IRA) and the CAD risk factors. Those under 49 years old (Group I, n=54, male/female : 50/4 : 92.6%/7.4%) and those over 50 years old ( Group II, n=140, male/female : 104/36 : 74.3%/25.7%). RESULTS: There are 54 and 140 patients in groups I and II respectively. 92% of group I and 74.1% of group II were male (p<0.01). At the time of study, more group I patients were smoking cigarettes and drinking alcohol(over 3 times per week 22.6% vs 11.5%, p<0.01) and insignificant stenosis was more common in group I than in group II. In both groups, the most common IRA was the left anterior descending artery and concurrently the anterior wall was the most common morphological type of coronary stenosis of IRA was concentric irregular in group I(27.7%) and eccentric smooth in groupII(31.5%). Although group I had the larger minimal cross sectional area of coronary stenosis(0.97+/-1.16mm2 and 0.54+/-0.80mm2, respectively, p<0.05, reference diameters 2.71+/-0.60mm and 2.66+/-0.67mm, respectively),the coronary lesion was shorter in group I patients(3.39+/-4.06cm and 5.49+/-6.13cm respecitively, p=0.03). CONCLUSION: These findings reveal that coronary atherosclerotic lesions of IRA in patients with AMI in the younger age group are less severe. However, they are more closely related to cigarette smoking and alcohol intake, than cases in the older age group.