Mechanisms of Paroxysmal Supraventricular Tachycardias according to Age and Gender

BACKGROUND AND OBJECTIVES: Age and gender are known to influence the mechanisms of paroxysmal supraventricular tachycardia (PSVT), but large scale data regarding this subject is limited. In addition, data regarding the mechanisms of PSVT in the Korean population is limited. In this study, we sought to investigate the different mechanisms of PSVT according to age and gender in Korean patients. SUBJECTS AND METHODS: Database of 3,176 patients diagnosed with PSVT excluded atrial flutter or atrial fibrillation and referred for electrophysiologic study from 1986 to 2004 was retrospectively analyzed. The mechanisms of PSVT were classified as: WPW syndrome (WPW), atrioventricular reentrant tachycardia (AVRT) due to a concealed bypass tract (CBT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT). RESULTS: The mean age was 40.7+/-16.0 (1-90) and 53.3% of the patients were male. The mean age of females was significantly higher than males. (43.0+/-16.1 vs. 38.6+/-15.6, p<0.001) Overall, the dominant mechanism of tachycardia was AVRT at 62.6% (WPW: 31.1%, CBT: 31.5%), compared to AVNRT at 34.1 and AT at 3.1%. This was mainly due to the predominance of AVRT (74.2%; WPW: 38.1%, CBT: 361%) in male. The mechanisms of PSVT differed according to gender with 63.2% (1257/1988) of AVRT patients being males where as 64.6% (700/1084) of the AVNRT patients were females. The distribution of PSVT mechanisms differed according to gender. In males, the proportions of AVNRT : CBT : WPW were 22.7 : 36.1 : 38.1%, whereas in females the proportion was 47.2 : 26.3 : 23.0%. Age had a significant influence upon the mechanism of PSVT in both genders with an increasing proportion of AVNRT and a decreasing proportion of AVRT in the older age groups. AVRT was the dominant mechanism of PSVT in all age groups for males, where as AVNRT was the dominant mechanism of PSVT for females over 50 years of age. CONCLUSION: The mechanism of PSVT differs significantly according to age and gender. This may be due to the increased degeneration of accessory pathway with age and difference in the conduction properties of the accessory pathway according to gender. In Koreans, the overall dominant mechanism of PSVT was AVRT mainly due to it a greater male population.

Open Heart Surgery in Patient with Heparin-Induced Thrombocytopenia / 대한흉부외과학회지

A 45 year old man was admitted for aggravated dyspnea, abdominal distension and poor oral intake.On Echocardiogram,mitral stenosis(severe),tricuspid regurgitaion(IV),and LA thrombus were diagnosed.We used heparin with continuous infusion for prevention of systemic thrombo embolism. On the 11 th day of admissin, the patient showed thrombocytopenia and we suspected Heparin-induced thrombocytopenia.Hirudin was used in this case as alternative anticoagulant during cardiopulmonary bypass to prevent serious complication of heparin.The patient was recovered without any complication as postoperative bleeding or systemic thromboembolism.

Assessment of Myocardial perfusion in Patients with Acute Myocardial infarction

BACKGROUND: Unlike 99mTc-Sestamibi, microbubbles used during myocardial contrast echocardiography (MCE) exist only in the vascular space. Therefore, there may be a difference in the pattern of myocardial perfusion between MCE and 99mTc-Sestamibi Single-Photon Emission Computed Tomography (SPECT) in acute myocardial infarction (AMI). OBJECTIVES: The purpose of this study was to assess myocardial perfusion using MCE with intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin microbubbles (IV MCE), and to compare it with SPECT and MCE with intracoronary injection of sonicated Hexabrix (IC MCE). METHODS: Seventeen patients with AMI (male 13, age 59.5+/-8.8 years, anterior MI 10) underwent IV MCE at 8.1+/-3.7 days after onset. SPECT and IC MCE were also performed at 1.2+/-1.0 days and 2.0+/-1.5 days from IV MCE respectively. Any revascularization procedures were not performed between three studies. Perfusion defect by three methods was scored semiquantitatively as 1 : normal perfusion, 0.5 : moderate defect, and 0 : severe defect at 16 segments of the left ventricle. RESULTS: 1) Perfusion defect in infarction territory was detected in 15 patients with SPECT, 12 patients with IV MCE and 11 patients with IC MCE. 2) Concordance of perfusion score at each segment was 93% between IV MCE and IC MCE, 65% between IV MCE and SPECT, and 64% between IC MCE and SPECT. 3) With IV MCE, perfusion defect was observed in all 32 segments which were considered as having defect (score 0 and 0.5) by IC MCE. However, defect by IV MCE was found only in 31 out of 108 segments considered as having defect by SPECT. CONCLUSION: In the assessment of myocardial perfusion in pts with AMI, IV MCE and IC MCE showed similar results. However, there was some discrepancy in the extent of perfusion defect between MCE studies and SPECT.

Age-Related Difference in Long-Term Prognosis of Acute Myocardial Infarction in Women

BACKGROUND AND OBJECTIVES: The purpose of this study was to evaluate the age-related differences in clinical features, coronary anatomy, risk factors, hospital courses, and long-term prognosis of acute myocardial infarction(AMI) in women. MATERIALS AND METHODS: Total 513 female patients with AMI were divided into 3 groups ; group 1(n=3, 50 years old or less), group 2(n=02, between 51 years and 70 years old), and group 3(n=68, older than 70 years). Clinical follow-up including cardiac events was performed for mean duration of 26 months(1~155 months). Cardiac events include cardiac death, reinfarction, CABG, PTCA, CHF, stroke, and recurrent angina. RESULTS: Minimal lesion(<50% stenosis) in infarct-related artery was more prevalent in group 1 than in group 3(p<0.05). In group 2, the number of low high density lipoprotein(HDL) was significantly more than in group 3(p<0.01). During hospitalization, death and shock were more prevalently observed in group 3 than group 1(p<0.005) and group 2(p<0.001). Group 3 had more heart failures than group 1(p<0.001) and group 2(p<0.001) and group 2 had more heart failures than group 1(p<0.05). The younger age group showed a significantly higher survial rate(7 years : group 1; 76.1%, group 2; 60.6%, group 3; 34.2%, p<0.0001, Log Rank Stat =49.4) and cardiac event-free survival rate(7 years : group 1; 48.4%, group 2; 32.3%, group 3; 16.0%, p<0.0001, Log Rank Stat =37.5) for each 3 comparisons. In Cox proportional harzard analysis, LV systolic function influenced the group 2 survival (odds ratio 3.8, 95% CI 1.7 to 8.3, p<0.005) and the group 3 survival (odds ratio 2.2, 95% CI 1.1 to 4.5, p<0.05). The cardiac event free survival was influenced by age(odds ratio 1.6, 95% CI 1.2 to 2.1, p<0.005) and LV systolic function(odds ratio 1.8, 95% CI 1.3 to 2.5, p<0.001). CONCLUSION: Younger female patients with AMI had a more favorable prognosis compared with older female patients. LV systolic fuction was important as a prognostic factor for long-term survival except younger female AMI patients.

More favorable long-term outcome after discharge in young adults with myocardial infarction / 대한내과학회지

BACKGROUND: The purpose of this study was to evaluate risk factors, angiographic characteristics and long-term prognosis of young adults with myocardial infarction(MI). METHODS: Of the 2,680 patients with a history of MI, there were 148 patients 40 years old(Group 1). Risk factors, angiographic characteristics, cardiac events and long-term prognosis of group 1 were compared with those of randomly selected 149 patients between 41 years to 70 years old(Group 2) for a mean follow-up duration of 38 months(1-147 months). Cardiac events include death, reinfarction, coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, congestive heart failure, stroke, and angina. RESULTS: Smoker and male gender were more frequent in group 1(p0.05). If hospital deaths were excluded, the 7-year survival was better in group 1(group 1; 99%, group 2; 92%, p0.05). Although a better left ventricular(LV) systolic function (ejection fraction(EF) 40%) showed more favorable survival in group 2(EF40%: 94%, EF<40%: 80%, p<0.05), survival was not influenced by LV systolic function in group 1. CONCLUSION: Young patients with MI have a more favorable long-term survival after discharge compared with that of the older patients regardless of LV systolic function. Cardiac event free survival was, however, not different between two groups.

Clinical Features and Prognosis according to the Left Ventricular Function in the Patients with Acute Myocarditis

BACKGROUND: Because of its protean clinical manifestations, diagnosis of acute myocarditis is quite limited unless proved by endomyocardial biospy. However endomyocardial biopsy is not always applicable in these patients. Neither there have been clear clinical criteria for diagnosis nor studies in regard to prognostic factors are available. We retrospectively evaluated clinical features and prognosis of patients with biopsy proven and/or clinically suspected acute myocarditis according to the status of the left ventricular systolic function. METHOD: Thirty six patients of acute myocarditis were enrolled. Eighteen patients were diagnosed by endomyocardial biopsy. We selected clinical diagnostic criteria for this disorder based on the clinicalpaboratory, echocardiographic and ECG findings obtained from this biopsy-proven acute myocarditis. Another 18 patients were selected matching these diagnostic criteria. We divided these thirty-six patients into two groups depending on the left ventricular systolic function : Group 1, EF(3)40(n=20); Group 2, EF<40(n=16). We compared clinical features and prognosis between the two groups. RESULTS: 1) The mean age of Group 1 was 39.7+/-13.6 years(male 12). The mean age of Group 2 was 34.0+/-14.7 years(male 11). Diastolic blood pressure at admission was significantly lower in Group 2 than in Group 1(82+/-10mmHg vs 67+/-15mmHg, p<0.05). 2) In transmitral Doppler findings, Group 1 had 4 patients(25%) with restrictive physiology while Group 2 had 12 patients(75%)(p<0.05). Global LV hypokinesia was more frequent in Group 2 than in Group 1(11/16(69%) vs 3/11(27%), p<(0.05). 3) During the follow up, there was no death in Group 1. But there were 5 deaths in Group 2. Three-year survival rate of Group 1 was better than that of Group 2(100% vs 75%, p<(0.05). In the eleven surviving patients in Group 2, seven patients(64%) showed recovery of the left ventricular systolic function. CONCLUSION: In acute myocarditis, patients who presented with depressed systolic function showed lower diastolic blood pressure at admission, more frequent occurrence of restrictive physiology, more global hypokinesia rather than regional asynergy, and poorer prognosis.

Clinical and electrophysiological characteristics in Korean patients with WPW syndrome

This study was designed to investigate the clinical and electrophysiologic characteristics of WPW syndromes in Korea. A total of 400 symptomatic WPW syndrome patients were consecutively recruited. The most common documented symptomatic tachyarrhythmia was orthodromic atrioventricar reentrant tachycardia (75.3%), followed by atrial fibrillation (31.3%), and antidromic atrioventricular reentrant tachycardia (6.2%). There was a higher incidence of multiple bypass tract in patients with antidromic tachycardia than in those with orthodromic tachycardia (30.4 vs 4.3%, P < 0.001). The inducibility of tachyarrhythmia with electrophysiologic study in this study population was 95.8%. The most frequent location of the accessory pathway was the left free wall (48.0%), followed by the right free wall (29.1%), posterior septum (17.5%) and anterior septum (3.5%). These results indicated that 1) clinical and electrophysiological characteristics of Korean patients with WPW syndrome were similar to those of western countries and 2) the electrophysiologic study was important in the evaluation of patients with WPW syndrome.

A Case of Hydroxyzine Induced Torsades de Pointes

Torsades de pointes is a polymorphic ventricular tachycardia associated with prolonged QT interval and increased U wave amplitude. It has been found to be induced by various drugs, electrolyte imbalances, and so on, but the mechanism of torsades de pointes has not been completely documented. Two hypotheses, early afterdepolarization and dispersion of repolarization have been known to be the possible mechanism. Terfenadine and astemizole are the antihistamines, known to be one of the etiologic agents of torsades de pointes, and factors associated with increased risk are significant liver disease, drug overdose, and concomitant administration of imidazole and macrolide antimicrobial drugs. There has been only one case reported that torsades de pointes had been induced by first-generation antihistamine, piprinhydrinate. We experienced a case of 43 year old male patient with torsades de pointes induced by first-generation antihistamine, hydroxyzine and treated successfully with drug cessation, MgSO

Apical Hypertrophic Cardiomyopathy: Clinical and Echocardiographic Follow Up

BACKGROUND: An unusual form of hypertrophic cardiomyopathy localized to the left ventricular apex has racial differences in phenotypic expression between many Japanese reports and most reports from outside Japan. In Japanese patients follow up study of apical hyertrophy has shown benign clinical course without demonstrable genetic transmission, but other ethnic patients with this variant was clinically different from Japanese patients. The purpose of this study was to evaluate the clinical course and the progression of hypertrophy of apical hyper- trophic cardiomyopathy by echocardiography and to define the relationship between the severity of apical hypertrophic cardiomyopathy and the clinical course. METHODS: Between June 1990 and August 1996, 35 out of 53 patients with apical hypertrophic cardiomyopathy diagnosed by echocardiography were studied. In 26 out of 35 patients, two- dimensional echocardiography and EKG were obtained at initial visit and follow up. We analyzed the sum of S wave in lead Vl and R wave in lead VS(mm) and T wave negativity in lead V4 on EKG. Measured echocardiographic parameters were apical thickness and apical cross-sectional area of left ventricle at end-diastole in apical tour chamber view, anteroposterior left atrial dirnension at end systole in parasternal short axis view and pulsed-wave Doppler pattern of transmitral inflow. RESULTS: 1) Mean age at presentation was 57.9+8.3 years(range 37 to 72). Mean follow up duration of echocardiography and EKG were 29.5+/-13.5 months and 27.7+ -1.4 months, respectively. 2) Eleven(31%) out of 35 patients were asymptomatic at initial presentation. In the remaining 24 patients, major symptoms included atypical chest pain(n=7), angina (n=11), dyspnea(n=12), palpitation(n=4) and fatigue(n=l), During follow-up, symptoms aggravated in 5/35(14%), no change in 22/35(63%) and allenated in 8/35(23%). The clinical event during follow up was transient ischemic attack in 1 patient, syncope in 1 patient and death in 1 patient with cerebral infarction and upper gastrointestinal bleeding. 3) Electrocardiography revealed normal sinus rhphm in 24 patients and atrial fibrillation in 2 patients at initial presentation. Paroxysmal atrial fibrillation was observed in 1 patient during follow up period at 24 hours Holter monitoring. Negative T wave amplitude was increased from 11.5+/-5.5 to 13.1+/-6.5mm(p<0.05), however the sum of SV, and RV, did not change significantly. 4) The apical thickness and apical cross-sectional area changed over time, frorn 19.9+/- 3.2 to 21.8+/-4.lmm(p<0.005) with interobservers difference of 2.3+/-1.2mm and from 11.4+/-2.4 to 12.5+/-3.1cm(p<0.05) with interobservers difference of 1.9+/-1.5cm, respectively. Left atrial dimension increased from 43.5+/-6.6 to 46.2+/-6.1mm(p<0.005). Transmitral inflow revealed norrnal E/A ratio and deceleration time of 150~ 40msec in 11 patients with changed to relaxation abnormalities in three and pseudonormalization in ovo and relaxation abnormalities in 14 patients with changed to pseudonormalization in three at follow-up. CONCLUSIONS: Patients with apical hypertrophic cardiomyopathy have relatively favorable prognosis during follow up period without any significant clinical event and symptomatic deterioration. T wave negativity on EKG and left atrial dimension on echocardiographic examination were increased during follow up, but these parameters were not associated with clinical presentation.

Dobutamine Echocardiography in the Prediction of Left Ventricular Remodeling after Acute Myocardial Infarction

BACKGROUND: Left ventricular remodeling after acute myocardial infarction has been identified as an important prognostic factor because it leads to ventricular enlargement, ventricular aneurysm, and increased mortality. However predictors of left ventricular remodeling are not clearly defined. This study was perforrned to evaluate the efficacy of dobutamine echocardiography in the prediction of left ventricular remodeling in patients with acute myocardial infarction. METHODS: Forty-five patients(39 males, age 56.9+/-10.2 years) with acute myocardial infarction(AMI) and patent infarct-related artery(no significant narrowing with/without revascularization) underwent dobutamine echocardiography at 2 7 days after AMI. The stages of dobutamine infusion were baseline, 5, 10, 20ug/kg/min, and images at each stage were directly compared and analyzed with the use of 16-segment model(by American Society of Echocardiography) and scoring system(1: normal, 2: mild to moderate hypokinesia, 3: severe hypokinesia, 4: akinesia, 5: dyskinesia). The viability of infarct zone was defined as improvement of wall motion score in more than 2 contiguous segments during dobutamine infusion in areas of resting asynergy. Coronary angiography was performed at 7~10 days after AMI and revascularization of infarct-related artery was done, if severe stenosis was present. Follow-up(F/ U) echocardiography was performed more than 3 months after AMI. We have measured left ventricular end-diastolic and end-systolic volume at baseline, dobutamine(peak dose) and follow-up echocardiography by modified Simpsons method. RESULTS: 1) Dobutamine echocardiography was performed at 5.5+3.9 days after acute myocardial infarction, and follow-up echocardiography was performed at 7.5+3.4 months after dobutamine echocardiography. 2) We assessed left ventricular end-diastolic volume(LVEDV) at follow-up echocardiography compared to LVEDV at baseline echocardiography, and patients were divided into 2 groups. Group 1(n=14) with increase in LVEDV during F/U period(mean change 13.9+14.2ml); Group 2(n=31) with no increase in LVEDV volume during F/U period(mean change 27.4+22.1). Between two groups, clinical parameters such as age, sex, incidence of anterior myocardial infarction, incidence of non-Q myocardial infarction, peak CK, peak CKMB, pre-infarction angina, incidence of reperfusion therapy, follow-up duration, were not significantly different. 3) Between group 1 and group 2, there were no singnificant differences in baseline echocardiographic parameters such as ejection fraction, wall motion score index, LVEDV, LV enddiastolic dimension. 4) In group 1, the incidence of patients with infarct zone viability assessed by dobutamine echocardiography was significantly snialler than the one in group 2(5 of 14 and 21 of 31, respectively, p <0.05). 5) Beween group 1 and group 2, the change of LVEDV at dobutamine echocardiography compared to LVEDV at baseline echocardiography was significantly different( -1.3+/-17.7 and -17.1+/-26.2, respectively, p<0.05). 6) Linear regression analysis indicated that the change of LVEDV during follow-up period was predicted by the change of LVEDV during dobutamine echocardiography. LVEDV(F/U) LVEDV(baseline) = 0.726[LVEDV(dobutamine) LVEDV(baseline) ] 5.648(r=0.65, p<0.05) CONCLUSION: The viability of infarct zone assessed by dobutamine echocardiography was predictive of left ventricular remodeling at F/U of acute myocardial infarction and the change in LVEDV during dobutamine echocardiography correlated with the change in LVEDV at follow-up of acute myocardial infarction. Dobutamine echocardiography can be an useful tool for the prediction of LV remodeling after acute myocardial infarction.

Clinical and Electrophysiologic Characteristics of the Patients with Wolff-Parkinson-White Syndrome

BACKGROUND: Wolff-Parkinson-White syndrome(WPW syndrome) is well known and somtimes causes life-threatening arrhythmias.To date,the clinical and electrophysiologic charicteristics of patients with WPW syndrome in Korea has not been available,though results of catheter ablation treatment for atrioventricular reentrant tachycardia(AVRT) including WPW syndrome were reported. METHOD: Clinical and electrocardiographic(ECG) characteristics and results of electrophysiologic study of consecutive 400 patients with WPW syndrome who underwent electrophsiologic study between December 1986 and September 1995 were analyzed. RESULTS: Mean age of the patients was 35 years and male patients were more common(262male patients,65.5%).Mean duration and frequency of palpitation episodes were 8.1 years and 4.2 times per month,respectively.Thirty six patients(9.0%) experienced syncopal episodes and the half of them were associated with atrial fibrillation.Two cases of aborted sudden cardiac death were associated with atrial fibrillation.Twenty four cases of congenital heart diseases and 13 cases of acquired heart diseases were found.The most commonly associated cardiac disease was Ebstein's anomaly(8 cases,2,0%).Clinically,368 patients(92,0%) had ECG-documented tachycardias and 46 patients had two or more types of tachycardia.Orthodromic AVRT was the most common tachcardia (227 patients including 44 cases with coexisting atrial fibrillation).Atrial fibrillation was documented in 115 patients(31.1%) and antidromic AVRT in 23 patients(6.2%).Patients with antidromic AVRT were more likely to have multiple accessory pathways compared to those with orthodromic AVRT (30.4% versus 4.3%).On electrophysiologic study,the most commonly inducible tachcardia was also orthodromic AVRT (334/389 cases,89.8%).Antidromic AVRT was induced in 23 cases(6.0%).Atrial fibrillation was present in 104 patients(27.2%),especially in those with clinically documented atrial fibrillation(71.3% vs 12.3%).In 17 patients without inducible tachycardias,ventriculoatrial conduction was absent or had long effective refractory period.Finally,396 patients(99.0%) had clinically documented or inducible tachycardias.Eight patients with Ebstein's anomaly had right-sided accessory pathway(87.5%)exept one case.Twenty four patients had secondary accessory pathway.The most common site of accessory pathway including secondary accessory pathway was left free wall(204 cases,48.1%).Other accessory pathways were found at right free wall(123 cases,29.0%),posteroseptal(54 cases,17.5%)and anteroseptal site(15 cases,3.5%)in order. CONCLUSIONS: The clinical and electrophysiologic characteristics of patients in this series were similar with those of previous reports of other countries.Because certain types of tachyarrhythmia were associated with characteristic electrophysiologic findings such as the relationships between antidromic AVRT and presence of secondary accessory pathways or clinical atrial fibrillation and higher occurrence rate of atrial fibrillation during electrophysiologic study,it is important to document clinical tachyarrhythmias with ECG.And electrophysiologic study can have important clinical implications in diagnosis and especially in curative treatment.

Comparision of thr Efficacy of Propafenone and Flecainide in Patients with Atrial Fibrillation

BACKGROUND: Atrial fibrillation is one of the most common cardiac arrhythmias which has been recieved relatively little attention until recently.Despite the variety of treatment modalities including drugs,surgery,catheter ablation and devices,the overall treatment of atrial fibrillation is not always satisfactory.Phalmacotherapy is still the most commonly used treatment through the unfavorable side effects of antiarrhythmic drugs are problematic.The purpose of this study is to compare the efficacy of class Ic antiarrhythmic drugs,propafenone versus flecainide. METHODS: We treated one hundred eighteen patients with atrial fibrillation by class Ic antiarrhythmic drugs,propafenone or flecainide with/without DC cardioversion to convert to and maintain the sinus rythm. We compared the clinical findings,drug efficacy,side sffects of drugs between two groups. RESULTS: 30 patients were treated by propafenne and 88 patients by flecainide.21 and 60 patients in each group were lone atrial fibrillation,14 and 49 patients were paroxysmal atrial fibrillation.Mean duration of drug administration were 360.9,339.4 days,respectively.The convesion rate to sinus rhythm by drugs was 25.0% in propafenone group and 30.7% in flecainide group(p=NS).The 300 days-manitenance rates of sinus rhythm after conversion by drugs or DC cardioversion were 63,3%,70.4%(p=NS)respectively. The side effects of drugs were dizziness,nausia and vomitting in both group and 1st degree AV block,transient sinus node dysfunction and decreased visual acuity in flecainde group.The drugs were discontinued in 11(37.7%) and 26(29.5%) patients in each group due to recurrence of atrial fibrillation or side effects of drugs. CONCLUSION: This study suggests that propafenone and flecainide are comparably effective in maintaining sinus rhythm in atrial fibrillation patients.Futher prospective and large study is required to confirm this findings.

Electrophysiologic and Clinical Characteristies of Antidromie Reentrant

BACKGROUND: Antidromic reentrant tachycardia(ART), in which an accessory atrioventricular pathway is used as the anterograde limb of an atrioventricular reentrant tachycardia, has been documented clinically in less than 10% of patients with the Wolff-Parkinson-White(WPW) syndrome. The wide QRS complex makes the distinction between antidromic AV reentrant tachycardia and ventricular tachycardia somewhat difficult. The purpose of this study is to evaluate the clinical and eoectrophysiologic characteristics of the antidromic reentrant tachycardia. METHODS AND RESULTS: During the electrophysiologic study of 355 patients, from December 1986 to April 1995, referred for evaluation of Wolff-Parkinson-White syndrome, 18(5.1%) patients had preexcited reciprocating tachycardia. 1) The age of the antidromic reentrant rnchycardia patients ranged from 15 to 53 years(28+/-12) and the mean age was younger than that of orthodromic reentrant tachycardia(ORT)patients(p<0.05). 2) Thirteen were male patients, five were females. 3) There were associated heart diseases in 3 cases. Two patients had Egstein's anomaly and ond had valvular heart disease. 4) The locations of accessory pathways(APs) documented on surface ECG were 7 left side(39%), 9 right side(50%)< 1 posteroseptal side(5.5%), and 1 anteroseptal side. 5) Nultiple bypass tracts were documented by electrophysiologic study in 7/18(38.9%) cases with ART, more common than cases with ORT(20/337(5.9%))(p<0.05). 6) 25 accessory pathways were documented by EPS in 18 patients(10 ;eft side, 11 right side, 2 posteroseptal side and 2 anteroseptal side). ART patients had more right sided AP(11/25,44%) than those with ORT(98/357, 27.5%), but ART patients had less posteroseptal AP(2/25, 8%)than those with ORT(63/357, 17.6%). 7) The types of ECG patterns naturally occurred were LBBB(11 cases), RBBB(6cases), and atrial fibrillation(4 cases). 8) The types of induced tachycardia in electrophysiologic study were 11 antidronic reentrant tachycardia, 10 orthodromic reentrant tachycardia, 7 reentrant tachycardia using two accessory bypass tracts, 3 AVnodal reentrant tachycardia, and 5 atrial fibrillations. CONCLUSION: ART patients were younger and had more multiple tracts than those with ORT. ART patients had less posteroseptal AP than ORT patients and more right sided AP than ORT patients. The posteroseptal AP was used as retrograde limb only.

Effects of Patency of the Infarct-Related Artery on the Signal-Averaged ECG in Acute Myocardial Infarction

BACKGROUND: In patients after acute myocardial infarction, signal-averaged electrocardiography is used as the one of the non-invasive methods for the prediction for ventricular arrhythmia, one of the causes ofn death in acute myocardial infarction. Signal-averaged electrocardiography has allowed the identification of low-amplitude, high-frequency signals(late potentials)in the terminal portion of the QRS complex. They are thougt to be occured in the portion of electrophysiologically unstable myocardium. The presence of late potentials identifies regions of delayed conducton in the elctrophysiologically unstable border zone of an acute infarction. These electrophysiologic change of myocardium is influenced by the patency of infarct-related artery. A patent artery is associated with electrical stability of myocardium, decreased in cidence of late potentials and improved survival. METHODS: 58 patients of acute myocardial infarction underwent signal-averaged electrocardiography, coronary angiography within 10 days after AMI, 20 of healthy persons underwent signal-averaged electrocardiography. RESULTS: In patent group, late potentials were recorded in 7 of 38 patients(18%) as compared with 13 of 20 patients(65%) of non-patent group. The statistically significant parameters of signal-averaged electrocardiography beteen patent and non-patent group were filtered total QRS duration(TQRS, 106.7+/-20.9msec), high frequency low amplitude signal (HLAS, 30.8+/-7.5 vs 41.3+/-16.5 msec)with HLAS being the most powerful varialble in the model. CONCLUSION: These results suggest that the patency of infarct-related artery is associated with electrophysiologic stability of myocardium and signal-averaged electrocardiography is one of the useful non-invasive method in risk stratification of acute myocrdial infarction.

The role of combined induction chemotherapy and radical radiation therapy in the treatment of advanced nasopharyngeal cancer / 대한암학회지

No abstract available.