Predictors of Neurodevelopmental Outcomes in Newborns Undergoing Hypothermia Therapy

PURPOSE: This study aimed to identify the early predictors of neurodevelopmental outcomes in infants undergoing therapeutic hypothermia for neonatal hypoxic ischemic encephalopathy. METHODS: The medical records of 24 neonates who underwent hypothermia therapy for hypoxic ischemic encephalopathy at the neonatal intensive care unit of Yeouido St. Mary's Hospital of the Catholic University of Korea between August 2013 and May 2016 were reviewed. Patients were divided into two groups according to their neurological outcome at the age of 18 to 24 months: a normal group (n=14), which included patients with normal neurological function, and an abnormal group (n=10), which included patients with neurological deficits. The clinical characteristics, clinical outcomes, and laboratory findings before and after hypothermia treatment were compared between the groups. RESULTS: There were no significant differences in the demographic characteristics between the two groups. With regard to clinical outcomes, only brain magnetic resonance imaging (MRI) findings showed significant differences between the normal and abnormal groups (21.4% vs. 100.0%, P 0.05). CONCLUSION: The presence of abnormal lesions on MRI was the most useful predictor of poor neurodevelopmental outcome in infants treated with therapeutic hypothermia after perinatal asphyxia.

Perinatal Factors Associated with the Preterm Thyroid Screening Test / 대한주산의학회잡지

PURPOSE: The aim of this study was to evaluate the usefulness of thyroid function screening in preterm infants and the relation between thyroid hormone level, perinatal environment, and clinical presentation after preterm birth. METHODS: We retrospectively evaluated 46 preterm infants from March 2013 to December 2014, who had been screened for congenital hypothyroidism during the 1st week with thyroid stimulating hormone (TSH), triiodothyronine (T3) and free thyroxine (fT4) measured by the radioimmunoassay method. The effects of pregnancy associated maternal factors, gestational age, growth parameters, Apgar score, 1st meconium passage time, respiratory distress syndrome and apnea on thyroid hormone levels were assessed by Mann-Whitney U-test and multiple linear regression analysis. RESULTS: With advancing gestational age, T3 and fT4 displayed a tendency to increase. FT4 showed a positive correlation pattern with antenatal steroid therapy, corrected gestational age at examination and a negative correlation pattern with 1st meconium passage time and apnea (P<0.05). TSH displayed a positive correlation pattern with 1st meconium passage time, 5-minute Apgar score and a negative correlation pattern with sampling age (P<0.05). CONCLUSION: In the preterm period, both fT4 and TSH seems to correlate significantly with various perinatal factors and clinical presentation. We recommend that early fT4 screening should be included in the screening for hypothyroidism in preterm infants.

Perinatal Factors Associated with the Preterm Thyroid Screening Test / 대한주산의학회잡지

PURPOSE: The aim of this study was to evaluate the usefulness of thyroid function screening in preterm infants and the relation between thyroid hormone level, perinatal environment, and clinical presentation after preterm birth. METHODS: We retrospectively evaluated 46 preterm infants from March 2013 to December 2014, who had been screened for congenital hypothyroidism during the 1st week with thyroid stimulating hormone (TSH), triiodothyronine (T3) and free thyroxine (fT4) measured by the radioimmunoassay method. The effects of pregnancy associated maternal factors, gestational age, growth parameters, Apgar score, 1st meconium passage time, respiratory distress syndrome and apnea on thyroid hormone levels were assessed by Mann-Whitney U-test and multiple linear regression analysis. RESULTS: With advancing gestational age, T3 and fT4 displayed a tendency to increase. FT4 showed a positive correlation pattern with antenatal steroid therapy, corrected gestational age at examination and a negative correlation pattern with 1st meconium passage time and apnea (P<0.05). TSH displayed a positive correlation pattern with 1st meconium passage time, 5-minute Apgar score and a negative correlation pattern with sampling age (P<0.05). CONCLUSION: In the preterm period, both fT4 and TSH seems to correlate significantly with various perinatal factors and clinical presentation. We recommend that early fT4 screening should be included in the screening for hypothyroidism in preterm infants.

Presentation Time of Necrotizing Enterocolitis Diagnosed by Sonography according to Gestational Age

PURPOSE: In this single center study, we assessed the timing of presentation of necrotizing enterocolitis (NEC) diagnosed by sonography according to the gestational age. METHODS: We retrospectively reviewed the medical records of 49 newborn patients who were diagnosed with NEC (modified Bell's stage II and higher according to abdominal sonography and simple abdominal radiography) and were admitted to the neonatal intensive care unit of St. Mary's Hospital between January 2008 and December 2012. Infants were grouped according to their gestational age (GA): Group I (GA or =37 weeks); early-onset NEC was considered when NEC developed at or =14 days of age. RESULTS: The number of infants in each group were: Group I (n = 16), Group II (n = 20), Group III (n = 11), and Group IV (n = 2). The mean age at diagnosis of NEC was: Group I (31.6 days), Group II (15.9 days), Group III (11.0 days), and Group IV (2.0 days). Early-onset NEC developed at a mean of 5.5 days of age, whereas late-onset NEC developed at a mean of 36.1 days of age. CONCLUSION: Based on early sonographic diagnosis, infants with lower gestational ages developed NEC at a more advanced postnatal age as compared to more mature infants. However, further studies are needed to understand the etiology of this disease process.

Neonatal Seizures in Preterm Infants / 대한소아신경학회지

PURPOSE: Neonatal seizures are the most prominent feature of neonatal neurologic dysfunction, and the lifespan risk for seizures is highest in the neonatal period, especially in preterm infants. This study was aimed to find and analyze the risk factors and clinical profiles of seizures in preterm infants. METHODS: Sixteen cases of preterms with seizures were retrospectively reviewed between Mar. 2009 and Feb. 2012. RESULTS: The average gestational age was 30.3+/-4.1 weeks and 11 patients (68.7%) experienced seizures within 1 week after the birth. Eight cases (50%) had a perinatal asphyxia during the delivery and 7 cases (43.8%) had a history of perinatal maternal illness. Various types of seizures were observed of which subtle seizures were the most common (50%). Electroecephalographies were performed in 12 cases, which showed abnormal findings in 9 cases (75%). Neuroimaging studies were performed in 16 cases and showed abnormal findings in 10 cases (62.5%). Thirteen patients were discharged in the improved state and 3 patients expired. Eight cases had normal outcome, while 3 cases showed developmental delay. Prognosis was unknown in 2 cases due to follow up loss. CONCLUSION: Neonatal asphyxia is the most important risk factor. Furthermore, infants with a history of perinatal maternal illness appear to be at risk for neonatal seizures. EEG is a sensitive method for assessing seizure activity and prognosis. Monitoring high risk infants with asphyxia and a history of perinatal maternal illness, and early postnatal tracing with EEG is required to detect and manage high risk preterms.

The preventive effects of the heparin-coated coronary stent in a porcine coronary stent restenosis model / 대한내과학회지

BACKGROUND: The coronary stent reduces acute coronary arterial occlusion and late restenosis during and after coronary intervention. However, stent thrombosis and restenosis are still major limitations in widespread use of coronary stent. Local drug delivery with use of heparin-coated stent will be a new approach reducing the incidence of stent thrombosis and restenosis. In order to evaluate the effects of heparin-coated stent on stent restenosis, heparin-coated stents were compared with control stents in a porcine coronary stent restenosis model. METHODS: Stent overdilation injury (stent:artery= 1.3:1.0) was performed with bare Wiktor (Group I, n=10) and heparin-coated Wiktor (Group II, n=20) stents (HEPAMEDTM, Medtronics, U.S.A.) in porcine coronary arteries. Follow-up quantitative coronary angiography (QCA) was performed at 4 weeks after stenting and histopathologic assessments of stented porcine coronary arteries were compared in both groups. RESULTS: 1) On QCA, percent diameter stenosis was significantly higher in Group I than in Group II (16.3+/-6.62% vs. 9.6+/-5.06%, p<0.05). 2) Injury score of stented porcine coronary artery was not different in both groups (1.26+/-0.23 vs. 1.20+/-0.22). 3) Pathologic area stenosis of stented artery was higher in Group I than in Group II (41.6+/-12.5% vs. 27.1+/-9.9%, p<0.005). 4) Neointimal area was higher in Group I than in Group II (4.58+/-1.41 mm2 vs. 2.57+/-1.07 mm2, p<0.05). 5) By immunohistochemistry, proliferating cell nuclear antigen (PCNA) index was higher in Group I compared with in Group II (11.2+/-6.75% vs. 6.3+/-4.14%, p<0.05). CONCLUSIONS: Heparin-coated stent is effective in the prevention of late coronary stent restenosis in a porcine coronary stent restenosis model, which may be related with the inhibition of neointimal cell proliferation.

Predictors of successful catheter ablation of AV nodal reentrant tachycardia / 대한내과학회지

Catheter ablation of the AV nodal slow pathway using radiofrequency (RF) energy has been established as the first-line curative therapeutic modality of recurrent symptomatic AV nodal reentrant tachycardia (AVNRT). In contrast to catheter ablation of the AV bypass tract, there was no useful marker to localize succesful site of the pathway. This study was performed to determine predictors of successful catheter ablation of the AV nodal slow pathway in patients with AVNRT. METHODS: Forty patients (18 men, 22 women; 47.9+/-13.3 years) with AVNRT undergoing successful catheter ablation of the AV nodal slow pathway were included in this study, in which 217 attempts were tried to ablate the AV nodal slow pathway. Characteristics of local atrial electrogram, anatomical site at each attempt, junctional rhythm during RF delivery were analyzed (40 successful, 177 failed). Maximum difference and duration of atrial electrograms were measured and local atrial electrograms were classified into 5 types (A1, A2, B1, B2 and C type) according to the type and the degree of fragmentation. Finally, the occurrence of junctional rhythm during RF discharge and its onset time were compared between successful and failed attempts. RESULTS: There was no significant difference in the maximum difference of amplitude and duration of atrial electrograms between successful and failed attempts. The success rate in each type of atrial electrogram was significantly different. And, the success rate in non-C type atrial electrograms (A1, A2, B1, and B2) was significantly higher than that in type C atrial electrograms (25.0% vs 10.3%, p<0.01). No significant difference was noted in success rates according to attempted sites. Junctional rhythms during radiofrequency application occured significantly more frequent in successful attempts than in failed attempts (87.5% vs 47.5%, p<0.001). The time to onset of junctional rhythm was not different between successful and failed attempts (5.2+/-4.9 sec vs 6.1+/-5.5 sec). CONCLUSION: Fragmented local atrial electrogram and junctional rhythm during RF energy delivery may be used to predict successful catheter ablation of AVNRT. It is recommended that RF energy should be applied to the site where fragmented atrial electrogram is recorded and terminated if junctional rhythm does not develop within 15 seconds after starting RF energy delivery.

Predictors of successful catheter ablation of AV nodal reentrant tachycardia / 대한내과학회지

Catheter ablation of the AV nodal slow pathway using radiofrequency (RF) energy has been established as the first-line curative therapeutic modality of recurrent symptomatic AV nodal reentrant tachycardia (AVNRT). In contrast to catheter ablation of the AV bypass tract, there was no useful marker to localize succesful site of the pathway. This study was performed to determine predictors of successful catheter ablation of the AV nodal slow pathway in patients with AVNRT. METHODS: Forty patients (18 men, 22 women; 47.9+/-13.3 years) with AVNRT undergoing successful catheter ablation of the AV nodal slow pathway were included in this study, in which 217 attempts were tried to ablate the AV nodal slow pathway. Characteristics of local atrial electrogram, anatomical site at each attempt, junctional rhythm during RF delivery were analyzed (40 successful, 177 failed). Maximum difference and duration of atrial electrograms were measured and local atrial electrograms were classified into 5 types (A1, A2, B1, B2 and C type) according to the type and the degree of fragmentation. Finally, the occurrence of junctional rhythm during RF discharge and its onset time were compared between successful and failed attempts. RESULTS: There was no significant difference in the maximum difference of amplitude and duration of atrial electrograms between successful and failed attempts. The success rate in each type of atrial electrogram was significantly different. And, the success rate in non-C type atrial electrograms (A1, A2, B1, and B2) was significantly higher than that in type C atrial electrograms (25.0% vs 10.3%, p<0.01). No significant difference was noted in success rates according to attempted sites. Junctional rhythms during radiofrequency application occured significantly more frequent in successful attempts than in failed attempts (87.5% vs 47.5%, p<0.001). The time to onset of junctional rhythm was not different between successful and failed attempts (5.2+/-4.9 sec vs 6.1+/-5.5 sec). CONCLUSION: Fragmented local atrial electrogram and junctional rhythm during RF energy delivery may be used to predict successful catheter ablation of AVNRT. It is recommended that RF energy should be applied to the site where fragmented atrial electrogram is recorded and terminated if junctional rhythm does not develop within 15 seconds after starting RF energy delivery.

The Effects of Local Endothelin Receptor Blocker Delivery on Porcine Coronary Stent Restenosis / 대한내과학회지

OBJECTIVES:Coronary stent is one of the most effective currently available devices in the treatment of coronary artery diseases. But, coronary stent restenosis is one of major limitations in clinical stenting. Local drug delivery may be a new strategy for the prevention of stent restenosis. Endothelin receptor blocker is known to have vasodilatory and antiproliferative activities. To investigate the effects of local endothelin receptor blocker delivery on stent restenosis, local delivery was performed in the porcine model of coronary stent restenosis. METHODS: Stent overdilation injury alone was performed in the control porcine coronary arteries (n=4, group A) and local delivery of endothelin receptor blocker prior to stenting was performed in the porcine coronary artery (n=9, group B). Endothelin receptor blocker (TAK-044, Takeda, Japan) was delivered at a rate of 1 ml/min (50 mg/10 ml) using the Dispatch Catheter. Follow-up quantitative coronary angiogram (QCA) and immunohistopathologic assessment were performed 4 weeks after stenting. RESULTS: 1) On QCA, percent diameter stenosis was significantly higher in Group A than in Group B (29.4+/-6.1 % vs. 14.5+/-11.6%, p<0.05). 2) Area stenosis was higher in Group A than in Group B (63.5+/-23.2 % vs. 40.9+/-13.3 %) measured by histopathologic method (p<0.05). 3) Neointimal area was higher in Group A than in Group B (3.53+/-1.9 mm2 vs. 1.75+/-0.8 mm2, p=0.03). 4) By immunocytochemistry, proliferating cell nuclear antigen index was higher in Group A compared with Group B (46.8+/-5.2 % vs. 31.1+/-3.7 %, p<0.05). CONCLUSION: Local delivery of endothelin receptor blocker is effective in the prevention of stent restenosis in a porcine model, which may be related with the partial inhibition of cell proliferation of neointimal cells.

The Effects of Therapeutic Duration of Combined Antiplatelets, Aspirin and Ticlopidine, on Coronary Stent Restenosis

BACKGROUND: One of most important mechanisms of coronary stent restenosis is neointimal hyperplasia. Although the process of neointima formation is not fully understood, a special role has been advocated for adherent platelets. Previous studies have shown a clear benefit with combined antiplatelet therapy such as aspirin plus ticlopidine in reducing the rate of thrombotic occlusions of stented vessels. The purpose of this study was to evaluate the effects of duration of antiplatelet regimens on coronary stent restenosis. METHODS: After successful placement of coronary artery stents in 222 patients, we performed follow-up coronary angiograms in 99 patients (42.3%). Forty-six patients were randomly assi-gned to receive aspirin and ticlopidine for four weeks (Group I: 54+/-9 years: M 38, F 8) and 48 patients for 6 months (Group II: 58+/-8 years: M 38, F 10). RESULTS: There were no significant differences in clinical and procedural variables or coronary lesion characteristics before and after stenting. At 6 months after stenting, minimal luminal diameter was 2.16+/-0.93mm in Group I and 2.04+/-1.07mm in Group II (p-0.57). Late lumen loss was 0.80+/-1.07mm in Group I and 0.92+/-1.11mm (p-0.58) in Group II. The stent restenosis rate of Group I at 28.3% and that of Group II at 29.2% were not statistically significant between the two groups (p-0.92). CONCLUSIONS: The therapeutic duration of combined antiplatelet regimen with aspirin and ticlopidine after coronary stent does not affect stent restenosis rate.

The Effects of Oral Nitric Oxide Donor (Molsidomine) in Patients with Variant Angina Unresponsive to Conventional Anti-Anginal Drugs

BACKGROUND: We observed the changes of clinical characteristics after oral Molsidomine, a nitric oxide donor, in patients who have documented coronary artery spasm by ergonovine coronary angiogram and refractory to conventional anti-anginal therapy. METHOD: Molsidomine, oral nitric oxide donor, was administrated over 12 weeks in 20 patients (6 male, 14 female, 54+/-11.5 years) in order to observe the clinical effects in patients with coronary artery spasm unresponsive to nitrate and calcium channel blockers. Changes in the frequency of pain and sublingual nitroglycerin use, blood pressure, heart rate, side effects, electrocardiogram, and laboratory findings were evaluated before and after Molsidomine therapy. RESULTS: The frequencies of pain and sublingual nitroglycerin use were 3.9+/-0.9/week before treatment and decreased to 2.9+/-0.9/week at 4th week after the additional Molsidomine treatment (pre-treatment vs. 4th week; p<0.001), to 1.0+/-0.8/week at 8th week (4th week vs. 8th week; p<0.001), and to 0.7+/-0.8/week at 12th week. Systolic blood pressure decreased after treatment, but there were no significant changes in diastolic blood pressure, heart rate, resting electrocardiogram and laboratory findings. Molsidomine was discontinued in one patient because of headache. CONCLUSIONS: Molsidomine is an effective and well tolerated anti-ischemic agent in patients with variant angina refractory to conventional anti-anginal therapy.

Successful Coronary Interventions with the Aid of Abciximab (ReoPro (R)) in High-Risk Patients: Report of Two Cases / 대한구급학회지

Abrupt closure of coronary artery during coronary intervention is one of major limitations especially in high-risk patients. Platelets are responsible for composing acute thrombotic occlusion at the site of therapeutic arterial injury. Abciximab (platelet glycoprotein IIb/IIIa receptor blocker) might be helpful in preventing the acute thrombotic occlusion. We experienced an excellent effects of the drug in two cases of high-risk patients, unsuccessful thrombolytics and PTCA with acute occlusion. With additional use of abciximab we overcame the complications and succeeded in getting normal coronary flow and resultant successful angioplasties.

The Early Results of Clinical and Angiographic Follow-up after Coronary Interventions for Restenotic Lesions

BACKGROUND: Coronary intervention is a well established treatment of ischemic heart diseases. However, acute arterial occlusion and restenosis have remained as the principal limitations of coronary intervention. This study was aimed to analyze the acute and long-term, and the clinical angiographic results of the coronary intervention for restenotic lesions. METHOD: Between March 1996 and July 1997 at Chonnam University Hospital, second interventions were performed in one hundred restenotic coronary lesions of ninety patients (age 58.5+/-9.0 year, M:F = 5:1), i.e. percutaneous transluminal coronary angioplasty (PTCA) or stent implantation for the treatment of restenosis. RESULTS: 1) Initial interventions were PTCA in 75 lesions (Group I) and stent in 25 lesions (Group II). There were no differences in clinical manifestations, angiographic findings and follow-up period between the two groups. 2) The method of the second intervention for the restenotic lesions after PTCA were either PTCA or stent implantation ; in Group I PTCA was performed in 27 (37%) lesions and stent in 46 (63%), In Group II, PTCA was performed in 20 (91%) lesions and stent in 2 (9%) lesions. The overall success rate of the second intervention for the restenotic lesion was 96%. 3) Follow-up angiogram at 5.5+/-2.9 months after the second intervention revealed the second restenosis rates of 44% (8/18) after stent and 50% (7/14) after PTCA. CONCLUSION: Second intervention for restenotic lesion can be performed with high success rate. Second restenosis rate are not different between the PTCA and stent groups.

Clinical Characteristics of Coronary Interventions in Old Aged Patients

BACKGROUND: Coronary intervention is one of well established therapeutic modalities for patients with ischemic heart diseases. With the prolonged life expectancy and changes in dietary habits in Korea, the number and percentage of elderly patients with ischemic heart disease have increased in interventional coronary therapies. METHOD: There were 1762 patients (age> or = 70 years : 253, age<70 years: 1509) who underwent diagnostic coronary angiogram at Chonnam University Hospital between Jan '96 and Jun '97. We compared clinical characteristics, coronary lesion morphology, success rates and complications of coronary interventions in control and aged groups. RESULTS: 1) Female patients were more prevalent in aged group (43 %; 145 male, 108 female) than in the control group (35%; 982 male, 527 female, p<0.05). 2) The diagnostic sensitivity of coronary angiogram was higher in the aged (169/253, 67 %) than in control group (738/1509, 49 %, p<0.05). Multivessel diseases were more prevalent in the aged (65 %) than in the control groups (49%). 3) Coronary interventions were performed less frequently in the aged group (119/169, 70 %) than in the control group (605/738, 82%, p<0.05). The success rates of PTCA were not different between in the aged (89%) and control (93%) groups, and the success rates in stenting was also not different between the aged (98%) and control (99%) groups. 4) Procedure-related complications (4.6 vs. 7.6 %) and mortalities (0.5 vs 0.8 %) during and after coronary interventions were not different in control and elderly groups. CONCLUSION: Coronary interventions in patients older than 70 years can be performed with high success and low complication rates ; the results do not differ from those of younger patients.

Clinical Characteristics of Korea Women with Ischemic Heart Disease

BACKGROUND: The prevalence of ischemic heart diseases (IHD) has increased remarkably during the past 10 years in Korea. Because only few reports on risk factors of IHD in Korean women exist, the aim of this study was to determine the clinical characteristics (including risk factors) of IHD in Korean women. METHODS: Fifty-six female patients and 122 (out of 655) of male patients with significant coronary artery stenosis were included in this study. There were 12 cases of angina pectoris and 35 cases of myocardial infarction in the 56 female patients. There were 54 cases of angina pectoris and 68 cases of myocardial infarction in the 122 male patients. Age and sexdistributions, risk factors of atherosclerosis, and coronary angiographic findings were compared between the female and male patients. RESULTS: The female patients were older than the male patients (63+/-8 years vs. 58+/-4 years, p or = 2) was greater in men than in women (43% vs. 25%, p<0.05). Hypertension was more prevalent (66% vs. 11%, p<0.001) and smoking was less (65% vs. 11%, p<0.001) in women than men. After age adjustment, hypertension was more frequent in women, and smoking was more in men (p=0.001). On coronary angiograms there were no difference in the morphology of coronary artery stenosis, the distribution of culprit vessels, and the number of vessels involved between women and men, In terms of therapeutic modalities, there were no differences between women and men in our study. CONCLUSIONS: In Koean women with IHD, hypertension is more common and smoking is less common. However, coronary artery lesion morphology and distribution are comparable between women and men.

Comparison of Porcine Corinary Stent Restenosis between MAC (Maximum Arterial Re-Creation)and Palmaz-Schatz Stent

BACKGROUND: Coronary stents are effective in the treatment of acute complications after angioplasty and the prevention of restenosis. However, complications may arise posttreatment, the major cinical problems are stent thrombosis and restenosis. All coronary stents are imported from western countries and are not covered by medical insurance in Korea. Korean stents should be developed to reduce patient's economic burden. METHODS: We placed five Maximum Arterial Re-Creation (MAC) and five Palmaz-Schatz (PS) stents in ten porcine coronary arteries. Stent and artery diameter ratio was 1.3 : 1.0. Follow-up coronary angiogram and histopathologic examinations were performed four weeks after stent overdilation injury. RESULTS: All of the stented arteries were patent on follow-up coronary angiograms. Angiographic diameter stenosis was 23.1+/-9.2% in MAC stents and 18.5+/-12.3% in PS stents and pathologic area stenosis was 35.6+/-11.4% in MAC stent and 39.8+/-9.9% in PS stent at 4 weeks after stenting, which were not different between two stents. Maximal intimal thickness (0.28+/-0.12 vs. 0.36+/-0.17mm) and neointimal area (1.83+/-1.01mm2 vs. 1.50+/-0.65mm2) were not different between MAC and PS stent. CONCLUSIONS: MAC stents are as effective as PS stents in the prevention of stent restenosis in a porcine stent restenosis model.

Alterations in Myocardial Perfusion and Regional Wall Motion in Patients with Permanent Pacemaker

BACKGROUND: The effect of right ventricular pacing on myocardial perfusion and regional wall motion is not well known, although some studies have suggested that it may be adverse. We investigated the effects of right ventricular pacing on myocardial perfusion and regional wall motion in patients with permanent pacemakers. METHOD: Thirty patients receiving permanent pacemakers for complete heart block or sick sinus syndrome were included in this study. All the patients showed normal coronary angiograms. Myocardial scintigraphy and two-dimensional echocardiography were performed to assess myocardial perfusion and to evaluate regional wall motion and global function of the left ventricle (LV). RESULTS: 1) Mean age was 66.2+/-8.2 (41-84) years, and the male-to-female ratio was 1 : 1.7 (11 male, 19 female). Indications for permanent pacemaker implantation were complete atrioventricular (AV) block in 21 patients and sick sinus syndrome in 9. The selected pacing modes were VVI in 14 patients, DDD in 8, VDD in 6, and AAI in 2. LV ejection fraction estimated by 2-dimensional echocardiography was 62.7+/-5.8 (53-86)%. 2) Perfusion defects were noted in 26 (87%) patients including 25 (89%) out of 28 patients with ventricular pacing modes such as VVI, DDD, and VDD, and 1 (50%) out of 2 patients with AAI mode. Locations of perfusion defects were septal in 19 (63%) patients, inferior in 17 (57%), apical in 16 (53%), lateral in 3 (10%), and anterior in 2 (7%). Extent of maximal perfusion defects was 17.0+/-9.5 (0-44)%. 3) Regional wall motion abnormalities were noted mainly over the apical region of the LV in 26 (93%) of 28 patients with ventricular pacing. However, LV ejection fraction did not differ significantly before and early after implantation of the pacemaker (62.7+/-5.8% vs. 61.0+/-5.8%, p-0.313). CONCLUSIONS: Right ventricular apical pacing frequently caused myocardial perfusion defects and regional wall motion abnormalities. These might be due to abnormal ventricular activation and abnormal interventricular septal motion. The long-term effects of these abnormalities remain to be determined, and the pacing technique to minimize these adverse effects should be developed.

Usefulness of a "Push Technique" for Atrial Lead Implantation

BACKGROUND AND OBJECTIVES: Dual-chamber pacing is commonly used as a pacing mode maintaining at-rioventricular synchrony. However, traditional technique for atrial J lead implantation is relatively time-consuming and not easy to get optimal sites for both atrial and ventricular leads, especially for less-experienced operators. We developed a new "push technique" for atrial J lead implantation. MATERIALS AND METHOD: This study included sixty-two consecutive patients (26 males 36 females, 55+/-10 years, 56 patients received DDD and 6 received AAI pacemakers) from Jan. 1992 through Dec. 1996. Atrial J leads were implanted using a "push technique", that is, simply advancing a straightened lead while holding the stylet in the pacing lead at the junction of the superior vena cava and the right atrium. We evaluated the early and long-term result of atrial J lead implantation by the "push technique". RESULTS: 1) Atrial leads were successfully inserted by the first or second trial of the "push technique" in the 62 patients (100%). The sensed P wave amplitude was 3.1+/-1.0 mV, pacing threshold 0.6+/-0.2 V at the pulse width of 0.5 ms, impedance 547.4+/-118.5 ohms at 5 V. 2) During follow-up of 28.1+/-15.7 months, significant changes in the pacing parameters and the dislodgement of atrial leads were not seen. CONCLUSION: The early and long-term result of atrial J lead implantation by the "push technique" was excellent. This "push technique" can be used as an easy alternative technique for atrial J lead implantation.

Effective Approaches to Successful Target Sites in Catheter Ablation of the Right-side Accessory Pathways / 대한내과학회지

BACKGROUND: Although radiofrequency catheter ablation (CA) of the accessory pathway (AP) is very effective and safe, it has been reported that CA is more difficult in the right-side AP than the left-side AP, requiring the refinement of the conventional CA technique for the right-side AP. This study was, therefore, aimed to develop an effective technique for CA of the right-side AP. METHODS: Fifty right-side APs in 45 patients which underwent CA were included in this study. The locations of APs were divided into 8 regions (anteroseptal, mid septal, posteroseptal, posterior, posterolateral, lateral, anterolateral, and anterior). After localizing APs, CA of the APs was attempted via the inferior vena cava (IVC) in all patients. If CA attempt via the IVC for more than 1 hour was failed, then CA was tried via the superior vena cava (SVC). Successful CA was defined as permanent loss of AP conduction even during infusion of isoproterenol (1-4microg/min). The ways of approaching the ablation catheter to the successful target sites were classified into over-the-tricuspid valve approach (OV) via the IVC (IVC-OV), OV via the SVC (SVC-OV), under-the-tricuspid valve (UV) approach via the IVC (IVC-UV), and UV via the SVC (SVC-UV) and evaluated according to the AP locations. RESULTS: The locations of the APs were anteroseptal in 5 APs, mid septal in 6, posteroseptal in 12, posterior in 3, posterolateral in 5, right lateral in 11, anterolateral in 4, and anterior in 4. Forty-eight (96.0%) of 50 APs were successfully ablated; 35 (70.0%) with primary IVC approaches and 13 (26.0%) with secondary SVC approaches. As a successful approach, IVC-OV was 26 (54.2%); IVC-UV, 9 (18.8%); SVC-OV, 4 (8.3%), and SVC-UV, 9 (18.8%). Secondary SVC approaches were required 7 (70.0%) in the lateral APs, 2 (50.0%) in the anterolateral APs, 1 (25.0%) of the posterolateral APs, 1 (25.0%) in the anterior APs, 1 (20.0%) of the anteroseptal APs, and 1 (8.3%) in the posteroseptal APs but none in the midseptal and posterior APs. SVC-UV approach was used in 9 (69.2%) in 13 APs which were ablated with SVC approach. CONCLUSIONS: The ways of approach to successful target site in CA of the right-side APs are different according to the location and SVC approaches are frequently required in ablation of the lateral or anterolateral APs. Therefore, SVC approaches should be considered in these locations if the initial IVC approaches are not successful.

Electrophysiologic Properties of the AV Conduction System in Patients with Sinus Node Dysfunction / 대한내과학회지

BACKGROUND: It is very important to evalute the function of the atrioventricular conduction system in selecting appropriate pacemaker, pacing and sensing mode in sick sinus syndrome. It has been reported that atrioventricular conduction abnormalities were commonly accompanied with sinus node dysfunction (SND). However, there were several long term follow-up studies indicating that incidence of AV conduction abnormalities was as low as below 1% a year in patients with SND implanted pacemaker. This study was performed to evaluate the properties of the AV conduction system in patients with SND. SUBJECT AND METHODS: Patients subjected to this study were fifty-eight who underwent electrophysiologic study on suspicion of SND. Sinus node recovery time (SNRT) was defined as the longest time among the times that sinus rhythm reappeared after rapid atrial pacing for 45 seconds with several cycle lengths, and corrected SNRT (cSNRT) was worked out by subtracting sinus cycle length (SCL) from SNRT. Criteria for sinus node dysfunction were 1550 msec or more on SNRT, 550 msec or more on cSNRT and group A (23 cases, 58+/-13 yrs) was defined as SND not retrieved to normal after intravenous administration of atropine 1-2 mg, group B (21 cases, 52+/-14 yrs) was retrieved to normal and group C (14 cases, 54+/-13 yrs) was normal control group. Abnormalities of the AV conduction system were defined as 150 msec or more on AH interval, 500 msec or more on AVblock cycle length (AV-BCL), 450 msec or more on AV nodeeffective refractory period (AVN-ERP). RESULTS: SCL in group A, B, C was 1197+/-340 msec, 1215+/-273 msec, and 898+/-129 msec, respectively at baseline and 886+/-218 msec, 798+/-106 msec, and 722+/-110 msec respectively after atropine administration, showing a significant prolongation of SCL in group A and B at baseline (p<0.001) and group A after atropine administration (p<0.05). SNRT in group A, B, C was 3520+/-1817 msec, 3180+/-2390 msec, and 1282+/-116, respectively at baseline and 4155+/-4281 msec, 1237+/-210 msec, 1020+/-245 msec, respectively after atropine administration, showing a significant prolongation of SNRT in group A and B at baseline (p<0.001) and group A after atropine administration (p<0.05). AH intervals at baseline and after atropine administration were 107+/-27 msec and 100+/-20 msec in group A, 101+/-21 and 91+/-14 in group B, and 118+/-32 and 83+/-23 in group C, showing no significant difference between 3 groups. AV-BCLs at baseline and after atropine administration were 428+/-151 msec and 453+/-301 msec in group A, 525+/-140 and 370+/-53 in group B, and 461+/-120 361+/-94 in group C, showing no significant difference between 3 groups. AVN-ERP was 315+/-57 msec in group A, 343+/-132 msec in group B, 347+/-132 in group C, showing no significant difference between 3 groups. There was no significant difference in the incidences of cases with abnormal AH interval, AV-BCL, AVN-ERP, HV interval between 3 groups. AV block greater than second degree was observed in one patient of group A but none of group B and C. CONCLUSIONS: Atrioventricular conduction abnormalities in patients with sinus node dysfunction were not more common than control subjects. Therefore, atrial pacing rather than ventricular or dual chamber pacing may be safely selected as a permanent pacing mode for sick sinus syndrome with no combined significant AV block.