Surface ECG findings in 29 patients with left isomerism were reviewed. Among the total 46 wave axis distributions, 25(54%) were abnormal axis, not originated from sinus node. Congenital atrioventricular block was found in 2 children. 6 patients showed the bradycardia and junctional escape rhythm intermittently or persistently. 4 of them, not related with heart surgery, were much older than 2 patients who showed these ECG findings after heart surgery. These ECG findings suggested the possibility of occurrence of sinus node or subsidiary pacemaker dysfunction in the patients with left isomerism, especially in the older patients. So we thought that electrophysiologic evaluation is necessary in some patients with left isomerism.
Atrioventricular Block ; Axis, Cervical Vertebra ; Bradycardia ; Child ; Electrocardiography* ; Humans ; Isomerism* ; Sinoatrial Node ; Thoracic Surgery ; United Nations

Clinical EPS was performed in 16 normal adults without evidence of conduction disease on the surface standard 12 lead electrocardiogram in order to provide normal electrophysiological values of the sinus node function and AV conduction. EPS was also performed in 15 patients with sick sinus syndrome and 10 patients with AV conduction disturbance to evaluate the clinical usefulness of EPS in detecting sinus node dysfunction and AV conduction disturbance. The results were as follows. 1) The results of sinus node function test in the normal group were m-SNRT 853+/-198msec(range 800-1,560msec), c-SNRT 230+/-66msec(range 120-370msec), and %m -SNRT/SCL 127+/-11%(range 114-149%). 2) In 15 patients with SSS, the M-SNRT were ranged from 1,270 to 12,330msec and 10 patients(66%) had significantly increased m-SNRT exceeding 1,560msec. The c-SNRT were ranged from 230 to 10,730msec and 13 patients(83%) had significantly increased c-SNRT exceeding 370msec. The % m-SNRT/SCL were ranged from 136 to 770% and 12 patients(80%) had significantly increased % m-SNRT/SCL exceeding 150%. 3) The SACT in normal group were 84+/-14msec(range 70-105msec) measured by continuous atrial pacing method and 80+/-19 msec(range 60-115msec) measured by atrial extrastimulation method. 4) In SSS, the SACT measured by continuous atrial pacing method was ranged from 80 to 1,050msec and 11/12 patients(92%) had significantly increased SACT exceeding 112 msec. The SACT measured by atrial extrastimulation method was ranged from 90 to 310msec and 7/8 patients(88%) had significantly increased SACT exceeding 118 msec. 5) C-SNRT, % m-SNRT/SCL, and SACT were more useful in detecting sinus node dysfunction than m-SNRT. 6) The AV conduction intervals in normal group were PA interval 17+/-6(range 5-25msec), AH interval 96+/-18 msec(range 70-135msec), and HV interval 46+/-7msec(range 35-55msec). 7) Rapid atrial pacing induced Wenckebach type second degree AV block proximal to H at pacing rate of 90 to 190/min in 14/16 normal adults. 2 patients maintained intact AV conduction upto maximum pacing rate of 200/min. 8) His bundle electrogram showed the site of AV block in 9 of 10 patients with AV conduction disturbances. The sites of AV block were AV nodal area 1 case, intraHis bundle 4 cases, and infraHis bundle 4 cases. 9) EPS provided a good supportive information that was useful in selecting pacemaker therapy in a patient with chronic bifascicular block who revealed prolonged HV interval and infraHis bundle block at a pacing rate of 70min. 10) The refractory periods of AV conduction system in normal group were AERP 274+/-54msec (range 170-410msec), AVN-FRp 467+/-74msec(range 285-600msec), AVN-ERP 341+76msec(range 190-460), and V-ERP 280+/-25msec(range 240-320msec).
Adult ; Atrioventricular Block ; Electrocardiography ; Electrophysiologic Techniques, Cardiac ; Humans ; Sick Sinus Syndrome ; Sinoatrial Node*

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.
Administration, Intravenous ; Atrioventricular Block ; Atropine ; Humans ; Incidence ; Sick Sinus Syndrome* ; Sinoatrial Node*

Sick sinus syndrome(SSS) constitutes a spectrum of cardiac arrhythmia, including sinus bradycardia, sinus pause-arrest, sinoatrial block, slow escape rhythm, bradyarrhythmia and tachyarrhythmia. SSS is relatively uncommon in children but its exact incidence is unknown because diagnostic criteria are not uniform and most children with SSS, in general are asymptomatic. SSS may be primary(organic sinus node disease) or secondary(cardiac surgery comprises much of SSS in children and adolescents), but it can hardly be caused by familial relations as well. We reports an occurrence of familial sick sinus syndrome. Mother was diagnosed as SSS, which was presented by symptoms of dizziness and treated by permanent pacemaker(DDD). Also, two daughters revealed SSS with non- compacted cardiomyopathy on neonatal screening and fetal echocardiography respectively. We concluded that familial SSS may occur, so familial screening should be suggested.
Arrhythmias, Cardiac ; Bradycardia ; Cardiomyopathies ; Child ; Dizziness ; Echocardiography ; Humans ; Incidence ; Infant, Newborn ; Mass Screening ; Mothers ; Neonatal Screening ; Nuclear Family ; Sick Sinus Syndrome* ; Sinoatrial Block ; Sinoatrial Node ; Tachycardia ; United Nations

BACKGROUND: Single pass lead VDD pacing preserves atrioventricular synchrony with a single lead system which incorporates floating atrial electrodes. The objectives of this study were to measure whether different body postures and physical activities cause significant changes of the atrial electrogram amplitudes and to evaluate the effectiveness of its atrial sensing, ventricular sensing and pacing. METHOD: Prospective study was done in 7 patients with high degree AV block and normal sinus node function in whom a single lead VDD pacing system was implanted. The P wave amplitude was been measured in different condition during follow-up period. RESULTS: 1) During follow-up period, the P wave amplitude showed variation with changes in posture and respiration, but there was no consistent increase or decrease in amplitude. The lowest P wave amplitude was above the minimal atrial sensing value of 0.2 mV. 2) The percentage of atrial synchronous ventricular pacing recorded in Holter ECG and during Treadmill exercise test was more than 99%. 3) Atrial oversensing or VA cross sensing were not observed in any of the patients. CONCLUSIONS: Despite floating atrial electrode, the single pass lead VDD pacing maintains reliable atrial sensing and ventricular pacing in different body position and physical activity, so it may offer an excellent alternative in patients with high grade AV block and intact sinus node function.
Atrioventricular Block ; Electrocardiography ; Electrodes ; Electrophysiologic Techniques, Cardiac ; Exercise Test ; Follow-Up Studies ; Humans ; Motor Activity* ; Posture ; Prospective Studies ; Respiration ; Sinoatrial Node

BACKGROUND: Single pass lead VDD pacing preserves atrioventricular synchrony with a single lead system which incorporates floating atrial electrodes. The objectives of this study were to measure whether different body postures and physical activities cause significant changes of the atrial electrogram amplitudes and to evaluate the effectiveness of its atrial sensing, ventricular sensing and pacing. METHOD: Prospective study was done in 7 patients with high degree AV block and normal sinus node function in whom a single lead VDD pacing system was implanted. The P wave amplitude was been measured in different condition during follow-up period. RESULTS: 1) During follow-up period, the P wave amplitude showed variation with changes in posture and respiration, but there was no consistent increase or decrease in amplitude. The lowest P wave amplitude was above the minimal atrial sensing value of 0.2 mV. 2) The percentage of atrial synchronous ventricular pacing recorded in Holter ECG and during Treadmill exercise test was more than 99%. 3) Atrial oversensing or VA cross sensing were not observed in any of the patients. CONCLUSIONS: Despite floating atrial electrode, the single pass lead VDD pacing maintains reliable atrial sensing and ventricular pacing in different body position and physical activity, so it may offer an excellent alternative in patients with high grade AV block and intact sinus node function.
Atrioventricular Block ; Electrocardiography ; Electrodes ; Electrophysiologic Techniques, Cardiac ; Exercise Test ; Follow-Up Studies ; Humans ; Motor Activity* ; Posture ; Prospective Studies ; Respiration ; Sinoatrial Node

BACKGROUND: Antibradycardia pacemaker is one of the treatment modalities for bradyarrhythmia. We present the clinical results of 440 implantations of permanent pacemaker between August 1984 and December 1997 at Department of Internal Medicine in Seoul National University Hospital. METHOD: We investigated the indication of permanent pacing, the pacing modes, the complications of permanent pacing, and the chronic pacing threshold. RESULT: The study was comprised of 440 patients (M/F : 179/261, mean age : 59+/-12 years, 58+/-14 years, respectively). Indications of the primary pacemaker implantations were sinus node dysfun-ction in 53% and atrioventricular conduction disorders in 47%. Twelve percent of total pacemaker procedures were pulse-generator replacements. Pacing modes were VVI in 59.1%, VVIR in 10.2%, DDD in 30.2%, and others in 0.5%. Complications developed in 21 cases (4.8%) during long-term follow-up. They included 8 cases of pacing failure due to increased pacing threshold, 2 cases of early power depletion, 2 cases of lead dislodgement, 6 cases of lead fracture, 3 cases of skin erosion, 3 cases of hematoma, 3 cases of infection, and 1 case of skeletal muscle stimulation. Chronic pacing thresholds at pacing width of 0.5 msec were 1.9+/-0.4 V for the epicardial ventricular leads (n=11), 1.3+/-0.5 V for the endocardial ventricular leads (n=36), and 1.1+/-0.2 V for the atrial leads (n=4) after 7 to 10 years of implantation. CONCLUSION: Sinus node dysfunction was the more common indication than atrioventricular block for the antibradycardia pacemaker implantation. Long-term follow-up of the pacemaker patients would be very useful to detect the pacing system abnormalities and to maximize the battery longevity by adjustment of pacing output according to the level of chronic pacing threshold.
Atrioventricular Block ; Bradycardia ; Dichlorodiphenyldichloroethane ; Follow-Up Studies* ; Hematoma ; Humans ; Internal Medicine ; Longevity ; Muscle, Skeletal ; Seoul ; Sick Sinus Syndrome ; Sinoatrial Node ; Skin

BACKGROUND: Antibradycardia pacemaker is one of the treatment modalities for bradyarrhythmia. We present the clinical results of 440 implantations of permanent pacemaker between August 1984 and December 1997 at Department of Internal Medicine in Seoul National University Hospital. METHOD: We investigated the indication of permanent pacing, the pacing modes, the complications of permanent pacing, and the chronic pacing threshold. RESULT: The study was comprised of 440 patients (M/F : 179/261, mean age : 59+/-12 years, 58+/-14 years, respectively). Indications of the primary pacemaker implantations were sinus node dysfun-ction in 53% and atrioventricular conduction disorders in 47%. Twelve percent of total pacemaker procedures were pulse-generator replacements. Pacing modes were VVI in 59.1%, VVIR in 10.2%, DDD in 30.2%, and others in 0.5%. Complications developed in 21 cases (4.8%) during long-term follow-up. They included 8 cases of pacing failure due to increased pacing threshold, 2 cases of early power depletion, 2 cases of lead dislodgement, 6 cases of lead fracture, 3 cases of skin erosion, 3 cases of hematoma, 3 cases of infection, and 1 case of skeletal muscle stimulation. Chronic pacing thresholds at pacing width of 0.5 msec were 1.9+/-0.4 V for the epicardial ventricular leads (n=11), 1.3+/-0.5 V for the endocardial ventricular leads (n=36), and 1.1+/-0.2 V for the atrial leads (n=4) after 7 to 10 years of implantation. CONCLUSION: Sinus node dysfunction was the more common indication than atrioventricular block for the antibradycardia pacemaker implantation. Long-term follow-up of the pacemaker patients would be very useful to detect the pacing system abnormalities and to maximize the battery longevity by adjustment of pacing output according to the level of chronic pacing threshold.
Atrioventricular Block ; Bradycardia ; Dichlorodiphenyldichloroethane ; Follow-Up Studies* ; Hematoma ; Humans ; Internal Medicine ; Longevity ; Muscle, Skeletal ; Seoul ; Sick Sinus Syndrome ; Sinoatrial Node ; Skin

Systemic sclerosis (SSc) is characterized by the presence of microvascular disease and various patterns of cutaneous and parenchymal fibrosis. Manifestation of SSc may occur in numerous tissues and organs and can be particularly problematic when present in the lungs, kidneys or heart. Cardiac involvement in SSc includes pericarditis, myocardial disease, conduction abnormalities, and arrhythmia. Sick sinus syndrome is described as a combination of symptoms (dizziness, confusion, fatigue, syncope and congestive heart failure) caused by sinus node dysfunction and manifested by marked sinus bradycardia, sinoatrial block, or sinus arrest. Sinus node dysfunction is most often seen in the elderly but also, rarely, in systemic amyloidosis and connective tissue disease. Sick sinus syndrome is rarely found in patients with SSc, of which there has been only one case report, according to a review of the literature. Therefore, we report a case of sick sinus syndrome in a 71-year-old female with SSc.
Aged ; Amyloidosis ; Arrhythmias, Cardiac ; Bradycardia ; Cardiomyopathies ; Connective Tissue Diseases ; Estrogens, Conjugated (USP) ; Fatigue ; Female ; Fibrosis ; Heart ; Humans ; Kidney ; Lung ; Pericarditis ; Scleroderma, Systemic* ; Sick Sinus Syndrome* ; Sinoatrial Block ; Syncope

BACKGROUND AND OBJECTIVES: It has been demonstrated that sleep apnea syndrome predisposes to cardiac rhythm disturbances and cardiovascular risks such as systemic hypertension. This study was conducted to investigate the types and frequency of cardiac arrhythmias which occurred during sleep and the effects of nasal continuous positive airway pressure (nCPAP) therapy in the patients with sleep apnea syndrome. SUBJECTS AND METHODS: The subjects were 197 patients who were referred to the Sleep Research Center of Korea University Medical Center for polysomnography due to snoring and sleep apnea from Jan. 1st 2000 to July 31st 2002. Of the 197 patients, 44 with severe sleep apnea syndrome, whose respiratory disturbance index (RDI) exceeded 40/hr, were enrolled. Their electrograms on polysomnography before and after nCPAP therapy were analyzed. RESULTS: Of the 44 subjects, 32 (72.8%) showed cardiac arrhythmias. The types of arrhythmias were atrial premature beats (APBs, n=17), premature ventricular complexes (PVCs, n=15), sinus bradycardia (heart rate less than 40 per minute, n=6), sinus pause (n=1), and sinoatrial block (n=5). No fatal arrhythmias were identified. Most, 93.2%, of these arrhythmias arose immediately after hypopneic or apneic episodes, and were accompanied by a significant decrease in SaO2, from 91.4% to 84.7% (p<0.05). After nCPAP therapy, these arrhythmias were completely disappeared in 11 patients (34.4%) and diminished in 15 (46.9%). Hypopneic or apneic episodes were preceded by cardiac arrhythmias in only 36.4% with nCPAP (p<0.05 vs. before). CONCLUSION: Cardiac arrhythmias were demonstrated in 72.8% of cases of severe sleep apnea syndrome, which were mostly benign and preceded by hypopneic or apneic episodes. nCPAP therapy decreased the frequency of hypopnea and apnea with elevated arterial O2 saturation, and effectively eliminated cardiac arrhythmias.
Academic Medical Centers ; Apnea ; Arrhythmias, Cardiac ; Bradycardia ; Cardiac Complexes, Premature ; Continuous Positive Airway Pressure ; Humans ; Hypertension ; Korea ; Polysomnography ; Positive-Pressure Respiration ; Sinoatrial Block ; Sleep Apnea Syndromes* ; Snoring ; Ventricular Premature Complexes