Evaluation of cardiac-electrophysiological balance according to National Institutes of Health Stroke Scale score at admission and discharge in acute ischemic stroke patients: A pilot study

SUMMARY OBJECTIVE: The main objectives of this investigation were to determine whether there were any relationships between corrected cardiac-electrophysiological balance value and National Institutes of Health Stroke Scale scores at admission and discharge in patients with acute ischemic stroke and to assess whether cardiac-electrophysiological balance value was an independent predictor of high National Institutes of Health Stroke Scale scores (National Institutes of Health Stroke Scale score ≥5). METHODS: In this retrospective and observational study, 231 consecutive adult patients with acute ischemic stroke were evaluated. The cardiac-electrophysiological balance value was obtained by dividing the corrected QT interval by the QRS duration measured from surface electrocardiography. An experienced neurologist used the National Institutes of Health Stroke Scale score to determine the severity of the stroke at the time of admission and before discharge from the neurology care unit. The participants in the study were categorized into two groups: those with minor acute ischemic stroke (National Institutes of Health Stroke Scale score=1-4) and those with moderate-to-severe acute ischemic stroke (National Institutes of Health Stroke Scale scores ≥5). RESULTS: Acute ischemic stroke patients with National Institutes of Health Stroke Scale score ≥5 had higher heart rate, QT, corrected QT interval, T-peak to T-end corrected QT interval, cardiac-electrophysiological balance, and cardiac-electrophysiological balance values compared with those with an National Institutes of Health Stroke Scale score of 1-4. The cardiac-electrophysiological balance value was shown to be independently related to National Institutes of Health Stroke Scale scores ≥5 (OR 1.102, 95%CI 1.036-1.172, p<0.001). There was a moderate correlation between cardiac-electrophysiological balance and National Institutes of Health Stroke Scale scores at admission (r=0.333, p<0.001) and discharge (r=0.329, p<0.001). CONCLUSIONS: The findings of this study demonstrated that the cardiac-electrophysiological balance value was related to National Institutes of Health Stroke Scale scores at admission and discharge. Furthermore, an elevated cardiac-electrophysiological balance value was found to be an independent predictor of National Institutes of Health Stroke Scale score ≥5.

Microvolt T-wave alternans complemented with electrophysiologic study for prediction of ventricular tachyarrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy: a long-term follow-up study / 中华医学杂志(英文版)

Background@#The long-term predicted value of microvolt T-wave alternans (MTWA) for ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. Our study explored the characteristics of MTWA and its prognostic value when combined with an electrophysiologic study (EPS) in patients with ARVC.@*Methods@#All patients underwent non-invasive MTWA examination with modified moving average (MMA) analysis and an EPS. A positive event was defined as the first occurrence of sudden cardiac death, documented sustained ventricular tachycardia (VT), ventricular fibrillation, or the administration of appropriate implantable cardioverter defibrillator therapy including shock or antitachycardia pacing.@*Results@#Thirty-five patients with ARVC (age 38.6 ± 11.0 years; 28 males) with preserved left ventricular (LV) function were recruited. The maximal TWA value (MaxValt) was 17.0 (11.0–27.0) μV. Sustained VT was induced in 22 patients by the EPS. During a median follow-up of 99.9 ± 7.7 months, 15 patients had positive clinical events. When inducible VT was combined with the MaxValt, the area under the curve improved from 0.739 to 0.797. The receiver operating characteristic curve showed that a MaxValt of 23.5 μV was the optimal cutoff value to identify positive events. The multivariate Cox regression model for survival showed that MTWA (MaxValt, hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.01–1.11; P = 0.01) and inducible VT (HR, 5.98; 95% CI, 1.33–26.8; P = 0.01) independently predicted positive events in patients with ARVC.@*Conclusions@#MTWA assessment with MMA analysis complemented by an EPS might provide improved prognostic ability in patients with ARVC with preserved LV function during long-term follow-up.

Inadvertently Developed Ventricular Fibrillation during Electrophysiologic Study and Catheter Ablation: Incidence, Cause, and Prognosis

BACKGROUND AND OBJECTIVES: Ventricular fibrillation (VF) can inadvertently occur during electrophysiologic study (EPS) or catheter ablation. We investigated the incidence, cause, and progress of inadvertently developed VF during EPS and catheter ablation. SUBJECTS AND METHODS: We reviewed patients who had developed inadvertent VF during EPS or catheter ablation. Patients who developed VF during programmed ventricular stimulation to induce ventricular tachycardia or VF were excluded. RESULTS: Inadvertent VF developed in 11 patients (46.7+/-9.3 years old) among 2624 patients (0.42%); during catheter ablation for atrial fibrillation (AF) in nine patients, frequent ventricular premature beats (VPBs) in one, and Wolff-Parkinson-White (WPW) syndrome were observed in one. VF was induced after internal cardioversion in six AF patients due to incorrect R-wave synchronization of a direct current shock. Two AF patients showed spontaneous VF induction during isoproterenol infusion while looking for AF triggering foci. The remaining AF patient developed VF after rapid atrial pacing to induce AF, but the catheter was accidentally moved to the right ventricular (RV) apex. A patient with VPB ablation spontaneously developed VF during isoproterenol infusion. The focus of VPB was in the RV outflow tract and successfully ablated. A patient with WPW syndrome developed VF after rapid RV pacing with a cycle length of 240 ms. Single high energy (biphasic 150-200 J) external defibrillation was successful in all patients, except in two, who spontaneously terminated VF. The procedure was uneventfully completed in all patients. At a mean follow-up period of 17.4+/-15.5 months, no patient presented with ventricular arrhythmia. CONCLUSION: Although rare, inadvertent VF can develop during EPS or catheter ablation. Special caution is required to avoid incidental VF during internal cardioversion, especially under isoproterenol infusion.

Catheter ablation of paroxysmal supraventricular tachycardia:a single-center prospective study of 1106 cases / 中国综合临床

Objective To investigate the efficacy and safety of catheter radiofrequency ablation of paroxysmal supraventricular tachycardia.Methods From Jul 2003 to Jan 2011,1106 cases with narrow QRS complex tachycardia who were treated by catheter radiofrequency ablation were recruited from our center and followed up for the rates of successful treatment,rcurrence and complications.Results There were in total 1106 patients (atrioventricular reentrant tachycardia:588 ; atrioventricular nodal reentrant tachycardia:477; atrial tachycardia:41 ),with a sex proportion of 1∶1.Successful ablation rate was 98.3 ％ (1087/1106).Of the 1087 successful ablation cases,43 (3.9％ )were warranted repeated ablation.The recurrent rates for trioventricular nodal reentrant tachycardia,atrioventricular reentrant tachycardia,left accessory pathway and right accessory pathway were 1.5％,5.6％,3.9％,and 9.1％ respectively.Complication rate was 1.5％.The major complications included pheumothorax ( 6 cases ),pulmonary embolism ( 1 case ),transient third-degree atrioventricular block ( 2 cases ),first-degree atrioventricular block ( 3 cases ),and persistent third-degree atrioventricular block(2 cases)with pacemaker implantation.There was one case of cardiogenic sudden death 5 days after the treatment procedure.The cause of his death was chronic stroke-related but not related to the operation procedure.Conclusion Catheter ablation has high efficacy and low complication rate in long-term follow-up,and is a promising treatment for paroxysmal supraventricular tachycardia.

A Case of Delayed Onset Nephrogenic Systemic Fibrosis After Gadolinium Based Contrast Injection

Nephrogenic systemic fibrosis (NSF) is a rare fibrosing disorder of the skin and joints that occurs in patients with advanced renal insufficiency. This condition is progressive and can be seriously disabling. Gadolinium based contrast agent (GBCA) has been identified as a potential cause of this condition. A 56-years-old man in hemodialysis developed stiffness and contracture of the whole limbs eight years after frequent GBCA exposure for cervical magnetic resonance imaging. For the first time in Korea, we report late-onset nephrogenic systemic fibrosis after GBCA exposure and performed an electrophysiologic study of this condition.

A Comparison of Diagnostic Usefulness of Sonography and Electrophysiologic Study in Patients with Carpal Tunnel Syndrome

OBJECTIVE: To compare the diagnostic accuracy of ultrasonography(US) and electrophysiologic study in patients with carpal tunnel syndrome (CTS). METHOD: Two hundred twenty-seven hands in patients and 40 hand in healthy control group were used. Patients were diagnosed clinically with CTS. All groups had nerve conduction study (NCS) and sonographic measurement of the cross-sectional area (CSA) of the median nerve. Using the receiver operating characteristic curve, the optimal cutoff value was obtained and the sensitivity and specificity was evaluated. The correlation between the Hi-Ob score and the electrophysiologic severity, Hi-Ob score and CSA of the median nerve, and between the electrophysiologic severity and CSA were assessed. RESULTS: The cutoff value of the difference of median sensory latency (DMSL) was 1.55 ms with a sensitivity and specificity of 94.7% and 92.3% respectively. The cutoff value of CSA was 9.5 mm2, had a sensitivity of 85.5% and a specificity of 92.3%. In mild CTS, NCS showed a sensitivity of 92.1% and CSA showed a sensitivity of 81.2%. The electrophysiologic severity and Hi-Ob score appeared to show a significant positive correlation (r=0.34, p<0.01), and as the Hi-Ob score increased, the CSA was increased (r=0.54, p<0.01). The increase in electrophysiologic severity and the CSA also showed a significant correlation (r=0.33, p<0.01) There was bifurcation of the nerve in 9 hands, persistent median artery in 4 hands and cyst in 1 hands. And tenosynovitis was observed in 1 hands. CONCLUSION: In clinical CTS, electrophysiologic study showed higher sensitivity than US. But US can give us anatomical informations.

A Case of Functional Bitemporal Hemianopia Respecting the Vertical Meridian

PURPOSE: To report a case of functional bilateral hemianopia which was not associated with any organic causes. CASE SUMMARY: A 35-year-old female patient presented with bilateral disturbance of visual acuity and visual field, which had begun 8 months prior. Goldmann perimetry showed bitemporal hemianopsia respecting the vertical meridian. Pupillary response was normal, and the anterior segment, fundus, and optic nerve were also normal bilaterally. However, the tangent screen test and Humphrey visual field test showed a widening of hemianopia not respecting the vertical meridian, and the crossing of isopters at 1 m and 2 m with the tangent screen test. In addition, multifocal electroretinogram and multifocal visual evoked potential did not reveal any abnormal findings corresponding to the bitemporal hemianopia. Brain magnetic resonance imaging showed no abnormal findings in the orbit and brain. CONCLUSIONS: Bitemporal hemianopsia can be developed functionally, although it may be rare. Repetition of various visual field tests and use of multifocal electrophysiologic studies can be helpful in the differential diagnosis.

Severe Stenosis of the Left Main Coronary Artery Detected on Electrophysiologic Study

A cardiac electrophysiologic study (EPS) is a safe procedure with a low complication rate. We report here a case of severe stenosis of the left main coronary artery (LMCA) that was incidentally detected during an EPS; this was successfully managed by stenting the LMCA. The patient was a 75-year-old man with recurrent chest fluttering and no previous angina underwent EPS and he developed acute ischemic chest pain due to induced atrial fibrillation. The coronary angiography showed a critical stenosis in the distal LMCA. The patient underwent percutaneous coronary intervention with a sirolimus-eluting stent in the LMCA. The patient has remained asymptomatic during a 1-year follow-up period. To prevent potentially catastrophic complications, performing a stress myocardial imaging test should be strongly considered before conducting EPS in elderly patients.

Clinical Characteristics of Hypervagotonic Sinus Node Dysfunction

BACKGROUND: Sinus node dysfunction (SND) is caused not only by intrinsic sinus node disease, but also by the extrinsic factors. Among the extrinsic factors, autonomic imbalance is most common. Symptomatic SND usually requires permanent pacemaker therapy. However, the clinical characteristics and patient response to medical therapy for hypervagotonic SND have not been properly clarified. MATERIALS AND METHODS: Thirty two patients (14 men, 18 women, 51 +/- 14 years) with hypervagotonic SND were included in this study, but those patients who had taken calcium antagonists, beta-blockers or other antiarrhythmic drugs were excluded. Hypervagotonic SND was diagnosed if the abnormal electrophysiologic properties of the sinus node were normalized after the administration of atropine (0.04 mg/kg). RESULTS: The presenting arrhythmias were 16 cases of sinus bradycardia (50.0%), 12 of sinus pause (37.5%), 3 of sinoatrial block (9.4%) and 1 of tachy-bradycardia (3.1%). Nine (28.1%) patients had hypertension, 7 (21.9%) smoked, 2 (6.3%) had diabetes mellitus, and 1 (3.1%) had hypercholesterolemia. Among the patients, 3 had no remarkable symptoms, 13 had dizziness, 7 had syncope, 3 had weakness and 6 had shortness of breath. Twenty five (78.1%) patients were treated with theophylline, 1 patient with tachy-bradycardia syndrome was treated with digoxin and propafenone, and 6 (18.8%) were treated with no medication. During the 43 +/- 28 month follow-up, 25 patients remained asymptomatic, but 6 who took no medication developed mild dizziness. One patient needed permanent pacemaker implantation owing to recurrent syncope despite of theophylline treatment. CONCLUSION: These results show that hypervagotonic SND has a benign course and most of the patients can be managed safely without implanting a pacemaker. (Ed note: I like the abstract. It is short and direct, as it should be.)

Repeated Local Injection of Triamcinolone Acetonide in Carpal Tunnel Syndrome

OBJECTIVE: The effect of the local steroid injection for the carpal tunnel syndrome (CTS) is well known, but there have been a few report of electrophysiologic evaluation for the effect of the local steroid injection. So this study was done to reveal the effect of local injection with triamcinolone acetonide (TA) into the carpal tunnel using the electrophysiologic changes and the improvement in symptoms. METHOD: The triamcinolone acetonide (40 mg/ml) was injected to 43 patients (70 wrists) with the CTS diagnosed clinically and electrophysiologically. And the patients were reevaluated with the visual analogue scale and the electrophysiologic study every month. The mean duration of follow-up was 6 months, and the mean number of the injection was two times. RESULTS: The improvement of symptoms was noted in 90% of the cases, and most of the electrophysiologic parameters revealed significant improvement after the local injection of TA. The number of injection did not correlate with the visual analogue scale and the electrophysiologic parameters. CONCLUSION: The local injection of TA into the carpal tunnel in the patients with CTS may be an effective therapeutic modality to improve the symptoms and the electrophysiologic parameters.

Multiple Cranial Nerve Injury by Single Cervical Stab Wound: A case report

The cranial nerve lesions can occur from a stroke, traumatic brain injury or direct cervical injury, and can produce various functional problems of the craniofacial structures. Usually the cranial nerve injury can be diagnosed by a simple clinical manifestation, and physical or neurological examination. Electrophysiologic study and imaging study such as MRI are frequently used as the sequential follow up studies for the objective evaluation of neurologic regeneration process. We report a case of multiple cranial nerve injuries, of the fifth, seventh, tenth, eleventh and twelfth cranial nerves from a single deep cervical stab wound of 4 cm in length from 0.5 cm anterior of the tragus to 1 cm posterior to the mandibular angle. Electrophysiologic study including an electromyography of tongue and vocal cord, blink reflex and facial nerve conduction study were used for the diagnosis and follow up.

Ambulation of Spina Bifida Patients

OBJECTIVE: To investigate the ambulatory status and its contributing factors in eighty one patients with spina bifida, and to obtain informations about the actual state and the problems of their orthotic uses for the lower limbs. METHOD: Eighty one spina bifida patients above thirty months of age who registered to the Myelomeningocele Clinic of Seoul National University Hospital were investigated through the telephone interviews and the retrospective reviews of the medical records by a physiatrist. RESULTS: About one half of 81 spina bifida patients had problems in their ambulation. It was significantly influenced by the neurological level, the type of spina bifida, the contractures and deformities of the lower limbs, and presence of hydrocephalus. The deformity of hip and the neurological level were revealed to be the most important factors contributing to their state of ambulation by the multiple linear logistic analysis(p<0.01). Forty patients had used the lower limb orthoses of which the ankle-foot-orthosis was most frequently used. The satisfaction and compliance of the patients, however, were not high and the most common complaint of the parents was a skin wound from the use of orthoses. CONCLUSION: The neurological level and the deformity of hip were the two most important contributing factors to the ambulation of the spina bifida patients. Early detection of the neurological level and an adequate prescription of the lower limb orthoses should be stressed for the management of ambulation in spina bifida patients.

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.

Electrophysiologic Study of Spina Bifida Patients

Electrophysiologic study including needle electromyograpy(EMG) was done in 66 patients with spina bifida who were referred to EMG laboratory. We have classified neurological impairments of spina bifida patients according to electrodiagnostic findings and the electrophysiologic study findings were compared with Magnetic Resonance Image(MRI) findings, and manual muscle test findings. Also electrophysiologic study findings were compared with urodynamic study(UDS) finding for the evaluation of neurogenic bladder in the same subjects. 55% of spina bifida patients had cauda equina lesions electrophysiologically and the most commonly involved, root was L5, and the next was S1. 42% of the subjects were normal electrophysiologically. 61% of patients with abnormal MRI findings had normal EMG findings. EMG findings did not correlated well with manual muscle tests in 44% of the subjects. Also in 44% of subjects, the electrophysiologic study was did not agree with urodynamic study findings. In conclusion, we asserts that cauda equina lesion is a most common lesion in spina bifida patients and electrophysiologic study is superior than MRI or manual muscle test in detecting neurologic deficit of spina bifida patients. However, electrophysiologic study alone offers less accurate information than urodynamic study for the evaluation of neurogenic bladder in spina bifida patients.

Electrophysiologic Changes of Tibial Nerve by Low Frequency Stimulation in Peripheral Polyneuropathic Patients

The changes of anterior horn cell excitability and conduction of the nervous system by the electrical stimulation of nerve have been reported in both vivo and vitro studies. Purpose of this study is to observe the neurophysiologic changes of nerves by 10 Hz electrical stimulation on polyneuropathic peripheral nerves. Subjects were 18 diabetic polyneuropathic patients diagnosed by the conduction studies. Electrophysiologic studies were performed in both right and left tibial nerves before and after conditioning of the right tibial nerve. Electrophysiologic studies included five tests which were the sural sensory and tibial motor conduction(abductor hallucis), F response(abductor hallucis), H reflex(gastrosoleus) and somatosensory evoked potential(ankle, SEP). Ten Hz rectangular electrical current was used for the conditioning stimulation. It was applied to the popliteal tibial nerve with the tolerable maximal intensity(10-24 mA) for 5 minutes. Following changes were statistically significant in statistics after the conditioning. Prolongation of F latency (p<0.05), increases of F chronodispersion, duration and area(p<0.05), prolongation of H latency(p<0.05), increase of H amplitude(p<0.05), decrease of P1 latency of SEP(p<0.01) and increase of P1N1 amplitude of SEP(p<0.01) were seen in both conditioned and unconditioned legs. Increase of F wave conduction time(FWCT) and decrease of F wave conduction velocity (FWCV) were seen in conditioned leg(p<0.05). Above findings suggest that certain electrical stimulation of polyneuropathic nerve may cause increase of the anterior horn cell excitability, fascilitation of the SEP conduction and slowness of alpha motor conduction to and from the spinal cord.

Electrophysiologic and morphologic changes of rat peripheral nerves induced by vincristine sulfate

Vincristine has been extensively need in chemotherapy to treat leukemia, lymphoma, and a variety of solid tumor. The major antitumor effect has been known to be associated with its high affinity binding to the basic protein sub unit of microtubule, tubulin, which causes disruption of the mitotic spindle apparatus and arrest of calls in metaphase. The principal side effect that has commonly limited the use of this agent is peripheral sensori-motor neuropathy, a feature probably related to the disruption of microtubule in neural tissues. There has been a need for animal experimental models w study the peripheral neuropathy induced by vincristine. However, it was not easy to develop an adequate model due to reported interspecies difference of susceptibility to vincristine. In addition, electrophysiologic test methods to confirm peripheral neuropathy in small experimental animals has not been properly addressed. The purpose of this experiment is to find out whether rat can be used as an animal experimental model of vincristine neuropathy. The authors also incorporated serial noninvasive electrophysiololgic tests, in attempt to correlate morphologic alterations induced by vincristine and functional status of peripheral nerve and muscle. Experiment Group 1 of 14 rats were given 0. 2mg/kg vincristine sulfate once a week, Group 2 of 14 rats were given same does twice a week and Group 3 of 14 rats were given 0. 4mg/kg intravenously, through tail veins for 6 weeks, to delineate the possible different effects from dosage and frequency of injections. The 14 rats for control were given only normal saline with the same methods. The electrophysiologic tests including motor nerve conduction study, sensory nerve conduction study and cervical somatosensory evoked potential were per formed 2 weeks interval. The morphologic examinations of posterior tibial nerves using light microscope and electron microscope were done 4 weeks interval up to 16 weeks. The H&E, modified Gomori-trichrome and histochemical stain(ATPase & NADH) 1. Vincristine induced peripheral neuropathy was successfully established in rat.. This was confirmed not only by morphologic measurements but also by noninvasive serial electrophysiologic examinations of peripheral nerves. 2. The vincristine neuropathy in rats was sensori-motor type similar to those in human. 3. The motor and sensory conduction velocity of posterior tibial nerve in rats fell significantly at ter 2-4 weeks in the vincristine injected groups A tendency of recovery was noted, but the conduction velocity failed to return to normal level up to 16 weeks follow up study. However, the amplitude of compound muscle action potentials as well as compound nerve action potentials showed a great deal of fluctuation during the genesis of neuropathy. Therefore, these electrophysiologic parameters were not optimal predictors in assessment of functional integrity of given nerves with the electrophysiologic test methods used in this experiments. 4, Morphologic examinations revealed that vincristine neuropathy I rats are clearly these of axonal degeneration, compatible to the findings of electrophysiologic examination. 5. The higher dose of vincristine induced the more damage to the peripheral nerves but it also resulted in high mortality rate. Administration of 0.2mg/kg/week would be adequate in generation of experimental neuropathy. 6. The examinations of gastrocnemius and soleus muscle showed same evidence of mild degree of myopathy but it was felt to be direct toxic effect, rather than secondary changes due to the neuropathy.

A Study on Electrophysiologic Mechanism and Clinical Characteristics of Paroxysmal Supraventricular Tachycardia / 대한내과학회지

OBJECTIVES: Accurate diagnosis of the mechanism and origin site of paroxysmal supraventricular tachycardia(PSVT) can be made using electrophysiologic study(EPS). Recently, radiofrequency catheter ablation technique has been introduced and widely used for the definitive treatment of various forms of PSVT, thereby precise determination of the mechanism of PSVT can be possible. It has been known that atrioventricular reentry tachycardia (AVRT) using concealed bypass tract is more frequent than atrioventricular nodal reentry tachycardia (AVNRT) in Korea. But it is not certain that those studies represent actual distribution of PSVT in Korea. This study was designed to determine the mechanism and clinical characteristics of PSVT in Korea. METHODS: We investigated 136patients in whom electrophysiolosic study was performed from October 1992 through October 1994 at the Chonnam National University Hospital, the only tertiary referral center of the Kwangju-Chonnam area of Korea. RESULTS: 1) The electrophysiologic mechanism of PSVT was AVNRT in 44patients(32.4%), WPW syndrome in 46(33.8%), AVRT using concealed bypass tract in 40(29.4%), sinoatrial nodal reentry tachycardia (SANRT) in 4(2.9%), and automatic atrial tachycardia(AAT) in 2(1.5%), ensuing that AVNRT is most common mechanism of PSVT with no preexcitation during sinus rhythm. 2) Male is more frequent than female in AVNRT, WPW syndrome, and AVRT, which was most prominent in WPW syndrome. 3) The first episode of symptom occured at the age of 34.9 +/- 17.3 years in AVNRT, 25.5 +/- 13.3 years in WPW and 26.3 +/- 15.0 years in AVRT(p<0.05). There was no significant difference in the duration of symptom. The tachycardia rate in WPW syndrome was 183.6 +/- 23.9 per minute and AVRT was 186.7 +/- 38.0 per minute, which were faster than that of AVNRT(161.7 +/- 28.6/min)(p<0.05). 4) There was no significant difference in the presenting symptoms and in the provocation factors between AVNRT and AVRT. CONCLUSION: AVNIlT is most common mechanism of PSVT with no preexcitation during sinus rhythm, developed at older age than WPW syndorme and AVRT, and had lower tachycardia rate than WPW syndrome and AVRT.

Preliminary study on the mechanism of 2:1 atrioventricular block during atrioventricular node reentrant tachycardia / 中国介入心脏病学杂志

Objective The purpose of this study was to clarify the mechanism of 2:1 atrioventricular block (AVB) during AV node reentrant tachycardia (AVNRT) induced during electrophysioloic study.Methods In consecutive patients with AVNRT referred for electrophysiologic study, the data of 2 : 1 AVB during induced AVNRT was retrospectively analysed. Results The data of 4 patients was excluded from analyzing because of the unsatisfactory recording of His bundle potential during AVNRT. A His bundle deflection was present in the blocked beats in three of the remaining 5 patients and absent in the other two. At the beginning of AVNRT induced in those patients whose His bundle deflection was present in the blocked beats, H-V Wenckebach sequence with a QRS pattern of RBBB or LBBB was seen preceding and following the 2 : 1 AVB. A pattern of H-V Wenckebach phenomenon occurred once during AVNRT with 2:1 AVB in one of the two patients whose His bundle deflection was absent in the blocked beats.Conclusion The induced 2:1 AVB during AVNRT is due to functional block in the His-Purkinje system regardless of the presence or absence of a His bundle deflection in blocked beats.

Clinical and Electrophysiologic Characteristics of Idiopathic Sustained Left Ventricular Tachycardia

Ventricular tachycardias(VTs) usually complicate iscemic heart disease. Cardiomyopathy or other organic heart disease and are aften associated with sudden cardiac death. Ventricular tachycardias with no apparent cardiac abnormalities, however, have been known to have different clinical features comprising a unique clinical entity among other tachycardias. Eleven patients(7men, 4 women) were investigated on their clinical features, electrophysiologic studies and late potentials. 1) The mean age at diagnosis was 23.4+/-6.5 years and the predominating clincal features were palpitation, syncope or congestive heart failure. No death occured over a mean follow up period of 29.2+/-26.5 months. 2) The resting ECGs were within normal limits in 8 patients and showed nonspecific ST-T changes in 3 patients. 3) Ventricular pacing induced sustained ventricular tachycardias in 7 patients and nonsustained VT in 1 aptient. Atrial pacing could provoke sustained VTs in 3 patients. 4) His bundle electrograms(HBE) were obtained in 7 patients during tachycardial. The HV intervals of the induced VTs distributed between 0 to -25msec in 5 patients and there was no definite His potentials in two patients. 5) The coupling interval of premature stimuli and the echo interval(the interval from the stimulus to the initiation of resulting VT) showed inverse relationship in 5 cases. No direct relationship was observed. 6) The termination mode, observed in 7 patients, showed delayed ternmination in 2 patients. 7) Late potentials(LPs) were pisitive in three patients but there was no significant statistical difference between LPs in normal control and those with idiopathic sustained left VTs. 8) Verapamil terminated VTs in 8 patients and slowed the rate of tachycardial in 1 patient. In conclusion, idiopathic sustained left ventricular tachycardias occur in younger age group and have more favorable prognosis. The findings of EPS and LPs suggest microreentry or triggered activity as their basic mechanism and verapamil can be used effectively for their termination.