Catheter ablation of epicardial accessory pathway associated with coronary sinus musculature / 中华心血管病杂志

<p><b>OBJECTIVE</b>To report the single-center clinical experience of catheter ablation of epicardial accessory pathway associated with coronary sinus musculature.</p><p><b>METHODS</b>The data of 721 cases of left sided accessory pathway ablation were retrospectively analyzed. Ablation in the coronary sinus was performed in 17 (2.4 %) cases [11 males, mean age (37 ± 11) years].</p><p><b>RESULTS</b>Among the 17 cases, the accessory pathway was successfully ablated in middle cardiac vein and posterior lateral coronary sinus in 11 and 6 cases, respectively. Deverticulum of middle cardiac vein was seen in 2 cases. Mean time required to block the accessory pathway was (4.7 ± 2.7) s. An accessory pathway potential could be recorded at the target site in 10 out of 17 patients (59%). During a mean (21 ± 16) months follow up, only one patient experienced recurrence who was successfully cured by a second ablation session. No procedure related complication was reported.</p><p><b>CONCLUSION</b>About 2.4% of left accessory pathway may have epicardial connection locating at middle cardiac vein or lateral part of the coronary sinus and require epicardial ablation. The epicardial ablation is safe and effective, warrants an excellent long-term results.</p>

Long-term outcomes and factors for predicting ventricular arrhythmia in patients with catecholaminergic polymorphic ventricular tachycardia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To evaluate factors for predicting ventricular arrhythmia, the clinical effect of drugs on patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), and their long-term outcomes.</p><p><b>METHODS</b>Six patients diagnosed with CPVT underwent a series of electrocardiograms and 24-hour Holter monitoring. β-blockers were recommended for all patients, while some patients were also prescribed propafenone and 1 patient underwent catheter-based renal sympathetic denervation (RDN). The characteristics of electrocardiogram, arrhythmia and long-term outcomes were monitored.</p><p><b>RESULTS</b>Syncope episodes did not occur any longer in 1 patient on β-blocker, but recurred in 3 other patients and 2 patients died (one due to his cessation of metoprolol for 3 months). Inverted and/or bifid T waves and abnormal U wave were observed in the precordial leads. T wave alternans was observed in 4 patients in the precordial leads. These abnormal electrocardiogram features disappeared or diminished with β-blocker treatment. All spontaneous episodes of ventricular tachycardia occurred prior to sinus tachycardia and frequent polymorphic premature ventricular contractions.</p><p><b>CONCLUSIONS</b>Bifid and/or inverted T waves, T wave alternans and abnormal U waves together with sinus tachycardia and frequent premature ventricular contractions are indicator for predicting ventricular arrhythmia and assessing the effect of β-blockers. Compliance with β-blocker treatment is a strong indicator of outcome.</p>

Clinical features of six patients with catecholaminergic polymorphic ventricular tachycardia / 中华心血管病杂志

<p><b>OBJECTIVE</b>To describe the clinical features of 6 patients with catecholaminergic polymorphic ventricular tachycardia.</p><p><b>METHODS</b>Clinical data including signs and symptoms, electrocardiograms, Holter monitoring electrocardiograms and echocardiography was analyzed. Definite diagnosis was made based on the mutations of RYR2 and CASQ2.</p><p><b>RESULTS</b>From July 2002 to March 2010, 6 consecutive patients referred to our center because of syncope [4 males, mean age (13.0 ± 4.2) years] were diagnosed with CPVT by clinical evaluation and genetic testing. Their electrocardiograms showed T waves with notch or bimodal and tall U waves in right chest leads. There was no J wave, no ST-segment deviation, no prolongation or shortening of QT interval. We captured the so-called "bidirectional and(or) polymorphic ventricular tachycardia (bVT and pVT)" in 2 out of 6 patients by ECG, in 5 out of 6 patients by 24-hours Holter monitor, in 3 out of 6 patients by exercise test. All patients received β blockers and no syncope occurred during the 3 months follow-up after discharge from hospital.</p><p><b>CONCLUSIONS</b>CPVT is an inherited cardiac channelopathy characterized by syncope and(or) sudden death relatived to motion. The ECG shows T wave alteration and tall U wave in right chest leads. The mode of its onset is bVT and(or) pVT, and can be captured by Holter easily. β blocker is a safe and effective remedy for suppressing its attack.</p>

Catheter ablation of focal atrial tachycardia:the topographic distribution and long-term outcome / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the topographic distribution and long-term outcome of catheter ablation for focal atrial tachycardia (AT).</p><p><b>METHOD</b>The data of 207 patients who underwent electrophysiologic study for AT were retrospectively analyzed.</p><p><b>RESULTS</b>A total of 200 AT were identified in 185 patients. The most common site for AT was ostium of the coronary sinus (23.8%), followed by crista terminalis (20.5%), perinodal area (20.0%), cava vena (17.8%), annulus (13.0%), and appendage (10.3%). Eighty percent AT originated from the right atrium, 17.8% originated from the left atrium. AT originated from the left atrium was more common in male than in female (25.0% vs. 13.3%, P = 0.042), while AT originated from the right atrium was more common in female than in male (69.4% vs. 86.7%, P = 0.004). Among the 185 patients, acute success ablation rate was 93.5% (n = 173). The acute success rate in the conventional mapping group was lower than that in the three-dimensional mapping group (79.3% vs. 96.5%, P < 0.01). During a median of 36 months follow up, the AT recurred in 20 patients (success ablation rate 88.4%). Success ablation rate was similar between the conventional mapping group and the three-dimensional mapping group (P > 0.05).</p><p><b>CONCLUSIONS</b>Focal AT commonly originates from ostium of coronary sinus, crystal terminalis, perinodal area, and cava veins. There is a gender related difference in the distribution of focal AT. The radiofrequency catheter ablation yields a satisfying success rate and very low complication rate and could be the first line choice for treating ATs in experienced electrophysiological center.</p>

Impact of metoprolol use in the treatment of patients with electrical-storm after cardioverter defibrillators implantation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the effectiveness of the metoprolol dosage adjustment on reducing the incidence of electrical-storm (ES) in patients with Implantable Cardioverter Defibrillators (ICDs).</p><p><b>METHODS</b>Data from patients with ICD implantation between Jan, 2003 and Jun, 2006 in our hospital were retrospectively analyzed. ES was defined as either ≥ 3 times of ventricular tachyarrhythmias (VTAs) resulting in ICD therapy or VTAs lasting more than 30 s detected by ICD without any therapy within 24 hours.</p><p><b>RESULTS</b>During a follow-up period of (27.5 ± 21.2) months, ES was recorded in 39 cases [34 males, average age (52.0 ± 13.1) years] out of 119 patients (32.8%) and 9 patients died after ES. During the period of storm attack, ES was successfully controlled in 25/30 patients by various interventions, including predisposing factors corrected in 5 cases, ICD reprogramming and antiarrhythmic drugs therapy optimized in 16 cases (one received intravenous injection of metoprolol), and VTAs eliminated by catheter ablation in 4 cases. ES was spontaneously resolved in the remaining 5 cases. In the chronic phase, 2 patients with Brugada syndrome were treated with Quinidine mono-therapy while the dosage of metoprolol was adjusted in the remaining 23 patients and the dosage of metoprolol was increased gradually from (26.8 ± 13.9) mg/d to (88.9 ± 53.5) mg/d without any adverse effects (9 patients received also oral amiodarone 200 mg/d). Post dosage adjustment, the total VTA episodes [(1.9 ± 1.7) times/month vs. (0.8 ± 0.6) times/month, P = 0.004], incidence of antitachycardia pacing therapies [(4.2 ± 3.8) runs/month vs. (2.3 ± 2.0) runs/month, P = 0.003], as well as electrical cardioversion or defibrillation [(1.1 ± 0.9) times/month vs. (0.4 ± 0.2) times/month, P = 0.001] were significantly decreased. ES was not controlled until a extremely high dosage [225 - 300 (255.3 ± 41.7) mg/d] of metoprolol was reached in the remaining 5 patients.</p><p><b>CONCLUSIONS</b>Metoprolol use is essential and its dosage should be individualized in the majority of ICD recipients with ES. In approximately 1/6 patients, the dosage of metoprolol should be higher than 200 mg/d.</p>

Clinical characteristics of congenital ventricular aneurysm and diverticula in inland China / 中华心血管病杂志

<p><b>OBJECTIVE</b>To summarize the clinical characteristics of congenital ventricular aneurysm and diverticula in inland China.</p><p><b>METHODS</b>To identify the literature of congenital aneurysm and diverticula from Wanfang, China National Knowledge Infrastructure (CNKI) and PubMed databases, and to analyze the clinical characteristics of congenital aneurysm and diverticula from January of 2001 to December of 2009.</p><p><b>RESULTS</b>A total of 116 patients [78 men, 1 - 80 (33.5 ± 21.3) years old] with congenital aneurysm or diverticula were included in 109 articles. Twenty-five patients (13 men) were congenital ventricular aneurysm, including a family of 4 patients. Ninety-one patients (65 men) were congenital ventricular diverticula. One hundred patients were detected by echocardiography during medical examination, 34 patients combined with other cardiac anomalies, 4 of which with extracardiac structures. There were 8 patients with ventricular arrhythmia, 8 patients with thrombosis, 2 patients died of cardiac rupture, 4 patients died of sudden death, surgical operation was performed in 46 patients and 3 patients received ablation procedure. All patient did not receive implantable cardioverter defibrillator (ICD) implantation.</p><p><b>CONCLUSIONS</b>Congenital ventricular aneurysm or diverticulum is a rare cardiac malformation. Most congenital left ventricular aneurysms and diverticula are asymptomatic and detected by echocardiography. Congenital ventricular aneurysm or diverticulum may cause ventricular tachycardia, ventricular wall rupture, systemic embolization or sudden death, which had to be treated individually.</p>

Prevalence of Epsilon wave in patients with arrhythmogenic right ventricular cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of Epsilon wave in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).</p><p><b>METHODS</b>The epsilon wave was detected in 32 patients [24 men, mean age (42.3 +/- 13.3) years] with ARVC using three different electrocardiography (ECG) recording methods: standard twelve leads ECG (S-ECG), right precordial leads ECG (R-ECG) and Fontaine bipolar precordial leads ECG (F-ECG). The Epsilon wave was defined as wiggler, small spike wave and smooth potential between the end of the QRS complex and the beginning of the ST segment.</p><p><b>RESULTS</b>Epsilon wave was detected in 37.5%, 37.5% and 50.0% patients with ARVC by S-ECG, R-ECG and F-ECG respectively. The detection rates derived from the three recording methods were similar (P > 0.05). The Epsilon wave was only detectable by S-ECG in one case, by R-ECG in three cases, and by F-ECG in five cases. The detection rate of Epsilon wave was 50.0% by combined use of S-ECG and R-ECG (SR-ECG), 56.3% by combined use of S-ECG and F-ECG (SF-ECG), and 65.6% by combined use of the three recording methods (SRF-ECG). The detection rate was significantly higher by SF-ECG (56.3%) and SRF-ECG (65.6%) than by S-ECG alone (37.5%, all P < 0.05). Most Epsilon waves detected by the S-ECG, R-ECG and F-ECG were small spiked waves.</p><p><b>CONCLUSION</b>Combined use of S-ECG, F-ECG and R-ECG could increase the detection rate of Epsilon wave in patients with ARVC.</p>

Detection of gene mutations of SCN5A in 7 patients with Brugada syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>Brugada syndrome is linked to sodium channel mutations and could induce arrhythmias that even lead to sudden death. The purpose of this study was to detect if there was gene mutation of SCN5A in 7 patients with Brugada syndrome and explore the molecular genetic characteristics of this disease.</p><p><b>METHOD</b>Genomic DNA was extracted from peripheral blood of all 7 patients with Brugada syndrome and 41 pairs of PCR primers were designed to amplify all the 28 exons of SCN5A.</p><p><b>RESULT</b>There was no novel mutation in exons of Gene SCN5A in these patients with Brugada syndrome.</p><p><b>CONCLUSION</b>Brugada syndrome might associated gene mutation or other mechanisms independent of SCN5A gene mutation.</p>

Cardiac troponin I gene mutation (Asp127Tyr) in a Chinese patient with hypertrophic cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the disease-causing gene mutation in Chinese patients with hypertrophic cardiomyopathy and to analyze the correlation between the genotype and the phenotype.</p><p><b>METHODS</b>Specimens of peripheral blood were collected and the genome DNA was extracted in 65 unrelated patients with hypertrophic cardiomyopathy and 60 normal controls. The exon 7 and 8 of cardiac troponin I gene were screened with PCR and direct sequencing technique.</p><p><b>RESULTS</b>A missense mutation in the exon 7 of the cardiac troponin I gene was identified in a 40-year-old male patient with hypertrophic cardiomyopathy (Asp127Tyr) which was absent in the controls.</p><p><b>CONCLUSION</b>A novel missense mutation of cardiac troponin I was identified in a patient with hypertrophic cardiomyopathy, this mutation might be the disease-causing gene mutation in this Chinese patient.</p>

Electrophysiological findings and ablation strategies in patients with atrial tachyarrhythmias after left atrial circumferential ablation in the treatment of atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To report the electrophysiological findings and the ablation strategies in patients with atrial tachyarrhythmias (ATAs) or atrial fibrillation (AF) recurrence after left atrial circumferential ablation (LACA) in the treatment of AF.</p><p><b>METHODS</b>91 patients with AF had LACA procedure from April 2004 to May 2006, 19 of which accepted the second ablation procedure due to ATAs or AF recurrence. In all the 19 patients [17 male, 2 female, age 25 - 65 (53 +/- 12) years], 11 presented with paroxysmal AF before the first ablation procedure, 2 with persistent AF and 6 with permanent AF. Pulmonary vein potentials (PVP) were investigated in both sides in all the patients.</p><p><b>RESULTS</b>Delayed PVP was identified inside the left circular line in 5 patients, in the right in 1 and both in 2 during sinus rhythm. "Gap" conduction was found and successfully closed guided by circular mapping catheter. In 3 cases, irregular left atrial tachycardia was caused by fibrillation rhythm inside the left ring via decremental "gap" conduction. Reisolation was done successfully again guided by 3-D mapping and made the left atrium in sinus rhythm but the fibrillation rhythm was still inside the left ring. Pulmonary vein tachycardia with 1:1 conduction to the left atrium presented in one case and reisolation stopped the tachycardia. No PVP was discovered in both sides in 4 patients but other tachycardias could be induced, including two right atrial scar related tachycardias, two supraventricular tachycardias mediated by concealed accessory pathway, one cavo-tricuspid isthmus dependent atrial flutter and one focal atrial tachycardia near the coronary sinus ostium. All the tachycardias in these 4 patients were successfully ablated with the help of routine and 3-D mapping techniques. In the rest 3, which were in AF rhythm, LACA was successfully done again. After a mean follow-up of 4 - 26 (11.5 +/- 8.5) months, 16 patients were symptom free without anti-arrhythmic drug therapy; 1 of them had frequent palpitation attack with Holter recording of atrial premature contractions; 2 of them with permanent AF became paroxysmal in one, and still in AF in the other.</p><p><b>CONCLUSIONS</b>Reconduction between the left atrium and the pulmonary veins is the dominant factor for post-LACA ATAs and AF recurrence. Other forms of atrial tachycardias or supraventricular tachycardias may coexist with AF or sometimes trigger AF. LACA can not sufficiently modify AF substrate in some permanent AF patients.</p>

Tpeak-Tend interval and risk of cardiac events in patients with Brugada syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the possible association between Tpeak-Tend (Tp-e) interval in surface standard ECG and cardiac events in patients with Brugada syndrome (BrS).</p><p><b>METHOD</b>Tp-e interval in surface standard ECG was compared between BrS patients (n = 23, all males) and paroxysmal supraventricular tachycardia (PSVT) patients (n = 20, all males) as well as between BrS patients with (n = 16) or without (n = 7) cardiac events.</p><p><b>RESULTS</b>There was significant difference in Tp-e interval between BrS patients and PSVT patients [(109.57 +/- 22.86) ms vs. (88.50 +/- 13.08) ms, P < 0.05]. Tp-e interval was also significantly longer in BrS patients with cardiac events (syncope, clinical ventricular fibrillation and induced VF during electrophysiological study) than BrS patients without cardiac events [(118.12 +/- 20.40) ms vs. (90.00 +/- 15.27) ms, P < 0.05] while Tp-e interval was similar between BrS patients without cardiac events and PSVT patients (P > 0.05).</p><p><b>CONCLUSION</b>The prolongation of Tp-e (> or = 120 ms) was associated with higher cardiac events in BrS patients.</p>

Time distribution of ventricular arrhythmias in patients with Brugada syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study the characterization of time distribution of ventricular arrhythmias in patients with Brugada syndrome (BrS) using Holter monitoring and ICD follow-up.</p><p><b>METHODS</b>Patients with BrS [all male, mean age (41.07 +/- 11.49) years], were divided into ventricular fibrillation (VF) group (n = 7) and no ventricular fibrillation (N-VF) group (n = 7). Premature ventricular capture (PVC) and VF episodes were detected by Holter monitoring and ICD recording.</p><p><b>RESULTS</b>The 24 hours total number of PVCs ranged from 0 to 74 (mean 9.61 +/- 17.23) in most of the patients and were similar between VF group and N-VF group. The percentage of PVC episodes in VF group was significantly higher than that in N-VF group from nocturnal time to early morning (22:00 to 7:00, 98.67% vs. 44.14%, P < 0.01). There were total 75 VF episodes during (23.18 +/- 17.96) months' follow-up in 5 patients with BrS, 93.3% of which occurred from nocturnal time to early morning (22:00 to 7:00).</p><p><b>CONCLUSIONS</b>The episodes of PVC were enriched from nocturnal time to early morning in BrS patients, this time distribution could be a new noninvasive risk stratification factor for BrS. The episodes of VF in BrS patients were also enriched from nocturnal time to early morning and this time characteristic of episodes of VF could be used to guide drug therapy.</p>

Left atrium linear lesion encircling pulmonary veins guided by EnSite-NavX and double-Lasso technique for paroxysmal atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy of left atrium linear lesion encircling pulmonary veins (PV) guided by EnSite-NavX and double-Lasso technique for paroxysmal atrial fibrillation (PAF).</p><p><b>METHODS</b>Twenty-two patients (male 19, mean age of 48.5 years +/- 11.4 years) with symptomatic PAF were enrolled. After a geometry of the left atrium was reconstructed by EnSite-NavX system, PV ostia were marked on the map based on venography. Two Lasso catheters were placed within the ipsilateral superior and inferior PVs. Irrigated radiofrequency energy was applied at 0.5-1.0 cm of distance from the PV ostia. Continuous linear lesion was done to obtain the disappearance of pulmonary vein potentials. Patients were on propafenone and perindopril for three months after the procedure.</p><p><b>RESULTS</b>The endpoint for ablation was reached in 21 Patients and 1 patient was not successful because of cardiac tamponade. The mean procedure time was 6.6 h +/- 1.3 h and the mean X-ray exposure time was 56.1 min +/- 18.0 min. After a mean 5.3 months +/- 2.7 months of follow-up, 10 patients were free of symptoms. Two patients had no PAF recurrence after the second procedure. Three patients had clinical recurrence of PAF in the first month. The total success rate in this study was 81% (17/21). Mortality was 0% and the overall complication rate was about 9% (2/22).</p><p><b>CONCLUSION</b>Left atrium circumferential linear ablation surrounding PV ostia guided by EnSite-NavX and double-Lasso technique is effective in PAF, but some patients will need more than one procedure in order to achieve a success.</p>

Clinical efficacy of endoscopic epicardial microwave ablation for isolated atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To assess the efficacy of endoscopic epicardial microwave ablation, a new completely endoscopic technique, for isolated atrial fibrillation (AF).</p><p><b>METHODS</b>From July to October of 2004, 5 patients with isolated permanent AF underwent this procedure. We performed epicardial microwave ablation using FLEX10 probe under the guide of VasoView 5 endoscope. The probe was placed around left and right pulmonary vein orifices, the microwave application was set 65 W/90 s, and a continuous ablation line was obtained encircling the pulmonary veins. Echocardiography and electrocardiography were carried out in all patients before and after operation.</p><p><b>RESULTS</b>Five patients received electrical conversion after ablation. Average ablation time was 35.0 min and average procedure time was 2.5 h without any procedure-related complications. At the 3-month, 6-month and 12-month follow-up, 4 patients (80%) were in sinus rhythm, associated with a reduced left atrial diameter and an improved cardiac function.</p><p><b>CONCLUSION</b>Endoscopic epicardial microwave ablation for isolated atrial fibrillation appears to be safe and effective.</p>

The electrophysiological study and implantable cardioverter defibrillator therapy for the patients with Brugada syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>Clinical observation of electrophysiological study and implantable cardioverter defibrillator (ICD) therapy in patients with Brugada syndrome.</p><p><b>METHODS</b>Ten patients (all male) with Brugada wave (spontaneous or propafenone test positive in ECG) underwent electrophysiological study (EPS). The mean age was (41 +/- 10) years. They had no structural heart disease with echocardiogram and the angiogram work-up. The ICD implanted in the patients with EPS-induced ventricular fibrillation in those who were available.</p><p><b>RESULTS</b>Three patients had the history of familial sudden cardiac death (SCD). Four patients had repeated syncope episodes, two of them had documented ventricular fibrillation during syncope episodes. The AH and HV intervals were 50 - 124 (86 +/- 21) ms and 41 - 84 (58 +/- 15) ms. The ventricular fibrillation was induced in four patients with syncope and atrioventricular reentry tachycardia in one patient with palpitation. Three patients had spontaneous or inducible atrial fibrillation. The ICD implanted in three patients with inducible ventricular fibrillation. Due to economic issue, one patient without ICD implantation had got SCD during follow-up. The patient with atrioventricular reentry tachycardia underwent a successful left atrioventricular accessory pathway ablation.</p><p><b>CONCLUSION</b>The Brugada patients with syncope and high rate of inducible ventricular fibrillation in EPS are the high risk population for SCD, in whom ICD should implant promptly to prevent SCD.</p>

Application of dynamic substrate mapping in ablation of ventricular tachycardias in arrhythmogenic right ventricular cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study the application of abnormal electrophysiological substrate mapping for guiding ablation of ventricular tachycardias in arrhythmogenic right ventricular cardiomyopathy (ARVC-VTs) using a non-contact mapping system.</p><p><b>METHODS</b>Dynamic substrate mapping was performed in three male ARVC patients during sinus rhythm. The sites of the earliest activation, exit point and activation sequence were mapped for each induced VT.</p><p><b>RESULTS</b>Three different patterns of substrates were determined in 3 patients, which located in right ventricular outflow tract, anterior right ventricular wall, and anterolateral right ventricular wall, respectively. Five different clinical VTs [mean CL (348 +/- 65) ms] were induced. Of 5 VTs, three were originated from substrate or boundary of substrate, and two had a remote origin. One VT conducted through the substrate. Linear ablations were created between the sites of the earliest ventricular activation and the VT exit point, or across the critical isthmus. The five clinical VTs were successfully ablated. There were no VT recurrences during 20 months of follow-up.</p><p><b>CONCLUSIONS</b>Defining the abnormal electrophysiologic VT substrates is useful for understanding the mechanisms of ARVC-VTs and determining an ablation strategy. Linear ablation across a critical isthmus or between the earliest activation and the exit point can effectively cure these arrhythmias.</p>

Adenosine-5'-triphosphate test for the noninvasive diagnosis of AV nodal dual pathways(AVNDP) and assessment of results of slow pathway ablation in patients with AV nodal reentrant tachycardia / 中国临床药理学与治疗学

Aim To assess the value of the administration of adenosine-5'-triphosphate (ATP) during sinus rhythm for noninvasive diagnosis of AV node dual pathways(AVNDP) and abolition or modification of the slow pathway (SP) after radiofrequency(RFCA) in patients with inducible sustained AVNRT. Methods Incremental doses of ATP were intravenously administrated during sinus rhythm to patients with spontaneous or inducible sustained AVNRT(study group, n=45)and to patients with no evidence of AVNDP or inducible AVNRT (control group, n=37) until ECG signs of AVNDP( 50 ms increase or decrease in P-R interval in two consecutive beats, or occurrence of AVNRT) or second-degree AV block were observed. Results Four patients (two in study patients and two in control patients) could not complete the trial and were excluded from analysis. AVNDP was observed by ATP in 36(84%) study patients, whereas it was diagnosed by electrophysiology criteria in 38(88%) patients. AVNDP was observed only in 1(3%) control patient. AVNDP by ATP test was disappeared in 18(90%) of 20 patients who underwent SP abolition and in 3(38%) of 8 patients who underwent SP modification. Conclusion ATP test during sinus rhythm enables noninvasive diagnosis of AVNDP in a high percentage of patients with inducible AVNRT and reliably confirms the results of RFCA of the SP.