Reversibility of tachycardiomyopathy after successful radiofrequency catheter ablation: intermediate results.

Left ventricular function in patients with tachycardia induced cardiomypopathy can improve after cessation of the arrhythmia. We reported the intermediate results of 10 patients, 6 men and 4 women, with tachycardiomyopathy who successfully underwent radiofrequency catheter ablation (RFCA) for incessant tachycardia. Three had right atrial tachycardia, 5 ventricular tachycardia (2 and 3 from the right and left ventricles, respectively), 1 atrial flutter and 1 right accessory pathway. During the mean follow-up period of 19 months (range 11-38 months), one patient, right atrial tachycardia, had recurrence and reablation was successfully done without recurrence. Left ventricular ejection fraction, endsystolic and diastolic diameters from echocardiography gradually improved from 35 per cent, 51 and 61 mm to 58 per cent, 36 and 52 mm, respectively (p<0.001). The mean duration of reversibility was 7 months (range 1-15 months). There was no recurrence of tachycardiomyopathy after the return of left ventricular function. Conclusion, RFCA can terminate tachyarrhythmia and lead to significant improvement of left ventricular diameters and systolic function in patients with tachycardia induced cardiomyopathy.

Radiofrequency catheter ablation of Wolff-Parkinson-White syndrome: report of 83 cases from Siriraj Hospital.

We described the characteristics of patients and accessory pathway and showed our results of Radiofrequency catheter ablation (RFCA). There were 41 males and 42 females at a mean age of 36 years. Accessory pathway associated with Wolff-Parkinson-White (WPW) syndrome in our population was more prevalent on the right side which is different from previous reports. Most commonly associated heart disease was Ebstein's anomaly. Overall success rate was 96.4 per cent. Right free wall accessory pathway needed a longer procedure time and fluoroscopy time, higher radiofrequency power and more radiofrequency applications compared to other locations. Although the recurrence rate was 12 per cent, all patients with recurrence were successfully reablated. We also described the comparison of our result with previous studies. To our knowledge this is the first report in Thailand with a reasonable number of cases. RFCA is a very effective treatment of WPW syndrome in the Thai population and should be considered in symptomatic patients especially those who are refractory to medication.

Radiofrequency catheter ablation in pediatrics: experience at Siriraj Hospital.

UNLABELLED: Tachyarrhythmia is one of the life threatening cardiac electrophysiology problems in children. It also affects quality of life of the patients. Radiofrequency catheter ablation (RFCA) has made a significant impact in the treatment of tachyarrhythmia since 1989. The present report is the first and largest report in Thai children. There have been 24 RFCA procedures in 21 children since it was initially performed at Siriraj Hospital from January 1996 to December 1999. The electrophysiology studies and medical records were analyzed retrospectively. Median age and weight at the time of the procedure were 11 (1.1-13) years old and 38.8 (6.8-78.2) kg respectively. The presenting symptoms were palpitation 66.7 per cent, presyncope 16.7 per cent, congestive heart failure and cardiogenic shock 8.3 per cent, syncope 4.2 per cent, and chest pain 4.2 per cent. Median duration of symptom was 3.5 (0.1-8.0) years. The underlying cardiac arrhythmias were Wolff Parkinson White (WPW) syndrome 50 per cent, concealed accessory pathway 16.7 per cent, atrioventricular node re-entry tachycardia (AVNRT) 16.7 per cent, atrial ectopic tachycardia (AET) 12.5 per cent, and WPW with AVNRT 4.2 per cent. The median fluoroscopy time and procedure time were 25 (4-145) minutes and 125 (60-320) minutes respectively. The median tachycardia cycle length was 332.5 (220-460) seconds. The immediate success rate was 21/24 (87.5%) procedures. The procedural complication was 1/24 (4.2%). Two patients (8.3%) had recurrences of tachycardia and were successfully controlled with antiarrhythmic drugs. CONCLUSION: RFCA is a safe, effective, and curative procedure with high success rate for pediatric tachyarrhythmias.

Comparison of supraventricular tachycardia from concealed bypass tract and Wolff-Parkinson-White syndrome.

Supraventricular tachycardia (SVT) is a common problem. There are 2 types of accessory atrioventricular pathway (AP) causing SVT: one can conduct antegradely (WPW syndrome) and another can conduct only in a retrograde direction (concealed bypass tract or CBT). There are little data of the significance and difference of the two types in Thailand. The objectives of this study were to compare characteristics of patients, accessory pathways and outcome of radiofrequency catheter ablation (RFCA) between the 2 types of accessory pathways. We reviewed the electrophysiology report of patients with supraventricular tachycardia from the accessory pathway who were referred for RFCA. There were 74 males and 74 females at a mean age of 37 years. CBT accounts for 44 per cent of SVT from AP. Compared to CBT, WPW syndrome was more in the right-sided location, more associated with heart disease, a higher number of accessory pathways, more inducible atrial fibrillation and more difficult to do ablation. However, the overall success rate of RFCA was similar. Although the recurrence rate was 8.4 per cent, all patients with recurrence were successfully reablated. We concluded from this study that RFCA is a highly effective method for the treatment for both forms of accessory pathway although there are some differences between WPW syndrome and CBT.

Effect of atenolol on symptomatic ventricular arrhythmia without structural heart disease.

Ventricular arrhythmia (VA) from right ventricular outflow tract (RVOT) is a common problem. Symptomatic patients are usually treated with beta-blockers. There is little data on the systematic evaluation of the drug efficacy. The objectives of this study were 1) To determine proportion of exercise induced ventricular arrhythmia among patients with symptomatic ventricular arrhythmia and 2) to determine the response to beta blockers and the correlation between the response to betablockers and exercise induced VA. We prospectively studied 46 consecutive patients with symptomatic ventricular arrhythmia. Patients recorded their symptom scores underwent exercise testing and 24-hour ambulatory monitoring before treatment and 1 month after atenolol. Exercise induced ventricular arrhythmia was demonstrated in 28 per cent of patients with symptomatic ventricular arrhythmia. Atenolol improves symptoms, decreases PVC count from ambulatory monitoring, increases exercise duration and suppresses malignant form of VA during exercise. These effects are at a similar extent in both groups of patients: those with and without exercise induced VA. However, the effect on ventricular arrhythmia suppression during exercise of atenolol was seen only in patients with increased PVC during exercise. In conclusion, atenolol is a good option in treating patients with symptomatic VA from RVOT regardless of the pattern of PVC response to exercise. Atenolol can suppress PVC during exercise testing better in patients with exercise induced VA compared to those without.

Reliability of Thai version of SF-36 questionnaire for the evaluation of quality of life in cardiac patients.

Quality of life is an important measurement of medical outcomes. Reliability of a Thai version of the SF-36 questionnaire has never been reported. The objective of this study was to determine the reliability of a Thai version of the SF-36 questionnaire in cardiac patients. We developed a Thai version of the SF-36 questionnaire and tested it in 212 cardiac patients. Reliability of the Thai version of the SF-36 questionnaire was assessed by internal consistency using Cronbach's Alpha statistic and inter-item correlation. We demonstrated that Cronbach's Alpha coefficient of every aspect of QOL exceeded 0.7, and all inter-item correlation exceeded 0.4. In conclusion, the Thai version of the SF-36 questionnaire is a valuable tool in assessing medical outcomes and medical research in Thai patients with cardiac disease. Whether it can be used in other diseases remains unknown.

The use of nonfluoroscopic catheter-based mapping system to perform radiofrequency ablation in complex ventricular tachycardia after cardiac surgery in congenital heart disease: a case report.

A nonfluoroscopic electroanatomical cardiac mapping system (CARTO) integrates anatomical and electrophysiological information to reconstruct a three-dimensional activation map. Information from the CARTO system helps to reveal the mechanism and perform successful ablation in scar re-entry ventricular tachycardia after cardiac surgery. Three-dimensional activation and propagation mapping was performed in a patient with ventricular tachycardia after surgical correction of a double outlet right ventricle. The ventricular tachycardia appeared in two morphologies and were refractory to antiarrhythmic medication including amiodarone. Both ventricular tachycardias were re-entered using the ventriculotomy scar but rotated in different directions. Successful radiofrequency ablation was performed by creating a line of conduction block from the pulmonic valve to the ventriculotomy scar using entrainment mapping and the ablation lesion tagging technique. The CARTO system is useful in mapping and guiding the ablation of complex ventricular tachycardia after surgical correction in congenital heart disease

Biosense mapping for ablation of ventricular tachycardia in cardiomyopathy.

Using conventional technology, radiofrequency ablation of ventricular tachycardia in cardiomyopathy is frequently unsuccessful because of hemodynamic instability, multiple foci and recurrences. The Biosense CARTO nonfluoroscopic mapping and navigation system, when used to locate the area of the scar or reentry circuit, has the potential to improve the successful ablation, and reduce the rate of recurrence. We report 2 cases here of ventricular tachycardia in cardiomyopathy in which Biosense mapping was useful to identify the area of scar in 1 case, and the area of microreentry circuits in another. Radiofrequency ablation was possible and successful, while the use of conventional mapping was impossible or had recurrence.

Myocardial injury after radiofrequency catheter ablation.

Radiofrequency catheter ablation has been a good treatment option for various types of cardiac arrhythmia. However there is concern about myocardial injury associated with radiofrequency catheter ablation. We studied myocardial injury with biochemical markers and echocardiogram in 41 consecutive patients who underwent electrophysiology study (EP study) and radiofrequency catheter ablation (RFCA) at our institute from April to July 2000. The concentration of biochemical markers (CK-MB mass, troponin T and myoglobin) and result of the echocardiograms were analyzed with other characteristics. In 41 patients subjected to EP study with possible RFCA, abnormal levels of troponin T, CK-MB mass and myoglobin were found in 46 per cent, 15 per cent and 44 per cent immediately after procedure, which went up to 64 per cent, 22 per cent and 2 per cent at twenty four hours. Compare to the group with normal troponin T level, the patients with abnormal level at 24 hours after RFCA had a longer procedure time (119+/-44 min. vs 90+/-22 min.), more frequent use of impedance ablation catheters (65% vs 27%), more RF applications (9+/-8 vs 18+/-16) and more ventricular ablation sites (69% vs 9%). The echocardiogram results showed no remarkable abnormality in any patients. Troponin T was the most sensitive marker to detect thermal myocardial injury associated with radiofrequency catheter ablation. Prolonged procedure time, RF applications, the use of impedance ablation catheter and ventricular ablation site were associated with elevated troponin T concentration after RFCA.

Radiofrequency catheter ablation: 5 years experience at Siriraj Hospital.

Between February 1995 to May 2000, 626 consecutive patients underwent radiofrequency catheter ablation for various types of cardiac arrhythmia. The mean age was 41 years, range 1-85 years. Mapping and ablation were guided by intracardiac electrogram and anatomical approaches. The initial success, compliction, recurrent and final success rates are shown below:- [table; see text] Conclusion, RFCA is an effective treatment and should be considered as first line treatment for certain tachyarrhythmia.

Quality of life of cardiac arrhythmia patients after radiofrequency catheter ablation.

UNLABELLED: Radiofrequency catheter ablation (RFCA) has been used to treat cardiac arrhythmias in Thailand since 1992. The effect of this procedure on quality of life has not been systematically studied. The purpose of this study was to assess the impact of RFCA on quality of life in patients with cardiac arrhythmias. Data were collected by interviewing 30 patients from February 1998 to August 1998, before and two months after RFCA. The questionnaire used for this study was created by researchers using Zhan's conceptual framework and SF36 in 4 dimensions--life satisfaction, self-concept and psycho-social well being, health functioning and physical well being, socio-economic and social well being. The questionnaire was validated by experts. Its reliability was tested by using Cronbach's test that gave an alpha coefficient of 0.81. Our study showed that the overall quality of life scores 2 months after RFCA (mean = 179.467, SD = 17.005) were higher than before RFCA (mean = 131.567, SD = 18.680). The results also showed a statistically significant difference (p = 0.000). CONCLUSION: It was found that RFCA significantly improved the quality of life of patients with various cardiac arrhythmias. However, this study consisted of a small sample size. Further work in this area with a large sample size is needed to confirm this finding.

Improved detection of radiofrequency current-induced minor myocardial injury by cardiac troponin T measurement.

Transcatheter radiofrequency current application in patients with cardiac arrhythmias was reported to be associated with a low rate of an increase in the activity of enzyme creatine kinase (CK) and CK-MB isoenzyme. As the novel heart-specific protein troponin T (cTnT) was shown to be superior to CK and CK-MB in detecting small damage to myocardial tissue in various clinical situations including unstable angina, a comparison of the diagnostic efficiency of these marker proteins to detect myocardial damage was made in 34 patients (mean age 38.3 +/- 15.6 years) undergoing radiofrequency (RF) catheter ablation of accessory pathways (n = 17) and atrioventricular nodal reentrant tachycardia (n = 17). Serial measurements of total CK and CK-MB activity before and every 8 hours for 24 hours after ablative procedure were performed with enzymatic and immunoinhibition method, respectively, using automated chemical analyzer Hitachi 717. Serum concentration of cTnT was determined by one-step sandwich ELISA performed on ES 300 analyzer (Boehringer Mannheim). With a median of 7.0 (range 1-39) RF current pulses only 12 (35%) and 10 (29%) of 34 patients showed an increase above the upper limit of normal CK and CK-MB activity, respectively. The peak activity of CK (mean peak = 285.8 +/- 517.7 IU/L) occurred at a variable time that infrequently coincided with those of peak CK-MB activity (23.1 +/- 8.0 IU/L). By contrast, all except 4 (88%) of 34 patients exhibited a distinct elevation of cTnT concentration (mean peak = 0.56 +/- 0.63 ng/ml), with almost all (33) of these 34 patients showed an early peak value at 8 hours postprocedural. There was, on the average, a small but distinct higher relative increase (5.6 times) in cTnT concentration from the upper limit of reference range compared with those of CK (1.5 times) and CK-MB peak activity (0.9 time). In conclusion, cTnT exhibited a minor but distinct elevation in its concentration and demonstrated a higher rate and magnitude of increase following radiofrequency current application than the conventional CK and CK-MB isoenzyme. Measurements of cTnT serum concentration may thus provide a useful test method for assessing the effect of the new transcatheter ablation procedures on myocardial tissue.

Radiofrequency catheter ablation for frequent premature ventricular contractions: a preliminary report of 15 cases.

Between February 1995 and March 1997, 15 patients, 13 women and 2 men, underwent radiofrequency catheter ablation (RFCA) for symptomatic frequent premature ventricular contractions (PVC's). The mean age was 43.3 +/- 11.9 years. Thirteen patients (86.7%) had right PVC's and the remainder had both right and left PVC's. RFCA were done under local anesthesia, using both earliest endocardial activation time and pace mapping in complement. The immediate success rate was 14/15 (93%) with only minor complications in 2 patients (13.3%). The fluoroscopic and procedure times were 40.6 +/- 24.0 and 170.7 +/- 81.2 minutes, respectively. From the Holter monitoring, total PVC count, per cent of PVC per total heart beat in 24 hours and couplets count were significantly reduced, (more than 90%, p < 0.05), by RFCA. Triplets and repetitive ventricular tachycardia were totally abolished. During the follow-up period of 10.1 +/- 7.5 months, 2 patients (14.3%) had recurrences of right PVC's within 2 weeks after ablation. Reablation was successfully done in both patients without recurrence, giving the final success rate of 93 per cent. In conclusion, RFCA could be safely performed with a high success rate in patients with symptomatic frequent PVC's. It can be considered an alternative treatment in patients resistant to medical therapy.

Radiofrequency catheter ablation in symptomatic ventricular arrhythmia.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is an effective method to cure both supraventricular and ventricular arrhythmia (VA) in certain centres. AIM: To assess the results of RFCA in VA at Siriraj Hospital. METHOD: Electrophysiologic study, mapping, using both earliest endocardial activation and pace mapping, and ablation were performed. RESULTS: Thirty patients with symptomatic VA underwent RFCA. The mean age was 44 years. Eight patients had underlying heart disease (two prolapsed mitral valve, three myocarditis, two dilated cardiomyopathy and one mitral stenosis). Thirty-six morphologies of VA were detected from the study. Thirty-three morphologic tachycardias attempted were successfully ablated; 17, 10 and six were right VT, left VT and premature ventricular contraction (PVC), respectively. Failure of ablation occurred in one patient with left VT. Only minor complications occurred in this study. There was no difference in cycle length and endocardial activation time between right and left VT. 12/12 identical pace mapping was more easily performed in right VT than in left VT. The fluoroscopic and procedure times in left VT were significantly longer than in right VT. Relapse occurred in six patients. Re-ablation was successfully performed in four patients, giving a final success rate of 93%. CONCLUSION: RFCA is an effective treatment and should be considered as an alternative method to cure VT and refractory PVC.

Radiofrequency catheter ablation in type I atrial flutter: preliminary experience of 10 cases.

Common atrial flutter results from macroreentry in the right atrium. Catheter ablation of slow conduction, between tricuspid annulus and inferior vena cava (TA-IVC) or tricuspid annulus and coronary sinus ostium (TA-CS os) has been reported to terminate and prevent recurrence of this arrhythmia. We reported 10 consecutive patients, 7 men and 3 women, who underwent radiofrequency catheter ablation of common atrial flutter. The mean age was 59.4 +/- 11.2 years (range 42-82 years). During the paroxysmal atrial flutter, all patients had palpitation, 4 had dyspnea on exertion, 3 patients had syncope and 1 patient had presyncope. The mean duration of symptoms was 5.7 +/- 4.9 years (range 0.5-13 years). Two patients had dilated cardiomyopathy, 1 Ebstein's anomaly and 1 chronic obstructive pulmonary disease. Four patients (40%) had history of atrial fibrillation (AF) before ablation. The mean cycle length of atrial rhythm was 257.2 +/- 36.6 ms. Ablation was done by anatomical approach and could terminate arrhythmia in 9 patients (90%), 7 from TA-IVC, 2 from TA-CS os without major complication. The mean number of applications was 20.4 +/- 16.9 and turned atrial flutter to normal sinus rhythm in 13.5 +/- 10.7 seconds. Fluoroscopic and procedure times were 38.4 +/- 31.4 and 157.2 +/- 68.8 minutes, respectively. During the follow-up period of 24.0 +/- 28.7 weeks, 2 patients had recurrent atrial arrhythmia, 1 atrial fibrillation and 1 atrial flutter type I, giving the final success rate of 70 per cent. All patients who had recurrence or failure had a history of paroxysmal AF before ablation. In conclusion, radiofrequency catheter ablation in atrial flutter type I, using anatomical approach, is an effective treatment to terminate and prevent this arrhythmia in short term follow-up. It may be considered as an alternative treatment in patients with atrial flutter who were refractory to antiarrhythmic agents.

Successful implantation of transvenous automatic implantable cardioverter defibrillator (AICD): the first case report in Thailand.

We successfully implanted transvenously the AICD in a case of sudden cardiac arrest survivor. Though the device is very expensive, it is useful in some selected cases. With its diagnostic capabilities, the device may be useful in elucidating the underlying mechanism of Lai Tai.

Radiofrequency catheter ablation in monomorphic ventricular tachycardia.

Twenty patients with symptomatic monomorphic ventricular tachycardia (VT) underwent radiofrequency (RF) energy catheter ablation. Four patients (20%) had underlying heart disease (1 prolapse mitral valve, 1 dilated cardiomyopathy and 2 myocarditis). Five patients (25%) had left sided VT and right sided VT in the remainder (75%). Radiofrequency catheter ablation was initially successful in all patients without major complication. Recurrence occurred in three patients (15%). In conclusion, RF ablation is an effective treatment for symptomatic monomorphic right and left sided VT especially in patients who do not want long term antiarrhythmic agents.

Resolution of dilated cardiomyopathy after radio-frequency catheter ablation of atrial tachycardia.

The dilated cardiomyopathies are characterized by an increase in left ventricular internal dimensions without an appropriate increase in ventricular wall thickness. Sustained tachyarrhythmia, either supraventricular or ventricular, may be associated with this condition and may improve after termination of the tachycardia. We report a case of secondary dilated cardiomyopathy caused by incessant atrial tachycardia who underwent successful radiofrequency catheter ablation and left ventricle returned to normal size and function in six months post ablation.

Radiofrequency catheter ablation in idiopathic ventricular tachycardia with structurally normal heart.

In conclusion, we reported two cases of idiopathic right and left VT who presented with syncope and palpitation. The surface QRS during VT and electrophysiologic studies showed the site of origin at RVOT in the first case and inferoapical area of left ventricle in the other. RF ablation was an effective treatment in both patients without any serious complication. Both of them are free of symptoms without any medication.