|Year : 2014 | Volume
| Issue : 2 | Page : 87-90
Review of outcome of radiofrequency cardiac catheter ablations carried out at Madras Medical Mission, India
Kelechukwu Uwanuruochi1, Sabari Saravanan2, Anita Ganasekar3, Benjamin Solomon4, Ravikumar Murugesan4, Jaishankar Krishnamoorthy5, Ulhas M Pandurangi5
1 Department of Medicine, Federal Medical Centre, Umuahia, Nigeria; Department of Cardiac Electrophysiology, Institute of Cardio-Vascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu
2 St. Jude Medical, Chennai, Tamil Nadu, India
3 Department of Cardiac Electrophysiology, Institute of Cardio-Vascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu, India
4 Department of Laboratory Technology, Institute of Cardio-Vascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu, India
5 Department of Cardiology, Institute of Cardio-Vascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu, India
|Date of Web Publication||16-Mar-2015|
Department of Medicine, Federal Medical Centre, Umuahia, PMB 7001, Nigeria
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Context: Radiofrequency ablation (RFA) is a recognised mode of therapy for cardiac arrhythmias. The procedure is carried our regularly at the Cardiac Catheterization Laboratory of Madras Medical Mission, India.
Aim: To evaluate the intermediate term follow-up results of radiofrequency catheter ablations.
Subjects and Methods: This was a retrospective study carried out in the Cardiac Electrophysiology Department of the Institute of Cardiovascular Diseases, Madras Medical Mission (MMM), India.
Records of consecutive cardiac electrophysiologic studies carried out between January and October 2009, together with records of follow-up to March 2014 for those that underwent RFAs were reviewed. In total, the records of 139 cases that had RFAs were analysed.
Results: The 139 patients comprised of 65 males and 74 females. The indication for RFA was drug refractory arrhythmias in the vast majority (137 patients). There was a very high success rate (97.1%), following cardiac ablations. Early complications were observed in only 3 (2.2%) patients. Recurrence rate of the indication for RFA was very low (1.43%), and there was no mortality associated with the procedure.
Conclusions: The treatment of patients with cardiac arrhythmias using RFA, was associated with a high rate of success, and low rate of complications.
Keywords: Madras Medical Mission, outcome, radiofrequency ablation
|How to cite this article:|
Uwanuruochi K, Saravanan S, Ganasekar A, Solomon B, Murugesan R, Krishnamoorthy J, Pandurangi UM. Review of outcome of radiofrequency cardiac catheter ablations carried out at Madras Medical Mission, India. Ann Nigerian Med 2014;8:87-90
|How to cite this URL:|
Uwanuruochi K, Saravanan S, Ganasekar A, Solomon B, Murugesan R, Krishnamoorthy J, Pandurangi UM. Review of outcome of radiofrequency cardiac catheter ablations carried out at Madras Medical Mission, India. Ann Nigerian Med [serial online] 2014 [cited 2021 May 6];8:87-90. Available from: https://www.anmjournal.com/text.asp?2014/8/2/87/153360
| Introduction|| |
Intra-cardiac catheter ablation techniques for treatment of cardiac arrhythmias in humans were first reported in 1982 by Gallagher et al.  Initially, direct energy was used, but later the use of radiofrequency energy was introduced.  It has since then become a standard modality of treatment in cases of symptomatic supraventricular tachycardia, and the modality of choice for patients with various drug refractory arrhythmias. 
From modest beginning in 1988, the number of centres having electrophysiology setup in India has increased from about 10 in 1997, to 30 in 2001, and to about 126 in 2011. ,
However, cardiac electrophysiology, as well as its benefits have not been widely appreciated in Sub-Saharan Africa. Furthermore, the increasing prevalence of cardiovascular disease driven by socio-economic factors implies that more patients will develop cardiac arrhythmias. There is a need for physicians to appreciate the vast benefit of the procedure, while also knowing the associated risks of the procedure. In this study, we therefore sought to evaluate the intermediate term follow-up results of radiofrequency catheter ablations of patients seen at the Cardiac Electrophysiology Department in Madras Medical Mission, Chennai, India.
| Subjects and Methods|| |
We retrospectively studied the records of consecutive ablations carried out between January and October 2009, and studied the follow-up records of these patients up to March, 2014. We described the demographic characteristics of the patients treated by radiofrequency ablation (RFA), the indications for the procedure, and the prevalence of associated cardiovascular morbidities in the patients. We also observed the percentage of cases needing repeat RFAs and documented the frequency of the various early complications of radiofrequency. Finally, we described the success rate of the procedure.
The study was carried out at the Cardiac Electrophysiology Department of the Institute of Cardiovascular Diseases, Madras Medical Mission, India. The study was done under two supervising cardiac electrophysiologists. The data collected from all 139 cases that had RFAs were analyzed using Statistical Package for the Social Sciences statistical software version 15 (SPSS, Inc. Chicago Illinois).
| Results|| |
Description of study population
One hundred and thirty-nine cases of consecutive RFAs were reviewed. They had a mean age of 44.98 years (±15.86) and consisted of 65 males and 74 females. The frequency of associated co-morbid conditions in the patients studied are diabetes mellitus 12 (8.57%), hypertension 13 (9.28%), coronary heart disease 13 (9.28%), atrial septal defect 2 (1.43%), dilated cardiomyopathy 4 (2.86%), valvular heart disease 2 (1.43%), hypothyroidism 2 (1.43%), mitral valve prolapse 1 (0.7%), rheumatic heart disease 1 (0.7%), and interstitial lung disease with cor pulmonale 1 (0.7%).
Indication for ablations
The indications for RFA were drug refractory arrhythmias in 137 cases, patient preference following one episode of palpitations in one case, and unsuccessful anti-tachycardia pacing conversion while on automatic implantable cardioverter defibrillator in another case. Prior to invasive electrophysiologic studies, 31 (22.3%) had no documented tachycardia, 88 (63.3%) had narrow QRS tachycardia, 12 (8.6%) had wide QRS tachycardia, 2 (1.4%) had multiple narrow QRS tachycardia, 1 (0.7%) patient had atrial flutter with fast ventricular rate, while another patient (0.7%) had persistent atrial tachycardia (AT).
The distribution of electrophysiologic diagnoses is described in [Table 1], with the distribution by gender in [Table 2]. Four patients had dual pathways; of which, one had typical atrio-ventricular nodal reentrant tachycardia (AVNRT) and paroxysmal atrial flutter/atrial fibrillation (AF), two had typical AVNRT and orthodromic accessory pathways, while, one had sick sinus syndrome (SSS) with AT. The locations of the accessory pathways are shown in [Table 3]. Four patients had multiple accessory pathways. Two had right mid-septal and right free wall, one had right postero-septal with right free wall, and one had left free wall with left postero-septal pathway.
In 121 of the ablations cases, single radiofrequency energy (60°C, 50 Watts, 120 s) was used. In the remaining patients, higher energy of up to 120 s was applied. Catheters used were quadripolar 6Fr for the high right atrium, his bundle, and the right ventricular apex; and EPT Blazer II, 7Fr (Boston Scientific Corporation) as the ablator. The mean fluoroscopy time was 16.91 min ± 10.55 min. Three-dimensional electro anatomical mapping was used in two of the cases, one a case of recurrent ventricular tachycardia (VT), and the other a case of recurrent nonsustained AT. For the pathways involving left lateral and postero-septal pathways, the mitral annulus was mapped, and the pathway ablated by trans-aortic approach, and this was done in 15 cases. In 10 cases, where signals were not satisfactory, or the pathway was not abolished, the trans-septal approach was used. The left atrium was also mapped by trans-aortic approach for a case of AT arising from the left atrium. The end-point of the procedure was noninduscibility of tachycardia following the stimulation protocol; when ablation was considered successful. In cases of AVNRT, the slow pathway was defined to be modified post-RFA if tachycardia could not be induced, but A-H jump and/or echo were present.
Immediate success rate
A total of 136 (97.9%) patients had successful ablations. In patients with AVNRT, the pathway was completely ablated in 48 (61.5%), but modified in 29 (37.2%). In two cases, RFA was unsuccessful; while the procedure was suspended in one in whom profound vasovagal syncope developed; and where it was decided to abandon the procedure for pacemaker implantation with redo RFA at a later date.
Early complications were observed in only 3 (2.14%) patients. One had cardiac tamponade during trans-septal approach, but was stabilized hemodynamically after pericardiocentesis. Another developed complete heart block following slow pathway ablation for AVNRT, and was implanted the next day with a permanent pacemaker; while the other had presyncope, which led to the procedure being deferred. There was no mortality associated with the procedure.
Patients' data at follow up were reviewed. Seventy-three (52.5%) of the patients' follow-up data were available. Of these who kept up with a follow-up, only 12.3% (nine patients) reported having palpitations. The mean interval between RFA and the last clinic attendance was 44.6 months (±15.44). The earliest follow-up visit was at 7 months, while the longest was at 77 months after RFA. Electrocardiogram at follow-up was available for review in 61 patients. Fifty of these (82.0%) had normal sinus rhythm. Preexcitation was seen in 3 (2.1%), and premature ventricular complexes in two patients (1.4%). AF, varying atrio-ventricular block, low atrial rhythm, paroxysmal supraventricular tachycardia, and VT were all reported each in one case (0.7%). RFA was repeated in three patients, in 2 (1.43%) because of recurrence of refractory palpitations, and in one because the initial procedure was unsuccessful.
| Discussion|| |
There have been a number of reports of cardiac arrthymias in Nigerian patients. ,,,,, A few studies have also reported cases of fatal cardiac arrhythmias in Nigerian subjects. , However, cases of drug-refractory and life-threatening arrhythmias are probably under-reported because of the lack of diagnostic facilities and incompetence at cardiac resuscitation in most centers. It has been appreciated that many of the cases of sudden cardiac death are most-probably arising from lethal arrhythmias.  The prevalence of these drug-refractory arrhythmias is also expected to increase in line with the increase in noncommunicable diseases driven by epidemiologic transition.
This study describes the results of catheter ablation therapy carried out in the Electrophysiology Department of Madras Medical Mission between January and October 2009, for cases of drug-refractory or life-threatening cardiac arrythmias. AVNRT was more common in females (58.97%), whereas orthodromic accessory pathway was more frequent in males (54.76%). Similarly, Teo et al. from Singapore  report having 67.7% of patients with accessory pathways as being males, while Udyavar et al. in another study from the same center  found that 54.2% of their patients with AVNRT were males. In line with the previous report from the same center, this study also shows that AVNRT is the most common arrhythmia requiring catheter ablation in adults.
Ablation was done in two cases of SSS. One had associated paroxysmal AF with fast ventricular rate, and was subjected to empirical pulmonary vein isolation. The second had persistent AT associated with episodes of paroxysmal flutter/fibrillation, and had a permanent VVIR pacemaker. In view of the AT and episodes of flutter/fibrillation, and after taking consent from the patient and relatives, atrio-ventricular nodal ablation was performed; and a prophylactic flutter line for typical atrial flutter was also drawn with radiofrequency energy. The pacemaker was then upgraded to atrial arrhythmia suppressing-DDDR mode-switching pacemaker.
There are explanations for the apparently few cases of atrial flutter. One patient with atrial flutter/AF also had AVNRT, and was included under dual pathways. Two other cases with atrial flutter also had features of SSS, under which they were grouped. Two other cases were not subjected to RFA, and therefore excluded; one had hypertrophic cardiomyopathy, while tachycardia was not inducible in the other.
There was a very high success rate (97.9%), and very low recurrence (1.43%) and complication rates (2.14%); with no mortality reported in this study. This compares favorably with success rates from centers in other parts of the world, ,,, ranging from 85% to 95% for accessory pathway ablation, and 96% for AVNRT.
The implications of this study are apparent. It is important that there must be increased awareness in the benefits of radiofrequency catheter ablations. It is also needful that emergency room physicians be trained to diagnose life-threatening arrhythmias, and on how to use of emergency drugs to manage arrhythmias; which give time for the definitive intervention of RFA, for which such refractory cases should be referred appropriately. In the same vein, there is need for increased interest among cardiologists for training in cardiac electrophysiology.
A limitation of this study is that a large number of patients were lost to follow-up, most likely being followed up in other centers from where they were referred from for the ablations. The sample size is relatively small, and the retrospective nature made it difficult to fill up missing data, including body weight, height, and the names and duration of use of anti-arrhythmic drugs, prior to RFA.
| Acknowledgment|| |
The Medical Director of Federal Medical Centre Umuahia, Dr Abali Chuku and the Staff of the Electrophysiology clinical research office of Madras Medical Mission.
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[Table 1], [Table 2], [Table 3]