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 Table of Contents  
Year : 2016  |  Volume : 13  |  Issue : 1  |  Page : 76-81

Four years spectrum of ectopic atrial tachycardias following invasive cardiac electrophysiologic studies

1 Department of Medicine, Federal Medical Centre, Umuahia, Nigeria; Department of Cardiac Electrophysiology, Institute of Cardio Vascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu, India
2 Clinical Engineer, Department of Electrophysiology, and Biomedical Engineering, 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 Medicine, Madras Medical Mission, Chennai, Tamil Nadu, India
6 Department of Cardiology, Institute of Cardio Vascular Diseases, Madras Medical Mission, Chennai, Tamil Nadu, India

Date of Web Publication13-Jan-2016

Correspondence Address:
Kelechukwu Uwanuruochi
Department of Medicine, Federal Medical Centre, Umuahia, PMB 7001, Nigeria

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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0189-7969.165169

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Background: Cardiac electrophysiologic study and radiofrequency ablation have become an established mode of treatment for patients with refractory arrhythmias. These procedures are carried out regularly at the cardiac catheterization laboratory of Madras Medical Mission India.
Objective: The purpose of this study was to evaluate our experience with cardiac electrophysiologic studies (EPS) and radiofrequency catheter ablations (RFA) of ectopic atrial tachycardias (AT).
Materials and Methods: This was a retrospective study carried out in the Cardiac Electrophysiology Department, of the Institute of Cardiovascular diseases, Madras Medical Mission, India. All cases diagnosed to have ectopic AT following cardiac EPS between January 2010 and April 2014 were selected for study. The records, which were obtained from the cardiac electrophysiology clinical research office of Madras Medical Mission, were reviewed. 73 cases were chosen for analysis, using SPSS statistical software version 15.
Results: There were 73 patients, comprised 31 males and 42 females. The mean age was 47.38 years. Commonly associated diseases were diabetes mellitus 16 (21.9%), hypertension 14 (19.1%), coronary heart disease 12 (16.5%) and congenital heart disease 8 (11%). The most common locations of AT were coronary sinus Ostial region 7 (14.0%), parahisian region 6 (12.0%) and crista terminaris region 4 (8.0%). Ablation was successful in 43 (84.3%). Complication rate was 4.11%.
Conclusions: Treatment of ectopic AT by RFA is highly effective and safe.

Keywords: 4 years spectrum, ectopic atrial tachycardias, invasive cardiac electrophysiologic studies, madras medical mission

How to cite this article:
Uwanuruochi K, Saravanan S, Ganasekar A, Solomon B, Murugesan R, Shah RA, Krishnamoorthy J, Pandurangi U. Four years spectrum of ectopic atrial tachycardias following invasive cardiac electrophysiologic studies. Nig J Cardiol 2016;13:76-81

How to cite this URL:
Uwanuruochi K, Saravanan S, Ganasekar A, Solomon B, Murugesan R, Shah RA, Krishnamoorthy J, Pandurangi U. Four years spectrum of ectopic atrial tachycardias following invasive cardiac electrophysiologic studies. Nig J Cardiol [serial online] 2016 [cited 2021 Jun 20];13:76-81. Available from: https://www.nigjcardiol.org/text.asp?2016/13/1/76/165169

  Introduction Top

There are three important mechanisms of supraventricular tachycardias (SVTs): Accessory pathway (AP) mediated atrioventricular reentry tachycardia (AVRT), atrioventricular nodal reentry tachycardia (AVNRT) and ectopic atrial tachycardias (AT). Some characteristics aid recognition on electrocardiography.[1] These common SVT usually have a rate ranging between about 100 and 250 bpm. In the typical AVNRT, the QRS are regular, narrow, with RP interval less than PR interval. Occasionally, the P-wave will not be seen, a pseudo R (a retrograde P wave) may be seen in V1, and pseudo S in inferior leads. The more common type of AVRT (orthodromic) has regular, narrow QRS, short RP interval, and retrograde P waves may be seen in inferior leads as well as leads I and V1. Delta wave may be seen with normal sinus rhythm. The AT may show a variable ventricular rate, variable P-shape and polarity [Figure 1] and most common has long RP interval. Multifocal types show different P morphologies unrelated to each other with irregularly RR interval.
Figure 1: Variable P waves and ventricular rate in surface electrocardiogram

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Atrial tachycardias are a SVT that does not require the atrioventricular (AV) junction, APs, or ventricular tissue for its initiation and maintenance. It is usually understood to exclude tachycardias that originate from the Sinus node. Various types of AT have been described.[2] These include Focal AT, Macroreentrant AT (including typical atrial flutter [AFL] and other macroreentrant circuits), atypical AFL, Sinus tachycardias and Fibrillatory conduction. Focal AT is characterized by atrial activation starting rhythmically at a small area (focus) from where it spreads centrifugally. Multiple AT foci have also been well reported in the literature.[3]

Atrial tachycardias can have a right or left atrial origin. Some AT actually originates outside the usual anatomic boundaries of the atria, in areas such as the superior vena cava, pulmonary veins, and vein of Marshall, where fingers of atrial myocardium extend into these locations.

Most commonly reported locations include the crista terminals, near the tricuspid and mitral annulus, within the pulmonary veins, at the ostium of the coronary sinus (CS), and at the para-hisian region.[4]

Atrial tachycardias have been reported to constitute 10–15% of SVT.[5] They may occur at any age although it has been reported more in children and adults with congenital heart disease.[6] Radiofrequency (RF) ablation has become a standard method of therapy with reported high success and low recurrence rate in patients with various types of AT.[7]

Ectopic AT following radiofrequency catheter ablations (RFA) in South-East Asia is under-reported, as most systematic have come from Western nations. In this report, we reviewed cases of focal AT in patients treated at the Cardiac electrophysiology Department of Madras Medical Mission, India, between the years January 2010 and March 2014, with view to describing the burden of focal AT, sites of origin, as well as the initial outcome following RFA.

  Materials and Methods Top

The study was carried out at the Cardiac Electrophysiology department, of the Institute of Cardiovascular diseases, Madras Medical Mission, India. Ethical approval was obtained. We retrospectively studied records of cases of focal AT following cardiac electrophysiologic studies (EPS) carried out from January 2000 to March 2014. In our study, we described the demographic characteristics of the patients, the indication for the procedure and the prevalence of associated cardiovascular morbidity in the patients. We also observed the percentage of cases with recurrent AT following previous RFA and documented the frequency of the various early complications of RFA and the success rate of the procedure. Patients had been chosen for cardiac electrophysiologic assessment if they had recurrent, drug refractory palpitations, recurrent palpitations with preference for ablative therapy over pharmacological, recurrent palpitations is association with syncopal attacks or dyspnea, symptomatic bradycardia, tachycardiomyopathy and recurrent shocks for patients with automatic implantable cardioverter defibrillator device. Two electrophysiologists carried out the RFA.

Access was obtained through the right femoral vein and right femoral artery. Catheters used were Quadripolar 6F for high right atrium, HIs and right ventricular apex, Decapolar 6F for CS and EPT BLAZER II 7F STD CURVE, J and J CORDIS WEBSTER MEDIUM CURVE 7F, COOL FLEX (ST.JUDE), and COOL PATH (ST JUDE IBI) irrigation catheter for the ablator. The tachycardia was induced on programmed atrial and ventricular stimulation or with isuprel infusion and vigorous protocols. AT was diagnosed based on standard criteria.[8]

Support for a diagnosis of AT included a post-ventricular overdrive pacing (VOP) response of V-ventricular depolarization, A-atrial depolarization (V-A-A-V), initiation of tachycardia with atrial depolarization, termination and entrainment of tachycardia by atrial pacing, spontaneous termination that was always without atrial depolarization, ability of VOP to dissociate the ventricle from the tachycardia, presence of intermittent atrioventricular block (AVB), changes in V-V intervals preceded by changes in A-A intervals and presence of variable ventriculo-atrial (VA) intervals during sustained tachycardia or with ventricular pacing. Failure of His-refractory premature ventricular complex (PVC) to advance A, inability of right ventricular pacing to entrain the tachycardia, and absence of the following: VA linking, atrio-hisian jump, VA conduction and eccentric atrial activation sequence were also supportive. Pharmacological interventions with Isoprenaline to induce tachycardia and Adenosine induced AVB to exclude APs were frequently employed.

The AT was localized by catheter mapping for earliest retrograde atrial activation during tachycardia or ventricular pacing. In 37 patients (50.7%) three-dimensional electroanatomical mapping system (ST JUDE ENSITE VELOCITY) was employed. The use of three-dimensional electroanatomical mapping increased from 36.4% in 2010 to 2050% in 2011. After that the average frequency remained the same, being 55.6% in 2012, 54.5 in 2013–2050 in 2014.


Using conventional imaging and EPT ablation catheter few RF energies (standard 50c, 50 watt and 240 s) were delivered at the earliest atrial activation site to terminate the tachycardia. Few more RF energies were also delivered to consolidate the lesion. In cases of AT located in the superior region of right free wall (along the crista terminalis) phrenic nerve injury was first excluded before RF energies were delivered. In 13 patients (17.8%) RF energy by conventional catheter was inadequate, and cool path irrigation tip catheter was used. Post RF ablation, tachycardia inducibility was tested using isuprel.

The data were analyzed using SPSS statistical software version 15 (SPSS, Inc., Chicago, Illinois, USA).

  Results Top

Totally, 73 cases of focal ATs diagnosed following cardiac EPS were reviewed. They consisted of 31 males and 42 females. They had a mean age of 47.38 years (±18.15).

The frequency of associated cardiovascular diseases in the patients studied are diabetes mellitus 16 (21.9%), hypertension 14 (19.1%), coronary heart disease 12 (16.5%), atrial septal defect 3 (4.1%), hypothyroidism 4 (5.5%), Eibstein's anomaly 2 (2.7%), dextrocardia 1 (1.4%), single ventricle 1 (1.4%), hypertrophic cardiomyopathy 3 (4.2%), chronic pericarditis 1 (1.4%), ventricular septal defect 1 (1.4%). Overall, 11% had congenital heart disease.

The distribution of indications for cardiac electrophysiologic assessment in the patients were recurrent, drug refractory palpitations 49 (67.1%), recurrent palpitations 12 (16.5%), recurrent palpitations and syncope 6 (8.2%), recurrent palpitations and dyspnea 3 (4.1%), symptomatic bradycardia 1 (1.4%) tachycardiomyopathy 1 (1.4%), and recurrent shocks 1 (1.4%) in a patient with automatic implantable cardioverter defibrillator device. There were 4 cases of recurrence following previous RFA. The mean duration before repeat RFA in these four was 2.4 years. The tachycardia was described as follows: Regular narrow QRS tachycardia in 44 cases (60.3%), wide QRS tachycardia in 10 (13.7%), irregular narrow QRS tachycardia 6 (8.2%), combinations of regular and irregular QRS tachycardia 4 (5.5%) and not documented in 1 (1.4%). The basic electrophysiologic characteristics of the study group are shown in [Table 1].
Table 1: Basic electrophysiologic characteristics of the study group

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The atrial activation pattern was recorded in 46 cases, being concentric and decremental in 32 (69.6%), eccentric in 1 (2.2%), while VA conduction was absent in 13 (28.3%). EPS findings supportive of AT were documented in respective number of cases as follows: Intermittent AVB (29), VA dissociation during tachycardia {26, [Figure 2], changes in V-V intervals preceded by changes in A-A intervals (21), absent VA linking (6), post-VOP VAAV response [9, [Figure 3], varying A-A interval (5), induction of tachycardia always with A (8), spontaneous termination without A (13), inability of His refractory PVC to advance A (6), termination with atrial overdrive pacing (3), and inability of right ventricular pacing to entrain tachycardia (1).
Figure 2: Ventriculo-atrial dissociation during atrial tachycardias

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Figure 3: Post-ventricular overdrive pacing response of V-ventricular depolarization, A-atrial depolarization

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The location of focal ectopic AT was recorded in 50 cases as shown in [Table 2]. 31 (62%) of these were in the right atrium.
Table 2: Distribution of focal ectopic AT

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Multifocal AT was present in 7 (9.5%) cases, the combination of foci were as follows: CS ostial region and right posteroseptal region near the CS ostium, multiple foci from right atrium, CS os and left upper pulmonary vein, CS os and pulmonary veins, right atrial superoseptal and posteroseptal regions and left atrium, roof of right atrium, right atrial appendage and low right atrium and base of right atrial appendage, superior crista terminalis and anterior tricuspid annulus.

Dual arrhythmias were present in 18 cases (24.7%). The frequency of associated arrhythmias are as follows: Atrial fibrillation (AF) 9 (12.3%), AFL 6 (8.2%), sick sinus syndrome (SSS) 5 (6.8%), ventricular tachycardia 2 (2.8%), AVRT 2 (2.7%) and AVNRT 1 (1.4%). In one case, Mahaim pathway was associated with AT, but there was no tachycardia where Mahaim could be considered as the reentry element. There was one case of familial AT.

Radiofrequency catheter ablations of the ectopic focus was carried out in 49 (67.1%) cases while AVN ablation with permanent pacemaker implantation (PPI) was done in 2 (2.7%) cases, one with associated AF with fast ventricular rate, the other a case of tachycardia-bradycardia SSS. Over the study period, 968 cases of EPS were carried out of which 842 underwent RFA. A total of 51 (6.06%) of these RFA were for patients with focal AT.

Radiofrequency catheter ablations was not considered in the rest due to a variety of reasons: AT was not inducible in a case of paroxysmal AT/AF (2), AT not sustained (4), dilated left atrium and multiple atrial trigger sites (1), AT noted was not the clinical tachycardia (1), associated automaticity, variable earliest activation site and underlying infiltrative hypertrophic cardiomyopathy (1), SSS (tachycardia-bradycardia syndrome) with infra-hisian conduction disease and multifocal AT (1), Associated AFL/AF with fast ventricular rate (2), significant biatrial enlargement (1), associated automaticity with involvement of a large area near the right posteroseptal region (1), lack of a fixed location for earliest “A” (1) and need for three-dimensional electroanatomical mapping system for reasons such as need to isolate pulmonary veins as AT rapidly degenerates to AF, difficulties associated with induction, ectopic focus in the parahisian region and multifocal AT (4).

A-V nodal ablation, followed by PPI was planned for most of these in the event of persistent symptoms and refractoriness to medications.

Radiofrequency catheter ablations was successful in 43 (84.3%) cases while early complications were observed in only 3 (4.11%) patients. One developed cardiac tamponade and emergency pericardiocentesis were done by subxiphoid approach by inserting a 6-F pigtail catheter. Another developed complete heart block. The patient had infra-hisian block at sinus rate >100/min, an indication for permanent pacemaker, but ablation of AT was still considered necessary since there was a chance of prolonged asystole with repeat AT. The patient was shifted to the coronary care unit with temporary pacemaker insertion for subsequent PPI. The third had a high degree A-V block following the ablation, few RF energies delivered in the peri. His bundle region caused prolongation of A-H interval, and the patient underwent successful dual chamber PPI. There was no mortality in this review.

  Discussion Top

This study describes the results of cardiac electropysiologic study and catheter ablation of cases of ectopic AT carried out in the Electrophysiology department of Madras Medical Mission between January 2000 and March 2014. AT was more common in females (63.6%) and the middle-aged. The mean age of 47.4 years in our sample is higher than the figure of 38 years reported by Goldberger et al.[9] This may be explained by late referrals in a center from the developing world. Frequently associated cardiac conditions include diabetes, hypertension, coronary heart disease and congenital heart disease similar to other publications.[9] It is important to observe that coronary heart disease as an association was less frequent than diabetes and hypertension. This is similar to the finding of Chen et al.[7] from Taiwan; of 36 patients with AT 5 had cardiomyopathy, 4 hypertension, 1 coronary artery disease, 1 congenital aortic stenosis, and 1 dextrocardia. This apparent relative reduced association of coronary heart disease in South-East Asian patients with AT would merit further study, but the relatively younger age of patients with AT may be contributory.

The sites of origin of most of the AT (62%) were in the right atrium. Of the 9 cases successfully ablated by Wang et al.,[10] 6 were right-sided and 3 were on the left. Poty et al.,[11] on the other hand, found the vast majority of AT to arise from the right atrium (33 of 36 patients) while the remaining three were from the left atrium.

On the other hand, of 12 patients reported by Walsh et al.,[12] the EAT focus was mapped to the left atrium in seven patients and to the right atrium in five.

These higher numbers of cases reviewed in our report support the assertion that most ectopic AT are right-sided.

It is noteworthy that 6.06% of total ablations in Madras Medical Mission over the study period were for cases of focal AT. This compares with the figure of 4% reported from Germany by Meissner et al.[13] A number of similar studies, however, have much lower figures, such as 1.5% in Nepal reported by Rajbhandari et al.[14] and 0.5% reported by Iturralde-Torres et al.[15] from Mexico.[14] Madras Medical Mission being a quaternary-level referral center for interventional cardiology in India, higher hospital prevalence for conditions requiring complex cardiac interventions would be expected.

The initial success rate was 84.3%. This compares favorably with 80% reported by Goldberger et al.[9] and 86% reported by Poty et al.[11] The complication rate was 4.11%, and there was no mortality in this study. Wang et al.[10] had a rate of 7.7% while Malacký et al.[16] reporting 10 cases, had no complication. The rates in our series are, therefore, comparable to that obtained in other reputable centers worldwide.

It is noteworthy that this is the first systematic report, to the best of our knowledge, of relatively large number of cases of focal AT from the Indian sub-continent. The reported distribution of sites of origin, the contribution of AT to cases requiring ablation, the success and complication rates of AT ablation from our center are thus new contributions to the medical literature.

This study had limitations. The nationality of patients was not included in the data collected and the study being retrospective, gaps in the data recorded could not be filled. Important characteristics including family history of arrhythmias and sudden deaths, blood pressures, body mass index, electrolytes, echocardiographic function indices, renal function indices, details of pharmacological treatments, serum lipid profile were also not part of the data retrieved during data acquisition.

  Conclusions Top

This study shows that AT from various sites responded favorably to RFA with a high success rate and very low incidence of complication.

  Acknowledgement Top

The Medical Director of Federal Medical Centre Umuahia, DrAbali Chuku and the Staff of the Electrophysiology clinical research office of Madras Medical Mission.

  References Top

Colucci RA, Silver MJ, Shubrook J. Common types of supraventricular tachycardia: Diagnosis and management. Am Fam Physician 2010;82:942-52.  Back to cited text no. 1
Saoudi N, Cosío F, Waldo A, Chen SA, Iesaka Y, Lesh M, et al. A classification of atrial flutter and regular atrial tachycardia according to electrophysiological mechanisms and anatomical bases; a Statement from a Joint Expert Group from The Working Group of Arrhythmias of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Eur Heart J 2001;22:1162-82.  Back to cited text no. 2
Kastor JA. Multifocal atrial tachycardia. N Engl J Med 1990;322:1713-7.  Back to cited text no. 3
Ouyang F, Ma J, Ho SY, Bänsch D, Schmidt B, Ernst S, et al. Focal atrial tachycardia originating from the non-coronary aortic sinus: Electrophysiological characteristics and catheter ablation. J Am Coll Cardiol 2006;48:122-31.  Back to cited text no. 4
Steinbeck G, Hoffmann E. 'True' atrial tachycardia. Eur Heart J 1998;19 Suppl E: E10-2, 48.  Back to cited text no. 5
Poutiainen AM, Koistinen MJ, Airaksinen KE, Hartikainen EK, Kettunen RV, Karjalainen JE, et al. Prevalence and natural course of ectopic atrial tachycardia. Eur Heart J 1999;20:694-700.  Back to cited text no. 6
Chen SA, Chiang CE, Yang CJ, Cheng CC, Wu TJ, Wang SP, et al. Sustained atrial tachycardia in adult patients. Electrophysiological characteristics, pharmacological response, possible mechanisms, and effects of radiofrequency ablation. Circulation 1994;90:1262-78.  Back to cited text no. 7
Knight BP, Zivin A, Souza J, Flemming M, Pelosi F, Goyal R, et al. A technique for the rapid diagnosis of atrial tachycardia in the electrophysiology laboratory. J Am Coll Cardiol 1999;33:775-81.  Back to cited text no. 8
Goldberger J, Kall J, Ehlert F, Deal B, Olshansky B, Benson DW, et al. Effectiveness of radiofrequency catheter ablation for treatment of atrial tachycardia. Am J Cardiol 1993;72:787-93.  Back to cited text no. 9
Wang L, Weerasooriya HR, Davis MJ. Radiofrequency catheter ablation of atrial tachycardia. Aust N Z J Med 1995;25:127-32.  Back to cited text no. 10
Poty H, Saoudi N, Haissaguerre M, Daou A, Clementy J, Letac B. Radiofrequency catheter ablation of atrial tachycardias. Am Heart J 1996;131:481-9.  Back to cited text no. 11
Walsh EP, Saul JP, Hulse JE, Rhodes LA, Hordof AJ, Mayer JE, et al. Transcatheter ablation of ectopic atrial tachycardia in young patients using radiofrequency current. Circulation 1992;86:1138-46.  Back to cited text no. 12
Meissner A, Stifoudi I, Weismüller P, Schrage MO, Maagh P, Christ M, et al. Sustained high quality of life in a 5-year long term follow-up after successful ablation for supra-ventricular tachycardia. Results from a large retrospective patient cohort. Int J Med Sci 2009;6:28-36.  Back to cited text no. 13
Rajbhandari S, KC MB, Raut R, Dhungana M, Shaha R, Shahaa KB. Cardiac electrophysiological study and radiofrequency ablation-our experience in Nepal. J Ayurveda Integr Med 2012;01:4-7.  Back to cited text no. 14
Iturralde-Torres P, Colín-Lizalde L, Kershenovich S, González-Hermosillo JA. Radiofrequency ablation in the treatment of tachyarrhythmias. Experience concerning 1,000 consecutive patients. Gac Med Mex 1999;135:559-75.  Back to cited text no. 15
Malacký T, Fenelon G, D'Avila A, Tsakonas K, Andries E, Brugada P. Radiofrequency catheter ablation of atrial tachycardia. Bratisl Lek Listy 1995;96:88-91.  Back to cited text no. 16


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]


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