Author + information
- Received June 11, 1997
- Revision received September 7, 1998
- Accepted October 22, 1998
- Published online February 1, 1999.
- Parvin C Dorostkar, MD, FACCa,b,†,
- Michael J Silka, MD, FACCa,b,†,
- Fred Morady, MD, FACCa,b,† and
- Macdonald Dick II, MD, FACCa,b,†,* ()
- ↵*Reprint requests and correspondence: Dr. Macdonald Dick II, F1310 Box 0204, C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, Michigan 48109-0204
The purpose of this study is to review the clinical course of persistent junctional reciprocating tachycardia (PJRT) in 21 patients spanning a wide age range to examine the electrophysiologic characteristics of the conduction system in these patients with PJRT, particularly in regards to its incessant nature and to evaluate the long-term response to radiofrequency ablation.
Persistent junctional reciprocating tachycardia is uncommon, occurring in 1% of patients with supraventricular tachycardia. Its presentation, course and treatment are incompletely characterized.
The clinical, electrocardiographic, electrophysiologic and echocardiographic data of 21 patients with PJRT were reviewed.
In 9 of these 21 patients, the mean tachycardia cycle length increased significantly (p < 0.0001) as the patients grew, from a mean tachycardia cycle length of 308 ± 64 ms in the patients less than 2 years, 414 ± 57 ms in the patients between 2 years and 5 years, to 445 ± 57 ms in the patients greater than 5 years, primarily due to slowing of retrograde conduction in the accessory pathway. Persistent junctional reciprocating tachycardia was associated with impaired ventricular function in 11, improving spontaneously in 4 and, after successful ablation of the accessory pathway, in 7. All patients except one were uncontrolled on one or more medications. Ablation of the accessory pathway was successful in 19 of 21 patients.
We conclude that PJRT is characterized by an onset in early childhood and by an age-related prolongation of the tachycardia cycle length mediated primarily through conduction delay in the concealed, retrogradely conducting accessory pathway. Ablation of the accessory pathway provides definitive treatment for PJRT.
Persistent or permanent junctional reciprocating tachycardia (PJRT), originally described by Coumel et al. in 1967 (1)is an infrequent form of reentrant supraventricular tachycardia (1% of patients presenting with supraventricular tachycardia to the Pediatric Arrhythmia Clinic at the University of Michigan). Tachycardia is virtually incessant, at a rate ranging from 120 to 250 beats/minute. The electrocardiogram inscribes inverted P waves in leads II, III, AVF, as well as left lateral leads, along with a P-R interval shorter than the R-P interval during the tachycardia. The characteristic, but not diagnostic, electrocardiographic feature is a long R-P interval consistent with slow retrograde conduction (Fig. 1)(2–6). During the tachycardia, the cardiac impulse conducts anterogradely through the atrioventricular node and His-Purkinje system, returning retrogradely through the slowly conducting accessory pathway that is usually, but not always, near the ostium of the coronary sinus (7). Since the advent of radiofrequency ablation (RFA), several reports have emphasized the usefulness of radiofrequency ablation or surgery for the treatment of PJRT (7–10). The purpose of this study is threefold: first, to review the clinical course of PJRT in a group of 21 patients across a wide age range collected from two centers; second, to examine the electrophysiologic characteristics of the conduction system in patients with PJRT, particularly in regards to its incessant nature; and, third, to evaluate the long-term response to radiofrequency ablation.
The clinical, electrocardiographic, electrophysiologic, and echocardiographic data of 21 patients with PJRT seen at 2 institutions between 1989 and 1995 were reviewed. Electrophysiologic criteria for the diagnosis of PJRT include the presence of a long R-P interval, narrow complex tachycardia, transient interruption of PJRT by programmed stimulation with resumption of tachycardia after one or a few sinus beats, either advancement or delay (or termination of PJRT without an atrial capture) of the atrial electrogram with identical atrial activation sequence during PJRT by a ventricular extrastimulus when the His bundle is refractory, atrial activation sequence during ventricular pacing identical to the pattern during tachycardia and, finally, no anterograde conduction (unidirectional block) through the accessory pathway, but intact, slow, decremental retrograde conduction through the accessory pathway (11).
Electrocardiograms (ECG) were reviewed and the R-R, P-R (defined as the onset of the P wave to the Q or R wave in the QRS complex), and R-P intervals (calculated as the difference between the R-R interval and the R-P interval) were measured. Serial ECG’s were available from 9 patients presenting within the first 2 years of life. The intervals from these serial ECG’s were then plotted as a function of the patient’s age. Serial echocardiograms were reviewed and the patients’ shortening fraction, ejection fraction, E-point sepal separation and associated valvar regurgitation were measured. Decreased ventricular function was defined by a shortening fraction of less than 0.30 and/or left ventricular ejection fraction of less than 0.50 and presence of E-point septal separation.
Informed consent for electrophysiologic (EP) study (n = 21) and radiofrequency ablation (n = 20) was obtained from all patients/parents who underwent electrophysiologic study (median age of 12.8 years; mean 17.1 years, range 3.7 to 83.6 years). The indications for EP study included determination of the mechanism of the arrhythmia (n = 21), drug testing (n = 3) and impaired ventricular function (n = 6, transient in 4 of these). With the advent of transcatheter treatment of arrhythmias, persistent tachycardia in all (except #14 when on amiodarone therapy) led to the recommendation of radiofrequency ablation. Medications were discontinued at least 5 half-lives prior to electrophysiologic study except in the one patient taking amiodarone (#14). Electrophysiologic study was performed as previously described (11,12). The retrograde effective and functional refractory periods were measured using extrastimulation coupled to either the ventricular depolarization during the tachycardia or the drive cycle length during ventricular pacing. In addition the ventricular pacing rate at which retrograde block occurred during rapid ventricular pacing was determined. Retrograde properties of the accessory pathway were distinguished from those of the His-Purkinje atrioventricular node system by recording and measuring at the mapped site of the pathway distant from the recordings in the His bundle region.
One 15-year-old boy was treated by intraoperative cryoablation prior to the advent of radiofrequency ablation. Radiofrequency energy was delivered to ablate the accessory pathway supporting the tachycardia in the other 20 patients.
Figures 1–3⇓⇓suggested that the electrocardiographic intervals increased with age. Therefore, the electrocardiographic intervals (R-R, P-R, R-P in msec) from the 9 patients who presented before age 2 years were classified by patient age into 3 groups (≤2 years, >2 ≤ 5 years, and >5 years). The grouped data were then expressed as the mean and 1 standard deviation and compared by an analysis of variance with Bonferroni correction (Statview v4.57 Abacus Concepts, Inc. 1992–1996). To examine for possible differences in retrograde and antegrade conduction times among the 7 patients in whom data were available, the means and the standard deviations of these 2 parameters were computed and compared by an analysis of variance (Statview v4.57 Abacus Concepts, Inc. 1992–1996). Finally, to examine for possible differences in retrograde conduction between our patients with either incessant tachycardia (n = 19) and paroxysmal tachycardia (n = 3), the mean cycle length and retrograde conduction intervals along with their standard deviations were computed and compared by a nonparametric t-test (Microsoft Excel v7.0a, Microsoft Corp. 1995). A p value ≤0.05 was taken to denote statistical significance.
The demographic and electrocardiographic data are summarized in Table 1. Twenty-one patients at two centers met electrocardiographic and electrophysiologic criteria for PJRT. There was an equal distribution between male and female. Ten patients presented at birth and one at 6 months of age, all with incessant tachycardia. By 5 years of age, (during Holter examination on no medication) one patient (#11) demonstrated only rare beats and brief nonsustained runs of PJRT; during isoproterenol infusion at electrophysiologic study at age 12 years, his tachycardia became constant. The remaining 10 patients presented from 4.4 years to 83 years of age; prior duration of PJRT was unknown. Two of these patients (#10 and #18) demonstrated persistent tachycardia when first seen 1 (#10) to 10 (#18) years prior to ablation; #18 had received antiarrhythmic medication intermittently without discernible effect. Both patients required isoproterenol infusion during the electrophysiologic study to render the tachycardia persistent. The 4 oldest patients presented with decreased exercise tolerance or syncope. All patients, except for 2, had been treated with more than one medication to control the tachycardia (Table 2). The tachycardia persisted despite multiple antiarrhythmic medications except one who was treated with amiodarone (#14). Tachycardia was eliminated in 19 of 21 patients (radiofrequency ablation in 18 and cryoablation at surgery in 1). Ventricular function improved in all patients who had prior evidence of decreased function. Follow up ranged from 2.9 to 8 years; all 21 patients are alive, including the 2 with unsuccessful ablation of the pathway.
Nine patients had serial ECG data available; all 9 of these patients had the tachycardia since birth. In this group the mean PJRT cycle length increased with age, resulting in a slower tachycardia rate (Fig. 2)at older ages. The mean tachycardia cycle length increased significantly (p < 0.0001) as the patients developed, resulting in a mean tachycardia cycle length of 308 ± 64 ms in the patients less than 2 years of age, 414 ± 57 ms in the patients between 2 years and 5 years, and 445 ± 57 ms in the patients greater than 5 years of age. This tachycardia slowing resulted from significant (p < 0.0001) increases in both the P-R interval and the R-P interval between the youngest group and both of the older age groups (Fig. 3 and 4). ⇓Importantly, the lengthening of the R-P interval from mean 204 ± 45 ms at age less than 2 years to mean 289 ± 52 ms at age greater than 5 years accounted for 64% of the increase in the tachycardia cycle length. In contrast, the lengthening of the P-R interval during this time frame from mean 109 ± 25 ms to 156 ± 26 ms accounted for only 36% of the increase in the tachycardia cycle length. Despite these slower heart rates the tachycardia continued to be unresponsive to multiple medications.
Electrophysiologic study in 21 patients (mean age 17.1 years, median age 12.8 years) demonstrated a tachycardia cycle length at the time of radiofrequency ablation of 330 ms to 510 ms, with a mean of 413 ms. Seventeen of the 21 patients had programmed ventricular extrastimulation during PJRT when the His bundle was refractory. Data were available from seven; the mean advancement of the atrial electrogram during ventricular extrastimulation and PJRT was 25 ms ± 12 ms. One of these seven had neither advancement or delay; however, the pathway in this patient was located on the left side and mapped to the middle of the coronary sinus. It was ablated from the left ventricle. Accessory pathway potentials were not detected in any patient and were not used as a guide for the ablation site. Electrophysiologic properties of the atrioventricular node during sinus rhythm and during the tachycardia, including multiple studies in 3 (Table 3), were normal in the 8 of the 9 patients in whom data were available (the 1 exception was patient #14 who at 16 years had recently [stopped 2 weeks before the second electrophysiology study] been taking amiodarone); no evidence for enhanced anterograde atrioventricular node conduction or anterograde or retrograde dual atrioventricular nodal pathways was found. Mean conduction retrograde across the accessory pathway, as measured by the ventriculoatrial (V-A) block cycle length was slightly, but not statistically significantly (p = 0.48), longer than that of anterograde conduction across the atrioventricular node (block occurring at a mean 374 ms anterograde versus 407 ms retrograde). The retrograde effective refractory period (ERP) of the accessory pathway available in 8 patients ranged from 220 ms to 420 (excluding the patient #14 recently on amiodarone), mean 302 ms. The functional refractory period (FRP) of the accessory pathway, available in 8 patients (excluding the data from patient #14), was mean 400 ms, similar to the mean tachycardia cycle length mean (440 ms). The anterograde ERP of the atrioventricular node was shorter than that of the retrograde accessory pathway in 8 of 11 patients in whom it was recorded. The anterograde FRP of the atrioventricular node was shorter than that of the retrograde accessory pathway in 8 of 9 patients in whom it was recorded. Three patients (excluding #14) had more than one electrophysiology study. Anterograde properties of the atrioventricular node changed only slightly; in patient #2, the ERP remained the same but the FRP lengthened, perhaps related to the longer drive interval. Patient #12’s FRP was the same, but the measured ERP was shorter in the 9 year interval, due to more vigorous study techniques such as stimulation at multiple sites. Patient #18 received isoproterenol at the third study confounding comparison over time. Serial retrograde data were available only on patient #18; there was little change except that most likely due to increased age and isoproterenol. The 3 patients (mean age 14 years) whose clinical course exhibited a paroxysmal pattern were compared to the 18 subjects (mean age 18 years) whose tachycardia was constant. Both the mean PJRT cycle length (423 ± 68 ms) and the retrograde conduction interval (279 ± 50 ms) of the 18 patients (mean age 17 years) (Table 1)with the constant form was significantly (p < 0.036) shorter than those (487 ± 25 ms; 327 ± 23 ms) of the 3 patients with the paroxysmal form (mean age 14 years).
The retrograde slowly conducting accessory pathway bridges the atrioventricular groove inserting near the groove in the ventricle (13)and was located at the coronary sinus ostium in 10 patients: in the right posterior septum region in 8 patients, just superior to the coronary sinus in 1 patient, in the midseptum area in 1 patient and in the left posterior septal region in 1 patient.
Fifteen of the 21 patients were evaluated by echocardiography at presentation; 11 demonstrated a mean shortening fraction of 0.22 ± 0.05 (range = 0.15 to 0.30; normal ≥0.28) and E-point septal separation, consistent with decreased ventricular function. Four of 11 patients with decreased myocardial function had clinical symptoms of severe congestive heart failure as infants. The remaining 7 patients increased their mean shortening fraction from 0.20 to 0.32 after successful ablation of the accessory pathway. Interestingly, shortening fraction increased spontaneously in 3 of the 11 patients (from a mean 0.23 to a mean of 0.36) with increasing age and slower heart rates (2 patients’ PJRT heart rate decreased from 183 to 119 and 128 to 104 respectively, and one patient’s rhythm converted to sinus rhythm on amiodarone therapy). Echocardiographic data could not be interpreted in one patient because of an implanted pacemaker. The clinical impression and follow-up of the infants suggested that tachycardia-related decreased ventricular function was prominent in this group (who had faster PJRT heart rates) and that an improvement in ventricular function was associated with decreasing heart rates; however, due to the limited number of infants studied, this association was not statistically significant.
Pharmacological management in these patients was unsuccessful in all but patient #14; he had received ineffectual trials of several medications but was eventually successfully treated with amiodarone; however, hyperthyroidism and noncompliance complicated this approach and ablation was recommended and successfully performed.
The median age at ablation was 12.8 years. One patient underwent successful surgical cryoablation of the accessory pathway at age 15 years prior to the advent of radiofrequency ablation. The remaining 20 underwent radiofrequency ablation. The shortest ventriculoatrial conduction time was used to identify the site of energy application. Seventeen of 21 accessory pathways (81%) were located at the coronary sinus ostium or in the right posterior septal region; the pathways of the remaining 4 patients were in the free wall (Table 1). Two to 35 radiofrequency energy applications were performed in the 19 patients; ablation of the pathway was successful in 16 of the 21 patients during the initial session. One patient was thought to have multiple pathways and the accessory pathway supporting PJRT was not successfully ablated. This patient declined a second trial of radiofrequency energy application. Transient ablation occurred in 5 patients; recurrence of the tachycardia was noted at less than one hour, and at 1, 3 and 7 days after ablation. Radiofrequency ablation for recurrence was successful in all but one. Patient #5, a 5-year-old boy with diminished ventricular function, developed complete heart block at his third session. The location of the pathway in this patient was posterior, near the coronary sinus os. During radiofrequency application, the catheter tip abruptly recoiled from its mapped site near the coronary sinus os to the apex of triangle of Koch; an immediate 3 second run of rapid junctional tachycardia ensued. The energy was discontinued at the end of the 3 seconds, but complete permanent heart block was present. The escape rhythm was a His bundle rhythm at 55 beats per minute with a narrow (normal) QRS complex; a pacemaker was implanted. During the procedure another patient with a left-sided pathway demonstrated persistent tachycardia after transient successful (15 min) radiofrequency ablation, but at follow-up electrophysiologic study 6 months later, he was in normal sinus rhythm, had no inducible tachycardia and no electrophysiologic evidence for a persistent pathway (20). Following radiofrequency ablation, retrograde conduction was absent in two patients of the seven patients studied (Table 4). In addition, the ventricular pacing rate at which retrograde block occurred, presumably through the His-Purkinje atrioventricular node, as indicated by the shortest V-A interval recorded in the His bundle region, was slower in the four other patients studied after ablation than that observed prior to ablation. Follow-up after definitive treatment (i.e., following all RFA sessions) ranges from 2.9 to 8 years without reoccurrence, except in the patient who has declined a second ablation attempt. The one patient with the pacemaker is doing well.
These data demonstrate a wide clinical spectrum and new features of PJRT. Most authors use the term permanent rather than persistent junctional reciprocating tachycardia (1–10,14); however, because of the wide age range at presentation, the lack of permanency in a number of patients and the advent of corrective therapy, we suggest the use of persistent, conveying more frequency than intermittent but less than permanent. Eighty percent of the patients in our study presented during childhood (≤18 years) and 50% presented during the first year of life. However, clinically asymptomatic patients presenting later are not uncommon, due to perhaps, as suggested by the clinical course of several of our patients, unrecognized paroxysmal relatively “slow” tachycardia for many years.
PJRT makes its appearance most often in early childhood. To examine for a trend in the data with age, the curvilinear lines in Figures 2, 3 and 4were created by subjecting the data to a nonparametric smoothing technique (Systat, Inc, Aurora, Colorado). The patients were on no medications for the initial electrocardiogram; within the first 2 years as well as later in their course digoxin, flecainide and propranolol were used predominantly, with no effect on the tachycardia. No measurements were made in the two patients during amiodarone therapy. Although drug effect cannot be fully excluded from the serial observations depicted in these figures, it is unlikely that marked effects occurred given the persistence of the arrhythmia and the uneven use of and inconsistent compliance with the antiarrhythmic agents. Thus, during the first several years of life, the rate tends to slow as a function of delay in conduction not only in the normal atrioventricular His-Purkinje axis but also, and most importantly, in the concealed accessory pathway. At about two years of age, the PJRT rate and conduction in both directions tend to stabilize (Fig. 3 and 4). Some patients, as illustrated by three patients in this cohort in whom “persistence” of the tachycardia was dependent upon isoproterenol, and, perhaps, by our older patients as well, may revert to a more paroxysmal form (14).
In contrast to our experience, Yagi et al. have reported that, despite the concordance in the mean PJRT cycle length between their paroxysmal and incessant groups, retrograde conduction through the accessory pathway was significantly shorter in the paroxysmal form compared to the incessant form (14). Conversely, anterograde conduction via the atrioventricular node was significantly shorter in the incessant form than in the paroxysmal form of tachycardia. Our patients differed from their group. Their patient group was, on the average, considerably older than our patient group. In addition, our younger patients (<10 years) had a significantly shorter mean PJRT cycle length and faster tachycardia then either of their 2 groups. Our three patients with the paroxysmal form, in contrast to the patients of Yagi et al., were converted to the incessant form with isoproterenol. Among our cohort the incessant tachycardia was associated not only with shorter PJRT cycle lengths and retrograde conduction intervals but also with slightly younger ages. Thus, our experience, in conjunction with the study of Yagi et al. and others (14,15), suggests that patients with PJRT comprise a wide clinical spectrum.
These data suggest that the cycle length of PJRT increases with age (Fig. 2, 3 and 4). Average tachycardia rates are much faster in infants and younger patients than in older patients. Although slowing of conduction both anterograde through the normal atrioventricular node–His-Purkinje axis and retrograde through the accessory pathway contributes to the increase in the tachycardia cycle length and occurs at similar rates (similar shaped curves in Fig. 3 and 4), this age-related change in the tachycardia rate is primarily dependent upon prolongation of retrograde conduction through the accessory pathway. Furthermore, as indicated by the data from these patients, the conduction properties of the retrograde accessory pathway are slower compared to those of the anterograde atrioventricular node and compared to those of the usual “fast” accessory pathway found in patients with atrioventricular reentrant tachycardia. However, a recent study indicating that the ventricular insertion of the accessory pathway inserts at the atrioventricular groove and not deep within the right ventricular rejects the notion that an increased length of the accessory pathway accounts for the “slow” retrograde conduction (13). On the other hand, because the conduction properties as well as the anatomic location of the retrograde accessory pathway in these patients are similar (but clearly anatomically independent) to those of the atrioventricular node anterograde, one may postulate that factors that are influential in atrioventricular conduction, such as abundant autonomic innervation, membrane-channel function, adenosine and beta1receptor densities and decremental conduction may also be similar between the two pathways. In addition, because the PJRT cycle length, as expected, tracks much more with the functional refractory period of the retrograde accessory pathway as the patient ages (Tables 1, 3 and 4)than with properties of the anterograde atrioventricular node, it is apparent that changes in the retrograde pathway are the major factors in the difference in clinical courses observed in different patients.
Patients with PJRT may present with clinical or laboratory findings of impaired ventricular function compatible with tachycardia related cardiomyopathy. The tachycardia has infrequent spontaneous, but intermittent periods of remission. In older patients the tachycardia appears to be less incessant, perhaps due to variable autonomic tone. Because the PJRT heart rates are faster at younger age and since congestive heart failure is more common at younger ages, the two may be related. Even though a general trend seemed to support this hypothesis, a statistical significance, due to limited sample size, could not be demonstrated. This observation may also be, in part, due to limitations to accurately assess ventricular function by available noninvasive means. Three patients with cardiomyopathy in this study improved spontaneously, perhaps associated with the progressively slower rate of the tachycardia as the patient grew older; however, one of these three patients improved with only a slight decrease in the tachycardia rate. Because reversibility of tachycardia induced cardiomyopathy is well known (16–19), intractable tachycardia-related decreased function in the older patient may be best managed with radiofrequency ablation of the retrograde accessory pathway. Furthermore, there are no ideal or even satisfactory antiarrhythmic medications for this arrhythmia. Because of uniform, full recovery of ventricular function occurring either postablation or spontaneously, intervention with either amiodarone or radiofrequency ablation should be considered only when cardiac function is severely impaired for a minimum of 1–2 yr or when the patient is of adequate size for a safe ablation attempt.
Several investigators have demonstrated that radiofrequency ablation can be used effectively for the treatment of PJRT (7,8,10,15). Our study confirms that radiofrequency ablation can be extended effectively for the treatment of PJRT to most patients. Five patients (24%) experienced recurrence and required repeat sessions for successful ablation; these patients received ablation during the first four years of our radiofrequency programs, perhaps accounting, in part, for the recurrence rate. Although one of our patients experienced complete heart block as a result of an abrupt spontaneous shift in the position of the catheter tip, this complication (20), given the usual anatomy of the pathway distant from the atrioventricular node and His bundle, should be a very rare event. Furthermore, the observation of spontaneous resolution of ventricular dysfunction and the increased complications at smaller than 15 kg along with the experimental evidence that links an expansion of radiofrequency lesion size (in the canine ventricle, but, interestingly, not the porcine ventricle) with subject growth and age (21–23)suggest deferment of ablation in small children until they are of sufficient size or until significant symptoms develop. However, radiofrequency should be considered as treatment for patients with intractable tachycardia, and especially for those with decreased ventricular function, or with symptoms attributable to the persistent tachycardia. Patients with recurrent or persistent tachycardia after the initial attempt of radiofrequency can be considered for repeat radiofrequency ablation of their accessory pathway.
PJRT is an arrhythmia that usually presents in infancy or childhood, but may not be recognized until adulthood. Symptoms of congestive heart failure are more common in younger patients. Some patients may be unaware of the underlying persistent tachycardia and may present with decreased ventricular function, exercise intolerance or syncope much later in life. Age-related changes in both the rate and the “persistence” of this tachycardia may mask its diagnosis. The heart rate relative to different ages may not be sufficiently fast to result in symptoms or to provoke further examination by the patient’s physician; thus, the diagnosis may be delayed until tachycardia related symptoms or paroxysms of palpitations and tachycardia become apparent to the patient or patient’s family. Since the heart rate associated with PJRT will most likely slow with age, radiofrequency ablation may be deferred in small children with this tachycardia. However, because the tachycardia has both an infrequent spontaneous (and intermittent) resolution (1/21 in our series) and a variable expression of impaired ventricular function, and since it may be effectively and safely treated with radiofrequency ablation, we recommend that electrophysiologic study and radiofrequency ablation should be considered at suitable patient size (≥15 kg) and upon the appearance of symptoms related to the tachycardia and/or impaired ventricular function.
- effective refractory period
- functional refractory period
- persistent junctional reciprocating tachycardia
- radiofrequency ablation
- Received June 11, 1997.
- Revision received September 7, 1998.
- Accepted October 22, 1998.
- American College of Cardiology
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