When and how does a single ventricular premature beat initiate and terminate supraventricular tachycardia?

Abstract

Background

The differential diagnosis of a supraventricular tachycardia (SVT) is accomplished using a number of pacing maneuvers. The incidence and mechanism of a single ventricular premature beat (VPB) on initiation and termination of tachycardia were evaluated during programmed electrical stimulation (PES) of the heart in patients with the two most common regular SVTs: atrioventricular re‐entrant tachycardia (AVNRT) and orthodromic atrioventricular tachycardia (AVRT).

Methods

Three hundred and thirty‐seven consecutive patients aged above 18 years with an inducible sustained AVNRT or AVRT were prospectively enrolled. Patients with more than one tachyarrhythmia mechanism were excluded. Two hundred and seventeen patients (64.4%) had typical slow/fast AVNRT and 120 (35.6%) had an orthodromic AVRT using a rapidly conducting accessory pathway for V‐A conduction. In this cross‐sectional study, we specifically report the analysis of tachycardia induction and termination by a single VPB.

Results

Tachycardia induction with a single VPB during sinus rhythm was seen in 7 of 120 AVRT and in only one of the 217 patients with AVNRT, (5.8% vs. 0.3%, p < 0.05). When a single VPB was delivered during basic ventricular pacing these values were 28% versus 4%, respectively, (p < 0.001). Termination of tachycardia by a single VPB was observed in nine (4.1%) patients with AVNRT and in 57 (47.5%) with AVRT (p < 0.001).

Conclusion

Initiation of SVT by a single VPB during sinus rhythm was uncommon and favored AVRT. Termination of SVT by a single VPB was commonly seen in AVRT but rarely in AVNRT. These findings can be of help when interpreting a noninvasive arrhythmia event recording.

1. METHODS

Starting 50 years ago (Coumel, Cabrol, Fabiato, Gourgon, & Slama, 1967; Durrer, Schoo, Schuilenburg, & Wellens, 1967; Wellens, 1971) programmed electrical stimulation (PES) of the heart combined with intracardiac activation mapping opened the door to unravel the type and mechanism of a supraventricular tachycardia (SVT). In the years that followed, several findings were reported useful to make a definite diagnosis during an electrophysiologic study (EPS; Al Mahameed, Buxton, & Michaud, 2010; Bennett et al., 2011; Calvo et al., 2018; Denes, Wu, Dhingra, Chuquima, & Rosen, 1973; González‐Torrecilla et al., 2011; Gonzalez‐Torrecilla et al., 2006; Hirao et al., 1996; Kalbfleisch, Tyler, & Weiss, 2012; Knight et al., 2000,1999; Martínez‐Alday et al., 1994; Michaud et al., 2001; Ormaetxe et al., 1993; Rosman et al., 2011; Wellens & Durrer, 1975). They are listed in Table 1. During our studies, we were impressed by the different effects of a single ventricular premature beat (VPB) on the initiation and termination of tachycardia in patients with an AVNRT in comparison to those with an AVRT using an accessory AV connection. There was no previous research aiming to study systematically the effect of a single VPB in those patients. Our findings may help those assessing ECG rhythm strips, Holter monitoring, and cardiac event recorders in the correct identification of the mechanism of a supraventricular tachycardia. This was the reason for us to undertake this cross‐sectional study.

Table 1.

Useful findings in the differential diagnosis of a supraventricular tachycardia

H‐A interval <70 ms	indicates AVNRT
AV block during tachycardia	rules out AVRT
Dual AV nodal pathways	indicates AVNRT
Increase in V‐A or H‐A interval with BBB	indicates AVRT
Resetting (advancing or delaying) or termination of tachycardia by a single VPB during His refractoriness	indicates AVRT
Delta H‐A (HA SVT‐HA pace) >10 ms	favors AVRT
Delta AH >40 ms during atrial pacing at the SVT cycle length	favors AVNRT
VA during pacing >90 ms longer than VA during tachycardia	favors AVNRT
Post pacing interval‐SVT cycle length >115	favors AVNRT
Para‐His pacing	Unchanged VA favors AVRT
Comparing VA time during apical versus basal pacing	basal < apical = OAVRT; apical < basal = AVNRT

Abbreviations: AH: Atrium‐His interval; AV: Atrio‐ventricular; AVNRT: Atrioventricular nodal tachycardia; AVRT: Atrioventricular tachycardia using an accessory pathway for VA conduction; BBB: Bundle branch block; HA: His‐atrium interval; SVT: Supraventricular Tachycardia; VA: Ventriculo‐atrial interval; VPB: Ventricular premature beat.

1.1. Population

From March 2017 to August 2018, 337 consecutive patients referred for catheter ablation from three Institutions (Arrhythmia Associates, Mumbai, India, Biocor Instituto, Nova Lima, Minas Gerais, Brazil, and Instituto Nacional del Torax, Santiago, Chile) with a slow/fast AVNRT or an AVRT with a rapidly retrogradely conducting accessory pathway were prospectively enrolled after informed consent. The present study was approved by the Institutional Committee on Human Research in all participating centers. All patients had a structurally normal heart, were above 18 years with an inducible sustained tachycardia. Patients with more than one tachyarrhythmia mechanism were excluded from the study.

1.2. Definitions

Diagnostic criteria for slow/fast AVNRT and orthodromic AVRT were based on previously reported criteria (Denes et al., 1973; Hirao et al., 1996; Knight et al., 2000,1999; Martínez‐Alday et al., 1994; Michaud et al., 2001; Ormaetxe et al., 1993; Wellens & Durrer, 1975). Sustained tachycardia was defined as an SVT, sustained for at least 3 min, decreasing the odds of spontaneous termination as a confounding factor and to ensure that all required diagnostic maneuvers could be performed.

1.3. EP study protocol

The EP study was performed with the patient awake, after 6 hr fasting, under local anesthesia. The EP Tracer polygraph (Cardiotek BV, Maastricht, The Netherlands) was used in the participating centers. In all patients the same stimulation protocol for tachycardia induction and termination was used, using the different steps mentioned in Table 1, when needed. Relevant for this study was the incidence of initiation and termination by a single VPB from the apex of the right ventricle during sinus rhythm and basic ventricular pacing, using a stepwise 10 ms decrement in the coupling interval, until refractoriness was reached. The initiation and termination of tachycardia by a single VPB were tested at least twice to check reproducibility.

Accessory pathway location: AP location was categorized in two regions, right and left sided (Table 2), and in three regions: septal (anteroseptal and left and right posteroseptal), right, and left‐free wall (Table 3).

Table 2.

Summary of selected variables comparing typical AVNRT and AVRT

Variables	AVNRT (n = 217)		AVRT (n = 120)		p‐value
	N	%	N	%
Gender
Female	148	68.2	50	41.7	<0.001a
Male	69	31.8	70	58.3
Age (years)
Mean ± SD	49.7 ± 14.5		37.3 ± 13.7		<0.001b
Tachycardia cycle length
Mean ± SD	326.2 ± 57.1		311.7 ± 51.2		<0.05b
Single VPB induction
During sinus	1	0.5	7	5.8	0.0026a
After ventricular pacing	9	4.1	23	19.1	<0.0001a
Single RV VPB termination
During tachycardia	19	8.7	57	47.5	<0.00001a

The p‐value refers to: ^achi‐squared test and ^b t test.

Abbreviations: AVNRT: AV nodal re‐entrant tachycardia; AVRT: Atrioventricular tachycardia; PAC: premature atrial complex; RV: right ventricle; SD: standard deviation; TCL: tachycardia cycle length; VPB: ventricular premature beat.

Table 3.

Single VPB initiation and termination of AVRT by AP location

Accessory pathway site	n patients	Single VPB induction – sinus rhythm	Single RV VPB induction – S2 (400)	Single RV VPB termination – AVRT
Right free‐wall	13	1 (7.6%)	4 (30.7%)	9 (69.2%)
Septal	28	0	0	19 (60%)
Left free‐wall	79	6 (7.6%)	19 (24%)	29 (37.1%)
Total	120	7 (5.8%)	23 (19.1%)	57 (47.5%)

Abbreviations: AP: accessory pathway; AVRT: atrioventricular tachycardia; n: number; RV: right ventricle; S2(400): premature extrastimuli after a train pulse of eight beats at cycle length of 400 ms; VPB: ventricular premature beat.

1.4. Assessment of the EP study tracings

The data were electronically transferred to a core group (EBS, FEC, HJW). This group in particular, assessed the incidence and mechanism of induction by a single VPB delivered at the RV apex during sinus rhythm and also after a train of eight paced beats with a cycle length of 400 ms, and termination by a single VPB from the RV apex in the different types of tachycardia. The core group always reached a consensus decision regarding analysis of the EP study tracings.

1.4.1. Statistical analysis

Descriptive analyses were made through frequency tables for categorical variables and by mean ± standard deviation (SD) for numerical variables. We calculated a sample size to compare the effects of single VPB in the termination of AVNRT and AVRT, using the following formula (Chow, Shao, & Wang, 2008):

$$n_{\mathit{AVRT}}=\left(\frac{p_{\mathit{AVNRT}}(1-p_{\mathit{AVNRT}})}{\tau }+p_{\mathit{AVRT}}(1-p_{\mathit{AVRT}})\right){\left(\frac{z_{1-\propto /2}+z_{1-\beta }}{p_{\mathit{AVNRT}}-p_{\mathit{AVRT}}}\right)}^2$$

$$n_{\mathit{AVNRT}}=\tau n_{\mathit{AVRT}}$$

where p_AVNRT and p_AVRT represent the proportions of termination of supraventricular tachycardia by a single VPB, AVNRT, and AVRT, respectively, τ = n_AVNRT/n_AVRT and $z_{1-\propto /2}$ e $z_{1-\beta }$ are quantiles of normal distribution associated with test significance and power. In the absence of similar previous studies, we assumed that termination would be more common during AVRT, and we estimated the values of 0.35 and 0.55 for the proportions of termination, values close to what would be expected as a maximal sample size (p = 0,5). It would be needed a minimum of 74 individuals with AVRT and 134 with AVNRT, assuming a power of 80%, a 5% significance.

The comparison between groups was performed using the chi‐squared test and t test. The analyses were made in the free software R version 3.1.3 and it was used 5% of significance.

2. RESULTS

2.1. Population

Three hundred and thirty‐seven consecutive patients were prospectively enrolled in this study, 217 with a slow/fast variety AVNRT, and 120 patients with an orthodromic atrioventricular tachycardia. As shown in Table 2, the mean age was 45.3 ± 15.6 years. A female preponderance was observed in AVNRT (68.2%) while males predominated in AVRT (58.3%; p < 0.001).

Of the 120 patients with an orthodromic AVRT, the accessory pathway was concealed in 67 (55.8%).

A shorter tachycardia cycle length (TCL) was observed during AVRT (311 ± 51.1 ms), as compared to AVNRT (326.2 + 57.1 ms, p < 0.05).

2.2. Results of programmed ventricular stimulation

2.2.1. Initiation

1. Initiation of typical AVNRT by a single VPB during sinus rhythm was observed in only one patient (1/217, 0.3%), as shown in Figure 1.

2. Initiation of orthodromic AVRT by a single VPB during sinus rhythm was observed in 7/120 (5.8%) patients, with a p‐value of 0.0019 compared to typical AVNRT patients.

3. Initiation of typical AVNRT by a single VPB after a basal train was seen in only 9/217 (4.1%) patients.

4. Initiation of orthodromic AVRT occurred in 23/120 patients (19.1%) by a single VPB after a basal train (p < 0.0001, compared to AVNRT).

5. Initiation of AVRT by a single VPB (during sinus rhythm and after a basal train) was as common in patients with a concealed bypass tract (CBT), 15/66 (22.7%) as in those with a manifest wolff‐parkinson‐white syndrome, where it was seen in 8/54 (14.8%) patients (p = NS). Interestingly, a single VPB could not induce AVRT in any patient with a septal accessory pathway (p = 0.01; Table 3).

6. Initiation of AVRT by a single VPB occurred in 4/34 (11.7%) patients with a right‐sided accessory pathway (AP) as compared with 19/86 (22%) of patients with a left‐sided AP (p = NS).

Figure 1.

Initiation of AVNRT by a single VPB during sinus rhythm. Five surface ECG's are shown, together with several intracardiac recordings, from the bundle of His, the coronary sinus (SC) and the apex of the right ventricle (VD). Paper speed 50 mm/s

2.2.2. Termination

1. Reproducible termination of typical AVNRT by a single RV apex VPB was observed in 19/217 (8.7%) patients. Using a tachycardia cycle length cutoff at >350 ms, typical AVNRT could be terminated by a single VPB in only 5/151 (3.3%) patients (Figure 2).

2. Modes of typical AVNRT termination by a single VPB were as follows: in three patients without retrograde atrial activation (Figure 3), by anterograde block in the slow AV nodal pathway; in two patients, after retrograde conduction over the fast pathway (Figure 3); in four patients, when after the VPB retrogradely conducted to the atrium over the fast pathway followed by very slow antegrade conduction over the slow pathway, followed by retrograde block in the fast pathway (Figure 4). The coupling interval of the VPB terminating AVNRT was 202 ± 33 ms (ranged from 190 to 340 ms). The coupling interval was ≤200 ms in only two patients (10.5%).

3. Termination of orthodromic AVRT by a single VPB was observed in 57/120 (47.5%, p < 0.0001 compared with typical AVNRT). Termination by a single RV VPB occurred in 23/35 (67.6%) of patients with a right‐sided AP as compared to 34/86 (39.5%) with a left‐sided AP (p = NS). Table 3 shows AVRT termination according to accessory pathway location. Termination of AVRT by a single VPB did not differ with accessory pathway site (p = NS). In 55 patients, AVRT terminated with VA block. In one patient AVRT terminated in the AV node after VA conduction and in one patient tachycardia terminated once with and once without VA conduction. The coupling interval of the VPB terminating AVRT was 232 ± 57 ms (ranging from 170 to 320 ms), p = 0.002 compared to AVNRT. The coupling interval was ≤200 ms in only 15 patients (26.3%).

Figure 2.

Scatterplot showing single VPB termination in AVNRT and AVRT, in relation to tachycardia cycle length with a cutoff 350 ms. A single VPB could terminate only five AVNRT's when the tachycardia cycle length was below 350 ms

Figure 3.

Upper panel‐termination of an AVNRT by a single right ventricular VPB. The VPB after 240 ms does not affect the timing of the next AVNRT QRS (400 + 480 = 2 × 440 ms), but the VPB after 230 ms invades the tachycardia circuit terminating the circulating AV nodal impulse. A 12‐lead ECG is shown with simultaneous recordings from the His bundle, coronary sinus, and right ventricle. Lower panel‐termination of an AVNRT after a single right ventricular VPB. The VPB, given after 220 ms, is retrogradely conducted to the atrium over the fast AV nodal pathway. The tachycardia terminates in the anterograde slow pathway. Paper speed 50 mm/s

Figure 4.

A VPB given after 340 ms retrogradely invades the His bundle (marked by arrow), which was activated 10 ms earlier than during AVNRT, without changing AA timing. The narrow QRS after the VPB is the result of anterograde slowing in the slow AV nodal pathway (HH prolongs by 25 ms). As shown by the absence of retrograde atrial activation the AVNRT terminates by retrograde block in the fast AV nodal pathway. Paper speed 100 mm/s

3. DISCUSSION

This was the first study designed to assess the diagnostic role of a single VPB in supraventricular tachycardia.

3.1. Major findings

Our study shows rare initiation of AVNRT by a single VPB. In AVRT, there was also a low incidence of tachycardia initiation by a single VPB during sinus rhythm, but higher than in AVNRT. Termination of the common AVNRT by a single VPB was very unusual while it was common in AVRT.

3.2. VPB termination of supraventricular tachycardia

Figure 5 explains how a VPB delivered during AVNRT has to invade the ventricular conduction retrogradely to reach the A‐V node via the bundle branch‐His axis in order to collide with the circulating impulse in the small and protected AV nodal circuit. The tachycardia rate and the coupling interval of the VPB will determine whether a VPB is able to invade the bundle branch system and reach the AV node. Apparently, this is rarely the case. Most patients with AVNRT termination by a single VPB had a rather slow AVNRT rate. Other factors playing a role in the differences between AVNRT and AVRT in termination by a single VPB are the distance between the AVRT circuit and the AVNRT circuit from the RV apical stimulation site, and the difference in electrophysiologic properties of the tissue between VPB and the two tachycardia circuits (Kalbfleisch et al., 2012; Logue, Greenspon, & Ho, 2018). As shown in Figure 4, in AVRT, a VPB can more easily invade and collide with the circulating impulse because of the large tachycardia circuit.

Figure 5.

Figure explaining why initiation and termination by a single VPB is more easy during orthodromic AVRT and unusual in AVNRT (see text)

3.3. VPB initiation of supraventricular tachycardia

To initiate AVNRT by a single VPB during sinus rhythm the impulse needs to be able to enter retrogradely the bundle branch‐His system, which can be refractory from the antegradely conducted QRS following a sinus impulse. When retrograde invasion is possible to start AVNRT, the impulse should be blocked in the slow AV nodal pathway and conducted up the fast pathway. This will not be possible if the slow pathway had a shorter retrograde refractory period, which is usually the case. In AVRT, block of the VPB in the bundle branch/His system with retrograde conduction over the AP can be followed by antegrade conduction over the AV node‐His‐bundle branch axis, initiating tachycardia.

3.4. Limitation

One may argue that a limitation of the study would be not including patients with atrial tachycardia, which would impact external validity of the study. However, noninclusion was based on our experience on peri‐hisian atrial tachycardia (Bohora, Lockandwala, Sternick, Anderson, & Wellens, 2018), were not a single patient from a cohort of 43 patients who underwent electrophysiologic study had termination of atrial tachycardia from a single RV VPB.

4. CONCLUSION

The information about the incidence of tachycardia initiation and termination of an SVT by a single VPB is clinically important to make the distinction between AVNRT and orthodromic AVRT when seen on the 12 lead ECG, but especially when a lesser number of ECG leads are used by currently available in‐ and noninvasive cardiac arrhythmia event recorders.

CONFLICT OF INTEREST

There is no conflict of interest to disclose.

Cunha Guerra M, Lokhandwala Y, Oyarzun R, et al. When and how does a single ventricular premature beat initiate and terminate supraventricular tachycardia? Ann Noninvasive Electrocardiol. 2019;24:e12650 10.1111/anec.12650