A ccurate electrocardiographic (ECG) diagnosisof wide complex tachycardia (WCT) as eithersupraventricular tachycardia (SVT) with
aberrancy or ventricular tachycardia (VT) is essentialin the management of cardiac arrhythmias. In this
m the aKrannert Institute of Cardiology, Indiana University School of Med
iversity of California San Francisco School of Medicine, San Francisco, C
nter, Indianapolis, Indiana; dTexas Cardiac Arrhythmia Institute, Austin, T
iversity of Utah School of Medicine, Salt Lake City, Utah. Dr.Natalehas rece
bster, Medtronic, and St. Jude Medical. Dr. Marrouche has ownership inter
tracted research funding from Biosense-Webster, Medtronic, St. Jude and B
ventice and Biotronik. Dr. Scheinman has received speakers honoraria fromM
dical, Biotronik, and BiosenseWebster; and serves on Amgen datamonitorin
ve no relationships relevant to the contents of this paper to disclose. Drs. Yad
authors attest they are in compliancewithhumanstudies committees andani
od and Drug Administration guidelines, including patient consent where app
ctrophysiology author instructions page.
nuscript received July 25, 2016; revised manuscript received December 9
regard, numerous ECG criteria have been developedto distinguish WCTs as either SVT with aberrancy orVT with a high degree of sensitivity and specificityin the correct diagnosis of VT (1–4). However, theseprior studies did not differentiate between VT
icine, Indianapolis, Indiana; bDivision of Cardiology,
alifornia; cCardiology Division, Saint Vincent Heart
exas; and the eDivision of Cardiovascular Medicine,
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associated with structural heart disease(SHD) and idiopathic (no structural disease)VT. These studies instead either pooled pa-tients with a variety of cardiac conditions ordid not precisely specify the patient cohort.The purpose of our study was to assess theability of established 12-lead ECG VT criteriato correctly distinguish idiopathic VT fromSVT with aberrancy.
METHODS
PATIENTS. We studied a series of 115 patientswho presented at 3 centers with sustained ornonsustained WCT or frequent monomorphicpremature ventricular complex (PVC; idio-pathic group). All patients underwent, atminimum, an examination consisting of acomplete history, a physical examination, a12-lead ECG, and an echocardiogram thatdemonstrated no evidence of SHD prior toelectrophysiology study (EPS). Where appro-priate, coronary angiography, right ventricu-lar (RV) angiography, and/or cardiac magnetic
resonance was performed, all of which were inter-preted as demonstrating normal results.
In addition, 42 consecutive patients with a knownhistory of myocardial infarction (MI) and 101 distinctWCTs served as a comparison (post-MI group).Finally, a control group of 111 ECGs from a cohort ofpatients with WCT known to show SVT with aber-rancy based on results of EPS was used to assess thespecificity of ECG criteria (SVT group).
The research protocol was approved by the insti-tutional review boards at all 3 centers. All patients’related data were de-identified and stored in apassword-protected database that was accessible onlyto the investigators.
ELECTROPHYSIOLOGY STUDY. All patients gavewritten informed consent. The patients underwentEPS in the fasting state after antiarrhythmic drugswere withdrawn (for at least 4 half-lives). Catheterswere placed through the femoral veins, and EPS wasperformed. WCT occurred spontaneously or wasinduced by burst pacing, programmed electricalstimulation with up to 3 extrastimuli and/or isopro-terenol infusion. Ventricular tachycardia was diag-nosed using standard EPS maneuvers, andelectroanatomic mapping and RF catheter ablationwere then performed based on the mechanism of VT.For idiopathic VTs, site or origin was reported by thephysician as the site of earliest local activation,best pace map, or successful RF termination site. For
post-MI VTs, site of origin was reported as presumedVT exit site based on mapping or successful RFtermination site. Success of ablation was confirmedby ventricular pacing with up to 3 extrastimuli bothwith and without isoproterenol (consistent with whatwas required for initiation prior to ablation).
ECG ANALYSIS. Twelve-lead ECGs of all WCTsrepresenting each patient’s clinical VT or SVT wereinterpreted by 2 independent cardiologists blinded tothe clinical data. Each patient’s tachycardia wascategorized as either left bundle branch block (LBBB)or right bundle branch (RBBB) morphology. Criteriaby Brugada et al. (1), Drew and Scheinman (2),Kindwall et al. (3), Wellens et al. (4), and Vereckeiet al. (5) (hereafter referred to as “conventionalcriteria”) were applied to categorize each ECG asfollows: VT if 1 or more criteria for VT were met andno SVT criteria were met; SVT if no VT criteria weremet and SVT morphological criteria were met; andindeterminate if 1 or more of both VT and SVTmorphological criteria were met.
Cr i ter ia favor ing VT. Criteria included:
1. Atrioventricular (AV) dissociation or VA block;2. QRS width of >0.16 s;3. Right superior axis (�90� to �180�);4. Absence of precordial RS complexes or, if present,
an RS >100ms (QRS onset to S nadir measurement);5. QRS morphology in lead V1 in RBBB-type
tachycardia:a. Monophasic R;b. Notched waveform with a taller left peak (Rr0);c. Biphasic RS or QR pattern (Figure 1);
6. QRS morphology in LBBB-type tachycardia equalto any 1 of the following in lead V1 or V2:a. R-wave >30 ms;b. Slurred or notched S wave downstroke;c. Delayed S nadir (QRS onset to S nadir >60 ms);
7. QRS morphology in lead V6:a. QS pattern;b. rS pattern (R-to-S<1) in RBBB-type tachycardias;c. QRS onset to predominant peak or nadir in lead
V6 of $70 ms (1,3);8. Presence of an initial R-wave in AVR and width of
an initial r or q wave >40 ms (5).
Cr i ter ia favor ing SVT. Criteria included:
1. QRS morphology in lead V1 in RBBB-type tachy-cardia equal to rR0 or rsR0;
2. QRS morphology in lead V1 in LBBB-typetachycardia:a. r-Wave width <30 ms;b. Smooth S-wave down stroke;c. QRS onset to S nadir <60 ms and no Q in lead V6;
FIGURE 1 Idiopathic RBBB VT Correctly Classified
(Top) ECG of VT. QRS duration >120 ms, Rsr0 pattern in V1 (red arrow) and R-to-S ratio of<1 in lead V6 (blue arrow) all support diagnosis of VT.
Site of origin was the anterolateral papillary muscle. (Bottom) ECG of the same patient in sinus rhythm. ECG ¼ electrocardiogram; RBBB ¼ right
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3. QRS morphology in lead V6:a. Intrinsicoid deflection #50 ms;b. Triphasic qRs pattern (R-to-S >1) in RBBB-type
tachycardias.
Sensitivity was defined as the proportion of WCTswhich were correctly diagnosed as VT by ECG criteriacompared to the gold standard of EPS diagnosis.Comparison of sensitivities was performed using chi-square tests, with p value of <0.05 considered sta-tistically significant.
RESULTS
BASELINE CHARACTERISTICS. In the idiopathicgroup, 79 patients were male and 36 were female.Each patient demonstrated only 1 VT morphology.
Sustainedmonomorphic VTwas present in 73 patients,and nonsustained monomorphic VT and/or frequentmonomorphic ventricular ectopic beats were presentin 42 patients. LBBB morphology was present in 76patients, whereas 39 had RBBB morphology (Table 1).
In the post-MI group, 37 patients were male and 5were female. All patients had prior MI as shown byechocardiographic segmental wall motion abnormal-ities and/or significant coronary arterial disease.Sustained monomorphic VT was present in 99 of 101morphologies. A LBBB pattern was present in 38,whereas 63 had RBBB morphology (Table 1).
IDIOPATHIC VT ECG ANALYSIS. The mean QRSduration of VT (widest measured in any lead) was139 � 20 ms. The overall sensitivity to correctlydiagnose VT using the “conventional criteria” in
TABLE 1 Categorization of Arrhythmia by Bundle Branch Pattern
and Diagnostic Criteria
ECGDiagnosis
LBBBMorphology
RBBBMorphology Total
Idiopathic VT(n ¼ 115)
VT 63 31 94
SVT 12 0 12
Indeterminate 1 8 9
Post-MI VT(n ¼101)
VT 35 61 96
SVT 1 0 1
Indeterminate 2 2 4
ECG ¼ echocardiograph; LBBB ¼ left bundle branch block; MI ¼ myocardialinfarction; RBBB ¼ right bundle branch block; SVT ¼ supraventricular tachycardia;VT ¼ ventricular tachycardia.
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patients with idiopathic VT was 82% (Table 2).Sensitivity was greater with LBBB than RBBB VTswhen the indeterminate classification was included(Table 2).
In the 76 patients with idiopathic VT and LBBBmorphology, 63 of 76 patients (83%) VT was correctlydiagnosed (Figure 2). In the remaining 13 of 76patients (17%), SVT was incorrectly diagnosed in 12patients (Figure 3). One patient’s condition wasclassified as indeterminate. In the 39 patients withidiopathic VT and a RBBB morphology, 31 of 39patients (79%) received correct diagnoses of VT. Theremaining 8 patients (21%) received indeterminatediagnoses (Figure 4).
LBBB idiopathic VTs were incorrectly diagnosed asSVT because of an absence of any of the conventionalVT criteria (1–4). Most of the correctly diagnosedLBBB idiopathic VTs met morphologic criteria inlead V1 (VT criteria 6 above), usually an initial R-wave>30 ms or an onset of R to nadir of the S-wave >60 ms(Figure 3). Thus, the 12 LBBB idiopathic VTs that wereincorrectly diagnosed as SVT lacked this otherwisecommon VT criteria.
In the 8 patients classified as indeterminate withRBBB morphology, the reason was due to a conflict inmorphologic criteria between leads V1 and V6 (VTcriteria 5 and 7 described above): rsR0 pattern in V1
(consistent with SVT) was associated with a lead V6
R-to-S ratio <1 (consistent with VT [Figure 4]). These8 patients were subsequently found to have Purkinje-associated VT.
TABLE 2 Sensitivity for Electrocardiographic Diagnosis of VT
Sensitivity % LBBB Morphology RBBB Morphology Total
Idiopathic VT 83 (86*) 79 (91*) 82 (88*)
Post MI VT 92 (97*) 97 (100*) 95 (99*)
*Denotes sensitivity with the exclusion of indeterminate tracings.
Abbreviations as in Table 1.
POST-MI VT ECG ANALYSIS. The mean QRS durationwas 158 � 20 ms and significantly wider than that inthe idiopathic group (p < 0.001). The overall sensi-tivity to correctly diagnose VT in this group was 95%(Table 2). When ECGs classified as indeterminate wereexcluded from the analysis, the sensitivity to di-agnose VT was 99% in the remaining 97 VT mor-phologies. The sensitivity to diagnose VT did notdiffer in the RBBB group (61 of 63 patients [97%])compared with the LBBB group (35 of 38 patients[92%]; p ¼ NS), even when the indeterminate tracingswere excluded (RBBB: 61 of 61 patients [100%] vs.LBBB: 35 of 36 patients [97%]; p ¼ NS]). Of the 4 VTsclassified as indeterminate, 2 demonstrated each typeof morphology (LBBB or RBBB). The 2 VTs diagnosedas indeterminate with an RBBB morphology had anrsR0 pattern in V1 with right axis deviation. In theremaining 2 VTs diagnosed as indeterminate with anLBBB pattern, some of the morphological character-istics of the QRS complex for VT were present (such asa qR or qS pattern in V4 and/or V5), but the Kindwallcriteria were not met. A diagnosis of indeterminatewas assigned with the possibility that SVT with priorMI could not be ruled out in these 2 patients withLBBB patterns.
ANALYSIS OF SVT ECG. Among 111 ECGs diagnosticfor SVT (based on EPS), 12 were classified incorrectlyas VT (11%), whereas 4, all with RBBB morphology,were classified as indeterminate (3%). The remaining95 of these ECGs failed to satisfy any of the criteria forVT and were classified as SVT (specificity: 86%).
SENSITIVITY OF VT CRITERIA. The sensitivity of ECGcriteria for VT was lower in the idiopathic group (82%)than in the post-MI group (95%; p <0.01) (Table 3).These results remained consistent when the indeter-minate ECGs from the analysis were excluded (88%vs. 99%, respectively; p < 0.01) (Table 2).
Because some of the patients in the idiopathic VTgroup had only frequent PVC (n ¼ 8), a source ofstatistical bias might have been AV dissociationcriteria, which could not be used in this subset. In asensitivity analysis, these patients were excluded, aswere the ECG criteria regarding AV dissociation, andsensitivity in the idiopathic group only decreasedfrom 82% to 80% (86 of 107 patients). Although allECGs in the post-MI group demonstrated VT and notPVC, exclusion of AV dissociation criteria was alsosimilarly applied, minimally changing sensitivityfrom 95% to 96% (89 of 93 patients).
ORIGIN OF VT SITE. In the idiopathic group, the siteof origin was available for 111 of the 115 patients.These sites were divided into 6 groups: right
FIGURE 3 Idiopathic LBBB VT Incorrectly Classified as SVT
Note absence of an initial R-wave in V1 (red arrow) and onset of the QRS to its nadir in V1 and V2 of <60 ms. There is no evidence of AV
dissociation. Site of origin was the distal RV free wall. SVT ¼ supraventricular tachycardia; other abbreviations as in Figure 1.
FIGURE 2 Idiopathic LBBB VT Correctly Classified
QRS width >140 ms, evidence of AV dissociation and probable fusion (red arrow) support a diagnosis of VT. Site of origin was the RV moderator
band. AV ¼ atrioventricular; RV ¼ right ventricular; other abbreviations as in Figure 1.
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FIGURE 4 Idiopathic RBBB VT Incorrectly Classified as Indeterminate
Conflicting criteria for VT are present in leads V1 and V6. Note the rsR0 pattern in V1 (red arrow) favors SVT but the R-to-S ratio in V6
(blue arrow) favors VT. Site of origin was the left posterior fascicle. Abbreviations as in Figure 1.
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ventricular outflow tract (RVOT), left ventricularoutflow tract (LVOT), Purkinje-associated sites(fascicular; mid-to-distal left ventricular [LV]septum), aortic cusp, or other RV and LV sites. Amajority of the idiopathic VTs were ablated in theRVOT region (58 of 111 patients [52%]), most of whichwere in the anteroseptal RVOT (36 of 58 patients[62%]), followed by the posteroseptal RVOT (14 of 58patients [24%]). The second most common site ofidiopathic VT was associated with the Purkinje fibersin the fascicles or mid-distal septal region of the LV(23 of 111 patients [21%]). LVOT sites consisted of 9 of111 patients (8%), and aortic cusp VT contributed 7 of111 patients (6%). The remaining patients (14 of 111[13%]) represented other sites within the LV and RV.
There was site-specific heterogeneity in sensitivityof VT ECG criteria: VT was correctly diagnosed in48 of 58 RVOT sites (83%), and only 13 of 23 Purkinje-associated VT sites (57%; p < 0.03). Within the RVOTgroup, VT was correctly diagnosed in 29 of 36
TABLE 3 Chi Square Analysis of Correct Diagnosis of VT Among
All ECGs (p < 0.01)
Correct Diagnosis of VT Idiopathic VT Post MI VT Total
Yes 94 96 190
No 21 5 26
Total 115 101 216
Abbreviations as in Table 1.
anteroseptal sites (78%) and in 20 of 22 other RVOTsites (91%; p ¼ 0.46). Idiopathic VT of any nonseptalorigin (i.e., RVOT of free wall origin, LVOT, aorticcusps, and other LV and RV sites) was correctlydiagnosed in 35 of 35 patients (100%). In contrast,idiopathic VT from all septal sites (i.e., LV septum,anteroseptal, midseptal, or posteroseptal RVOT) wascorrectly diagnosed in only 56 of 76 patients (74%;p < 0.005: compared with nonseptal sites) and allRVOT septal sites in only 43 of 53 patients (81%; p <
0.03: compared with nonseptal RVOT sites).QRS notching, an ECG sign associated with
myocardial activation delay and scar tissue, was moresignificant in post-MI VT than in outflow tract VT(89% vs. 65%, respectively; p ¼ 0.001). Among theidiopathic group, notching was most frequently seenin Purkinje-associated VT (87%).
DISCUSSION
Although idiopathic VT is usually associated with abenign prognosis, the delay in establishing the correctdiagnosis may lead to inappropriate therapy, asidiopathic VT can be readily treated with eitherappropriate medical therapy or RF catheter ablation,and implantable cardioverter-defibrillators are usu-ally not warranted in this patient population (6). Ourfindings indicate that nearly 20% of idiopathic VTsmay not be recognized as ventricular in origin, usingconventional criteria.
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Criteria for the differentiation of SVT with aber-rancy from VT have been associated with a highdegree of sensitivity and specificity (1). These criteriawere developed from a cohort of patients largely withischemic heart disease. Thus these criteria would beexpected to be more accurate in the diagnosis of VTassociated with SHD as opposed to idiopathic VT.
The conventional criteria demonstrate an inherentbias toward the diagnosis of VT associated with SHD.Specifically, the absence of any R wave in any pre-cordial lead to assess for negative concordance in theprecordial leads would favor anterior or apical exitsites from the LV. Idiopathic VTs are unlikely to havenegative concordance because they typically origi-nate from the LV septum or right or left outflowtracts. Although this criterion is very specific for VT, itoccurs so rarely in idiopathic VT that it is of littlediagnostic value (7). In addition, the criteriaregarding the onset of R to nadir of S >100 ms alsotends to favor VT associated with SHD, as VT withSHD tends to have a wider QRS than idiopathic VT asdemonstrated in previous studies (8). This may bedue to the fact that VT due to SHD is associated withmyocardial scarring and fibrosis that contributes todelayed activation of the ventricles. In contrast, pa-tients with idiopathic VT have no SHD and aregenerally younger. Hence, idiopathic VT would beexpected to have more rapid global ventricular acti-vation and a narrower QRS morphology than in VTwith SHD (9,10). Accordingly, our data also demon-strate a shorter QRS duration for idiopathic VT thanfor post-MI VT. This narrower QRS duration may leadto a reduced sensitivity to diagnose VT by conven-tional QRS width criteria.
Although AV dissociation is 1 of the most specificECG features for diagnosing VT, its sensitivity is pooras AV dissociation has been shown to occur in onlyapproximately 20% of patients with VT (11).Conversely, up to 30% of VTs have 1:1 retrograde VAconduction (11). Our series demonstrated AV dissoci-ation in only 8 of 115 patients (7%) of our idiopathicgroup, possibly due to greater likelihood of VA con-duction among younger patients without SHD.
Bundle branch block morphology criteria in leadsV1 and V6 have been established to differentiate VTfrom SVT (3,7). It has been demonstrated that, inRBBB pattern VT, an Rsr0 morphology in V1 favors VT(7). In our analysis, all patients with idiopathic VT andan RBBB pattern who were classified as indeterminatehad an rsR0 pattern in V1, consistent with SVT,whereas lead V6 demonstrated an R-to-S ratio of <1.0,consistent with VT. Ventricular activation in an SVTwith an RBBB-type aberration first proceeds down theleft bundle branch with delayed activation of the RV,
providing an rsR0 pattern in V1. In SHD VT with anRBBB pattern the exit site in the LV often produces aninitial vector pointing toward the RV, producing alarge initial R-wave. Subsequent activation of theremaining right and left ventricles would produce asmaller 0r0 wave, leading to the Rsr0 pattern oftennoted in V1 with SHD-related VT. This may not applyto idiopathic VT, where initial activation is unlikely tocome from LV myocardium and may not produce alarge initial R-wave in V1.
Our findings showed that, in idiopathic VT with anRBBB pattern classified as indeterminate, all patientshad fascicular VT. In these patients there is earlyactivation of the His-Purkinje system, initial activa-tion of the posteromedial LV, and late activation ofthe anterolateral LV, which explains the markedlysuperior axis and the r/S pattern in V6. The pattern ofWCT with a relatively narrow QRS with an rsR0
pattern in V1 and an r/S in V6 should immediatelysuggest this type of idiopathic VT.
Idiopathic patients with LBBB VT who were mis-classified as SVT by ECG criteria most often had septalRVOT VT. Foci from this region of the RV would alsotend toward simultaneous activation of the ventriclesproducing a relatively narrow QRS complex. In addi-tion, our findings are in agreement with those ofKrebs et al. (12), who reported that some VTs with afocus in the RVOT lack an initial r-wave in V1. Thesefactors may have contributed to the reduced sensi-tivity to diagnose VT by conventional morphologicalcriteria.
Prior studies pooling patients with and withoutprior MI have demonstrated a wide variation in thesensitivity to diagnose VT (12,13). Brugada et al. (1)noted a sensitivity of 98.7% and a specificity of96.5% for the diagnosis of VT in 554 patients whensimilar conventional criteria were used. In that study,there was a preponderance of patients with SHD.Similarly, our 101 ECGs in patients with SHD demon-strated a sensitivity of 95% to correctly diagnose VT.Only the previous study by Vereckei et al. (14) sys-tematically assessed sensitivity of VT criteria foridiopathic VT: a VT cohort of 348 VTs included 38idiopathic VTs in whom sensitivity of their proposedECG criteria for VT was 86.5% (similar to our finding of82%). Although that study did not directly comparethis with sensitivity in SHD VT patients, the criteria’ssensitivity among their entire VT cohort was 95.7%(similar to our finding of 95% among SHD patients).
STUDY LIMITATIONS. One limitation of our study isthe lack of a prospective application of the ECGcriteria to patients presenting with previously undi-agnosed WCTs. As a historical cohort was used, many
PERSPECTIVES
COMPETENCY IN MEDICAL KNOWLEDGE:
Conventional criteria to distinguish VT from SVT with
aberrancy were developed from cohorts of patients
with ischemic and structural heart disease. Sensitivity
of these criteria to correctly diagnose VT are lower for
idiopathic VT (82%) than for post-MI VT (95%).
COMPETENCY IN PATIENT CARE: When evalu-
ating wide complex tachycardias among patients
without underlying structural heart disease, conven-
tional criteria should be used with caution, particularly
RBBB V1 rSR0 (conventionally associated with SVT but
present in 21% of RBBB idiopathic VTs) and LBBB V1 or
V2 R of >30 ms or QRS onset to S nadir of >60 ms
(conventionally associated with VT but absent in 17%
of our idiopathic VT cohort).
TRANSLATIONAL OUTLOOK: Future criteria
specific to idiopathic VT may be developed by
excluding criteria that rely on QRS duration (a marker
of slow ventricular conduction due to myocardial
fibrosis from structural heart disease) and RBBB V1
morphology (Rsr0 vs. rsR0).
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of the baseline characteristics of the SVT patients arenot known, limiting a more thorough comparisonwith this group. There were no patients in our cohortwith pre-excited tachycardias, epicardial VTs (whichmay be idiopathic or due to structural heart disease),and wide complex tachycardia due to class Iantiarrhythmics, reducing generalizability of our datato these populations. Our blinded ECG analysis wasperformed by 2 cardiologists in a rigorous manner,using the conventional criteria and the algorithmdescribed above, but it is possible that sensitivity andspecificity for VT may differ if analyzed by clinicianswith less experience in ECG analysis. As our datafrom 3 centers were analyzed centrally and in ananonymous manner, we were not able to performstatistical analysis for among-center variance.Another limitation of the study was the inability touse AV dissociation criteria fully in the idiopathic VTgroup as 8 of 115 patients (7%) had only isolated PVC,although a sensitivity analysis was performed.Finally, a Bayesian approach, as demonstrated by Lauet al. (15), using likelihood ratios instead of ouralgorithmic approach to VT versus SVT diagnosismight have affected sensitivity and specificity, asthey noted an increased sensitivity for fascicular VTwhen Bayes0 theorem was used compared withclinician judgment. Future research using this orother cohorts may identify novel ECG criteria thatmay specifically be used to differentiate idiopathicVT from SVT.
CONCLUSIONS
In patients with idiopathic VT, conventional criteriato distinguish VT from SVT have a lower sensitivity(82%) for the diagnosis of VT. In contrast, in ourcohort of patients with post-MI VT, the ability tocorrectly diagnose VT was 95%. This reduced sensi-tivity to diagnose idiopathic VT was noted forPurkinje-associated VTs and VT with septal sites oforigin and was similar in patients regardless of bundlebranch block morphology. In particular, the reduced
sensitivity to diagnose VT with RBBB morphology ispredominantly due to conflicting criteria, with an rsR0
pattern in V1 which favors SVT and an R-to-S ratioof <1 in V6, favoring VT. In contrast, in patients withLBBB morphology VT, the conventional criteria areoccasionally not met, typically because of a lack of aninitial R of >30 ms or rS of >60 ms in V1 or the absenceof a Q-wave in V6. This leads to an erroneous diag-nosis of SVT.
ADDRESS FOR CORRESPONDENCE: Dr. Melvin M.Scheinman, University of California-San Francisco,500 Parnassus Avenue, San Francisco, California 94118.E-mail: [email protected].
RE F E RENCE S
1. Brugada P, Brugada J, Mont L, Smeets J,Andries EW. A new approach to the differentialdiagnosis of a regular tachycardia with a wide QRScomplex. Circulation 1991;83:1649–59.
2. Drew BJ, Scheinman MM. ECG criteria todistinguish between aberrantly conducted supra-ventricular tachycardia and ventricular tachy-cardia: practical aspects for the immediate caresetting. Pacing Clin Electrophysiol 1995;18:2194–208.
3. Kindwall KE, Brown J, Josephson ME. Electro-cardiographic criteria for ventricular tachycardia inwide complex left bundle branch blockmorphologytachycardias. Am J Cardiol 1988;61:1279–83.
4. Wellens HJ, Bar FW, Lie KI. The value of theelectrocardiogram in the differential diagnosis of atachycardia with a widened QRS complex. Am JMed 1978;64:27–33.
5. Vereckei A, Duray G, Szénási G, Altemose GT,Miller JM. New algorithm using only lead aVR for
differential diagnosis of wide QRS complextachycardia. Heart Rhythm 2008;5:89–98.
6. Tanawuttiwat T, Nazarian S, Calkins H. The roleof catheter ablation in the management of ven-tricular tachycardia. Eur Heart J 2016;37:594–609.
7. Sandler IA, Marriott HJ. The differentialmorphology of anomalous ventricular complexesof RBBB-type in lead V: ventricular ectopy versusaberration. Circulation 1965;31:551–6.
J A C C : C L I N I C A L E L E C T R O P H Y S I O L O G Y V O L . 3 , N O . 7 , 2 0 1 7 Yadav et al.J U L Y 2 0 1 7 : 6 6 9 – 7 7 Conventional ECG Criteria in Patients With Idiopathic VT
677
8. Coumel P, Leclercq JF, Attuel P,Maisonblanche P. The QRS morphology in post-myocardial infarction ventricular tachycardia. Astudy of 100 tracings compared with 70 cases ofidiopathic ventricular tachycardia. Eur Heart J1984;5:792–805.
9. Lerman BB, Stein KM, Markowitz SM, Mittal S,Iwai S. Ventricular tachycardia in structurallynormal hearts. In: Zipes DP, Jalife J, editors. CardiacElectrophysiology fromCell toBedside, 4th edition.WB Saunders: Philadelphia, PA: 2004:668–82.
10. Dixit S, Gerstenfeld EP, Callans DJ,Marchlinski FE. Electrocardiographic patterns ofsuperior right ventricular outflow tract tachy-cardias: distinguishing septal and free-wall sites
of origin. J Cardiovasc Electrophysiol 2003;14:1–7.
11. Miller JM, Das MK, Arora R, Alberte-Lista C,Wu J. Differential diagnosis of wide QRS complextachycardia. In: Zipes DP, Jalife J, editors. CardiacElectrophysiology from Cell to Bedside. 4th edi-tion. WB Saunders: Philadelphia, PA: 2004:747–57.
12. Krebs ME, Krause PC, Engelstein ED, Zipes DP,Miles WM. Ventricular tachycardias mimickingthose arising from the right ventricular outflowtract. J Cardiovasc Electrophysiol 2000;11:45–51.
13. Isenhour JL, Craig S, Gibbs M, Littmann L,Rose G, Risch R. Wide-complex tachycardia:continued evaluation of diagnostic criteria. AcadEmerg Med 2000;7:769–73.
14. Vereckei A, Duray G, Szenasi G,Altemose GT, Miller JM. Application of a newalgorithm in the differential diagnosis of wideQRS complex tachycardia. Eur Heart J 2007;28:589–600.
15. Lau EW, Pathamanathan RK, Ng GA, Cooper J,Skehan JD, Griffith MJ. The Bayesian approachimproves the electrocardiographic diagnosis ofbroad complex tachycardia. Pacing Clin Electro-physiol 2000;23:1519–26.
KEY WORDS catheter ablation,electrocardiogram, idiopathic ventriculartachycardia, wide complex tachycardia
