Idiopathic VT refers to VT occurring in structurally normal hearts in the absence of myocardial scarring. Classification of monomorphic idiopathic VT includes outflow tract VT, fascicular VT, papillary muscle VT,annular VT, and miscellaneous (VT from the body of the RV and crux of the heart). It is commonly seen in young patients and usually has a benign course. The 12-lead lectrocardiogram is critical in distinguishing the specific form and locations of idiopathic VT. Treatment options include medical therapy specific to the underlying mechanism of VT or catheter ablation.

1. Ramachandra

3. IVT refers
 structurally normal hearts.
 Young patients
 Benign course
 focal
 Monomorphic
 No scar
 12-lead ECG extremely useful
 Treatment :reassurance, medical therapy, and
catheter ablation.

4.  Prevalence estimates accounted for 7%-38% of all
patients referred for VT
 Realistic estimation is closer to 10%.

8.  RVOT Tachycardia
 LVOT/Aortic Cusp Tachycardia
 Epicardial Outflow Tract VT
Mechanism
triggered activity due to catecholamine-mediated delayed after-depolarizations.This
triggered activity results from a catecholamine-mediated increase in cyclic adenosine
monophosphate, with subsequent increase in intracellular calcium from the sarcoplasmic
reticulum, resulting in delayed after-depolarizations and triggered activity. This underlying
mechanism leads to tachycardia initiation with catecholamines and termination with
adenosine, -blockers, or calcium channel blockers.

9.  most common IPVT-70%
 LBBB/Inf axis
 F>X2M
 triggered by exercise or stress, and may also occur
during hormonal cycles in women
 third to fifth decade of life
 C/F: palpitations/chest pain, fatigue, and
presyncope or syncope/isolated PVCs/nonsustained
VT/sustained VT.

10.  10%-15% of IPVT,M>F
 Anatomy
Noncoronary cusp does not directly contactventricular
myocardium, ventricular arrhythmias are rare.
The base of the left and right coronary cusps lies in direct
contact to the ventricular myocardium, and LV muscle fibers
may extend into the aortic root,serving as a source of these
PVCs. These extensions may be a remnant from embryonic
development, and these myocardial fibers persist providing an
arrhythmogenic substrate. When mapping more inferiorly in
the aortic root, successful ablation may be related to necrosis
of ventricular myocytes arising from the most superior portion
of the ostium of the LV.

11. LBBB /inferior axis/ precordial transition earlier than
their RVOT-VT . The precordial R-wave transition
typically occurs at or before lead V3. VT originating
from the left.coronary cusp has an earlier R-wave
transition (typically by V1/2) than the right
coronary cusp (V2/3). A broader R-wave duration
(_0.5 ms) and a taller R/S-wave Amplitude in V1
and V2 favor aortic cusp location.When the
precordial transition occurs at lead V3, a precordial
transition earlier than sinus rhythm transition is
suggestive of LVOT-VT.

13.  Idiopathic left fascicular VT= fascicular VT=LBB-
ANT/POST
 ECG classify to left posterior fascicular VT, left anterior
fascicular VT, and left upper septal VT.
 LPFVT- most common then LAFVT & septal is rare
 young male(60%)- 15 and 40 years, younger female.
 paroxysmal
 Exertion.
 Symptoms – palpitations/syncope /tachycardia-
mediated cardiomyopathy .

15.  RBBB/LAD/ VT induced by atria pacing.
 Verapamil sensitive
 tachycardia originates from the Purkinje network of the
 mechanism of verapamil-sensitive left VT is
reentry/induced, entrained, and terminated by
ventricular or atrial stimulation. The proposed
reentrant circuit consists of an area of slow conduction
that forms the orthodromic limb in the LV septum from
base to apex, with the retrograde limb using the
Purkinje network
 false tendons is arrythmogenic.

16.  RBBB/left superior axis pattern/narrow/confused
for SVT
 LPFT - RBBB and left axis deviation(LAFB)
 LAFT-RBBB/RAD(LFBB)
 septal VT demonstrates an incomplete
RBBB and normal axis.

17.  Excellent prognosis
 Medical Therapy
Intravenous verapamil is effective for acute termination.
Chronic oral verapamil therapy is often an effective regimen
for patients with symptoms who do not wish to pursue
catheter ablation.-adrenergic blockers have also been used
with some success.
 Catheter Ablation: successful-90%,

18.  2008, Doppalapudi et al. first to report idiopathic VT from posterior
PM
 Posterior papillary muscle origin is more common.
Papillary muscle VT is usually exercise induced and is catecholamine
sensitive, requiring isoproterenol or epinephrine for induction
 mechanism is typically focal in nature and not reentrant. This VT cannot
be entrained, and has a lack of late potentials at the site of ablation.
 Papillary muscle VT often exhibits multiple QRS morphologies, with
subtle changes seen spontaneously or during ablation. These subtle
morphologic changes are thought to be from preferential conduction to
different exit sites or multiple regions of origins within the complex
structure of the papillary muscles.
 RFA-quite usuful.

19.  majority from anterior mitral annulus
 ECG in MAVT:RBBB pattern/ monophasic R or Rs in
leads V2-V6.
 Catheter ablation is highly successful with ablation
delivered at the site of earliest ventricular
activation or sites with a 12/12 pace-map match by
mostly endocardial approach or coronary venous
system(GCV)

20.  8% of IPVT
 5% of right-sided VT
 Septal sites > free-wall sites
 septal locations-anteroseptal or para-Hisian.
 ECG: A positive component (any r or R) was recorded in lead aVL in 95%
of patients
 QRS duration and Q-wave amplitude V1-V3 were greater in VT/PVCs
arising from the free wall of the tricuspid annulus compared with the
septum. Notching of the QRS complex was seen more often in free-wall
sites, as well as later precordial transition. A Q-wave in lead V1 was
observed more often in septal tricuspid annular VTs.
 RF catheter ablation successful for the free wall (90%) compared with
the septal (57%) group. Low success rate in the septal tricuspid annular
group was thought to be due to the likelihood of impairing AV nodal
conduction with RF ablation.

21.  Van Herendael reported 278 IPVT from
10% -lower RV body.
48% -Within 2 cm of the tricuspid annulus
28% -Basal RV
24% -the apical RV.
 VT/PVC from the RV free wall had a longer QRS
duration and deeper S-wave in lead V2/V3.
 Apical VT/PVC more often had precordial R-wave
transition V6, smaller R-waves in lead II, and an S-wave
in aVR.
 RF catheter ablation was acutely successful in 96% of
patients.

22.  Doppalapudi described 4/340 patients referred for IPVT
 Epicardial , junction of the middle cardiac vein and the coronary sinus
 Sustained / syncope or presyncope
 Induced/timulation or burst pacing from the RV, and often required
Isoproterenol
 ECG demonstrates a leftward superior axis QRS
morphology with an early precordial transition and delayed intrinsicoid
deflection.
 EP study: The earliest activation was present in the middle cardiac vein.
Coronary angiography
demonstrated the site of earliest activation within 5-10 mm of the
proximal posterior descending artery or proximal coronary sinus
 Ablation from the coronary sinus or middle cardiac vein was attempted
in all, but was successful in only one.Percutaneous epicardial ablation
was attempted in two of the remaining three, and successfully
abolished VT in both.