Summary features of idiopathic monomorphic VTs and inherited arrhythmia syndromes
| Idiopathic ventricular arrhythmia type | Age group (years) | Gender | Likely mechanism | ECG characteristics | Effective medications | Success rate of ablation | Miscellaneous comments |
| Non-inherited VT in structurally normal hearts | |||||||
| Outflow tract VT | 30–50 | F>M | DAD | LBBB more common than RBBB, inferior axis | BB, CCB, Class IC or III AAD | >80% | Atrial/ventricular burst pacing usually induce VTIsoproterenol or epinephrine facilitate induction |
| Interfascicular VT | 20–40 | M>F | Re-entry | RBBB/LS axis (LPF exit); RBBB/RI axis (LAF exit) | CCB (Verapamil), BB | 80% | |
| Automatic fascicular VT (propranolol sensitive) | Variable | Variable | Abnormal automaticity or triggered activity | Typical or atypical LBBB or RBBB | BB (Propranolol) | Not established | |
| Mitral annular VT | 50–70 | M≥F | Abnormal automaticity of triggered activity | RBBB morphology, R>S in V1–V4 | BB, class Ic or III AAD | >90% | |
| Tricuspid annular VT | 50–70 | M≥F | Abnormal automaticity of triggered activity | LBBB morphology, −aVR, +I. Other features vary depending on exact location | BB, class Ic or III AAD | 90% | Success rate of ablation lower if arising from septal aspect of tricuspid annulus |
| Papillary muscle VT | 40–70 | M≥F | Abnormal automaticity of triggered activity | QRS>150 ms, RBBB morphology RS or rS in V3–V6Axis is superior if from PPM | BB, CCB, class Ic or III AAD | Limited data | |
| Inflammatory VT (eg, cardiac sarcoidosis, myocarditis) | Variable: depends on underlying condition | Variable: depends on underlying condition | Functional or scar-related re-entry most common depending on phase of disease | Variable, depending on site of inflammation | Supportive with immunosuppressionMechanical support and cardiac transplantation may be required in fulminant cases | Cardiac sarcoidosis: ~50% at 1–2 years44 Myocarditis: 90% at 2 years45 | Cardiac MRI, FDG-PET scan and endocardial biopsy important |
| Inherited VT in structurally normal hearts | |||||||
| LQTS | Variable | M = F | APD prolongation Re-entry | PMVT QTc usually 460 ms in sinus rhythm | BB, LCSD, pacing, ICD | N/A | Variable additional pharmacological options depending on subtype |
| SQTS | Variable. Consider in young patient with AF and short QT interval | M = F | APD shortening Re-entry | PMVT QTc<360 ms, short/absent ST segment, peaked T-wave, PR depression | ICD, Quinidine | N/A | Caused by shortening of repolarisation and APD. 2○ to gain of function (K+ channel) or loss of function (Ca2+ channel) mutations |
| CPVT | <30 | M = F | DAD | PMVT, bidirectional VT Normal sinus rhythm ECG at rest | BB (nadolol), CCB, flecainide, propafenone, LCSD, avoidance of competitive sport | N/A | Due to a malfunctioning ryanodine receptor → results in diastolic Ca2+ overload with DAD |
| BrS | 20–40 | M >> F | Re-entry | PMVT ST elevation in V1–V3 in sinus rhythm (may require provocation) | ICD Quinidine, isoproterenol (for VT storm) | Limited data: reportedly >80% | |
| ERS | 20–50 | M ≥ F | Re-entry | VF J-point elevation in sinus rhythm | ICD Quinidine | N/A | |
AAD, antiarrhythmic drug; AF, atrial fibrillation; APD, action potential duration; BB, beta-blocker; BrS, Brugada syndrome; CCB, calcium channel blocker; CPVT, catecholaminergic-polymorphic VT; DAD, delayed after depolarisation; ERS, early repolarisation syndrome; F, female; FDG, flurodeoxyglucose; ICD, implantable cardioverter defibrillator; LAF, left anterior fascicle; LBBB, left bundle branch block; LCSD, left cardiac sympathetic denervation; LPF, left posterior fascicle; LQTS, long QT syndrome; LS, left superior; M, male; N/A, not applicable; PMVT, polymorphic ventricular tachycardia; PPM, permanent pacemaker; R, R-wave; RBBB, right bundle branch block; RI, right inferior; S, S-wave; SQTS, short QT syndrome; VF, ventricular fibrillation; VT, ventricular tachycardia.