From the Guidelines
Monomorphic ventricular tachycardia is primarily caused by structural heart disease, particularly coronary artery disease and prior myocardial infarction that creates scarring and reentry circuits. The causes of monomorphic ventricular tachycardia can be broken down into several key categories, including:
- Structural heart disease, such as coronary artery disease and prior myocardial infarction, which can lead to scarring and the formation of reentry circuits 1
- Cardiomyopathies, including dilated, hypertrophic, and arrhythmogenic right ventricular cardiomyopathy, which can disrupt the normal electrical activity of the heart
- Myocarditis and cardiac sarcoidosis, which can cause inflammation and scarring in the heart
- Valvular heart disease, which can lead to abnormal blood flow and increased pressure on the heart
- Electrolyte abnormalities, such as hypokalemia, hypomagnesemia, and hypocalcemia, which can disrupt the normal electrical activity of the heart
- Medication toxicity, particularly from antiarrhythmic drugs like flecainide, propafenone, and amiodarone, which can paradoxically cause monomorphic ventricular tachycardia
- Congenital heart defects, especially those involving surgical repair with resultant scarring, which can lead to monomorphic ventricular tachycardia.
According to the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death, catheter ablation is recommended in patients with ischaemic heart disease and recurrent ICD shocks due to sustained VT 1. This highlights the importance of addressing the underlying cause of monomorphic ventricular tachycardia, whether it be through catheter ablation or other means.
The management of monomorphic ventricular tachycardia typically involves a combination of acute and long-term strategies, including:
- Electrical cardioversion for hemodynamically unstable patients
- Intravenous antiarrhythmic medications, such as amiodarone or procainamide, for stable patients
- Implantable cardioverter-defibrillator placement for high-risk patients
- Catheter ablation to eliminate the arrhythmogenic substrate
- Antiarrhythmic medications, such as amiodarone or sotalol, to prevent recurrence.
It's worth noting that the 2015 ESC guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death also recommend urgent catheter ablation in patients with scar-related heart disease presenting with incessant VT or electrical storm 1. This highlights the importance of prompt and effective treatment in patients with monomorphic ventricular tachycardia.
In terms of specific management strategies, the 2017 AHA/ACC/HRS guideline recommends optimizing ICD programming to deliver therapy for VF and to minimize inappropriate shocks and the risk of potentially fatal electrical storms 1. This highlights the importance of careful device management in patients with monomorphic ventricular tachycardia.
Overall, the causes and management of monomorphic ventricular tachycardia are complex and multifaceted, requiring a comprehensive and individualized approach to treatment.
From the Research
Causes of Monomorphic Ventricular Tachycardia
The causes of monomorphic ventricular (V) tachycardia are not explicitly stated in the provided studies. However, the studies suggest that monomorphic ventricular tachycardia can occur in various conditions, including:
- Ischemic heart disease 2, 3
- Repaired tetralogy of Fallot 4
- Structural heart disease 5, 6
- Patients with implantable cardioverter-defibrillators (ICDs) 2, 3
Associated Factors
Some studies mention associated factors that may contribute to the occurrence of monomorphic ventricular tachycardia, such as:
- Right ventricular dysfunction 4
- Left ventricular dysfunction 4, 5
- Prior infarction 2
- Sustained monomorphic VT despite first-line antiarrhythmic drug therapy 2
Underlying Mechanisms
The underlying mechanisms of monomorphic ventricular tachycardia are not fully discussed in the provided studies. However, it is mentioned that catheter ablation can be effective in treating monomorphic ventricular tachycardia by targeting specific sites in the heart, such as the right ventricular outflow tract 4.
Key Findings
Some key findings from the studies include:
- Catheter ablation can be an effective treatment for monomorphic ventricular tachycardia in patients with ischemic heart disease 2 and repaired tetralogy of Fallot 4
- Antiarrhythmic drugs may be limited by incomplete efficacy and adverse effects 2
- The optimal first-line suppressive therapy for VT remains to be determined 2
- Catheter ablation alone may be a viable alternative to ICD implantation in selected patients with preserved left ventricular function and well-tolerated arrhythmias 6