Ventricular tachycardia

Structural heart diseases

In most cases, ventricular tachycardia occurs in the context of structural heart disease:

• Ischemic heart disease: the most common cause of ventricular tachycardia in adults. Post-infarction scar tissue provides an ideal substrate for the development of reentry circuits. VT usually occurs several years after a heart attack, once the myocardial scar has matured;
• Cardiomyopathies: dilated, hypertrophic, arrhythmogenic right ventricular, or other rarer forms;
• Inflammatory conditions: acute or post-inflammatory myocarditis;
• Advanced valvular heart disease: particularly long-standing severe aortic or mitral regurgitation;
• After cardiac surgery: postoperative ventricular scars;
• Infiltrative myocardial diseases: sarcoidosis, amyloidosis.

In these cases, the main mechanism is the formation of a reentry circuit: the myocardial scar contains islands of viable myocardial cells within fibrotic tissue, creating “electrical channels” that allow the impulse to propagate slowly and abnormally, forming a self-sustaining circuit.

Ventricular tachycardias without structural heart disease

More rarely, ventricular tachycardia can occur in an apparently healthy heart:

• Idiopathic ventricular tachycardia: mainly right or left ventricular outflow tract tachycardia, and fascicular tachycardia;
• Channelopathies: genetic disorders affecting cardiac ion channels, such as long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia;
• Drug-induced causes: certain antiarrhythmics, antipsychotics, and antihistamines can prolong the QT interval and promote the onset of torsades de pointes (a particular form of polymorphic ventricular tachycardia);
• Electrolyte imbalances: severe hypokalemia, hypomagnesemia, hypocalcemia;
• Intoxications: cocaine, amphetamines, other stimulants;
• Severe hyperthyroidism.

These idiopathic ventricular tachycardias are generally benign and have an excellent prognosis. Their mechanism is often linked to triggered activity or abnormal automaticity, rather than scar-related reentry.

The clinical presentation of ventricular tachycardia is highly variable and depends on several factors:

• The heart rate during tachycardia;
• Its duration;
• Underlying left ventricular function;
• The presence or absence of associated heart disease;
• Individual hemodynamic tolerance.

Clinical manifestations may include:

• Palpitations: a sensation of rapid, forceful, or irregular heartbeats. This is the most common symptom, especially in well-tolerated forms;
• Dyspnea (shortness of breath) on exertion or at rest, depending on severity;
• Chest pain: ischemic in origin, caused by increased myocardial oxygen demand or reduced coronary blood flow;
• Signs of cerebral hypoperfusion: dizziness, lightheadedness, blurred vision;
• Syncope (brief loss of consciousness): occurs when cardiac output drops significantly;
• Signs of acute heart failure: acute pulmonary edema, low blood pressure, signs of low cardiac output;
• Sudden cardiac death: due to degeneration into ventricular fibrillation.

It is important to note that some episodes of ventricular tachycardia may be asymptomatic, particularly brief or non-sustained episodes (lasting less than 30 seconds), and are only detected during electrocardiographic monitoring. Even without symptoms, these episodes require evaluation as they may indicate an increased risk of more serious events.

Depending on the clinical presentation, several forms of ventricular tachycardia can be distinguished:

• Well-tolerated VT: the patient experiences palpitations but remains hemodynamically stable;
• Poorly tolerated VT: presence of severe signs (hypotension, syncope, acute heart failure);
• Non-sustained VT: brief episodes (less than 30 seconds), often asymptomatic but potentially indicative of higher risk;
• Polymorphic VT: a particular form with variable QRS morphology, often associated with long QT syndrome (torsades de pointes);
• Electrical storm: occurrence of three or more episodes of VT/VF within 24 hours.

Main diagnostic methods

The diagnosis of ventricular tachycardia relies primarily on electrocardiographic documentation of the arrhythmia:

• Standard electrocardiogram (ECG): if the arrhythmia is present at the time of the exam, the ECG typically shows a wide-complex tachycardia (QRS ≥ 120 ms) with specific criteria that help distinguish it from supraventricular tachycardia with aberrancy;
• Holter ECG: continuous ECG recording over 24 to 48 hours, particularly useful for intermittent arrhythmias and for quantifying arrhythmic burden (number and duration of episodes);
• Event monitor or implantable loop recorder: for very sporadic arrhythmias, these devices allow for longer-term recording (up to several years for implantable recorders).

These diagnostic tests can be performed at all Rythmopôle Paris centers, including Cardiopôle Yvart (Paris 15th) and Centre Damrémont (Paris 18th).

Assessment of underlying heart disease

Once the diagnosis of ventricular tachycardia has been established, it is essential to assess the presence and extent of any underlying heart disease:

• Transthoracic echocardiography: a key test to assess left ventricular function, detect regional wall motion abnormalities suggestive of previous infarction, and identify other structural abnormalities;
• Cardiac MRI: enables precise tissue characterization, particularly the detection and quantification of fibrosis or myocardial scars that constitute the substrate for ventricular tachycardia;
• Coronary angiography: indicated when ischemic heart disease is suspected, to evaluate the condition of the coronary arteries;
• Cardiac CT scan: may complement the assessment, particularly for coronary anatomy analysis or calcification detection.

These advanced imaging tests are available at Institut Mutualiste Montsouris (Paris 14th), where Rythmopôle Paris electrophysiologists have access to a comprehensive technical platform.

Electrophysiological studies

In some cases, invasive electrophysiological exploration may be necessary:

• Intracardiac electrophysiological study: helps confirm the diagnosis in uncertain cases, assess ventricular vulnerability using stimulation protocols, and precisely locate the origin of the tachycardia in preparation for ablation;
• Electroanatomical mapping: advanced technology that creates a three-dimensional reconstruction of the heart with superimposed electrical data, essential for guiding complex ablation procedures.

These specialized procedures are performed at Institut Mutualiste Montsouris by the expert electrophysiologists of Rythmopôle Paris.

Risk assessment is a crucial step in determining the optimal therapeutic strategy. Several factors are taken into account:

• Presence and severity of underlying heart disease: the main prognostic determinant. Left ventricular ejection fraction is particularly important (major risk if LVEF < 35%);
• Characteristics of the tachycardia: sustained VT and/or VT poorly tolerated from a hemodynamic standpoint is associated with a higher risk than non-sustained or well-tolerated VT;
• Circumstances of occurrence: VT occurring at rest generally has a worse prognosis than VT triggered only by exertion;
• Response to medical treatment: recurrence despite optimal antiarrhythmic therapy is a poor prognostic factor;
• Comorbidities: renal failure, COPD, and diabetes can worsen prognosis.

This personalized risk assessment, carried out by the electrophysiologists at Rythmopôle Paris, helps guide therapeutic decisions, including the indication for implantation of an implantable cardioverter-defibrillator (ICD).

Acute phase treatment

Management of an acute episode of ventricular tachycardia depends on its hemodynamic tolerance:

• Poorly tolerated VT (hypotension, syncope, signs of acute heart failure):
  • Emergency external electrical cardioversion under brief sedation;
  • Then intravenous antiarrhythmic therapy to prevent immediate recurrences.
• Well-tolerated VT:
  • Intravenous drug therapy (amiodarone, lidocaine, procainamide);
  • Electrical cardioversion if drug therapy fails.

These emergency treatments are provided in emergency departments and intensive cardiac care units, in collaboration with the electrophysiologists at Rythmopôle Paris.

Long-term preventive treatments

To prevent recurrences of ventricular tachycardia, several strategies are available:

• Treatment of the underlying heart disease:
  • Coronary revascularization in cases of ischemic heart disease;
  • Optimal medical treatment for heart failure;
  • Correction of triggering factors (electrolyte imbalances, arrhythmogenic drugs, etc.).
• Antiarrhythmic drug therapy:
  • Beta-blockers: first-line therapy, particularly in ischemic heart disease;
  • Amiodarone: class III antiarrhythmic, the most effective but with potentially serious side effects during long-term use;
  • Other antiarrhythmics (sotalol, mexiletine, etc.) depending on the clinical context.
• Implantable cardioverter-defibrillator (ICD):
  • Reference treatment for secondary prevention (after an episode of sustained VT or ventricular fibrillation);
  • Also indicated for primary prevention in high-risk patients (LVEF ≤ 35% despite optimal medical therapy);
  • Does not treat the cause of the arrhythmia but prevents potentially fatal consequences by delivering an electric shock or anti-tachycardia pacing (ATP) in case of recurrence.
• Catheter ablation:
  • Curative treatment aimed at eliminating the arrhythmogenic substrate;
  • Particularly effective for reentry-related VT (post-infarction VT, idiopathic VT);
  • May be proposed in addition to ICD implantation to reduce recurrences and therefore defibrillator therapies;
  • Performed percutaneously under local or general anesthesia, this procedure includes precise electroanatomical mapping of the tachycardia circuit, followed by radiofrequency or cryotherapy ablation of critical areas.

ICD implantation and complex ablation procedures are performed at Institut Mutualiste Montsouris by the electrophysiologists of Rythmopôle Paris. It is important to note that these invasive treatments are only for a small number of patients—those with significant ventricular tachycardia or at high risk of serious complications.

Recommended medical follow-up

Patients with ventricular tachycardia require regular electrophysiology follow-up:

• Cardiology consultations with ECG every 3 to 6 months;
• Periodic Holter ECG to assess arrhythmic burden and treatment effectiveness;
• ICD checks every 3 to 6 months;
• Regular assessment of left ventricular function via echocardiography;
• Adjustment of antiarrhythmic therapy based on progression.

This specialized follow-up is provided at several Rythmopôle Paris centers, including Cardiopôle Peupliers-Trubert and Centre Cœur et Santé Bernouilli (Paris 8th).

Physical activity

Recommendations regarding physical activity depend on the type of ventricular tachycardia and the underlying heart condition:

• For idiopathic VT without structural heart disease: moderate physical activity is generally allowed, with occasional restrictions for intense sports depending on the type of VT;
• In cases of structural heart disease: recommendations are tailored to the severity of the condition and the stability of the arrhythmia;
• For patients with an implantable cardioverter-defibrillator (ICD): contact sports and certain activities with a high risk of trauma are generally discouraged.

A supervised cardiac rehabilitation program can be offered at Cardiopôle Yvart, allowing for a gradual and safe return to adapted physical activity.

Trigger factors to avoid

Certain factors may promote the occurrence of ventricular tachycardia and should be identified and avoided:

• Intense emotional stress;
• Excessive consumption of stimulants (caffeine, nicotine);
• Potentially arrhythmogenic medications;
• Electrolyte imbalances (restrictive diets, uncontrolled diuretic use);
• Certain environmental factors (extreme altitude, scuba diving) depending on the type of arrhythmia.

Personalized therapeutic education is offered to patients followed at Rythmopôle Paris to help identify and manage these trigger factors.

Rythmopôle Paris offers comprehensive expertise in the management of ventricular tachycardia:

• A team of electrophysiologists specializing in the diagnosis and treatment of complex ventricular arrhythmias;
• An advanced technical platform at Institut Mutualiste Montsouris for performing three-dimensional electroanatomical mapping and complex ablation procedures;
• Expertise in the implantation and programming of implantable cardioverter-defibrillators (ICDs);
• Personalized follow-up with monitoring of implantable devices in several centers across Île-de-France;
• A multidisciplinary approach involving interventional cardiologists, electrophysiologists, and heart failure specialists for comprehensive patient care;
• Access to innovative techniques such as irrigated radiofrequency ablation, cryotherapy, and high-density mapping systems.