Supraventricular Extrasystole: Definition, Causes, Risk Factors, Symptoms, Diagnosis and Treatment

We are talking about one of the most frequent causes of visits to the emergency department and doctor’s office.

Supraventricular extrasystole, also known as supraventricular tachycardia (SVT), is defined as an abnormally fast heart rhythm that has an electropathological substrate that emerges above the bundle of His (atrioventricular bundle), causing the heart to increase at speeds greater than 100 beats per minute.

Most types of SVT are caused by a reentry mechanism that can be induced by premature atrial or ventricular ectopic beats and are classified according to the location of the reentry circuit.

Accelerated heart rate can be alarming for a patient, because the onset is usually abrupt and, in some cases, the episodes can be recurrent and persistent.

Although most cases of SVD are not considered dangerous or life-threatening, frequent episodes can weaken the heart muscle over time and therefore must be addressed with medical intervention to prevent further complications.

Risk factors and causes of supraventricular extrasystole

Although SVT episodes can occur in anyone, there are certain factors that can increase an individual’s risk.

Examples of these risk factors include:

  • Excessive use of caffeine or alcohol.
  • History of tobacco use.
  • use of illicit drugs
  • Extreme psychological stress and anxiety.
  • Hyperthyroidism .
  • Low levels of potassium and magnesium.
  • Family history of tachycardia.
  • Structural abnormalities of the heart.
  • Adverse reactions from certain pharmacological agents (i.e. antihistamines, theophylline, cough and cold preparations, appetite suppressants).
  • Certain medical conditions (eg, cardiovascular disease, long-term respiratory disease, diabetes, anemia, cancer).

Symptoms commonly associated with episodes of supraventricular extrasystole or SVT.

Although some patients with SVT may not experience any symptoms, other patients present during childhood, adulthood, or middle age with symptoms that generally have a sudden onset and end.

When the patient is asymptomatic or presents with few symptoms, it can cause a delay in diagnosis.

Results from various studies have noted that symptoms commonly reported by SVT patients can mimic other conditions and are sometimes mistaken for anxiety attacks or panic disorders , especially among the female patient population.

The most common symptom during an SVT episode is palpitations or the feeling that the heart is beating rapidly, fluttering, or racing. These episodes can last a few seconds or several hours.

The other symptoms associated with SVTs include dizziness or lightheadedness, chest pain, dyspnea, anxiety, palpitations including throbbing in the neck area, sweating, fatigue, vision changes, and, in some rare cases, syncope .

SVT is generally not a serious or life-threatening condition, but medical attention should be sought, especially if it is a person’s first episode or if the episodes are severe and recurring.

Diagnosis of supraventricular extrasystole

Because SVT can be episodic, it can sometimes be misdiagnosed as anxiety or a panic disorder. For this reason, obtaining a complete medical and medication history of the patient is very important in the diagnosis of SVTs and to help determine possible triggers.

In addition to a physical exam, a diagnostic EKG can be used to provide clues to the type of SVT, reveal any damage to the heart muscle, and identify any other conduction disorders.

Doctors may also choose to use other diagnostic tools such as event monitor or Holter monitor, blood tests (i.e. thyroid stimulating hormone levels, metabolic profile, complete blood count, cardiac enzymes), electrophysiology study or an echocardiogram.

Treatment of supraventricular extrasystole

For some patients, most or all of their SVD episodes may stop on their own; Other patients require medical intervention. The management of SVT can be classified as short-term (immediate / acute) or long-term.

Short term management

Short-term management treatment options may include pharmacological and non-pharmacological measures. In most patients, the drug of choice for acute treatment is adenosine or verapamil.

The use of intravenous adenosine or the calcium channel blocker verapamil is considered a safe and effective therapy to control SVTs.

The advantages of adenosine include a rapid onset of action (usually within 10 to 25 seconds through a peripheral vein), a short half-life (less than 10 seconds), and a high degree of efficacy.

The short half-life of this agent minimizes the severity of adverse effects, including facial flushing, chest tightness, dyspnea, and transient sinus arrest and / or atrioventricular block.

The use of adenosine is contraindicated in those patients with sinus node dysfunction or second or third degree block and should be used with caution in patients with severe obstructive pulmonary diseases.

The efficacy of verapamil is comparable to adenosine, but its negative inotropic effect, vasodilator effects, and prolonged half-life make it unsuitable for patients with congestive heart failure or for those patients classified as hypotensive.

Adenosine and calcium channel blockers are contraindicated for use in patients with Wolff-Parkinson-White syndrome.

Intravenous administration of calcium channel blockers, such as diltiazem, or beta-blockers, such as esmolol, is also commonly used for short-term treatment of SVT.

Vagal maneuvers, a non-drug approach to short-term treatment, are techniques that increase vagal tone to decrease the patient’s heart rate.

Vagal maneuvers include the Valsalva maneuver, in which you try to exhale forcefully through a closed airway, cough while sitting with your upper body bent forward, and splash ice water on your face.

In some cases, vagal maneuvers are used as the initial measure to terminate SVT. Vagal maneuvers are often considered the first line of therapy in younger patients who are hemodynamically stable.

Long term management

For patients with recurrent SVT episodes, long-term therapy may be necessary.

Long-term treatment of SVT most often depends on the type of SVT, the patient’s medical history, the frequency, and the severity of the episode. Long-term treatment includes surgical options or the use of pharmacological agents.

Radiofrequency ablation (RFA) is considered a safe, effective and cost-effective surgical procedure to prevent or suppress SVT episodes in those patients with frequent SVT episodes and / or those who wish to avoid the use of pharmacological agents.

It is also beneficial for those patients who do not respond to or cannot tolerate pharmacological agents.

Studies report that the RFA procedure has high efficacy rates (single procedure success, 93.2%), low overall all-cause mortality (~ 0.1%), and is associated with low adverse events (~ 2 , 9%). Despite reports of high success rates, this procedure is not always used in clinical practice.

Pharmacological agents commonly used in the long-term treatment of SVT include amiodarone, procainamide, calcium channel blockers (eg, diltiazem and verapamil), and beta blockers (eg, metoprolol or atenolol).

The results report that for chronic oral reentry of AV nodes, the use of calcium channel blockers and beta-adrenergic blockers is preferred and has been shown to improve symptoms in 60-80% of patients.

The role of the pharmacist

Patients who have experienced an episode of supraventricular extrasystole will probably agree that it can be alarming and disturbing.

Patient counseling that focuses on how to effectively manage SVT episodes and possible treatments and preventive strategies can have a positive impact on patients’ overall quality of life. With the right information, patients can make informed decisions regarding the treatment of this condition.

Pharmacists should advise patients on the proper use of any prescription medication, including proper use, possible adverse effects, contraindications associated with the selected therapy, and the importance of adherence.

Patients should also be reminded to keep routine appointments with their primary health care provider to monitor and not use any medications, including over-the-counter products and herbal supplements, without first consulting their health care provider. primary health care.

Patients can better manage supraventricular extrasystoles by avoiding tobacco, alcohol, and caffeine consumption, lowering stress levels by incorporating relaxation techniques into their daily routine, eating a balanced diet, and exercising regularly.

Patients should be reminded to seek medical attention immediately if an episode of supraventricular extrasystole does not end within a few minutes after using preventive techniques or if they experience chest pains, palpitations, or syncope episodes, or if new or new symptoms develop. if existing symptoms get worse.

As one of the most accessible healthcare professionals, pharmacists can help alleviate the concerns of those patients experiencing SVT by making sure they are well informed about this condition.

They can also reassure patients that supraventricular extrasystoles can be managed and that they lead normal, productive lives.