DOI: https://doi.org/10.62204/2336-498X-2023-3-13

MODERN APPROACHES TO THE TREATMENT

AND PREVENTION OF CARDIAC ARRHYTHMIAS: ATRIAL FIBRILLATION

Tetiana Silko,

Doctor Cardiologist,
Department of Electrophysiology and X-Ray Surgical Treatment of Cardiac Arrhythmias,
Academic and Research Medical Centre of Pediatric Cardiology and Cardiac Surgery, clinic for adults, Ukraine,
silcotanya1995@gmail.com; ORCID: 0009-0004-7426-0558  

Maryna Meshkova,

Department of Electrophysiology and X-Ray Surgical Treatment of Cardiac Arrhythmias,
Academic and Research Medical Centre of Pediatric Cardiology and Cardiac Surgery, clinic for adults, Ukraine,
mcmcardio@gmail.com; ORCID: 0009-0009-6575-7585

Annotation. The article analyzes modern methods of diagnosis and treatment of cardiac arrhythmias – atrial fibrillation.

The author primarily focuses on the fact that the most important thing for atrial fibrillation is administering an anticoagulant, since failure to follow this recommendation can lead to negative consequences, such as stroke. The article also says on the effectiveness of taking antianrhythmic agents that is proven and recommended.

Atrial fibrillation is a kind of pandemic of the 21st century, since, as of 2023, it was found in 43.6 million people worldwide. Particularly, there is a dynamic increase in the frequency of AF after the COVID-19 pandemic. Therefore, updated studies on the follow-up examination and treatment of this arrhythmia are quite relevant.

Keywords: atrial fibrillation, AF classification, AF diagnosis, ABC approach, AF drug treatment.

Introduction. Atrial fibrillation is a rapid (350–700/min), uncoordinated activation of the atria, which leads to a loss of hemodynamic efficiency of their contractions, accompanied by an irregular ventricular rhythm. The frequency of ventricular rhythm depends on the electrophysiological properties of the AV node, the function of the autonomic system, as well as the action of drugs, and can be normal (70–90/min at rest), accelerated (tachyarrhythmia) or delayed (bradyarrhythmia).

Classification of atrial fibrillation.

AF can be:

  1. Paroxysmal (with the rhythm restored independently within 7 days):
  • bradycardic (with ventricular rate less than 60 per minute);
  • tachysystole (with ventricular rate greater than 110 per minute);
  1. Persistent (the episode lasting more than 7 days, when intervention is necessary to restore sinus rhythm):
  • bradycardic (with ventricular rate less than 60 per minute);
  • tachysystole (with ventricular rate greater than 110 per minute);
  1. Long-term persistent (an episode lasting one year or more, when it is advisable to restore the sinus rhythm):
  • bradycardic (with ventricular rate less than 60 per minute);
  • tachysystole (with ventricular rate greater than 110 per minute);
  • constant (when it is not possible or advisable to restore the sinus rhythm):
  • bradycardic (with ventricular rate less than 60 per minute);
  • tachysystole (with ventricular rate greater than 110 per minute);

Table 1

Atrial fibrillation assessment classes by symptoms

AF class by symptoms
EHRA class Assessment of arrhythmia symptoms (explanation)
EHRA 1 Absence of clinical manifestations
Mild symptoms that do not impact normal daily activities
Mild impact on daily activities
Severe symptoms that restrict normal daily activity
EHRA IV Disabling symptoms that make normal daily activities impossible

Atrial fibrillation diagnostic program:

  1. Collecting complaints and medical case history
  2. Сlinical examination3. Blood pressure measurement
  3. Laboratory examination:
    • general blood test;
    • general urinalysis;
    • ALT;
    • AST;
    • bilirubin;
    • creatinine;
    • lipidogram and triglycerides;
    • blood glucose;
    • thyroid and pituitary hormones (T3, T4 free, thyroid-stimulating hormone); • coagulogram and INR, APTT.
  4. 12-lead ECG
  5. Echocardiography
  6. Physical activity test
  7. Daily ECG monitoring or case registration
  8. Electrophysiological examination.
  9. Transesophageal echocardiography.
  10. Chest radiography
  11. Markers of the inflammatory process in the myocardium.
  12. MRI of the heart to exclude myocarditis.

AF is a potentially dangerous heart rhythm disorder. As we know, in 2020, the European Society of Cardiology Guidelines (ESC, 2020) were published in cooperation with the European Association for Cardio-Thoracic Surgery (EACTS) on the diagnosis and management of patients with AF. The highlight of these guidelines was the ABC algorithm, which had been suggested for a holistic and comprehensive approach to the AF treatment.

The ABC approach (Atrial Fibrillation Better Care); “A” means anticoagulation/ stroke prevention; “B” means better symptom management; “C” means optimization of cardiovascular deceases and comorbidities), it streamlines comprehensive treatment of patients with AF at all healthcare levels.

Compared to conventional treatment, the introduction of the ABC algorithm is associated with a lower risk of all-cause death, a lower combined outcome of stroke/ major bleeding/death from cardiovascular disease (CVD) and first hospitalization, a lower incidence of cardiovascular events, and lower healthcare-related costs.

In particular, at A stage, which involves anticoagulant treatment and stroke prevention, it is necessary to perform the following steps:

Identify low-risk patients (according to СНА2DS-VASc score – 0 for men and 1 for women).

Suggest stroke prevention actions if the CHA2DS-VASc score is ≥1 in men or 2 in women. One should also assess the risk of bleeding and take into account risk factors for bleeding that can be modified.

Choose an oral anticoagulant (OAC) – a novel OAC (NOAC) or vitamin K antagonist (VKA) with a well-controlled time estimate in the therapeutic range (TTR).

To assess the risk of stroke occurrence, it is recommended to introduce a risk factor approach using the СНА2DS-VASc score, in particular for the primary identification of patients with a low risk of stroke (with СНА2DS-VASc score being 0 for men or 1 for women) who should not be provided antithrombotic therapy (recommendation class I, evidence level A). According to the researchers, before taking OAC, each 11th patient with a CHA2DS-VASc score of 1-4 points has a risk of developing a stroke within a year, and it is each 6th patient with a score of 5-6 points, and each 5th patient with a score of ≥7 points (Olesen et al., 2011).

The use of NOAC was more effective than warfarin, as it helped reduce the risk of stroke by 19% and reduce the risk of death by 10%. The ESC/EATS guidelines give preference to NOAC over VKA in both primary and secondary prevention in patients who have had a stroke or transient ischemic attack (TIA) (recommendation class I, evidence level A). The exception is patients with mechanical prosthetic heart valve or moderately severe/severe mitral stenosis.

To assess the risk of bleeding, it is recommended to use a formal risk-score scale that helps identify unmodified/modified bleeding risk factors in all patients with AF, and identify patients with a potentially high risk of bleeding who should be suggested earlier and more frequent checkups and follow-ups (recommendation class I, evidence level B).

As for the secondary prevention of stroke in patients with AF after acute ischemic stroke or TIA, long-term OAC therapy is recommended for such patients without strict contraindications to their use, with a predominance of NOAC over VKA in patients who meet the criteria for the use of NOAC (recommendation class I, evidence level A).

Oral anticoagulant therapy is recommended for the prevention of stroke in patients with AF and a CHA2DS-VASc score of ≥2 in men or ≥3 in women (recommendation class I, evidence level A). The next step, according to the ABC algorithm, involves better/proper symptom control (“B”), which requires an assessment of the patient’s symptoms and quality of life. In particular, at this stage, it is necessary to optimize the control of heart rate (HR) and consider a strategy for rhythm control (cardioversion, antiarrhythmic therapy, radiofrequency ablation).

Beta blockers, diltiazem or verapamil (recommendation class I, evidence level B) are recommended as the first choice drugs for heart rate control in patients with AF with a left ventricular ejection fraction (LVEF) ≥40%.

Beta blockers and/or digoxin are recommended for heart rate control in patients with AF and LVEF <40% (recommendation class I, evidence level B).

 Selective beta blockers (recommendation class I, evidence level C) are recommended for monitoring heart rate for AF in patients during pregnancy.

Proven studies show that beta blockers are used to reduce the risk of sudden coronary death based on the findings of multicentre studies. Betaxolol also has the same proven efficacy in reducing the risk of sudden coronary death as carvedilol.

In turn, pharmacological cardioversion of AF is recommended only for hemodynamically stable patients after assessing thromboembolic risk (recommendation class I, evidence level B). Emergency electrical cardioversion is recommended for patients with AF with acute hemodynamic instability or rapid deterioration of the hemodynamic state (recommendation class I, evidence level B). Pharmacological cardioversion is contraindicated in patients with sinus node syndrome, antrioventricular conduction disorders, or prolonged QTc (>500 ms), except in situations where the risks of proarrhythmogenic effects and bradycardia are taken into account (recommendation class III, evidence level C).

For medical cardioversion in case of recent AF, the recommended medications are intravenous vernacalant (except for patients with recently developed acute coronary syndrome (ACS) and severe heart failure (HF), or flecainide, or propafenone (except for patients with severe structural heart disease) (IA).

Flecainide and propafenone, which are used according to the “pill-in-pocket” principle, remain relevant.Cardioversion in case of AF (electrical or medical) is recommended for symptomatic patients with persistent AF as a stage of therapy aimed at controlling sinus rhythm (recommendation class I, evidence level B).

Medical cardioversion for AF is recommended only for hemodynamically stable patients, with due account for the risk of thromboembolic complications (recommendation class I, evidence level B).

The term “without organic heart damage” implies: absence of acute myocardial infarction (MI) with a history of pathological Q wave and hypertrophic cardiomyopathy or dilated cardiomyopathy; LVEF >45%; absence of congestive or progressive HF and stage of HF no more than II A; absence of congenital or rheumatic heart defects, distinct LV hypertrophy (with thickness of one of the LV walls ≥14 mm).

In turn, arterial hypertension (AH), chronic forms of coronary heart disease (CHD) and others are not contraindications to prescribing of class I antiarrhythmic drugs (AAD), if they do not provoke the occurrence of the above changes. However, if these changes are present, physicians may administer amiodarone intravenously, which is recommended for medical cardioversion in case of AF in patients with HF or structural heart disease, if the delayed cardioversion is clinically acceptable (recommendation class I, evidence level A).

Sinus rhythm maintenance should be performed according to a convenient algorithm, according to which, if signs of structural heart disease are absent or minimal, a wide range of drugs can be used: dronedarone, flecainide, propafenone (recommendation class I, evidence level A), ethacyzine (recommendation class III, evidence level C), sotalol (recommendation class IIb).

Ethacyzine (a phenothiazine derivative), as well as propafenone and flecainide, are class 1C AAD according to the Vaughan-Williams Classification of Antiarrhythmic Drugs, which are characterised by a clear slowdown in conduction and reduction in the action potential. During their application, the QRS complex may increase, which is acceptable for this class, but it should not be allowed to expand by >25% compared to the original value.

For patients with arrhythmia without organic cardiac pathology, ethacyzine is the best option, as it reduces the effect of the parasympathetic nervous system on the heart. It does not affect repolarization and the QT interval, so the risk of developing ventricular life-threatening arrhythmias is minimal. Besides, ethacyzine reduces the automatism of conduction and increases the threshold of excitation (sodium channel blockade), provides an anti-ischemic effect (calcium channel blockade), reduces the effect of the vagus nerve on the heart (anticholinergic drug administration), and as a phenothiazine derivative stabilizes the autonomic nervous system. According to the results of studies, the use of ethacyzine was effective for supraventricular extrasystoles, since it significantly reduced their number after a month of treatment – by 96.9%, and after 6 months, it was reduced by 97.4%, which in turn reduced the incidence of atrial fibrillation.

It should be noted that ethacyzine has no effect on heart rate, blood pressure and QT interval, therefore, the target group for its administration is patients with bradyarrhythmias. Before prescribing ethacyzine, it is necessary to evaluate the indications and contraindications, and take an ECG to make sure that the rhythm disturbance is not accompanied by a clear organic pathology of the heart. After that, ethacyzine is prescribed at a dose of 50 mg under ECG control (repeatedly after 2 hours). In the absence of expansion of the QRS complex, the drug is used in a maintenance dose of 50 mg three times a day. After three days, one more consultation and ECG are required to achieve the antiarrhythmic effect.

Ultimately, С stage involves identifying comorbidities and managing cardiovascular risk factors. Identification and management of risk factors and comorbidities is an integral part of the treatment of patients with AF (recommendation class I).

Risk factors contributing to the development of AF and creating a substrate for poor heart rate control include hypertension, glycemia, obesity and overweight, smoking, lack of physical activity, obstructive sleep apnea, hyperlipidemia, and use of alcohol. To reduce the burden of AF and the severity of its symptoms, modification of an unhealthy lifestyle and targeted therapy of intercurrent conditions (recommendation class I) are recommended. Patients with hypertension and obstructive sleep apnea are recommended to have opportunistic screening for AF performed (recommendation class I). Comprehensive treatment and adjustment of AF risk factors are also necessary to optimize catheter ablation outcomes.

It is also necessary to take care of the state of mental discomfort in patients with AF, in particular those who are being prepared for electrical cardioversion. According to the recommendation of the World Health Organization (WHO), benzodiazepine tranquilizers should be prescribed for ≥2 weeks, whereas non-benzodiazepine tranquilizers can be taken for a long time (up to 100 days) and at any time of the day, since they do not cause inhibition and do not affect the driving ability. Also, these drugs provide a vegetative stabilization effect.

Conclusions. Atrial fibrillation is a relatively common heart rhythm disorder that significantly increases the risk of stroke and heart attack. The review presents the current classification of atrial fibrillation, etiological factors and mechanisms of its development. Special attention is paid to the principles of diagnosis and tactics of primary treatment of patients with atrial fibrillation – heart rate monitoring. Treatment methods in accordance with national guidelines are also listed.

References:

  1. Electronic Document “Adapted Clinical Guidelines Based on Evidence. Atrial Fibrillation”, 2016.
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Ministry of Health of Ukraine No. 597 of June 15, 2016

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the Establishment and Maintenance of the Introduction of Medical and Technological Documents on Standardization of Medical Aid in the System of the Ministry of Health of Ukraine”, registered in the Ministry of Justice of Ukraine on November 29, 2012 under No. 2001/22313.

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  2. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS): The Task Force for the diagnosis and management of atrial fibrillation of the European Society of Cardiology (ESC) Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC.

7.https://health.ua.com/multimedia/userfiles/images/2017/ZU_22_2017/ ZU_22_2017_tabl1_st13.jpg

  1. Treatment of cardiac tachyarrhythmias by RFA method, Kyiv-2008. O. V. Doronin