Vol 2, No 4 (2022)

According to Russian epidemiological studies, the incidence of chronic heart failure (HF) in the general population is approximately 7%, increasing from 0.3% in the group aged 20–29 years to 70% in patients aged > 90 years [1]. In the general population, the incidence of atrial fibrillation (AF) ranges from 1% to 2%, which increases with age, that is, from 0.5% at the age of 40–50 years to 5%–15% at the age of 80 years [2]. HF and AF aggravate significantly each other’s course and mutually increase the risk of adverse outcomes [3, 4]. Moreover, the incidence of AF in patients with HF increases with increasing New York Heart Association (NYHA) grade; that is, among patients with HF of NYHA grade I, the incidence of AF is < 5%, whereas among patients with HF NYHA grade IV, the AF incidence in > 50% [5].

Chronic HF is a syndrome with complex pathophysiology, which is characterized by the activation of neurohumoral systems, namely, the renin–angiotensin–aldosterone system (RAAS), sympathetic nervous system (SNS), and insufficient activity of the natriuretic peptide (NUP) system. In the early stage of HF, i.e. asymptomatic dysfunction of the left ventricle, the activation of the SNS and RAAS plays a compensatory role aimed at maintaining cardiac output and circulatory homeostasis [6]. Moreover, the NUP system has a counter-regulatory function in relation to the RAAS and SNS, and with prolonged and excessive activation of the SNS and RAAS or with insufficient NUP system activity, imbalance occurs and HF progresses [7].

The brain natriuretic peptide (BNP) and biologically inactive N-terminal fragment of BNP (NT-proBNP) are the most studied and significant in clinical practice representatives of the NUP system. BNP and NT-proBNP are secreted by cardiomyocytes of the left ventricular (LV) myocardium in response to an increase in the mechanical load and stress of the LV myocardium. NT-proBNP is widely used as a test to rule out HF in patients with dyspnea. The NUP level also correlates with the severity and prognosis in patients with an established diagnosis of HF, and studies have reported that the NUP level acts as a criterion for treatment efficiency in patients with HF [8]. NT-proBNP is a biomarker not only for HF but also for several other conditions, such as acute coronary syndrome and myocardial infarction (MI), because it is associated with an increased risk of death from all causes, regardless of age, stable effort angina grade, myocardial infarction history, and LV ejection fraction (LVEF) [9].

NT-proBNP levels can be influenced by several additional factors such as age, obesity, or glomerular filtration rate. The prognostic value of NT-proBNP is relevant in comorbid patients with AF associated HF because AF can increase NT-proBNP levels independently [10]. Given that NUP secretion depends on intracardiac hemodynamics, the NT-proBNP levels may also depend on the approach to managing AF. Tachycardia is associated with high NT-proBNP levels [11].

The rhythm control approach has advantages over the heart rate control approach in patients with HF and LVEF < 50% to reduce mortality and the number of unplanned hospitalizations due to HF progression [12].

To date, the prognostic significance of NT-proBNP levels in relation to the risk of adverse events in patients with HF and reduced LV systolic function associated with AF, depending on the approach of AF management, remains unresolved.

This study aimed to assess the predictive value of NT-proBNP in relation to the development of adverse cardiovascular events in patients with permanent or persistent AF associated with HF and LVEF < 50%.

OBJECTIVE: to compare the dynamics of left atrial remodeling in patients with AF with various CP recovery options and to identify the most reliable predictors of AF recurrence.

MATERIALS AND METHODS: 153 patients with non-valvular AF lasting from 24 hours to 6 months were examined. All patients were divided into 3 groups depending on the type of cardioversion: the 1^st group included 49 patients whose CP was restored against the background of drug therapy; the 2^nd group included 57 patients after electro-pulse therapy (EIT); the 3^rd group included 47 patients who underwent radiofrequency isolation of the pulmonary veins (RFI LV). All patients underwent ECHO-cardiographic examination (ECHO KG) at the time of AF, as well as on 1, 3, 5, 15 days and 6 months after CP recovery with an assessment of indexed indicators of linear left atrium size (LP), LP volume, LP function recovery time by the rate of peak A transmittal flow (TMF) and LP filling pressure in relation to E/E’ with the help of a fabric Doppler imaging.

RESULTS: it was revealed that the absence of AF paroxysms in any variant of cardioversion for 2 weeks is a reliable predictor of maintaining CP after 6 months (p < 0.001) and reducing the number of AF paroxysms for 6 months (p < 0.001). Accordingly, relapses of AF during the first 2 weeks indicate an increase in their probability within 6 months [OR (risk ratio) = 15.37]. A significant relationship was found between the timing of recovery of LP function (peak A > 0.5 m/sec) and recurrence of AF during 2 weeks and 6 months of follow-up (p < 0.05). In patients after LV RF, the linear size and volume of LP significantly decreased in dynamics while maintaining CP in comparison with those who had AF relapses for 6 months (p < 0.05). In patients after conservative cardioversion and RF ILV, LP filling pressure (E/E’) significantly decreased after 14 days (p < 0.05) in the absence of AF relapses and did not change significantly by 6 months of follow-up (p < 0.05).While in the presence of repeated paroxysms of AF, this indicator did not change significantly by 6 months of follow-up. In the EIT group, no reliable dynamics of the estimated parameters of LP remodeling was found.

CONCLUSIONS: The peak A > 0.5 m/s measured by TMF on 1 day after the rhythm restoration is a reliable predictor of CP retention for 6 months in any variant of cardioversion (p < 0.001). The absence of AF paroxysms within 2 weeks after CP recovery reduces the likelihood of their occurrence also within 6 months with any choice of cardioversion (p < 0.001). In patients with CP recovery on the background of drug therapy and after RF ILV, the absence of recurrence of arrhythmia for 6 months is associated with a significant decrease in the size of LP (ILP and IOLP), (p < 0.05). A decrease in LP filling pressure (E/E’) 2 weeks after conservative cardioversion and LV RFI can be considered a reliable predictor of maintaining sinus rhythm by 6 months (p < 0.05).

The article presents a description of a clinical case of a patient with structural myocardial pathology (postinfarction cardiosclerosis) with recurrent paroxysmal sustained monomorphic ventricular tachycardia (VT) refractory to the nominal recommended ICD (implantable cardioverter defibrillator) settings; as well as discusses the shortcomings of existing standard algorithms for antitachycardia pacing (ATP) of implantable cardioverter defibrillators and potential ways to increase its efficiency. The refractoriness of recurrent paroxysms of ventricular tachycardia to ATP therapy increases the risk of repeated ICD shocks.

Despite the existence of universal recommendations for ICD programming and ATP therapy, there is a need in clinical practice for individualized ATP programming in patients refractory to nominal settings. Increasing the number of ATP series and changing algorithms enables to increase the efficiency of ATP up to 80–89%. Refractoriness to standard ATP settings may be also overcome by using alternative ATP pacing algorithms (Ramp, Burst-plus, or Ramp-plus instead of Burst), changing the pacing interval, ATP sequence duration, pacing type, and even adding 1–2 extra stimuli, as well as using data from the previous intracardiac electrophysiological heart test.

The presented clinical case of a patient with postinfarction cardiosclerosis and paroxysmal stable monomorphic VT (SM-VT) of several morphologies demonstrates that the arrhythmogenic substrate after myocardial infarction changes for a long time without new stenoses in large coronary arteries and without new episodes of acute coronary syndrome, as well as generates several different morphologies of VT from one scar (with different heart rates) and the effect on hemodynamics. The efficiency of early ATP pacing may differ for VT of various morphologies, which makes it reasonable to use alternative pacing algorithms (in addition to the standard Burst sequences recommended by the 2019 Consensus on ICD programming) and testing possible ATP algorithms during ablation of monomorphic VT, including during preventive VT ablation before ICD implantation.