[Mechanical circulatory support in refractory cardiogenic shock: retrospective register study].

Cardiogenic shock (CS) is one of the main causes of death in patients with acute myocardial infarction (AMI). Mortality from CS remains high, despite the introduction of myocardial revascularization and the use of modern medication. The use of mechanical circulatory support (MCS) is promising, it could reduce mortality in patients with AMI and CS. AIM: To define effectiveness and safety of MCS in patients with AMI and CS. MATERIALS AND METHODS: Our study includes 47 patients with AMI and refractory CS, who were treated at the University Clinic of Cardiology of the Yevdokimov Moscow State University of Medicine and Dentistry from 2019 to 2022. Mortality and various complications were analyzed in patients with refractory CS, patients who received and did not receive mechanical circulatory support (intra-aortic balloon pump IABP, extracorporeal membrane oxygenation ECMO). RESULTS: Mortality among patients with refractory CS was significantly lower in the subgroup of patients who received mechanical circulatory support devices (59% vs 93%; p=0.02). Moreover, reliability is achieved mainly due to patients in whom were VA-ECMO implanted (p=0.02), not IABP (p=0.16). CONCLUSION: VA-ECMO associated with reduced mortality and should be considered in patients with AMI and refractory CS. Further research is needed to select the optimal method of mechanical circulatory support in patients with CS.

[Peculiarities of hemostasis in patients with COVID-19].

AIM: Analysis of the dynamics of different stages of clot formation and its lysis in patients with different COVID-19 severity. MATERIALS AND METHODS: We prospectively included 58 patients with COVID-19 (39 patients with moderate disease severity and 18 patients with severe disease) and 47 healthy volunteers as a control group. All participants underwent the assessment of flow-mediated dilation (FMD) of brachial artery, impedance aggregometry, rotational thromboelastometry and thrombodynamics. Von Willebrand factor antigen (vWF:Ag) quantification was also performed in patients with COVID-19. Measurements were repeated on the 3rd and 9th day of hospitalization. RESULTS: Compared to the control group, patients with COVID-19 showed reduced values of platelet aggregation and greater values of the clot growth rate, as well as its size and density. On the first day of hospitalization, we found no differences in the activity of plasma hemostasis and endogenous fibrinolysis between subgroups of patients. With the progression of the disease, the growth rate and size of the clot were higher in the severe subgroup, even despite higher doses of anticoagulants in this subgroup. An increase in platelet aggregation was noted during the progression of the disease, especially in the severe subgroup. There were no differences in the results of the FMD test by subgroups of patients. The vWF:Ag level was significantly higher in the severe subgroup. CONCLUSION: Thus, plasma hemostasis followed by secondary platelet activation correlates with the severity of COVID-19. Patients with moderate to severe coronavirus infection have predominantly local rather than generalized endothelial dysfunction.

The state of platelet and plasma hemostasis as a predictor of coronary blood flow in patients with acute myocardial infarction.

Aim      To study the relationship of the platelet function and plasma homeostasis with the blood flow in the infarct-related artery (IRA) and with the course of acute myocardial infarction (AMI).Material and methods  This study included 93 patients with AMI (75 patients with ST-elevation AMI and 18 patients without ST segment elevation). 63 patients had TIMI 0-1 blood flow in the IRA and 30 patients had TIMI 2-3. Rotational thromboelastometry, impedance aggregometry, the endothelium-dependent vasodilation (EDVD) test, and the thrombodynamics test were performed for all patients. The primary clinical endpoint included the totality of in-hospital complications of AMI, and the secondary endpoint included the totality of out-of-hospital complications of AMI. Major bleedings (BARC 3-5) and minor bleedings (BARC 1-2) were evaluated separately.Results Patients with IRA TIMI 0-1 flow were characterized by a shorter blood clotting time (BCT), larger thrombus size and density, more intense platelet aggregation induced by arachidonic acid and ADP, and lower values of the EDVD test. It was found that the parameters of platelet aggregation induced by arachidonic acid (AUC Asa) in combination with BCT allowed assessment of the severity of IRA blood flow disorder (sensitivity 76 %, specificity 71 %) in patients with AMI, regardless of the presence of ST segment elevation on the ECG. In addition, the incidence of the primary endpoint was greater in patients with IRA TIMI 0-1 flow (41.3% and 16.7%, respectively; p=0.015). In patients with TIMI 2-3 flow in the long-term period of the disease, the incidence of minor bleedings was significantly higher (8.5% and 30.4 %, respectively; p=0.045).Conclusion      Compared to patients with preserved blood flow, patients with AMI and IRA TIMI 0-1 flow are characterized by endothelial dysfunction and more intense processes of thrombogenesis and platelet aggregation. It has been shown for the first time that the combination of two simple criteria for assessing hemostasis (AUC Asa; BCT) allows assessment of the degree of IRA blood flow disorder in patients with AMI.

[The role of thrombin in the pathogenesis of atherosclerosis and its complications].

Thrombin is a key regulator of the homeostasis system. Also, it actively participates in progression of various systemic diseases, including atherosclerosis. There is a large amount of experimental and clinical data on the involvement of thrombin in the pathogenesis of ischemic heart disease (IHD). Thus, studying thrombin activity regulation is promising. Also, the question whether it is possible to use biomarkers of thrombin activity as predictors of cardiovascular complications in IHD patients is relevant. The present review focuses on major mechanisms of thrombin functioning, its role in development and progression of atherosclerosis, and available tests for evaluation of thrombin functional activity. Major clinical studies are discussed that evaluated the efficacy of thrombin inhibitors and protease-activated receptor antagonists.

Duration of Applications Affects the Long-Term Efficacy of Cryoballoon Ablation Pulmonary Veins.

Aim      To evaluate the effect of cryo-exposure duration and the use of the Achieve circular mapping catheter on efficacy of cryoballoon ablation (CBA).Material and methods  CBA of pulmonary vein ostia (PVO) is a major method for heart rhythm control in patients with atrial fibrillation (AF). Since the inception, the PVO CBA method has evolved; the recommended application time was changed, and the Achieve circular catheter appeared. We performed a retrospective analysis of PVO CBA administered to patients with AF in the I.V. Davydovsky Municipal Clinical Hospital from 2017 through 2019. The study included 100 patients with available clinical and demographic characteristics and remote results of the intervention. Three patient groups were analyzed based on differences in surgical techniques: group 1, Guidewire / 240 (n=31) with the cryoballoon placing on a guidewire and PVO exposure duration of 240 s; group 2, Guidewire / 180 (n=26) with the cryoballoon placing on a guidewire and PVO exposure duration of 180 s; and group 3, Achieve / 180 (n=43) with the cryoballoon placing on the mapping catheter Achieve and PVO exposure duration of 180 с. The follow-up period was 33.2±4.5, 15.2±6.1, and 12.2±4.1 months in the Guidewire / 240, Guidewire / 180, and Achieve / 180 groups, respectively. The intervention was considered effective when there was no relapse at the time of interview. A relapse of AF was determined as one or more paroxysms recorded on electrocardiogram (ECG) or during 24-h ECG monitoring; the "blind period" (first 3 months after the procedure) was excluded from the follow-up. Safety evaluation included clinically significant complications, such as phrenic nerve damage, hemopericardium, gastroparesis, hemoptysis, acute cerebrovascular disease, and formation of atrio-esophageal fistula. Effects of independent factors were determined with binary logistic regression.Results In the Guidewire / 240 group, efficacy of PVO CBA for the maximum follow-up period was 74.4%, which was significantly different from the value for the Guidewire / 180 group (57.7 %, р=0.015). At the same time, the difference between the Guidewire / 240 and Achieve / 180 groups was statistically non-significant for a comparable follow-up period (р=0.144). Clinically significant complications were absent in all 3 groups. The independent factors that significantly increased the PVO CBA efficacy were the cryo-exposure duration of 240 s compared to 180 s (р= 0.018) and the use of the Achieve catheter (р=0.014).Conclusion      Decreasing the cryo-exposure duration to less than 240 s is impractical (in absence of Achieve mapping catheter) since it impairs the long-term efficacy of PVO CBA and does not influence the risk of complications.

[Novel coronavirus infection COVID-19: extrapulmonary manifestations].

The novel coronavirus infection COVID-19 in most cases manifests with respiratory symptoms and fever, however, some patients may have cardiovascular and gastroenterological manifestations. A feature of the clinical syndrome of COVID-19 is the development of pronounced immunopathological reactions and disorders of hemostasis, leading to the development of a wide range of cardiovascular complications. The course of COVID-19 may be complicated by the development of acute myocardial infarction, venous and arterial thrombosis and thromboembolism in various vascular pools, the development of acute myocardial damage and myocarditis. Among the gastroenterological manifestations, diarrhea, nausea or vomiting, as well as abdominal pain, are most often detected. These symptoms may precede the appearance of respiratory signs of the disease, and in some cases come to the fore in the clinical picture of the disease. In addition, in some patients there are laboratory signs of liver injury (increased serum transaminases). The exact pathogenesis of the above disorders continues to be studied.

[Impact of endothelial dysfunction on the course of acute ST-elevation myocardial infarction and its correction by remote ischemic preconditioning].

Aim of the study - to assess the effect of remote ischemic preconditioning (RIPC) on the incidence of endothelial dysfunction (ED) and its impact on hospital prognosis in patients with ST segment elevation acute myocardial infarction (STEMI). MATERIALS AND METHODS: We conducted a single - centre, open - label prospective study that included 173 patients with STEMI who underwent primary percutaneous coronary intervention within the first 24 hours of the symptoms onset. Before the PCI, patients were randomized into two groups. In the first group (n=86) during the preparation for PCI, we performed RIPC procedure by inflation of the cuff of the tonometer to 200 mm Hg and its further deflation on patient's shoulder, thus creating short cycles of controlled ischemia/reperfusion in hand (4 cycles of ischemia/reperfusion for 5/5 minutes respectively). In the second, control group (n=87), the standard primary PCI was performed without the previous RIPC. Evaluation of the endothelial function was performed on the 2-7th day after admission using the endothelium - dependent flow - mediated dilatation test (FMD) of the brachial artery. Primary endpoints in this study included the presence of ED, in - hospital mortality, life - threatening arrhythmias (ventricular fibrillation/ventricular tachycardia after first 24 hours upon admission), stent thrombosis, clinical signs of heart failure, and a combined endpoint consisting of all the listed above. RESULTS: The median values for FMD-test did not differ significantly between the study groups upon admission. Assessment of the FMD of the brachial artery on the 2-7th day after PCI showed that among the patients who underwent RIPC there was a significantly lower percentage of patients with ED than in the patients with STEMI who did not undergo RIPC before PCI (43.1% vs. 75.8% respectively, p=0.0001). We found a significant reduction in the incidence of heart failure and of combined endpoint in the group of patients without ED compared with patients with ED: 0% vs. 9.3% (n=7; p=0.023) and 3.8% (n=2) vs. 16% (n=12; p=0.032) respectively. When assessing the effect of RIPC on hospital prognosis, we also found a significant decrease in the incidence of heart failure and a trend towards a decrease in the combined endpoint in the group of patients who underwent RIPC compared to the control group: 1.5% (n=1) vs. 9.7% (n=6; p=0.045) and 6.2% (n=4) vs. 16.1% (n=10; p=0.073) respectively. CONCLUSION: Performance of RIPC before the primary PCI significantly reduces the incidence of ED in patients with STEMI on the 2-7th day of the disease onset. The presence of ED in patients with STEMI is associated with a significant increase in the incidence of heart failure and of the combined endpoint during in - hospital period. RIPC significantly reduces the incidence of heart failure in patients with STEMI during in - hospital period.

[Cytomegalovirus Infection and Endothelial Function in Patients With Acute Myocardial Infarction].

PURPOSE: to study elucidate association of active cytomegalovirus (CMV) infection with endothelial dysfunction in patients with acute myocardial infarction (AMI). MATERIALS AND METHODS: The study included 42 volunteers without ischemic heart disease (IHD) and 63 patients with AMI. Blood samples for analysis of the deoxyribonucleic acid (DNA) of CMV in plasma by real-time polymerase chain reaction were taken in patients - before coronary angiography, in volunteers - at admission. In addition, in patients with AMI and volunteers without IHD, endothelial function was analyzed using endothelium-dependent vasodilatation (EDVD) test of the brachial artery. RESULTS: We showed that in patients with AMI, the concentration of CMV DNA in plasma was statistically significantly increased when compared with that in volunteers without IHD, which reflects active CMV infection - 1185.7 (0; 3003.0) vs. 0 (0; 910.8) copies of DNA / ml plasma (p=0.011). In comparison with volunteers without IHD, patients with AMI also more often had endothelial dysfunction - 11.5 (7.5, 15.2) % vs. 4.4 (0; 9.6) % of cases (p.

[Myocardial Infarction Due to Coronary Artery Embolism].

Coronary artery embolism (CAE) takes an important place among non-atherosclerotic causes of acute myocardial infarction (AMI). The features of embolic AMI are difficulties in diagnostics and absence of evidence-based guidelines for the management of CAE. Purpose of this review - to present synthesis of available data on embolic AMI. We also report here three cases demonstrating new approaches to treatment of CAE.

Cytomegalovirus Infection in Cardiovascular Diseases.

Atherosclerosis underlies the development of many cardiovascular diseases that continue to hold a leading place among the causes of death in developed countries. The role of activated immune cells in atherosclerosis progression has been convincingly demonstrated, but the mechanism of their action remains poorly investigated. Since atherosclerosis is associated with chronic inflammatory response, involvement of viral and bacterial infections in atherogenesis has been examined. A special place among the infectious agents is held by human herpesviruses as the most common persistent viruses in human population coupled to chronic inflammation during atherosclerosis. We found that activation of cytomegalovirus (CMV, human herpesvirus 5) infection is associated with the emergence of acute coronary syndrome, which is in a good agreement with the data on productive CMV infection published elsewhere. In this review, we discuss the data obtained by us and other researchers regarding the role of cytomegalovirus infection and related potential mechanisms resulting in the expansion of atherosclerotic plaques during ischemic heart disease and stroke, including virus transfer to immune and endothelial cells via extracellular vesicles. In particular, the data presented in the review demonstrate that virus spreading in the vascular wall triggers immune system activation in atherosclerotic plaques and causes endothelial dysfunction. Moreover, productive CMV infection in patients with acute myocardial infarction correlates with the extent of endothelial dysfunction. The mechanisms described by us and other researchers may explain the role of CMV infection in atherosclerosis and development of ischemic heart disease.

Acetylsalicylic Acid Produces Different Effects on the Production of Active Oxygen Species by Activated Platelets in Different Inflammatory Diseases.

We studied the effect of acetylsalicylic acid on ROS generation by platelets in patients after surgical interventions and in patients with bronchial asthma was studied. Platelets stimulated with platelet-activating factor are characterized by weak luminol-enhanced chemiluminescence in healthy people and patients after operations with laparoscopic incisions. Addition of platelet activation factor to platelet samples from patients after open abdominal surgery caused intensive chemiluminescence that was suppressed after platelet incubation with acetylsalicylic acid. At the same time, platelets of patients with aspirin-sensitive asthma did not respond to addition of platelet activating factor, but after incubation with acetylsalicylic acid, an intensive burst of chemiluminescence was detected with a maximum in 5-10 sec after the addition of a platelet-activating factor. In patients with bronchial asthma tolerant to aspirin, platelet activation factor did not induce chemiluminescence irrespective of incubation with acetylsalicylic acid.

Cytomegalovirus in Plasma of Acute Coronary Syndrome Patients.

The relationship between acute coronary syndrome (ACS) and local and systemic inflammation, including accumulation of macrophages in atherosclerotic plaques and upregulation of blood cytokines (e.g., C-reactive protein (CRP)), has been known for more than 100 years. The atherosclerosis-associated inflammatory response has been traditionally considered as an immune system reaction to low-density lipoproteins. At the same time, some data have indicated a potential involvement of cytomegalovirus (CMV) in the activation and progression of atherosclerosis-associated inflammation, leading to ACS. However, these data have been tangential and mainly concerned the relationship between a coronary artery disease (CAD) prognosis and the anti-CMV antibody titer. We assumed that ACS might be associated with CMV reactivation and virus release into the bloodstream. The study's aim was to test this assumption through a comparison of the plasma CMV DNA level in patients with various CAD forms and in healthy subjects. To our knowledge, no similar research has been undertaken yet. A total of 150 subjects (97 CAD patients and 53 healthy subjects) were examined. Real- time polymerase chain reaction (RT-PCR) was used to determine the number of plasma CMV DNA copies. We demonstrated that the number of plasma CMV genome copies in ACS patients was significantly higher than that in healthy subjects (p = 0.01). The CMV genome copy number was correlated with the plasma CRP level (p = 0.002). These findings indicate a potential relationship between CMV activation and atherosclerosis exacerbation that, in turn, leads to the development of unstable angina and acute myocardial infarction. Monitoring of the CMV plasma level in CAD patients may be helpful in the development of new therapeutic approaches to coronary atherosclerosis treatment.

Analysis of Extracellular Vesicles Using Magnetic Nanoparticles in Blood of Patients with Acute Coronary Syndrome.

Extracellular vesicles (EVs) are released from various cell types and play an important role in intercellular interactions. In our study, we investigated abundance of individual EVs in patients with acute forms of ischemic heart disease. Previously, we developed an approach for individual analysis of EVs conjugated with magnetic nanoparticles (MNPs), which was applied in the current study for analyzing phenotypic composition of EVs (by staining for markers CD31, CD41a, and CD63). EVs were isolated using fluorescently labeled MNPs containing anti-CD31, CD41a, or CD63 antibodies and analyzed by combining fluorescently labeled anti-CD41a and CD63, CD31 and CD63, or CD41a and CD31 antibodies, respectively. EVs were analyzed in 30 individuals: 17 healthy volunteers and 13 patients with acute coronary syndrome (ACS). Six and seven ACS patients were with acute myocardial infarction and unstable angina, respectively. It was found that patients with ACS and healthy volunteers contained a dominant subset of EVs expressing surface CD41a antigen, suggesting that they originated from platelets. In addition, the total number of EVs isolated using either of the surface markers examined in our study was higher in patients with ACS compared to healthy volunteers. The subgroup of patients with acute myocardial infarction was found to contain significantly higher number of blood EVs compared to the control group. Moreover, increased number of EVs in patients with ACS is mainly due to the increased number of EVs in the subset of EVs bearing CD41a. By analyzing individual EVs, we found that plasma of patients with ACS, particularly upon developing of myocardial infarction, contained dominant platelet-derived EVs fraction, which may reflect activation of platelets in such patients.

[Immunological Analysis of Human Atherosclerotic Plaques in ex vivo Culture System].

THE AIM OF THE STUDY: to analyze the dynamics of lymphocytic composition of human atherosclerotic plaques in ex vivo culture system. MATERIALS AND METHODS: The study included 15 atherosclerotic plaques obtained from patients who underwent carotid endarterectomy. Plaques were cultured as ring-shaped explants on collagen rafts in culture medium of special composition in CO2 incubator according to the previously developed technique. On day 0, and also on the 4th and 19th days of culture we extracted cells from plaque explants and analyzed B- and T-lymphocytic content of the tissue, as well as the percentage of CD16+ natural killer (NK) cells, using multichromatic flow cytometry. For this purpose we digested the explants with an original enzymatic cocktail, which allows preservation of cell surface markers, and we stained extracted cells with fluorescence-labelled monoclonal antibodies against CD45, CD3, CD19, CD4, CD8, CD16. In addition, we estimated the amount of interleukin 2 (IL-2) and interferon-gamma (IFN-)-producing T-cells by means of flow cytometry. RESULTS: After 4 days of culture the amount of lymphocytes in plaques explants decreased, however live lymphocytes were still preserved (2619.3 [1680.4, 3478.2] cells/100mg tissue). Viable lymphocytes population included T cells (2123.4 [484.9; 3181.2] cells/100 mg tissue), B cells (5.6 [3.4, 27.9] cell/100 mg tissue) and CD16+ NK cells (10.6 [1.8, 23.7] cell/100mg tissue). On the 4th day of culture T cells were presented by CD4+CD8- (797 [475.5, 1000.7] cells/100mg tissue, 37.5 [32.1; 46.3]%) and CD4-CD8+ (686.2 [423.6; 1158.4] cells/100 mg tissue, 45.6 [38.1; 47.9]%) populations. The percentage of CD4+CD8- T cell population decreased compared to the 1st day of culture, and this decrease correlated with the increase in CD4-CD8- T cells content (p<0.05). Additionally, after 4 days of culture we found in tissue explants both CD8+ (17.5[13.3;19.9]%) and CD8- (9.9 [6.4; 14]%) IFN--producing T-cells, however, their percentage, as well as the percentage of IL-2-producing T cells tended to decrease. After 19 days of culture explants of atherosclerotic plaques also contained lymphocytes (2830.1 [2350.3, 5900.2] cells/100mg tissue). Lymphocytes population included T cells (2594.5 [2035.7, 5306.7] cells/100mg tissue), presented by CD4+CD8- (1016.8 [671.2, 2201.7] cells/100mg tissue, 42.3 [34.3; 47.8]%) and CD4-CD8+ (1534.3 [813.8; 2207.2] cells/100mg tissue, 50.8 [45.6; 56.5]%) subsets, B cells (31 [18.3; 64.4] cell/100 mg tissue) and CD16+ NK cells (44.9 [33.4; 138.9] cells/100 mg of tissue). DISCUSSION: An ex vivo model of human atherosclerotic plaque culture that we previously developed enables to preserve viability of various lymphocyte subsets for up to 19 days. We also found that cultured tissue explants retain T cells that can maintain T-helper-1-dependent immune response, which demonstrates inflammation in atherosclerotic plaques. Our results allow to perform experiments on immunological mechanisms of atherogenesis and to develop new approaches for treatment of atherosclerosis, devoted to the suppression of local inflammatory processes in atherosclerotic plaques. CONCLUSIONS: An ex vivo model of human atherosclerotic plaque preserves CD4+CD8- and CD4-CD8+ T cells, B cells, and CD16+ NK cells for a long time. Moreover, after 4 days of culture tissue explants also retain IFN-++ T cells.

[Effect of Remote Ischemic Preconditioning and Postconditioning on Blood Flow in the Infarct-Related Artery and Endothelial Function in Patients With ST-Elevation Myocardial Infarction].

AIM OF STUDY: To assess influence of remote ischemic preconditioning (RIPC) and local ischemic postconditioning and their co-application.

[Combined reperfusion in patients with acute myocardial infarction].

Three schemes of treatment were used in the management of 230 patients with acute myocardial infarction: immediate thrombolysis (group 1, n=71), immediate thrombolysis followed by angioplasty in 12 hours-7 days depending of the clinical picture of the disease (group 2, n=65), primary angioplasty not later than 12 hours after onset of pain (group 3, n=94). Clopidogrel was given to all patients at least in 2 hours before primary angioplasty and no less than in 6 hours in combined reperfusion. Composite end point (total number of lethal outcomes and nonfatal reinfarctions) was significantly higher in group 1 (14.1%) compared with groups 2 (3.0%) and 3 (3.2%). Invasive intervention improved results of treatment after both effective and ineffective preceding thrombolytic therapy. Thus efficacy of combined reperfusion therapy is not inferior to primary angioplasty if interval between thrombolysis and invasive intervention varies between 12 hours and 7 days and angioplasty is carried out at the background of antiaggregant therapy with clopidogrel and aspirin.

[The Use of Clopidogrel in Conjunction With Thrombolytic Therapy in PatientsWith ST-Elevation Acute Myocardial Infarction.]. / Primenenie klopidogrelia v sochetanii s tromboliticheskoi terapiei u bol'nykh ostrym infarktom miokarda s pod''emom segmenta ST.

Clopidogrel (300 mg before initiation of thrombolysis and 75 mg/day thereafter) was given to 46 of 131 patients with streptokinase treated ST-elevation acute myocardial infarction. Mortality and efficacy of thrombolysis were similar in 2 groups, however deaths of acute heart failure were distributed unevenly (0 in clopidogrel group and 8 or 9.4% among other patients, p <0.03). Clopidogrel treated compared with other patients had significantly higher left ventricular ejection fraction on days 1-2 of disease (52.5+/-2.2 and 45.9+/-2.0%, respectively, p<0.03). Number of bleedings did not differ significantly between 2 groups. Thus patients addition of clopidogrel to aspirin and thrombolysis with streptokinase was associated with better myocardial contractile function and lower mortality due to acute heart failure.

[Treatment of ventricular arrhythmia resistant to sodium channel blockaders]. / Lechenie zheludochkovykh narushenii ritma serdtsa, rezistentnykh k blokatoram natrievykh kanalov.

The efficacy of antiarrhythmic agents of various groups (Na(+)- and Ca(2+)-channel blockers, cordarone) was comparatively evaluated in the same patients with ventricular arrhythmias. Cordarone and Na(+)-channel blockers were equally effective, whereas verapamil was significantly less potent. Then the antiarrhythmic efficacy of verapamil and cordarone was assessed individually in rhythm disturbances responsive to Na(+)-channel blockers and resistent to their action. The efficacy of verapamil was significantly higher in patients resistant to Na+ blockers than in those responsive to them. The action of cordarone was equal in these two groups of patients, however, it occasionally abolished arrhythmias resistant to both Na(+)- and Ca(+)-current blockers. The findings suggest the pattern of choosing antiarrhythmic therapy in ventricular arrhythmias.