This research is a multi-center prospective cohort interventional study aimed to determinate the capabilities of remote 1-minute single-lead electrocardiogram monitoring for cardiotoxicity detection, during two- three weeks (depending on the scheme of polychemotherapy) after the first cycle of polychemotherapy in patients with the first diagnosed cancer.

The study planned to include 130 patients and will be conducted in three stages:

Stage one - screening (the day before chemotherapy treatment):

1. Signing a voluntary informed consent to participate in the study;

2. Clinical examination; Questioning: finding out the complaints. Anamnesis morbid: investigation of the history of cardiovascular diseases (the presence of hypertension, ischemic heart disease, diabetes mellitus, congenital heart disease, heart surgery in the past).

   Anamnesis vitae: investigation of the history of patient's life (place of birth, development in childhood and adolescence, tobacco smoking, consumption of alcohol beverage, narcotic drugs, sleeping pills and sedatives, strong tea and coffee).

3. Assessment patient's risk profile according to the cardiotoxicity risk assessment scale for treatment of tumors (C.M. Larsen assessment scale 2014).

   Risk level-the sum of points of all risks ((1) the risk associated with the specific chemotherapy that will be received and (2) the risk related to co-existing cardiac risk factors, age and sex of patients), these factors can be used to generate a risk score: >6 points-very high risk, 5-6 points - high risk; 3-4 points- intermediate risk; 1-2 points-rare risk;

4. All patients included in the study will be registered in single-lead ECG server base and will be trained to use single-lead electrocardiograph themselves. Before starting chemotherapy, each patient will record an 1-minute single-lead ECG.

5. Instrumental examination: transthoracic echocardiography with assessment of left ventricular ejection fraction (LVEF) and speckle-tracking global longitudinal strain (GLS), standard 12-lead electrocardiography;

6. Laboratory testing: cardiac serum biomarkers-n-terminal pro b-type natriuretic peptide(NT-proBNP), highly sensitive troponin I.

Stage two - interim home control (during 2-3 weeks after first cycle of the chemotherapy):

During this period, patients will registrate a single-lead electrocardiogram by themselves using single-lead ECG device, every day the patient should do at least 5 ECG records. The data will be sent to the server database, where cardiologist will check it for pathology, poor quality and will contact patients, if needed.

Stage three - final control (after first course of the chemotherapy):

1. Patients' clinical examination, complaints registration;
2. Instrumental examination: transthoracic echocardiography with assessment of left ventricular ejection fraction (LVEF) and speckle-tracking global longitudinal strain (GLS), standard 12-lead electrocardiography;
3. Laboratory testing:cardiac serum biomarkers -n-terminal pro b-type natriuretic peptide (NT-proBNP), highly sensitive troponin I);
4. Evaluation of outcomes,depending on the patient's complaints, the results of instrumental and biochemical test methods carried out. The patient will be given recommendations necessary for their cardiovascular disorders correction;
5. Database compilation and statistical processing.

1. Inclusion Criteria:

   • chemotherapy-naive patients with first time diagnosed various kinds of tumors, planned for the first cycle polychemotherapy treatment over 18 years old
   • Written informed consent to participate in the study.
   • Patients without decompensation of cardiovascular diseases

2. Non-inclusion criteria:

   • Pregnancy;
   • Severe hepatic and\or renal failure(glomerular filtration rate below 30 (ml\min\1.732) Cockcroft-Gault, Child-Pugh score less than 6 points;
   • Radiation therapy and\or any surgical treatment in last 30 days.
   • Heart failure with left ventricular ejection fraction< 50 %, III-IV functional class New York Heart Association Functional Classification (NYHA)
   • Cardiac arrhythmias - permanent form of atrial fibrillation\flutter, atrioventricular block (AV block) II-III degree
   • Congenital or acquired heart valve disease
   • Patients with impaired motor function or tremor of the upper limb. As well as patients with severe cognitive impairments
   • Patients with a minimum life expectancy of less than 1 month

3. Exclusion Criteria:

   • Refusal to further participate in the study;
   • Non-compliance to the therapy regimen.
   • Poor quality ECG, poor echocardiography visualization,detection a defect of the preanalytical stage of the blood biochemical analysis (hemolysis, non-compliance with the temperature regime, long-term transportation, long-term storage, long-term or repeated centrifugation).
   • Development of other toxicity during chemotherapy treatment, which might prevents the evaluation of the study results

local ethics committee prohibits disclosure patients' information Information can be provided upon official request addressed to the principal investigator