The purpose of this study was to explore the relationship between early myocardial injury caused by tumor drug therapy and intestinal microbial structure changes by echocardiographic two-dimensional speckle tracking technique and intestinal microflora structure detection. The investigators will also explore prevention and treatment through randomized controlled trials to initiate early intervention before clinical symptoms appear.

This is a single-center randomized controlled trial in which 100 patients treated with antineoplastic agents will be enrolled. All participants will be followed for 6 months after the initiation of oncology drug therapy. Echocardiography and 2D speckle tracking will be performed and stool and blood samples will be tested before treatment initiation and at 3 and 6 months after initiation. All patients will be randomly divided into test and control groups. Patients in the test group will receive oral Bifidobacterium trivium capsules for 6 months in addition to conventional treatment, whereas patients in the control group will receive conventional antitumor treatment only.

Inclusion Criteria:

• With malignant tumors
• Will receive antitumor drugs
• Could receive regular follow-up for 6 months
• Written informed consent

Exclusion Criteria:

• Satisfactory echocardiographic images could not be obtained
• Cardiomyopathy
• Coronary artery disease
• Heart failure
• Arrhythmia requiring intervention
• Moderate or severe valvular disease
• Acute myocarditis
• Refractory hypertension
• Participating in other studies of drug intervention