Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. This can cause heart failure, arrhythmia, myocarditis, and cardiomyopathy in patients. Some effects are reversible, while in others, permanent damage requiring further treatment may arise. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by

chemotherapy Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents or alkylating agents) in a standard chemotherapy re ...

(a usual example is the class of

anthracyclines Anthracyclines are a class of drugs used in cancer chemotherapy that are extracted from '' Streptomyces peucetius'' bacterium. These compounds are used to treat many cancers, including leukemias, lymphomas, breast, stomach, uterine, ovarian, b ...

) treatment and/or radiotherapy; complications from

anorexia nervosa Anorexia nervosa (AN), often referred to simply as anorexia, is an eating disorder characterized by Calorie restriction, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. Individuals wit ...

; adverse effects of

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intake; the long-term abuse of or ingestion at high doses of certain strong

stimulant Stimulants (also known as central nervous system stimulants, or psychostimulants, or colloquially as uppers) are a class of drugs that increase alertness. They are used for various purposes, such as enhancing attention, motivation, cognition, ...

s such as

cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...

; or an incorrectly administered drug such as

bupivacaine Bupivacaine, marketed under the brand name Marcaine among others, is a medication used to decrease sensation in a specific small area. In nerve blocks, it is injected around a nerve that supplies the area, or into the spinal canal's epidural ...

Mechanism

Many mechanisms have been used to explain cardiotoxicity. While many times, differing etiologies share the same mechanism, it generally depends on the agent inducing cardiac damage. For example, the primary mechanism is thought to be oxidative stress on cardiac myocytes. It is thought that reactive oxygen species (ROS) overwhelm the antioxidant defenses of cardiac cells, causing direct cellular damage. This oxidative damage can disrupt mitochondrial function, therefore disrupting energy production in the heart muscle itself, leading to energy depletion via depleted ATP and promoting cell death through apoptosis or necrosis. Other mechanisms of cardiotoxicity include inflammatory, DNA damaging, and disrupted cell signaling. DNA damage and disrupted cellular signaling are the proposed mechanism for many cardiotoxic chemotherapeutics. Regardless of the mechanism, clinical manifestations include heart failure, arrhythmia, myocarditis, and cardiomyopathy that can be permanent. These conditions can greatly alter mortality and morbidity in patients meaning careful monitoring is necessary in patients exposed to cardiotoxic agents.

Inciting agents

The list of inciting agents is vast and involves various classes of medication as well as environmental agents. The effects of the cardiotoxic substances vary and are not all identical.

Chemotherapy drugs

Source: * Anthracyclines such as doxorubicin also referred to as "The Red Devil" * Alkylating Agents such as cyclophosphamide * HER2 Inhibitors * Tyrosine Kinase Inhibitors * Antimetabolites * Proteasome Inhibitors

Other medications

* Antipsychotics such as

thioridazine Thioridazine (Mellaril or Melleril) is a first generation antipsychotic drug belonging to the phenothiazine drug group and was previously widely used in the treatment of schizophrenia and psychosis. The branded product was withdrawn worldwid ...

which can prolong QT interval * Antibiotics such as Erythromycin and levofloxacin due to QT prolongation

Environmental toxins

* Heavy Metals like lead and mercury * Pesticides such as

organophosphate In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered ...

Abused substances

Source: * Alcohol: Chronic heavy consumption leading to

alcoholic cardiomyopathy Alcoholic cardiomyopathy (ACM) is a disease in which the long-term consumption of alcohol (drug), alcohol leads to heart failure. ACM is a type of dilated cardiomyopathy. The heart is unable to pump blood efficiently, leading to heart failure. It ...

* Recreational Drugs: Cocaine, Methamphetamine

Others

* Biological Toxins such as Diphtheria toxin * Radiation Therapy is known to cause radiation-induced heart disease (RIHD) These agents can lead to varying degrees of cardiotoxicity, and their effects may be dose-dependent and influenced by individual factors such as pre-existing cardiovascular disease and genetic predispositions that can foster greater sensitivity to any cardiac damage.

Treatment

The most likely effective treatment is to stop exposure to the inciting agent as soon as possible whether a pharmacologic or environmental agent. While some may fully recover from cardiotoxicity caused from exposure, many are left with permanent damage that may need further management. The management varies on the damage sustained, but generally follows guidelines for each condition such as heart failure, arrhythmias, and myocarditis. Patients taking anthracyclines can take Dexrazoxane as a cardioprotective agent to prevent extensive cardiac damage.

References

{{Authority control Cardiotoxins Heart diseases Toxins by organ system affected