Medicine

Difference between Inotropic Chronotropic and Dromotropic




  • Main Difference

    The main difference between the three terms which will be discussed can be expressed just by the way they function and their primary uses. Inotropic are the drugs which help in changing the force which is applied to the muscles and the speed at which the contraction takes place. On the other hand, chronotropic drugs are the ones which are used to manage the heart rate of a human being, and they do so with the help of electrical conduction system. While the dromotropic drugs are the ones who assist in making changes in the condition of electrical impulses and in this case improves the conduction of such impulses to the heart.

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    Comparison Chart

    Basis of Distinction Inotropic Chronotropic Dromotropic
    Definition The drugs which help in changing the force of heart muscles. The drugs which are used to manage the heart rate. The drugs which are used to control the impulses of the heart.
    Origin Greek word in-, meaning fiber Greek word chrono-, meaning time, and tropos, which means a turn. The Greek word “dromos,” meaning running over a long time.
    Types Positive and negative inotropic drugs. Positive and negative chronotropic drugs. Positive and negative dromotropic drugs.
    Examples Digoxin and Diltiazem Dopamine and acetylcholine Phenytoin and Verapamil
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    Inotropic

    These are the drugs which help in changing the force which is applied to the muscles and the speed at which the contraction takes place. There is two primary type of such drugs which are known as positive inotropic and negative inotropic. The first one has the function of weakening the muscle contraction between the heart while the second one has the job of increasing the strength of contraction of the muscle of the heart. This is a state which is used to refer to the various drugs which are used in influencing the power of contraction of heart muscles, and this process is known as myocardial contractility. But that is not the only way it can be utilized. This also has the meaning in the pathological conditions such as enlarging of the heart, which increases the inotropic state while dead heart muscle is the process which is opposite and decreases the rate. The primary use of this drug is to control and manage the activities related to the heart, and the choice of which one is to be used depends on the condition of the person and the factors such as the level of nutrition and calcium in the muscle cell. The main examples of these two types of positive and negative include Digoxin and Diltiazem respectively, but there are much more.

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    Chronotropic

    This term has been originated from the Greek words chrono-, meaning time, and tropos, “a turn” and is a most common drug which is used to manage the heart rate of a human being. They do so with the help of electrical conduction system of the heart and the nerves which are associated with the system. It produces signals which change the rhythm which is produced by sinoatrial nodes. There are two types of these as well which are known as positive chronotropes and negative chronotropes and play the opposite role. The first one help in increasing the heart rate while the second ones contribute to decreasing the heart rate. The process of chronotropic is carried out in two ways, the first one is known as the systolic myocardial left, and the another one is systolic myocardial right. They both run the process with the help of different values which in the case of the first one is the aortic value and in the case of the second one is the pulmonary valve. They also are of the various types of examples for them, the negative chronotropic substances are the ones such as beta blockers, acetylcholine while the examples for positive ones is atropine and dopamine.

    Dromotropic

    It is an agent that helps in making changes in the condition of electrical impulses and in this case improves the conduction of such impulses to the heart. This word is derived from the Greek word ‘Dromos’ which running over a long distance. The change in the conduction takes place through the myocardium. These are considered a type of drug and the ones which are positive are the ones which increase the electrical impulse conduction while the ones who are negative are the ones which decrease the rate of electrical conduction. The best example or the positive one will be Positive dromotropic –  phenytoin while the best example for negative one will be Negative dromotropic –  verapamil. It is used to influence the cardiac nerve according to the requirement. Another definition of the term can be that the drug which helps in controlling the velocity of conduction of excitation, as in nerve or cardiac muscle fibers. The regular rate of them working is around 200 to 300 bpm of the atria, and they control the fibers.

    Key Differences

    • The word inotropic has been derived from the Greek word in-, meaning fiber or sinew and tropic are the turns. The word chronotropic has been derived from chrono-, meaning time, and tropos, which means a turn. The word dromotropic has been derived from the Greek word “dromos,” meaning running over a long time.
    • Inotropic are the drugs which help in changing the force which is applied to the muscles. Chronotropic drugs are the ones which are used to manage the heart rate of a human being. Chronotropic drugs are the ones which help in making changes in the condition of electrical impulses of the heart.
    • The main types of Inotropic drugs are positive and negative inotropic drugs. The main types of chronotropic drugs are positive and negative chronotropic drugs, and the main types of dromotropic drugs include positive and negative dromotropic medicines.
    • The best example for Inotropic positive and negative will be Digoxin and Diltiazem respectively. The best example for chronotropic positive and negative drugs will be dopamine and acetylcholine respectively while the best illustration of dromotropic positive and negative drugs will be phenytoin and verapamil respectively.

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