6 Big Difference between Inotropic, Chronotropic and Dromotropic

The Difference between inotropic, chronotropic, and dromotropic are based on their biological usage in the real-life application.

The three terms are closely related but there are some slight differences that make each one stand apart from each other.

Understanding the relationship of these terms to the way the heart works might make things even much easier to grasp.

The article provides detailed insight into inotropic vs chronotropic vs dromotropic in relation to heart function. Let’s find out: 

Difference between Inotropic, Chronotropic & Dromotropic

What Is Inotropic?

Inotropic is a kind of force the control the contraction of the heart muscle. Inotropic drugs tend to affect myocardial contraction in two ways.

The positive inotropic drug is one that increases muscle contraction while negative inotropic decreases muscle contraction.

Some of the popular positive inotropic drugs used to increase contraction are dopamine and isoprenaline while negative inotropic drugs are beta-blockers, quinidine, and flecainide.

According to research, inotropes are typically used to deal with impaired cardiac contractility. It plays are a vital role in treating heart attack and stroke. 

What Is Chronotropic?

Chronotropic is a drug that normally affects the heart rate of human beings. It can either be a positive chronotropic drug or a negative chronotropic drug.

The positive chronotropic drug is known for increasing heart rate while negative chronotropic drug for decreasing heart rate.

What Is Dromotropic?

Dromotropic is a heart muscle drug that tends to affect the way conducting tissues in the function. It typically helps to improve the heart impulse of a human being.

The dromotropic drug can either be positive or negative. Positive dromotropic drugs help to increase cardiac electrical impulses while negative dromotropic decreases cardiac electrical impulses.

Some of the common positive dromotropic drugs are phenytoin while that of negative dromotropic drugs is verapamil.

You should note that these drugs are administered to the patient according to the current condition being experienced.

Comparison Chart: Inotropic Vs Chronotropic Vs Dromotropic 

Basic Terms Inotropic Chronotropic Dromotropic
Definition These are heart drugs that affect contraction These are heart drugs that affect heart rate These are cardiac drugs that affect conducting tissues of the heart.
Types Either positive or negative medication Either positive or negative medication Either positive or negative medication
Examples Positive: dopamine and isoprenaline Negative: beta-blockers, quinidine, and flecainide Positive: Atropine, Milrinone, and Theophylline Negative: Digoxin, acetylcholine, and metoprolol. Positive: Phenytoin Negative: verapamil
Purposes Heart regeneration Control heart rate Conducting tissues of the heart
Origin of the Term From Greek where In-means fibre From Greek where chromo means time and tropos means a turn From Greek where dromo means race or running.

Core Difference between Inotropic, Chronotropic, and Dromotropic In Point Form

  1. Inotropic is a cardiac drug that affects contraction. Chronotropic is a cardiac drug that affects heart rate while dromotropic is another cardiac drug that affects conducting tissues in the heart.
  2. The categories of inotropic drugs are positive medication and negative drugs. Chronotropic drugs are either positive medication or negative drugs. Dromotropic drugs are favorable positive medication and negative drugs.
  3. Inotropic cardiac drugs are known for altering the force causing muscle contraction in the heart. Chronotropic cardiac drugs help to take care of a patient’s heart rate.
  4. Dromotropic cardiac drugs are typically used in the regulation of conducting tissues in the heart of an individual.
  5. Example of inotropic drugs is beta-blockers or dopamine while that of chronotropic cardiac drugs are Atropine or metoprolol. Dromotropic drugs are either Phenytoin or verapamil

Similarities between Inotropic, Chronotropic, and Dromotropic

  1. Both have long term effect
  2. Both deal with the functioning of the heart
  3. Both terms originated from Greek
  4. Both Have negative and positive types

Frequently Asked Questions

  • What Are Inotropic Effects?

Inotrope is an agent that alters the energy or force of muscular contraction. The positive inotropic increases the strength of muscular contraction while negative inotropic decreases muscular contraction. 

  • Is Digoxin Chronotropic or Inotropic?

Digitalis glycosides foster positive inotropic which increases myocardial contraction while glycosides are negative chronotropic which lowers the heart rate. 

  • Are Beta-Blockers Inotropic or Chronotropic?

Both negative inotropic and chronotropic effects result from Antianginal effects. These two effect causes a decrease in cardiac workload and oxygen demand. 

Therefore, the negative effect of chronotropic enhances the life-saving property of heart rate control. Beta-blockers are readily titrated to optimal rate control in many pathologic states.

  • Is Dopamine Inotropic, Chronotropic, or Dromotropic?

Positive inotropic that increases muscular contraction, positive chronotropic that increase heart rate and positive dromotropic that increases the rate of conduction through AV node are as a result of stimulated Beta1-adrenergic receptors in the heart. 

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Comparison Video

Conclusion

The discussion above and the podcast video highlight some of the essential things regarding the difference between inotropic, chronotropic and dromotropic terms.

The article also provides some information about the types and examples of medication rotating around each type.

I hope the article was useful. Feel free to use the comment section below and share your views or experience. Good Luck.

More Sources and References

  1. Osowski U. Congestive Heart Failure. National Institute of Health
  2. E. N. Moore. Effect of Inotropic, Chronotropic, and Dromotropic. Wiley Online Library 
  3. Reginald P. Sequeira. Dromotropic. Science Direct 

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