Author:- Mr. Ritesh Sharma
The study of heart rhythm is deeply intricate and fascinating. Various factors contribute to the beating of your life’s core. When the heart rhythm is in harmony with the heartbeat dictated by the sinoatrial node (the heart’s natural pacemaker), everything works perfectly, and there is no irregularity. However, when this harmony is disrupted, irregularities in the heart, or cardiac arrhythmia, arise. To study the Pathophysiology of Cardiac Arrhythmia, we need to understand this medical condition in its entirety.
For this, we have to dive deeper into heart rhythms, heart abnormalities, and everything associated with them. Hence, we will do the same below. We will discuss Cardiac Arrhythmia and its pathophysiology in all of its complexities in an elaborate manner.
What is Cardiac Arrhythmia?
Before delving into its pathophysiology, let’s understand what Cardiac Arrhythmia is. The concise definition of cardiac arrhythmia states that it refers to irregularities in heart rhythm. In other words, in this condition, the heart either beats too fast, too slow, or irregularly. Several types of arrhythmias are characterized by everything wrong with heart rhythms.
While Cardia Arrhythmia involving heart palpitations is common among people, if not treated timely, it can lead to hazardous heart problems. Cardiac arrhythmias are capable of causing serious problems like heart failure and cardiac arrest. Hence, it can have a substantial negative impact on heart health. Prior to learning more about the Pathophysiology of Cardiac Arrhythmia, let’s try to understand what normal heart rhythm and disruptions in it encompass.
Normal Heart Rhythm
The heart rhythm is orchestrated by the cardiac conduction system. This system has a complex network of pathways that regulate the heartbeat. The conduction system of the heart consists of the Sinoatrial Node (SA Node), which is the normal pacemaker of the heart situated at the right atrium. The electrical impulses in the heart are initiated from here.
After this, these electrical impulses go through the atrioventricular node which slows down the electrical impulses acting as a gatekeeper. The electrical impulses now travel through the Bundle of HIS and Purkinje Fibres which transmit them rapidly ensuring the synergy of contractions in the heart chamber. Through this complete process, the blood flow remains seamless in the body, and all the tissues receive an adequate amount of oxygen and nutrients.
Disruption in the Normal Rhythm of the Heart
Disruption in the normal rhythm of the heart is caused when its conduction system is disturbed because of various factors. This disturbance is characterized by cardiac arrhythmias which are responsible for irregularities in heart rhythm. Let’s discuss the causes of this disruption in the normal rhythm of the heart below:
- Dysfunction of the Sinus Node:
The most common form of arrhythmias takes place when the sinoatrial node, i.e. the natural pacemaker of the heart, is dysfunctional. This dysfunction occurs due to multiple factors ranging from genetics to underlying heart conditions. - Atrial Arrhythmias:
Arrhythmias arising in the atrium of the heart are common factors for disruption of normal heart rhythm. Atrial Fibrillation and atrial flutter are some of the most common arrhythmias disrupting the heart rhythm through chaotic atrial contractions which lead to an irregular response to the ventricles and disturb the overall heart rhythm. - Atrioventricular Block:
If the connection through the AV node is not proper, then it can lead to first-degree, second-degree, or complete heart block. Due to this, the heart rate gets slowed abruptly causing an arrhythmia called bradycardia. - Ventricular Arrhythmias:
Arrhythmias originating in the ventricles of the heart can cause the heart rate to exceed its normal range and go too fast. This type of arrhythmia can potentially lead to various heart abnormalities. - Imbalances of the Electrolytes:
Due to imbalances of the electrolytes, such as magnesium, potassium, and calcium, the normal heart rhythm gets disrupted as they normally lead to various arrhythmias. - Supraventricular Arrhythmias:
The Wolf-Parkinson-White Syndrome is a type of arrhythmia belonging to supraventricular arrhythmias that can cause heart abnormalities through rapid heartbeats. - Ischemic Heart Disease:
Ischemic heart disease leads to conditions where the blood flow to the heart through the coronary arteries is reduced. This causes abnormalities in the heart rhythm and leads to myocardial infarction (heart attack), scar tissue formation, and different arrhythmias. - Cardiomyopathies:
Structural abnormalities arise in the heart’s muscles at various times propelling different types of arrhythmias.
Overview of Triggers and Abnormalities
The pathophysiology of cardiac arrhythmias is connected with various triggers and abnormalities. The following are the details regarding this:
- Age of the Person:
Older people are more prone to cardiac arrhythmias due to wearing and tearing of the heart’s conduction system. - Underlying Heart Disease:
If you already have heart disease, then the arrhythmias get further triggered, and the heart develops more abnormalities in its rhythm. - High Blood Pressure:
High Blood Pressure can affect the heart and trigger cardiac arrhythmias. - Bad Habits:
Bad habits like smoking and drinking alcohol can immediately trigger arrhythmias and affect the heart rhythm. - Genetics:
Some people inherit bad cardiovascular conditions from their parents. Hence it can also potentially trigger cardiac arrhythmias.
Underlying Causes and Risk Factors of pathophysiology of cardiac arrhythmia
The pathophysiology of cardiac arrhythmia has many causes and underlying risk factors that we will discuss below:
- CAD and MI:
Since the blood supply to the heart muscle is reduced, it can cause Coronary Artery Diseases and Myocardial infarction (heart attacks). - Structural Heart Diseases:
Cardiomyopathies, valvular heart diseases, and congenital heart defects are capable of badly impacting the heart’s anatomy and function. - Elevated Blood Pressure:
Due to high blood pressure, a condition called hypertrophy arises, in this the heart muscles enlarge abnormally. - Diabetes Mellitus:
Diabetes causes metabolic changes and inflammation in the heart. - Stress and Emotional Factors:
Stress and emotional factors can negatively influence the autonomic nervous system. Due to this, many hormonal responses are rapidly triggered.
Impact on Cardiovascular Function
You can identify cardiac arrhythmias through an abnormal ECG in the diagnostic and various other blood tests. Once you find out you are affected by cardiac arrhythmia, you can adopt the following treatments based on the type of arrhythmia and its severity:
- Modifications of Lifestyle:
Apart from taking medications, you must revamp your lifestyle as well. Quit drinking alcohol and smoking, eat highly nutritious food, and engage in physical activities. - Medications:
Take medications for the type of cardiac arrhythmia you are affected by to restore heart abnormalities. - Cardioversion:
If the cardiac arrhythmia is too severe, use controlled electric shocks to reset the heart’s electric rhythm. - Catheter Ablation:
Opt for Catheter Ablation if your arrhythmia is incurable with medications and lifestyle modifications. In this, the catheters, radiofrequency energy, or cryotherapy are used to interrupt the abnormal conduction pathways. - Surgery:
Some arrhythmias like Atrial Fibrillation require surgeries to be cured. For example, the Maze procedure is used in the case of atrial fibrillation.
Understanding the pathophysiology of cardiac arrhythmias is an important practice. Through it, accurate diagnosis and effective management of the medical condition can be done on time. Each cardiac arrhythmia has its unique mechanisms and it impacts the cardiovascular system differently. If you suspect any cardiac arrhythmia or heart abnormalities, consult a healthcare professional and get tests like ECG done for early detection and treatment.