Dysrhythmias I: Introduction

Dysrhythmias refers to abnormalities in the heart's rhythm. They result from disruptions in the heart's electrical conduction system, which includes the sinoatrial(SA)node, atrioventricular(AV) node, the bundle of His, bundle branches, and Purkinje fibers.

Definition and Pathophysiology

Dysrhythmias result from disorders of impulse formation, impulse conduction, or both. The heart contains specialized cells in the sinoatrial node, atrioventricular node, and the bundle of His and Purkinje fibers that can generate electrical impulses spontaneously. This electrical conduction system is essential for initiating and regulating the heartbeat. Dysrhythmias may present as irregular timing, rate, or pattern of electrical impulses, leading to health complications.

Causes and Risk Factors

The etiology of dysrhythmias includes many causes and risk factors. Common causes include myocardial ischemia, electrolyte imbalances, hypoxia, and certain medications. Structural heart disease, such as cardiomyopathy or valvular disorders, can predispose individuals to dysrhythmias. Lifestyle habits such as high intake of caffeine or alcohol, smoking, and experiencing stress also play a role. Additionally, underlying conditions such as hyperthyroidism and chronic lung disease are significant risk factors.

Clinical Manifestations

Dysrhythmias have many symptoms depending on their type and severity. Common manifestations include palpitations, dizziness, syncope, shortness of breath, chest discomfort, and fatigue. Severe dysrhythmias can lead to hemodynamic instability, presenting as hypotension, confusion, or even cardiac arrest.

Arrhythmias vs. Dysrhythmias

Arrhythmia broadly describes any irregular heart rhythm, whereas dysrhythmia emphasizes an abnormal or disordered rhythm without implying a complete absence of rhythm.