The coronavirus that causes COVID-19, SARS-CoV-2, is primarily known for its respiratory effects, but its impact on the cardiovascular system is a widespread concern. A fast heart rate, medically known as tachycardia, is a frequently reported symptom during the acute illness and can persist long after the initial infection has cleared. COVID-19 can indeed cause tachycardia, and the mechanisms behind this rapid heart rate range from a temporary response to illness to a complex, long-term disruption of the body’s regulatory systems. This effect manifests in distinct ways during the different phases of the illness.
Defining Tachycardia
Tachycardia is defined as a resting heart rate exceeding 100 beats per minute (bpm) for most adults. A normal resting heart rate usually falls within the range of 60 to 100 bpm. Tachycardia is not a disease itself but a symptom of an underlying issue causing the heart’s electrical system to fire too quickly.
Types of tachycardia are classified based on where the rapid rhythm originates. Sinus tachycardia starts in the heart’s natural pacemaker, the sinus node, and is often a normal response to stress, fever, or exercise. More serious types, such as supraventricular or ventricular tachycardia, are arrhythmias involving abnormal electrical pathways. Tachycardia reduces the heart’s efficiency because a heart beating too fast cannot fill completely with blood between beats.
Acute Tachycardia During COVID-19 Infection
During the active phase of COVID-19, a rapid heart rate is common, usually resulting from the body’s intense systemic response to the viral invasion. The most frequent cause is appropriate sinus tachycardia, where the heart works harder to compensate for physiological stress. Fever and dehydration are powerful triggers, causing the heart to increase its rate to regulate body temperature and maintain blood pressure when blood volume is low.
A lack of oxygen, known as hypoxia, prompts the heart to beat faster to circulate the limited oxygen supply. The SARS-CoV-2 virus can also exert direct effects, such as myocarditis (inflammation of the heart muscle), which damages electrical signal generation and leads to abnormal rhythms. Furthermore, the systemic inflammatory response, sometimes called a cytokine storm, releases molecules that irritate the heart’s tissues. This inflammation can contribute to various tachyarrhythmias, including atrial fibrillation, and is monitored closely as it can signal severe cardiac injury.
Post-Viral Tachycardia and Long COVID
A distinct presentation of a fast heart rate occurs in individuals experiencing Long COVID, the persistence of symptoms weeks or months after infection. This chronic tachycardia is often rooted in dysautonomia, a disorder affecting the autonomic nervous system (ANS). The ANS regulates involuntary functions like heart rate, blood pressure, and digestion.
The most recognized form of post-viral dysautonomia is Postural Orthostatic Tachycardia Syndrome (POTS), characterized by orthostatic intolerance. For individuals with POTS, moving from lying or sitting to standing causes an exaggerated and sustained increase in heart rate. This increase is typically defined as a rise of at least 30 bpm in adults within the first ten minutes of standing, without a significant drop in blood pressure.
This phenomenon occurs because the ANS fails to constrict blood vessels appropriately when standing. To compensate for the resulting drop in blood return, the body activates the sympathetic nervous system, causing the heart to race. This persistent heart rate spike, often accompanied by dizziness, lightheadedness, and cognitive difficulties, is a hallmark of long-term cardiovascular effects of COVID-19.
Monitoring Symptoms and Seeking Care
Monitoring symptoms is the first step for individuals experiencing a fast heart rate after COVID-19. Simple home monitoring, such as checking your pulse or using a tracking application, helps identify patterns of rapid heart rate. Tracking symptoms like palpitations, lightheadedness, or fatigue in relation to activity or posture provides valuable information for a healthcare professional.
Certain symptoms warrant immediate medical attention, including sudden, severe chest pain, significant shortness of breath, or episodes of fainting. If tachycardia is persistent, even without these severe symptoms, consultation with a primary care physician or cardiologist is advisable for a thorough evaluation.
A medical assessment rules out other causes of tachycardia, such as anemia or thyroid dysfunction, using blood tests and an electrocardiogram. For those diagnosed with post-viral symptoms like POTS, management often involves lifestyle adjustments. These include increasing fluid intake to two to three liters daily and increasing salt consumption, unless contraindicated, to boost blood volume and stabilize blood pressure.