What Is a Normal Heart Rate

Typically, a normal heart rhythm is referred to as sinus rhythm, with a healthy resting heart rate ranging between 60 and 100 beats per minute. When the heart rate exceeds 100 beats per minute, it is classified as sinus tachycardia. Conversely, if the heart rate drops below 60 beats per minute, it is known as sinus bradycardia.

Causes of Tachycardia and Bradycardia

Sinus tachycardia is often linked to conditions such as infections, hyperthyroidism, and anemia. On the other hand, sinus bradycardia may result from issues like myocardial disease, coronary artery disease, myocardial ischemia, or hypothyroidism. While sinus rhythm is the most common and normal type of heart rhythm, there are other types such as atrial rhythm, junctional rhythm, and ventricular rhythm.

Understanding Abnormal Heart Rhythms

Ventricular arrhythmias are particularly serious and can lead to life-threatening situations. One example is ventricular tachycardia, which may cause sudden collapse, as sometimes seen in individuals on the street. This condition requires immediate medical intervention, including emergency cardioversion or cardiopulmonary resuscitation (CPR).

Atrial Arrhythmias: Atrial Fibrillation and Atrial Flutter

Atrial arrhythmias include conditions like atrial fibrillation and atrial flutter. In atrial flutter, the atrial rate typically ranges between 250 and 350 beats per minute. In atrial fibrillation, the atrial rate can be even higher, reaching up to 350–600 beats per minute. However, the ventricular rate usually remains between 60 and 150 or even up to 160 beats per minute. If the heart rate becomes excessively rapid, it can lead to a drop in blood pressure and, in severe cases, cause shock.