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Different Heart Rhythms

Updated on September 08, 2012

Different heart rhythms both normal and abnormal

A normal heart rhythm is generated from the area of the heart called the sinoatrial node. The sinoatrial node is also known as the pacemaker of the heart. In order to be considered a normal heart rhythm your heart rate should be around 60 to 100 bpm. Both the atrial and ventricular rhythms should be regular. The P waves(which I will go over in another article very soon.) Are present, evenly spaced, there is one P wave before each QRS complex. The PR interval measures 0.12 - 0.20 seconds and is steady. The QRS duration is 0.04 - 0.10 seconds and is steady as well. The variables that I mentioned above can all be measured using an EKG also known as an electrocardiogram. An echocardiogram is able to measure the electrophysiological properties of heart rhythms. Also, learn about the anatomy of the heart and how the heart works.

Normal Sinus Rhythm


The heart rhythm known as the sinus arrhythmia

A sinus arrhythmia is a normal sinus rhythm with a slight modification. A sinus arrhythmia normally occurs due to a pressure change in the chest wall caused by breathing. Arrhythmia in the case of a sinus arrhythmia does not mean that the heart does not have a rhythm. The heart rhythm in this case, increases when a person breathes in and decreases a little bit when the person breathes the air out. This irregular heart rhythm is normally seen in fairly healthy people. The sinus arrhythmia is the same as normal sinus rhythm the only difference is the irregularity of the heart rhythm. On an EKG a sinus arrhythmia would read like this: the rate of the heart rhythm is between 60 and 100 beats a minute. The heart rhythm however, is irregular when referring to the PP and RR intervals are greater than 0.12 seconds. The other three factors which include P waves, PR interval, QRS duration are all the same as normal sinus rhythm. Sinus arrhythmias can be common with the use of medications such as digitalis and morphine. These drugs have a direct effect on the vagus nerve which causes decrease in heart rate and sometimes irregular heart rhythm.

When heart rhythms become disorders

When heart rhythms become a disorder, it is called a dysrhythmia. A dysrhythmia occurs when the electrical conductivity and mechanical response of the myocardium become disrupted. Also, by disruption of an abnormal heart rate or electrical impulses firing in different spots other than the Sinoatrial node. Dysrhythmias also occur with disruptions in the conduction system of the heart known as blocks and delays. Some dysrhythmias have no need for intervention, while others can be life-threatening if not treated properly.

Different Heart Rhythms

Sinus Arrhymia from EKG



Characteristics of abnormal heart rhythms or dysrhythmias.

A tachydysrhythmia is a heart rate that exceeds 100 beats a minute. Tachydysrhythmias are concerns for people with coronary artery disease. This is a critical concern because the blood flow of coronary arteries happens mostly during diastole. This is when the aortic valve is closed, the amount of blood that flows is also based on blood pressure in the aorta. Tachydysrhythmias are a major concern when it comes to heart rhythms being abnormal. This is due to the fact, that the amount of time available for blood to flow into the coronary artery is shortened. This is a health concern because the coronary arteries are providing much-needed oxygen to the myocardium. To add insult to injury, cardiac output and blood pressure are increased, but as the heart rate continues to elevate,this does not allow the ventricles to fill properly. This alone decreases stroke volume. If the tachydysrhythmias are allowed to go on unchecked, blood pressure will begin to decrease. This further reduces the oxygen getting to the myocardium. Needless to say, the heart continues to try to compensate for this and this increases the workload of the heart and the need for more oxygen by the heart. So, you see the danger, by the heart working harder to get more oxygen, the heart needs even more oxygen to continue to function. This is why a tachydysrhythmia must be taken care of appropriately. Symptoms of the tachydysrhythmia may involve palpitations(feeling of rapid heart rate whether irregular or not), chest discomfort, anxiety, pale and cool skin, dizziness due to low blood pressure. Prolonged tachydysrhythmias can lead to heart failure. The symptoms for heart failure are shortness of breath, crackles in the lungs, fatigue, and weakness.

Bradydysrhythmias is a heart rate less than 60 beats a minute. Bradydysrhythmias can be good as long as the blood pressure is stable. The benefits of great dysrhythmias are the opposite of tachydysrhythmias. With Bradydysrhythmias the heart requires less oxygen because the heart rate is slow. That allows the coronary arteries to provide the much-needed oxygen to the myocardium. But the heart rate may decrease due to the pressure in the coronary arteries. This does not allow the heart to produce enough cardiac output blood pressure. This creates a problem because bradydysrhythmias can lead heart not receiving enough blood, other dysrhythmias, hypotension, and heart failure.

Premature complexes occur when impulses are fired from places other than the sinoatrial node. Premature complex meaning, an impulse fires just before the SA node does, these can come from atrial, junctional, or ventricular areas of the heart. Because of the premature complex, there is a pause before the normal complex. This causes an irregular heart rhythm. If somebody experiences a premature complex, they may not even notice. They may also feel like their heart is skipping a beat. If the premature complexes happen continuously there may be a decrease in cardiac output. There are three different kinds of premature complexes: bigeminy, trigeminy, and quadrigeminy. A bigeminy is a repetitive alternating premature complex beat with a normal beat. A trigeminy is a 3 beat pattern with the normal heart rhythm following 2 premature complexes . A quadrigeminy is the same except with a four beat pattern with 3 premature complexes and then the normal heart rhythm. These premature complexes can occur in the atria, junctional, or ventricular areas of the heart. Sometimes there are no symptoms and sometimes a person may feel like their heart skipping a beat. Another type of complex, our escape rhythms. This is when the sinoatrial node fails to fire properly or is blocked or if the arterial ventricular nodule is blocked. Escape rhythms serve as an emergency pacemaker. These escape rhythms normally come from the arterial ventricular junctional or the ventricular tissue themselves. These escape rhythms will quit when the sinoatrial node or the arterial ventricular node can go back to doing their jobs. Symptoms of an escape rhythm involves a person feeling dizzy and lightheaded.


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