The heart’s rhythm is coordinated by its own electrical system. With each heartbeat, the electrical impulse begins at the sinus (or sinoatrial, SA) node, also called the heart’s natural pacemaker. The SA node is a cluster of specialized cells, located in the right atrium. The SA node produces the electrical impulses that set the rate and rhythm of your heartbeat. The impulse spreads through the walls of the right and left atria, causing them to contract, forcing blood into the ventricles.
The Heart's Electrical System
The impulse then reaches the atrioventricular (AV) node, which acts as an electrical bridge allowing impulses to travel from the atria to the ventricles. There is a short delay before the impulse travels on to the ventricles. From the AV node, the impulse travels through a pathway of fibers called the HIS-Purkinje network. This network sends the impulse into the ventricles and causes them to contract. The contraction forces blood out of the heart to the lungs and body.
The SA node fires another impulse and the cycle begins again.
The heartbeat is triggered by electrical impulses that travel down a special pathway through your heart muscle.
Women and men are similar when it comes to the basic heart rate and rhythm. However, while the basic electrical system is the same (impulses originating in the SA node, traveling to the AV node, through the HIS-Purkinje, and then starting over), there are differences:
Women Have a Faster Baseline Heart Rate Than Men
First of all, on average, women tend to have a faster baseline heart rate than men. This difference is seen in girls, on an average, as young as five years old. There is also a shorter sinus node refractory time – this means that it takes a shorter time for the SA node to recover and become ready to fire an impulse again ¹
Women’s ECG Readings may be Different
The ECG (also called EKG or electrocardiogram) is a test used to record on graph paper the electrical activity of the heart. The picture, drawn by a computer from information supplied by electrodes placed on the skin of the chest, arms and legs, shows the timing of the different phases of the heart rhythm.
The p wave represents the electrical activity of the upper chambers of the heart (atria). There is a short pause followed by the QRS complex - the electrical activity of the lower chambers (ventricles) - and ends with a small T wave, the recovery phase of the ventricles. The QT interval is the distance from the beginning of the QRS to the end of the T wave and represents the time it takes for the heart muscle to contract and then recover, or for the electrical impulse to fire and then recharge.
On average, the QT interval is shorter in men than in women, beginning after puberty with a linear increase through the major part of adulthood to at least age 55. This period corresponds to the time period when androgen levels are highest in men. Therefore, androgen and estrogen levels may explain the gender differences in QT interval².
Certain types of arrhythmias are more prevalent in women than in men.
These arrhythmias occur more often in men, but may present differently in women:
An arrhythmia may be "silent" and not cause any symptoms. A doctor can detect an irregular heartbeat during an examination by taking your pulse, listening to your heart or performing diagnostic tests.
If symptoms occur, they may include:
Symptoms of palpitations represent 15-25 percent of all the symptoms reported by female heart patients. They are associated with:
When palpitations are present, the doctor begins his or her evaluation by looking for underlying heart disease. The importance of palpitations and the need for treatment is determined by the presence of underlying heart disease, the type of irregular heart beats that are occurring and other symptoms that are present.
Estrogen and progesterone levels rise and fall in women with a normal menstrual cycle during the days of the month. The rise of progesterone and the fall of estrogen correspond with:
During perimenopause (the time period before menopause), there is a marked decrease in ovarian estrogen production. This is associated with an increase in heart rate (sinus tachycardia) and an increased frequency in palpitations and non-threatening arrhythmias, such as premature ventricular contractions or PVCs.
Menopause causes a further decline in estrogen as the menstrual cycle stops. This time period is associated with irregular heart beats, palpitations, spasmodic chest pain and nightmares in women 40 -64 years old².
The Heart and Estrogen/Progestin Replacement Study (HERS) found no benefit in the use of hormone replacement therapy to reduce cardiovascular events, and hormone replacement therapy may even increase the risk of thromboembolism (blood clot) during the first year³. HRT is also associated with lengthening the QT interval [link to the explanation above], although the relevance of this finding is not known⁴. On the other hand, HRT may decrease palpitations and other symptoms such as hot flashes, insomnia, and sweating. Therefore, it may be considered a treatment option in low risk female patients to relieve symptoms of palpitations.
Premature atrial beats occur in about 50 percent of women during pregnancy, although most are harmless and do not last¹. While sustained arrhythmia is somewhat rare, for those who have supraventricular tachycardia or paroxysmal SVT, the symptoms are worsened in 20 percent of cases¹. Symptoms of SVT may include shortness of breath, palpitations, and dizziness². Arrhythmias may occur more frequently during pregnancy due to changes in hormones, changes in associated hemodynamic, hormonal and autonomic changes and changes in circulating blood volume, sleep, and emotion during pregnancy.
Women who have had congenital heart defects repaired have an increased risk of arrhythmias during pregnancy. In 27 women who had repaired congenital heart defects and 29 pregnancies, SVT occurred in 15, ventricular tachycardia in nine, high </ grade heart block in four and sick sinus syndrome in three women³.
Arrhythmias in pregnancy are treated conservatively. After determining the type of arrhythmia, the physician will evaluate for underlying causes. If symptoms are minimal, rest and vagal maneuvers may be used to help slow the heart rate. Vagal maneuvers include carotid massage applying ice to the face, and the Valsalva maneuver, which is the most successful in stopping tachycardias⁴. The Valsalva maneuver involves a person exhaling forcibly with a closed glottis (the windpipe) so that no air exits through the mouth or nose as, for example, in strenuous coughing, straining during a bowel movement or lifting a heavy weight.
When the arrhythmia causes symptoms or a drop in blood pressure, antiarrhythmic medications may be used. No anti-arrhythmic medication is completely safe during pregnancy; therefore medications are avoided during the first trimester if possible to limit risk to the fetus. Drugs with the longest safety record should be tried first. Propranolol, metoprolol, digoxin, and adenosine have been tested and shown to be well tolerated and safe during the second and third trimester⁵.
Cardioversion is safe during all trimesters of pregnancy and can be used if necessary¹. In addition, women who have an ICD who become pregnant do not have an increased risk for ICD discharges or ICD complications. A woman who has an ICD can safely become pregnant unless she has an underlying heart condition that would increase health risks during pregnancy⁶.
If you have symptoms of an arrhythmia, you should make an appointment with a cardiologist. You may want to choose an electrophysiologist, a cardiologist who has received additional specialized training in the diagnosis and treatment of heart rhythm disorders.
After evaluating your medical history and discussing your symptoms, a physical exam will be performed. The cardiologist also may perform a variety of diagnostic tests to help confirm the presence of an arrhythmia and determine its causes.
Some tests that may be done to confirm the presence of an irregular heart rhythm include:
Treatment options include:
Medications – antiarrhythmic drugs are medications used to convert the arrhythmia to normal sinus rhythm or to prevent arrhythmia. Other medications may include heart-rate control drugs; anticoagulant or antiplatelet drugs such as warfarin (a "blood thinner") or aspirin, which reduce the risk of blood clots or stroke.
Concerns for women: Because women have a longer QT interval than men. some medications that are used in men to treat irregular heart rhythms prolong the QT interval even more. These medications include Quinidine, Sotalol, Dofetilide, and Amiodarone. These medications may increase a woman's risk of developing a life-threatening arrhythmia (torsades de pointes) more than in men who take these medications. Women who take these medications should follow their’ doctor’s and dietitian’s dietary guidelines for potassium and avoid becoming low in potassium, which enhances the arrhythmia affect¹.
The biggest concern for all patients with atrial fibrillation is preventing blood clots or stroke. Warfarin (also called Coumadin) is most often used to prevent strokes in patients. According to The Canadian Registry of Atrial Fibrillation (CARAF), women were half as likely to be prescribed warfarin as compared to men, although they would benefit from it as much².
Lifestyle changes– arrhythmias may be related to certain lifestyle factors. Here are some ways to change these factors:
Invasive Therapies – the following invasive therapies may be used to treat or eliminate irregular heart rhythms. Your doctor will discuss the benefits and risks of these therapies and whether they are appropriate treatments for your condition.
Electrical devices – a small device may be implanted under the skin that can detect an irregular heart rhythm and/or treat it. Your doctor will discuss the benefits and risks of implantable devices and whether they are an appropriate treatment for your condition.
Heart surgery – The Maze, modified Maze, and minimally invasive ablation surgeries are used to correct atrial fibrillation that is not controlled with medications or non-surgical treatment methods. Arrhythmia surgery also may be recommended if you need surgery to correct other forms of heart disease (such as valve disease or coronary artery disease).
Treatment also includes regular follow-up with a physician. While women have specific concerns related to irregular heart rhythms, communication with your physician will ensure safe and effective treatment.
Doctors vary in quality due to differences in training and experience; hospitals differ in the number of services available. The more complex your medical problem, the greater these differences in quality become and the more they matter.
Clearly, the doctor and hospital that you choose for complex, specialized medical care will have a direct impact on how well you do. To help you make this choice, please review our Miller Family Heart and Vascular Institute Outcomes.
Choosing a doctor to treat your abnormal heart rhythm depends on where you are in your diagnosis and treatment. The following Heart and Vascular Institute Sections and Departments treat patients with Arrhythmias:
The Heart and Vascular Institute has specialized centers to treat certain populations of patients:
Learn more about experts who specialize in the diagnosis and treatment of arrhythmias
For younger patients with abnormal heart rhythms:
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 08/14/2019