Generality
Tachycardia in pregnancy is a condition that occurs rather commonly, especially in the second half of gestation.
Within certain limits, the increase in heart rate during the nine months of pregnancy can be considered physiological. In fact, tachycardia is related to fetal development : already in the early stages of gestation, the beats of the maternal heart accelerate to provide the child with an adequate supply of oxygen and nutrients.
In some cases, however, tachycardia in pregnancy can be aggravated by several factors (including anxiety, dehydration and fever) or may suggest an underlying problem (heart disease, lung disease, thyroid dysfunction, anemia, etc.).
The most common type of tachycardia in pregnancy is sinus. Symptoms associated with the disorder include: fatigue, chest pain, difficulty breathing, dizziness, numbness in the body and sometimes fainting.
Women receiving a diagnosis of tachycardia during pregnancy should not be alarmed: if recognized early and properly managed, this condition can be controlled until the baby is born.
What's this
Tachycardia: short introduction
Tachycardia is defined as the increase in heart rate above 100 beats per minute ( bpm ). This condition is part of the tachyarrhythmias (disorders of the electrical conduction of the heart), which are distinguished according to the site from which the impulse starts.
During pregnancy, the most common and least dangerous tachyarrhythmia is sinus tachycardia, a condition in which the contraction of the heart is regular, but faster, physiologically dictated by the sinoatrial node.
What is tachycardia in pregnancy?
Tachycardia in pregnancy can be considered a phenomenon, within certain limits, normal. During gestation, in fact, the cardiovascular system undergoes a physiological adaptation to provide the child with the oxygen and nutrients it needs, as it grows. For this reason, in the first months after conception, tachycardia appears more mild and contained, while in the second part of pregnancy it occurs to a greater extent.
Causes
Tachycardia in pregnancy recognizes different causes, which can be distinguished into physiological and pathological .
Physiological Causes of Tachycardia in Pregnancy
Tachycardia is one of the most common hemodynamic alterations that occur during pregnancy. Usually, the increase in heart rate occurs in small increments during the nine months of gestation.
The accelerated beats of the maternal heart result from a series of adaptations, which begin around the third week of conception and coincide with the development of the child's organs. In practice, the increase in heart rate is the most efficient mechanism the maternal heart has at the moment it finds itself having to beat for two.
The "stress" factors that can predispose to tachycardia in pregnancy include:
- Increased oxygen consumption and hemoglobin reduction;
- Increased blood volume and decreased hematocrit;
- Increased systolic range;
- Increased cardiac output (from 30 to 50%, based also on individual body composition).
These haemodynamic alterations reach a peak between the 28th and 34th week of gestation .
Towards the end of pregnancy, tachycardia can also be amplified due to:
- Weight gain of the pregnant woman : during pregnancy, on average, between eight and ten kilos are earned. As a result, the heart finds itself sustaining more intense work than usual;
- Anxiety : considering the novelties that are experienced from the physical point of view, in addition to those expected on an emotional level and in everyday life, this sensation appears completely normal.
Note
The expected increase in heart rate during pregnancy is approximately 10-20 bpm more than the usual values for women. This phenomenon is closely related to the increase in cardiac output.
Pathological Causes of Tachycardia in Pregnancy
Tachycardia in pregnancy may suggest an underlying problem. During gestation, in fact, the cardiovascular system is subjected to various "stressful" conditions that can worsen heart ailments, while minor problems may occur for the first time in this particular period.
At the base of tachycardia in pregnancy there is often a low blood pressure (hypotension) . In the first months, this condition results from a physiological vasodilation that can easily cause pressure drops in the pregnant woman. In these circumstances, tachycardia consists of a temporary event: the heart of the future mother increases the frequency with which she beats, thus allowing the spraying of all tissues. Usually, there is no need for interventions, since from the end of the second quarter, the pressure values tend to fall within the norm.
Tachycardia in pregnancy can also be associated with a thyroid dysfunction (thyrotoxicosis, hyperthyroidism, etc.) which, at times, occurs for the first time precisely during gestation. In these nine months, in fact, the thyroid is particularly "busy" in order to guarantee the somatic and cerebral development of the fetus. A similar problem can be highlighted with blood tests.
Another possible reason for tachycardia in pregnancy is iron deficiency anemia : in the case of iron deficiency, the body produces less hemoglobin and, consequently, the blood carries less oxygen. During gestation, this occurrence is rather frequent, as the need for iron increases. If the concentration of oxygen decreases, the heart is forced to pump more to ensure the circulation of oxygen that the pregnant and unborn baby needs in the blood. Also in this case, a blood test is sufficient to detect an eventual anemia situation.
Other conditions that can determine and / or aggravate tachycardia in pregnancy are:
- Hypoxemia : if the amount of oxygen in the blood decreases, more blood must reach the tissues, to maintain the optimal supply of the same gas;
- Hypercapnia : if, in the bloodstream, the concentration of carbon dioxide increases, the heart beats faster to supply more blood to the lungs, so as to allow its elimination;
- Hydro-electrolyte imbalances : they determine repercussions on pressure and ion concentrations responsible for cardiac electrical conduction.
Tachycardia in pregnancy can also be associated with the following causes:
- Stress (fever, dehydration, physical exertion, anxiety, nervousness, etc.);
- Taking stimulants (eg caffeine, theine, alcohol and nicotine);
- Heart disease;
- Asthma;
- Pulmonary infection;
- Obesity of the expectant mother;
- Drug or drug abuse;
Sometimes, tachycardia can be associated with obstetric-gynecological problems, such as:
- Placental detachment;
- Rupture of the uterine sac;
- Embolism of amniotic fluid;
- Hemorrhage.
In these cases, tachycardia in pregnancy can signal a dangerous situation for the pregnant and the unborn child, therefore it requires a timely intervention. Finally, tachycardia could be a symptom of an ectopic pregnancy .
Symptoms and Complications
Often, tachycardia during pregnancy is perceived as palpitations, which can be defined as an intermittent or persistent sensation of accelerated beats (due to the greater systolic range of the post-extrasystic beat). The manifestations can be both regular and irregular. If it is contained, tachycardia in pregnancy may not even be felt by the expectant mother.
Tachycardia in Pregnancy: how to recognize it
Palpitations are often noticed when the patient is at rest, during which the other stimuli are minimal.
Tachycardia can be associated with other symptoms, such as:
- Dizziness and / or syncope (manifestations caused by a reduction in cardiac output);
- Exhaustion and feeling of deep fatigue;
- agitation;
- Lung congestion with dyspnea (shortness of breath, breathlessness or air hunger) and / or sloping edema (swollen legs and feet).
Occasionally, symptoms also include chest pain that simulates the symptoms of myocardial ischemia (angina pectoris or myocardial infarction).
Diagnosis
Tachycardia in pregnancy is easily diagnosed based on symptoms (palpitations) and physical examination (cardiac auscultation). The gynecologist will prescribe a simple blood test through which he can identify any disorders affecting the thyroid, anemia or other problems that can be exacerbated during pregnancy.
To establish the characteristics of the disorder, the doctor instead uses the electrocardiographic examination ( ECG ), or the recording of cardiac electrical activity and its graphic representation.
If the tachycardia in pregnancy is intermittent and is not detected with the electrocardiogram (ie, when performed, the examination is normal), a cardiac Holter (or dynamic ECG according to Holter) may be indicated, in which the heartbeat is monitored for 24 hours.
The Holter allows to verify even if the tachyarrhythmia is paroxysmal, that is it arises and suddenly disappears.
Treatment and Remedies
Tachycardia in pregnancy is a common phenomenon and, often, specific treatment is not necessary unless it causes unpleasant symptoms.
If the causes that cause the disorder are not of a physiological nature, the indication for therapy arises when the arrhythmia compromises the contractile function of the heart, altering the hemodynamics. Treatment is also recommended when there is a risk that tachycardia during pregnancy can degenerate into more serious arrhythmias (in particular, ventricular fibrillation). In these cases, the underlying pathological conditions must be searched and managed; possible interventions include, for example, the treatment of any thyroid disease or iron intake in the event of a deficiency.
If atrial fibrillation or supraventricular tachyarrhythmia is found, the doctor may indicate an antiarrhythmic drug therapy, preferring the use of safe medicines in pregnancy, such as beta-blockers (probably safe) and calcium channel blockers (verapamil). For the treatment of tachycardia during pregnancy, amiodarone should be avoided, as it can cause fetal deformities.
In the case of atrial fibrillation, the doctor can then prescribe an anticoagulant therapy, to avoid thromboembolic phenomena (intestinal ischemia, stroke, etc.).
Note : It is important to remember that you should not take any medication to treat this condition unless it has been prescribed by your doctor. Drug therapy of tachycardia in pregnancy, if not adequately modulated on the basis of each clinical case, could be harmful for both the child and the pregnant woman.
Ventricular tachyarrhythmias are generally a cardiological emergency and are treated with defibrillation, identification and resolution of the cause (coronary thrombosis, electrolyte imbalance, etc.).
Non-pharmacological therapies of tachycardia in pregnancy include, instead, vagal maneuvers, such as carotid sinus massage or the Valsalva maneuver. These are well tolerated, but should only be performed by an experienced doctor.
Another procedure practiced in case of tachycardia in pregnancy is electrical cardioversion . This consists in the application on the surface of the chest of an electric current discharge, in order to provoke a simultaneous depolarization of the whole myocardium. This allows the sinus node (which, as a rule, is the first center to reactivate after the electric shock) to resume command of the heart's rhythm.
Some advice
The management of tachycardia during pregnancy involves the following precautions:
- Try to eliminate or reduce stress;
- Avoid taking stimulants that can aggravate symptoms (tea, coffee, energy drinks, etc.);
- Refrain from smoking and alcohol consumption (both strongly contraindicated in pregnancy);
- Ensure abundant hydration;
- Take natural remedies, such as infusions or relaxing herbal teas.
