Atrial flutter
Introduction
Introduction to atrial flutter Atrial flutter can be thought of as an intermediate between atrial tachycardia and atrial fibrillation. When the atrial ectopic pacemaker frequency reaches 250-350 beats/min and is in a regular state, the rapid and coordinated contraction of the atrium is called atrial flutter. Patients may have hypotension, dizziness, palpitations, angina, and even cardiogenic shock. basic knowledge The proportion of illness: 0.02%-0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: cerebral embolism
Cause
Atrial flutter
(1) Causes of the disease
Organic heart disease (35%):
Atrial flutter is almost always seen in patients with structural heart disease, rarely seen in normal people, most commonly in rheumatic heart disease, most common in patients with mitral stenosis or left atrial enlargement with heart failure, followed by coronary heart disease Sclerosing type, acute myocardial infarction with atrial flutter accounted for 0.8% to 5.3%, in addition, can also be seen in cardiomyopathy, myocarditis, hypertensive heart disease, chronic pulmonary heart disease, sick sinus syndrome, some Congenital heart disease (especially atrial septal defect), pulmonary embolism, chronic constrictive pericarditis, acute pericarditis.
Other (25%):
Such as hyperthyroidism, thoracic surgery, cardiac surgery, cardiac catheterization, diabetic acidosis, hypokalemia, hypothermia, hypoxia, acute cholecystitis, cholelithiasis, burns, systemic infection, subarachnoid hemorrhage, In particular, patients with original organic heart disease are more likely to occur, excessive mental stress, agitation, excessive fatigue, etc. can induce atrial flutter. Occasionally seen in normal people without structural heart disease.
Pre-excitation syndrome (15%):
Atrial flutter is prone to occur when congenital heart disease patients with atrial septal defect have pre-excitation syndrome.
Drug factors (10%):
Drug-induced people are less common, but can be seen in digitalis poisoning.
(two) pathogenesis
It is currently believed that the atrial flutter caused by the annular reentry mechanism in the atrium may be one of the factors due to the increased autonomic increase in focal ectopic pacemakers.
According to whether the slow conduction zone of the atrial fluttering large reentry loop is located in the isthmus of the tricuspid annulus, the atrial flutter is divided into typical atrial flutter, also known as isthmus-dependent atrial flutter, ie II, III, aVF Type I atrial flutter with F-wave down; atypical atrial flutter, also known as non-isthral-dependent atrial flutter, ie II, III, aVF-guided F-wave type II atrial flutter, partial atrial flutter A rapid, continuous, ordered or disordered electrical activation that originates in the muscle sleeve triggers or drives the atrial to cause a regular or relatively regular atrial agitation with a frequency greater than 250 beats/min. This is called a muscle sleeve atrial flutter.
Prevention
Atrial flutter prevention
1. Atrial flutter is mostly seen in patients with structural heart disease or organic disease. Therefore, active treatment of primary disease is the main measure to prevent atrial flutter, such as improving myocardial ischemia, treating hypertension and hyperthyroidism.
2. Multiple recurrent episodes of atrial flutter should be taken prophylactically. Chronic persistent atrial flutter should actively control ventricular rate and oral anticoagulant to prevent thromboembolism.
3. Life conditioning is normal, do not overwork, can walk properly, practice Tai Chi, has made the circulation of blood circulation, but the ventricular rate is too fast atrial flutter and the primary disease is acute myocardial infarction, acute myocarditis and other patients Must rest treatment.
4. Light diet, quit smoking and alcohol, avoid strong tea, coffee, should be rich in nutrients, high-protein diet, supplemented with fresh vegetables, seasonal fresh fruit, avoid over-satisfaction, keep the stool smooth, and appropriate supplemented with Chinese medicine diet .
5. Avoid mental stimulation and fatigue, mental optimism, emotional stability can reduce the onset of the disease.
Complication
Atrial flutter complications Complications
After the occurrence of atrial flutter, it is easy to cause thrombosis in the room. Part of the thrombus can cause systemic arterial embolism. Clinically, cerebral embolism is the most common, often leading to death or sickness.
Cerebral embolism refers to the occlusion of fat, blood clot, wall plug, gas and other emboli in other parts of the brain through the bloodstream into the intracranial artery, causing cerebral artery occlusion and brain dysfunction in the corresponding blood supply area. The source of the embolus is more common in the heart. Sudden onset, no aura, common symptoms are hemiplegia or monotherapy, seizures, sensory disturbances and aphasia, sometimes rapid coma and acute symptoms of increased intracranial pressure. Physical examination revealed that patients often have focal neurological signs such as aphasia, hemiplegia or monolingual, sensory disturbance, and coma. Depending on the embolization of the blood vessels, other signs of focal nervous system and other parts of the body, as well as signs of primary disease, may occur.
Symptom
Atrial flutter symptoms Common symptoms Palpitation angina pectoris dyspnea chest dizziness dizziness holiday heart syndrome heart failure
Episode characteristics
Most of the atrial flutter is paroxysmal, often sudden, sudden termination, each episode lasts for a few seconds, hours, days, if the duration is more than 2 weeks, it is a persistent episode, also known as chronic atrial flutter, individual In cases with cases for several years, atrial flutter can also be transformed from atrial fibrillation. If the atrial flutter is persistent, most of them become chronic (permanent) atrial fibrillation, and some of the paroxysmal atrial flutter can be converted to Chronic atrial fibrillation.
2. Symptom
Symptoms depend on whether there is a change in basic heart disease and ventricular rate. The rate of ventricular rate is related to the ratio of atrioventricular conduction in the atrial flutter. When the atrioventricular conduction is 3:1 and 4:1, the atrial fluttering ventricle The rate is close to the normal value, the hemodynamic effect is small, the symptoms can be no or light, only mild palpitations, chest tightness, etc.; when the atrioventricular conduction is 2:1 or even 1:1, the ventricular rate can exceed 150~ 300 times / min, hemodynamics can be significantly affected, patients may have palpitations, chest tightness, dizziness, dizziness, mental anxiety, fear, difficulty breathing, etc., and can induce angina or cerebral arterial insufficiency, especially in elderly patients, especially At the initial onset and in the original severe heart disease, the ventricular rate increases more significantly, and can induce or aggravate heart failure.
3. Physical examination
(1) The ventricular rate is often around 150 beats/min (2:1 atrioventricular conduction), and the heart rhythm is uniform. When 1:1 conduction, the ventricular rate is faster, the heart rhythm is uniform; when it is 3:1 or 4:1 conduction, the ventricular rate is normal, the heart rhythm is homogeneous; but when it is 3:1, 4:1 and 5:1, 6: When the first-order conduction alternates, the heart rate is not fast, but the rhythm is not uniform. At this time, the first heart sound of the auscultation is different, and the interval is different. It should be differentiated from atrial fibrillation.
(2) The jugular vein beats quickly and shallowly, and its frequency is inconsistent with the ventricular rate, exceeding the ventricular rate.
(3) Exercise can accelerate the ratio of atrioventricular conduction in atrial flutter. If the ratio is changed from 4:1 to 2:1, the ventricular rate can be increased and multiplied. When the exercise is stopped, the ventricular rate can be gradually restored. The original heart rate value.
(4) Compression of the carotid sinus can inhibit the ratio of atrioventricular conduction in atrial flutter, so that 2:1 becomes 3:1 or 4:1, and the ventricular rate becomes slow. When there is different ratio of atrioventricular conduction, the rhythm is not uniform. After stopping the carotid sinus, the original heart rate can be restored.
Examine
Atrial flutter check
Mainly rely on ECG diagnosis, the common features are as follows:
1. Typical ECG characteristics of atrial flutter
(1) The sinus P wave disappears and is replaced by a shape, amplitude, and spacing, and the atrial flutter wave (F wave) with a frequency of 250-350 beats/min is serrated or wavy (typically in II, III, the aVF lead appears), there is no wire between the F waves.
(2) The QRS complex is the same as the sinus. Sometimes the shape of the QRS complex can be slightly different due to the influence of the F wave.
(3) The ratio of common atrioventricular conduction is 2:1, which can also be 3:1, 4:1. The ventricular rhythm can be irregular if the ratio of atrioventricular conduction is not fixed.
(4) Sometimes the F-wave frequency and morphology are not absolute rules, called impure atrial flutter or atrial flutter-fibrillation.
2. Classification of atrial flutter
(1) Type I atrial flutter: also known as typical atrial flutter or common atrial flutter, is the most common atrial flutter in the clinic:
1 The frequency of F-waves in the atrial flutter is 250-350 times/min.
2 In the II, III, avF lead, the F wave is inverted, showing an acute angle.
3 is easy to be stimulated by the program electrical stimulation.
(2) Type II atrium: Fluttering, also known as atypical atrial flutter, rare atrial flutter, rarely seen clinically:
1 The frequency of F-waves in the atrial flutter is 340-430 times/min, often more than 400 times/min;
2 On the II, III, aVF leads, the F wave is erect, showing more F-waves with rounded upwards (upright, rounded);
3 is not easy to be stimulated by the program electrical stimulation.
There is a close relationship between type I and type II atrial flutter. The same patient may have type I and type II atrial flutter alternately. Type II may be converted from type I or may be converted to type I by itself.
3. Detailed description of a typical ECG of atrial flutter
(1) F wave in II, III, aVF lead: F wave tip is called down to type I atrial flutter, also known as "tail type", which is atrial impulse from the posterior internode, and then before the internode Downward conduction, forming an inverse clockwise circular motion; in the II, III, aVF lead F wave tip upwards called type II atrial flutter, also known as "head and tail type", the atrial impulse is in a clockwise movement, from the posterior The beam is descending (forward) conduction, and then the anterior internode junction is retrogradely transmitted. The F wave can change in the tip direction of the same patient at different times. At the same time, the F wave tip can be reversed in the same lead.
(2) FR interval: FR interval is similar to PR interval, representing the conduction time of the atrioventricular. When the atrial flutter is accompanied by 2:1 or 3:1 conduction, the FR interval is prolonged, between the same lead FR. The period is equal and fixed, but the FR interval is also extended, not equal, not fixed, the reason:
1 occult conduction.
2 when accompanied by second degree, altitude or third degree atrioventricular block.
3 When the ventricular tachycardia is transferred to the room.
The FR interval is usually determined using the same peak as the initial portion of the F wave, typically 0.26 to 0.45 s.
(3) Atrioventricular conduction: Atrioventricular conduction in the atrial flutter can be in the following forms:
11:1 atrioventricular conduction: rare, more common in patients with severe heart disease, pulmonary embolism, pre-excitation syndrome with atrial flutter, rarely seen in patients with no obvious organic heart disease, physical labor, emotional, In the case of induction of anesthesia, the sympathetic tone is increased, and the physiological refractory period is shortened. It is more common in children than in adults. If combined with indoor differential conduction, it is easily misdiagnosed as ventricular tachycardia, and ventricular rate due to 1:1 conduction. Too fast, mostly in 240 ~ 300 times / min, can have heart palpitations, chest tightness, shortness of breath, angina pectoris, dizziness, syncope and other symptoms, can cause a sharp drop in cardiac output, induced blood pressure drop or heart failure or ventricular tachycardia, The occurrence of ventricular fibrillation and death, ECG shows that each F wave has a supraventricular or indoor differential conduction QRS wave group, FR interval prolonged, time fixed, is the result of interfering atrioventricular conduction delay.
22:1 atrioventricular conduction: the most typical atrial flutter, the most common conduction mode, also known as 2:1 atrial flutter, with the same waveform, amplitude, time, and conduction ratio, FR interval and RR interval are equal The FR interval is extended and fixed by six features. One of the two F waves appears in the early or middle stage of contraction, and occasionally in the late diastole, the FR interval is too short, so the F wave is atrioventricular The junction area is in absolute refractory period, and it is not interfered by absolute interference. Another F wave appears in late systolic or diastolic phase, so it can be transmitted downstream to produce supraventricular QRS complex, FR interval is fixed, and FR interval is prolonged. It is generally 0.26 to 0.45 s.
33:1 atrioventricular conduction: atrial flutter When the first F wave is transmitted, occult conduction occurs in the atrioventricular junction, so that the second F wave cannot be transmitted (the ventricular refractory period is refractory). The third F wave can be transmitted to the ventricle (the reaction period of the atrioventricular junction), that is, only one out of every three F waves is transmitted to the ventricle. This odd ratio of atrioventricular conduction is not common.
44:1 atrioventricular conduction: only one of the four F-waves is transmitted to the ventricle, which is also caused by occult conduction. It occurs mostly in patients treated with digitalis, although it has not been converted into sinus rhythm. However, the ventricular rate has decreased significantly, improving hemodynamics and cardiac function, and the patient's symptoms can be significantly improved.
54:1, 3:1, 2:1 alternating or irregular atrioventricular conduction: two or more types of atrioventricular conduction may occur on the same lead or the same electrocardiogram, which may alternately occur, intermittently Occurred or irregularly, their FR intervals may not be equal or fixed.
3:1, 4:1 conduction or alternating such a higher degree of conduction block, often occurs after treatment with digitalis, or after compression of the carotid sinus, or inflammation or ischemic tissue from the atrioventricular junction Pathological atrioventricular block caused by lesions, ie atrial flutter with 3:1, 4:1 atrioventricular conduction, is possible
(4) QRS wave: The QRS wave shape during atrial flutter is mostly the same as the sinus rhythm QRS wave, but the amplitude and shape can be changed by the influence of overlapping flutter waves. Still in refractory period, and formed in the phase of indoor differential conduction, most of the right bundle branch block pattern, which is more common in the 4:1 atrial flutter to 2:1 atrial flutter, because after a long period It is prone to indoor differential conduction, and can also be accompanied by bundle branch block, pre-excitation syndrome, etc., and presents a wide, deformed QRS wave.
(5) ST-T wave: The ST segment generally has no obvious change, the T wave is erect, and the F wave overlaps with the ST-T wave.
4. Special types of atrial flutter ECG
(1) occult atrial flutter: occult atrial electrical activity is rare, including occult sinus rhythm, occult atrial flutter and occult left atrial rhythm, most commonly in patients with rheumatic heart disease, due to atrial muscle fibers Seriously, the atrial activity potential is significantly reduced, making it difficult to record the atrial flutter waveform on the ECG machine, or being masked by a seemingly ultra-fine atrial fibrillation wave, usually in the case of esophageal electrocardiogram or intracardiac electrogram, in addition to high blood Potassium is also one of the reasons.
(2) Atrial flutter with second-degree block is rare, and can be of the following two types:
1 atrial flutter with Wenshi type (second degree I) efferent block: ECG is characterized by a gradual shortening of the FF interval in a series of well-balanced F waves, a sudden lengthening (simplification of the length) a period of variability; or a variegated Venturi period of "sudden lengthening and lengthening"; or an atypical celestial period of "increasing length", the long interval is greater than 1 FF interval and less than 2 FF intervals .
2 Atrial flutter with second-degree type II efferent block: The electrocardiogram shows that the F wave suddenly disappears in a series of well-balanced F waves, and the long FF interval formed by it is just an integral multiple of the usual FF interval.
Atrial flutter with second-degree blockade can obviously not be explained by the theory of reentry, so it should be considered that the trigger mechanism of autonomic increase in the mechanism of atrial flutter is present.
(3) Atrial flutter with second degree I and second type II atrioventricular block:
1 atrial flutter with second degree I atrioventricular conduction: atrial flutter can be combined with some of the following types of Venturi phenomenon:
A. 2:1 atrial flutter accompanied by Venturi-type atrioventricular block ECG showed the second F wave, only one F wave followed by the QRS complex, the downstream FR interval gradually extended, Following the leak, the RR interval between the QRS waves of the downlink is expressed as a "sudden and long" or "slower and longer" or "gradually longer" rule, and it is repeated.
B.4:1 atrial flutter with Venturi-type atrioventricular conduction: The electrocardiogram shows that only one F wave in the four F waves transmits the ventricle, followed by QRS waves, and the FR interval is gradually extended. Take a leak.
C. Atrial flutter with alternating descending Venturi-type atrioventricular block: for example, the electrocardiogram shows an alternating phenomenon of 2:1 and 4:1 atrioventricular conduction with constant F waves, indicating that there are two compartmental junctions. One block zone, one at the proximal end of the atrioventricular junction, is a 2:1 block zone.
Diagnosis
Diagnosis of atrial flutter
diagnosis
According to the medical history, symptoms, signs and electrocardiogram performance can be clearly diagnosed.
Differential diagnosis
1. Identification of atrial flutter and paroxysmal atrial tachycardia: the atrial rate of atrial flutter is 250-350 beats/min, and the atrial rate of paroxysmal atrial tachycardia is 160-250 times/ Min, atrial flutter has F wave in II, III, aVF lead is clear, there is no equipotential line between F waves, ventricular rate is slow, stimulating vagus ventricular rate can be reduced or become irregular (differential conduction ratio) The F wave can often be more clearly manifested; and the paroxysmal atrial tachycardia P' wave has an equipotential line, the ventricular rate is faster, and the stimulation of the vagus nerve can cause the atrial tachycardia to terminate or invalidate.
2. Identification of atrial flutter and ventricular tachycardia: usually the identification of the two is not difficult, but in the following two cases, attention should be paid to the identification.
(1) Atrial flutter combined with ventricular tachycardia: At this time, the QRS complex is widened and the ventricular rate is fast. It is easy to drown the F wave of the atrial flutter and miss the diagnosis. At this time, unless the esophageal lead is added, The lead cannot make an identification, but fortunately it is rare.
(2) Atrial flutter ventricular rate is fast and accompanied by indoor differential conduction: QRS complex is also widened, it is easy to be mistaken for ventricular tachycardia, such as by slowing the rate of ventricular rate (such as compression of carotid sinus When the ventricular rate is slowed down and the QRS wave is narrowed, it can be distinguished.
