Increased pacing rate

Introduction The pacemaker delivers the fundamental frequency of the stimulation pulse as needed by the patient. Generally, 70 to 90 beats/min is the optimal heart rate, and the pacing frequency requirement is greater than 10% of the patient's own heart rate. Pacemaker syndrome refers to a group of clinical syndromes caused by hemodynamic and electrophysiological abnormalities after pacemaker implantation. Any pacing mode can occur as long as the compartment is separated. Generally seen in VVI (suppressed on-demand ventricular) pacing mode. Mainly manifested as neurological symptoms, low cardiac output and congestive heart failure. About 38% of patients with syncope in the clinic.

Cause

The cause of the disease is multifactorial:

Loss of synchronous contraction in 1 compartment can reduce cardiac output by 20% to 30%, and the original cardiac dysfunction can be reduced by more than 50%.

2 atrioventricular valve insufficiency caused systolic blood reflux back to the atria, increasing atrial load.

3 increased atrial pressure inhibits normal contraction reflexes of surrounding blood vessels leading to a drop in blood pressure.

4 right ventricular pacing causes the biventricular systole to be out of sync.

5 Ventricular atrial electrical activity of the chamber reverse conduction.

an examination

Related inspection

Dynamic electrocardiogram (Holter monitoring) ECG

The clinical manifestations of pacemaker syndrome are mainly a series of symptoms and signs caused by low cardiac output. However, due to different compensatory abilities of different functions, different individuals have different performances. In general, older people are more common.

General pacemaker syndrome is caused by VVI pacing but can also occur in AAI (suppressed on-demand atrial pacing) or frequency-adapted atrial pacing (AAIR)

1, symptoms

(1) Dizziness: About 92% of patients with pacemaker syndrome may have dizziness, 60% of which are persistent, and the rest are intermittent.

(2) vertigo: about 85% of patients may have seizures.

(3) syncope: About 49% of patients may have syncope. Symptoms occurred in 38% of patients.

(4) shortness of breath: difficulty breathing, palpitations, lethargy, chest pain.

2, signs

(1) Hypotension: Hypotension is an important sign of pacemaker syndrome. The incidence rate is about 25%. Some patients show orthostatic hypotension and some have blood pressure fluctuations.

(2) Signs of congestive heart failure: About 30% of patients with pacemaker syndrome may present with signs of congestive heart failure such as pulmonary edema and jugular vein engorgement.

(3) Heart sound changes and heart murmurs: There may be heart sounds and weaknesses, heart rhythm irregularities, and heart murmurs during pacing.

(4) Liver pulsation.

Differential diagnosis

The emergence of escape: the so-called escape refers to when the sinus node is excitatory or arrested, the diastolic phase of the recessive pacemaker has a chance to reach the threshold potential, which causes excitement and drives the whole heart, called escape. Passive ectopic heart rhythm is a physiological protection mechanism, which does not require treatment itself. If the ventricular rate is too slow to produce symptoms or hypotension, it is necessary to increase the ventricular rate and give treatment.

Premature beat: premature beat (cardiovascular) referred to as premature beats. It refers to the heart beat caused by premature impulses issued by the ectopic pacemaker, which is the most common arrhythmia. Can occur on the basis of sinus or atopic (such as atrial fibrillation) heart rhythm. It may occur occasionally or frequently, and may occur irregularly or regularly after each or every number of normal beats to form a bipolar or premature beat. According to the origin, it can be divided into four types: sinus, atrial, atrioventricular junction and ventricular. Among them, ventricular premature beats are the most common, followed by atrial and less common. Sinus premature beats are rare. Premature beats can be seen in normal people, or in patients with structural heart disease, common in coronary heart disease, rheumatic heart disease, hypertensive heart disease, cardiomyopathy. Premature beats can also be seen in quinidine, procainamide, digitalis or tincture poisoning; hypokalemia; mechanical stimulation of the heart during cardiac surgery or cardiac catheterization.

Accelerated atrial escape rhythm is also called non-paroxysmal atrial tachycardia, accelerated atrial autonomic rhythm, accelerated atrial rhythm and so on. Diagnosis can be confirmed based on medical history, symptoms, signs, and electrocardiogram findings.

Apical beats diffuse: Myocarditis, in addition to apical beats often weakened with apex beats. Myocarditis is a localized or diffuse inflammation of the heart muscle that can occur primarily in the heart muscle or as part of a systemic disease. Fatigue, fever, chest tightness, palpitations, shortness of breath, dizziness, severe heart failure or cardiogenic shock. The heart rate increases, which is not proportional to the increase in body temperature, the heart is enlarged, the noise is changed, and the arrhythmia is abnormal.

The clinical manifestations of pacemaker syndrome are mainly a series of symptoms and signs caused by low cardiac output. However, due to different compensatory abilities of different functions, different individuals have different performances. In general, older people are more common. General pacemaker syndrome is caused by VVI pacing but can also occur in AAI (suppressed on-demand atrial pacing) or frequency-adaptive atrial pacing (AAIR).

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