Pacemaker syndrome

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Pacemaker syndrome is a disease that represents the clinical consequences of suboptimal atrioventricular (AV) syncrony or AV dissynchronization, regardless of pacemaker, after pacemaker implantation. This is an iatrogenic disease - a bad effect resulting from medical care - often undiagnosed. In general, the symptoms of syndrome are a combination of decreased cardiac output, loss of atrial contribution to ventricular filling, loss of total peripheral resistance response, and nonphysiological pressure waves.

Individuals with low heart rates before implantation of pacemakers are more at risk of developing pacemaker syndrome. Usually the first chamber of the heart (atrium) contracts when the second chamber (ventricle) relaxes, allowing the ventricles to fill before contracting and pumping blood out of the heart. When the time between two chambers comes out of sync, less blood is sent on every beat. Patients who develop pacemaker syndrome may require pacemaker adjustment, or other tin mounting to better coordinate atrial and ventricular contraction times.

Video Pacemaker syndrome

Signs and symptoms

No specific criteria were developed for the diagnosis of pacemaker syndrome. Most signs and symptoms of pacemaker syndrome are not specific, and many are common in the elderly population at baseline. In the lab, pacemaker interrogations play an important role in determining whether pacemaker mode has contributed to symptoms.

Symptoms commonly documented in patient history, classified according to cause:

• Neurological - Dizziness, near syncope, and confusion.
• Heart failure - Dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and edema.
• Hypotension - Seizures, changes in mental status, diaphoresis, and signs of orthostatic hypotension and shock.
• Low cardiac output - Fatigue, weakness, dyspnea during activity, lethargy, and mild headaches.
• Hemodynamics - Pulsation in the neck and abdomen, choking sensations, jaw pain, right upper quadrant pain (RUQ), chest colds, and headaches.
• Heart rate related - Palpitation associated with arrhythmia

In particular, the examiner should look for the following in a physical examination, as this is often found at the time of admission:

• Vital signs can show hypotension, tachycardia, tachypnea, or low oxygen saturation.
• Pulse amplitude may vary, and blood pressure may fluctuate.
• Look for neck venous distension and cannon waves in the neck veins.
• The lungs may show cracks.
• Cardiac examination may reveal regurgitation murmur and heart rate variability.
• The heart may be pulsating, and RUQ may be soft for palpation. Ascites can be found in severe cases.
• The lower extremities may have edema.
• Neurological examination may reveal confusion, dizziness, or mental status changes.

Complications

Studies have shown that patients with Pacemaker syndrome and/or with sinus syndrome are at increased risk of developing fatal complications that require patients to be carefully monitored in the ICU. Complications include atrial fibrillation, thrombo-embolic events, and heart failure.

Maps Pacemaker syndrome

Cause

The cause is poorly understood. However, some risk factors are associated with pacemaker syndrome.

Risk factors

• In the preimplantation period, two variables are predicted to predispose to syndrome. First is the low sine level, and the second is the lower lower programmed limits. In postimplantation, an increase in the percentage of ventricular-grade heart rate is the only variable that significantly predicts the development of pacemaker syndrome.
• Patients with full VA conduction are at greater risk for developing pacemaker syndrome. Approximately 90% of patients with preserved AV conduction have complete VA conduction, and about 30-40% of patients with complete AV block have maintained VA conduction. Whole VA conduction may not be seen at the time of pacemaker implantation or may even develop at any time after implantation.
• Patients with non-adherent ventricle and diastolic dysfunction are highly sensitive to loss of atrial contribution to ventricular filling and have a greater chance of developing syndrome. These include patients with cardiomyopathy (hypertension, hypertrophic, restrictive) and elderly individuals.
• Other factors associated with the development of Pacemaker syndrome include decreased stroke volume, decreased cardiac output, and decreased left ventricular fraction of left atrium associated with ventricular runway.

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Pathophysiology

The loss of physiological time of atrial and ventricular contraction, or sometimes called AV dyssynchrony, leads to different mechanisms of symptom production. This altered ventricular contraction will decrease cardiac output, and in turn will lead to a systemic hypotensive reflex response with various symptoms.

Loss of atrial contraction

Unsuitable removal of patients with reduced ventricular adherence, which may be caused by diseases such as hypertensive cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, and aging, can lead to a loss of atrial contraction and significantly reduced cardiac output. Because in such cases the atrias is required to give 50% of the heart output, which usually provides only 15% - 25% of cardiac output.

A wave cannon

Atrial contraction of the closed tricuspid valve can cause pulsation in the neck and abdomen, headache, cough, and jaw pain.

Increased atrial pressure

The ventricular rhythm is associated with elevated right and left atrial pressures, as well as increased pulmonary and pulmonary venous arterial pressure, which can cause symptomatic symptomatic lung and symptomatic lung congestion.

Increased production of natriuretic peptide

Patients with pacemaker syndrome show elevated plasma ANP levels. It is due to increased left atrial pressure and left ventricular filling pressures, caused by a decrease in cardiac output caused by synchronization in atrial and ventricular contractions. ANP and BNP are potent arterial and venous vasodilators that can override carotid and aortic baroteceptor reflexes that seek to compensate for a decrease in blood pressure. Usually patients with wave cannons have higher plasma ANP levels than those without a wave cannon.

conduction VA

The main cause of AV dyssynchrony is VA conduction. VA conduction, sometimes referred to as retrograde conduction, leads to delay, nonphysiological time of atrial contraction in relation to ventricular contraction. However, many conditions other than VA conduction promote AV dissynchronization.

This will further lower blood pressure, and a secondary increase in ANP and BNP.

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Prevention

At the time of implantation of the pacemaker, the AV synchrony must be optimized to prevent the occurrence of pacemaker syndrome. Where patients with optimized AV synchrony have shown excellent implantation results and the incidence of pacemaker syndrome is very low compared to patients with suboptimal AV synchronization.

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Treatment

Diet

Diet alone can not treat pacemaker syndrome, but a proper diet for the patient, in addition to other mentioned treatment regimens, may improve the patient's symptoms. Some of the cases mentioned below:

• For patients with heart failure, a low-salt diet is indicated.
• For patients with autonomic insufficiency, a high-salt diet may be appropriate.
• For patients with dehydration, oral fluid rehydration is required.

Drugs

There is no specific drug used to treat pacemaker syndrome directly because the treatment consists of improving or reprogramming the pacemaker.

Medical Treatment

• For some patients who are ventricularly paced, usually the addition of atrial leads and optimizing the AV synchrony usually resolve symptoms.
• In patients with other pacemakers, in addition to ventricular runways, symptoms usually disappear after adjusting and reprogramming pacemaker parameters, such as adjusting the AV delay, altering the postventricular atrial refraction period, the sensing rate, and the threshold voltage. The optimal value of this parameter for each individual is different. Thus, achieving the optimal value is by experimenting with successful reprogramming and measurement of relevant parameters, such as blood pressure, cardiac output, and total peripheral resistance, as well as symptomatological observations.
• In rare cases, using hysteresis to help maintain AV synchrony can help relieve symptoms in patients who have ventricularly inhibited (VVI) because they have an intact sinus node function. Hysteresis reduces the amount of time spent in pacing mode, which can relieve symptoms, especially when the pacemaker produces synchronous AV.
• If symptoms persist after all these treatment modalities, replacing the pacemaker itself is sometimes helpful and may relieve symptoms.
• Medical care includes supportive care, if any complications occur, the medical team should be ready. Possible complications include heart failure, hypotension, tachycardia, tachypnea, and oxygenated deficits.

Surgical Treatment

Sometimes surgical intervention is required. After consultation with an electrophysiologist, additional pacemaker placement may be required, which in turn eases some symptoms.

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Epidemiology

The reported incidence of pacemaker syndrome ranges from 2% to 83%. A variety of reported events are likely to be caused by two factors that are the criteria used to determine pacemaker syndrome and therapies used to complete the diagnosis.

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History

Pacemaker syndrome was first described in 1969 by Mitsui et al. as a collection of symptoms associated with right ventricular velocity. The name pacemaker syndrome was first coined by Erbel in 1979. Since the first invention, there have been many definitions of pacemaker syndrome, and an understanding of the cause of pacemaker syndrome is still under investigation. In a general sense, pacemaker syndrome can be defined as symptoms associated with the right ventricular pacemaker being released with the return of A-V and V-V sync.

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References

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External links

• PreOp Education Patient Permanent Implant Patient Pacemaker

Source of the article : Wikipedia