CZ306786B6 - Connection of an external pacemaker - Google Patents

Abstract

The connection of an external pacemaker consisting of the pulse generator (1) and the inhibitory circuit (2) and is complemented with the nodal circuit. This connection allows you to prevent a stimulation outage.

Description

Technical field

External pacemakers are used for short-term stimulation of the patient's cardiac activity and are used to bridge the period before implantation of a permanent pacemaker. The application deals with circuit arrangement in an external pacemaker.

BACKGROUND OF THE INVENTION

The purpose of pacemaker is to approach the normal heart function as much as possible. Cardiostimulation thus serves to correct bradycardia (or tachycardia) caused by the interruption of atrial conduction during myocardial infarction or in situations where the sinoatrial nodule does not perform a stimulatory function.

As is known, for example from the textbook author prof. Ivan Dylevsky / ZdAWy Functional Human Anatomy. ”CTU, 2013, the cardiac conduction system of which the sinoatrial node is a part, works by causing an electrical pulse to normally originate from an area of the right atrium called a sinoatrial node. Another part of the cardiovascular system is the atrioventricular (atrial-ventricular) node, from which the atrial-ventricular bundle of fibers - His's bundle, is divided into the right and left arm - Tawar's arms. The fibers of both arms curl under the endocardium of the ventricles and continue branching into a Purkinje fiber network that distributes electrical impulses to the ventricular muscle.

In a healthy person, the sinoatrial node emits about 70 electrical pulses per minute and determines the underlying rhythm of heart activity. The atrioventricular node transmits only 40 to 50 pulses to the ventricular myocardium, and this pulse rhythm does not normally occur as it is covered by faster pulses from the primary sinus node. However, if the transfer system between the sinus and atrioventricular nodes is interrupted, the atrioventricular node will take the lead and the heart contractes more slowly in the rhythm of the pulses transmitted by that node.

Thus, the cardiovascular system is trying to replace cardiac pacing. The first pacemaker experiments were carried out at the turn of the 19th and 20th centuries by J. M. William, who applied electrical impulses to the heart during asystole. The external pacemaker was first designed and constructed in 1950 by John Hopps. This large-scale device used tubes to transcutaneously stimulate the heart. The application was painful and unpleasant for the patient.

External pacemakers can be divided into temporary stimulators and diagnostic stimulators. Stimulation may be direct or indirect. These devices are most often used before implantation of a permanent pacemaker, as well as for postoperative securing of at-risk patients, for the management of an acute failure of the pacing system of a permanent pacemaker, etc.

In addition to the historical disadvantages, which in particular included the size of the device, its weight, the condensation of water vapor, it is possible to determine the current disadvantage, for example, of the life of the power cells or of the pacing circuit failure.

Based on their functions, pacemakers can be divided into the following types:

- the type in which the heart muscle stimulation site is determined.

- the type in which the ECG location is determined,

- the type in which cardiac muscle stimulation is guaranteed,

a type that is programmable, and

- type defining antiarrhythmic function.

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However, these types and combinations do not address the pacing activity of the pacemaker in the event of a pacing circuit failure, without intervention from the outside.

SUMMARY OF THE INVENTION

The device according to the invention removes the above-mentioned drawback in the case of a pacing circuit failure by simulating the functions of the cardiac conduction system.

The proposed solution is in accordance with the standard ČSN EN 60601-2-31 of 1.4.2009 “Medical electrical devices. Part 2: Specific safety requirements for external pacemakers with internal power supply ”therefore addresses the risk of accelerating the pace rate of the runaway. This eliminates the possibility of a pacing failure due to a malfunction of the pacemaker's main circuit.

In a conventional pacemaker, the basic pacing circuit provides sinoatrial nodal function and determines the underlying heart rate. Thus, the device of the application complements the external pacemaker with a 40 ppm nodal rhythm generator (40 pulses / minute = 2/3 Hz), which is equal to the number of pulses that the atrioventricular node in the heart sends. The nodal circuit in this case is a switch that is controlled by a restartable monostable of 1.5 s. The nodal circuit thus simulates the function of the atrioventricular node, which is part of the cardiac pacing system in the human heart, ensuring that the cardiac pacemaker remains functional. it does not send any electrical impulses.

The nodal circuit is connected between the pulse generator and output K. The output of the inhibitory circuit is then connected to the nodal circuit.

For the purposes of this application and based on available literature, the word nodal means - referring to a node, usually atrioventricular (atrial), which is part of the cardiac conduction system (eg, the Great Medical Dictionary) online http: // medical, dictionaries. Y

Clarification of drawings

Figure 1 is a schematic of the proposed solution.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Connection of an external pacemaker consisting of a pulse generator 1 and an inhibitory circuit 2, with a nodal circuit 3 being connected between the pulse generator 1 and output K, is the electronic switch, controlled by a restartable monostability of 1.5 s. 2. In the active monostable operation, the pulse generator 1 is switched to output K. When the monostability decreases (after 1.5 s), astabil 2 / 3Hz, contained in the nodal circuit, is switched to output K.

Example 2

If the patient has intrinsic cardiac activity, circuits 2 and 3 are off. If the intrinsic heart rate decreases below 40 beats per minute (bradycardia) and the pulse generator 1 does not deliver pulses due to failure, then the nodal circuit 3 will generate life-sustaining pacing pulses. with a frequency of 2 / 3Hz, simulating the activity of the atrioventricular node in the transferring cardiac system.

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Example 3

If the patient does not possess intrinsic heart activity, the inhibitory circuit 2 is off and the pulse generator 1 supplies pulses to the output K via the nodal circuit 3 (as a switch). If for any reason the pulse generator 1 frequency falls below 2/3 Hz, the nodal circuit 3 generate pacing pulses to maintain the underlying heart activity.

Industrial applicability

The proposed device is usable in the field of production of cardiovascular medical devices, especially external pacemakers.

Claims (1)

An external pacemaker comprising an inhibiting circuit pulse generator, characterized in that a nodal circuit (3) is connected between the pulse generator (1) and the K output to provide pacing when the pacing circuit of the pacemaker is lost while the inhibitory circuit output (2) is connected to the nodal circuit input (3).