External pacemaker

Abstract

External pacemaker (1) for biatrial stimulation, with a control or regulating unit for delivering at least one stimulation pulse, wherein the stimulation of the left or right atrium can be selectively deactivated, characterized in that the control or regulating unit is designed such that a common stimulation pulse amplitude is set for the left and right atrium during stimulation operation, and the control or regulating unit is designed such that the common stimulation pulse amplitude is automatically increased by a definable safety amount during stimulation operation.

Description

[0001] The invention relates to an external pacemaker for cardiac stimulation, wherein the pacemaker has a control unit for delivering at least one stimulation pulse.

[0002] External pacemakers are often used during cardiac surgery for temporary cardiac stimulation and intracardiac ECG monitoring. For stimulation and monitoring, electrodes are used. These electrodes are sewn onto the heart muscle and connected to the external pacemaker via cardiac wires. Conventional pacemakers are known, for example, from publications DE 20 2010 011 244 U1, US 2006 / 0 287 685 A1, and DE 21 49 428 A.

[0003] The pacemaker's output is determined by pulse amplitude (in volts) and pulse duration. Pulse strength is expressed by pulse amplitude, and pulse width indicates the duration of the pulse. It is usually expressed in milliseconds.

[0004] To avoid unnecessary energy supply to the patient, the pacing threshold for the heart is determined before normal operation begins. The pacing threshold defines the minimum amplitude value of the pacing pulse at which sufficient stimulation of the heart is achieved or detected. The pacing threshold can vary for different areas of the heart, i.e., the ventricle or atrium. Deviations can also occur between the left and right ventricle or atrium.

[0005] In the future, bi-atrial pacing modes will be increasingly used. These monitor the right and / or left atrium and, if no intrinsic cardiac activity is detected, deliver a pacing pulse. This approach is primarily intended to reduce the likelihood of atrial fibrillation. To date, no external pacemakers for bi-atrial pacing are known. In addition, a common pacing threshold and pacing amplitude are regularly determined and delivered for the left and right atrium.

[0006] The object of the present invention is to provide an external pacemaker that is suitable for biatrial stimulation and also optimizes the effectiveness of biatrial stimulation.

[0007] This object is achieved by an external pacemaker having the features of claim 1. Advantageous embodiments of the pacemaker are the subject of the dependent claims.

[0008] According to claim 1, an external pacemaker for bi-atrial stimulation is proposed, which has a control unit for delivering at least one stimulation pulse. For effective bi-atrial stimulation, it is expedient to determine the stimulation threshold for the left and right sides of the heart separately and / or to deliver individual pulse amplitudes for the left and right atrium. For this reason, the control unit is now designed such that stimulation of the left or right atrium can be selectively deactivated. This allows targeted stimulation of either the left or right atrium. For normal operation, parallel, simultaneous, or delayed stimulation of both atria is naturally possible.

[0009] The pacemaker according to the present invention can be designed as such or can be designed or connected to a cardioversion device or defibrillator.

[0010] The pacemaker comprises at least two stimulation outputs that can be connected to the corresponding electrodes. Stimulation can be delivered as intracardiac or extracardiac stimulation. The control unit can have separate control circuits for the left and right atrium on the hardware side. Alternatively, the control unit can have a common control circuit for the left and right atrium on the hardware side, whereby the at least two stimulation outputs can be selectively deactivated.

[0011] The inventive design of the control unit is designed for individual pacing threshold determination of the left and right atrium. For this purpose, stimulation of the left or right atrium can be selectively deactivated, allowing for targeted stimulation of either the left or right atrium. Typically, the pulse amplitude is set low and gradually increased until the effectiveness of the stimulation is evident via ECG monitoring and the pacing threshold is defined.

[0012] In principle, it can be advantageous if the control unit is designed so that different pulse amplitudes can be set for the left and right atrium during control operation. This allows the amplitude values ​​to be specifically defined for the side-dependent pacing threshold. In addition to the option to deactivate pacing in bi-atrial pacing modes, this also requires separate control of the pulse amplitudes for both atria. This separate control is preferably provided via hardware and / or software.

[0013] According to the invention, the control unit is designed such that a common stimulation pulse amplitude can be set for the left and right atrium during control operation. This option can be used with separate control loops if a uniform amplitude value can be set for both control loops. The control unit can be designed such that it automatically configures a common amplitude value for both control loops after the pacing threshold has been determined.

[0014] However, this advantageous feature of the control unit is also useful if the pacemaker does not provide the necessary hardware for delivering separate stimulation pulses to the right and left atrium. In this case, it is sufficient for the control unit to allow deactivation of the respective stimulation pulse or stimulation output. The individually determined pacing thresholds for the left and right atrium then define a common value for delivering the stimulation amplitude.

[0015] Advantageously, the control unit automatically configures itself based on the pacing threshold determination, so that the determined and larger stimulation amplitude from the side-individual pacing threshold determination is used for regular bi-atrial pacing. Consequently, the atrium, which requires the larger amplitude for effective pacing, determines the common pacing amplitude in regular operation.

[0016] Furthermore, the control unit can be designed so that the one or more specific stimulation pulse amplitudes are automatically increased by a definable safety margin during normal operation. This further increases the probability of effective stimulation, as a certain safety margin from the respective stimulation threshold is maintained.

[0017] In an advantageous embodiment of the invention, the external pacemaker comprises a display element for displaying a configuration menu. The configuration menu provides a configuration option for the user, allowing them to selectively activate or deactivate left or right atrial pacing.

[0018] For safety reasons, the configuration menu is designed so that only one deactivation of the left or right atrium is permitted. This means that at least one pulse delivery must be active for either the left or right atrium. Deactivation of both pulse deliveries is not permitted and is actively denied to the user.

[0019] The external pacemaker or control unit may further comprise means for triggering and / or inhibiting the pulse delivery. During the inhibited mode, the delivery of a pulse is suppressed in the presence of intrinsic cardiac activity, while in the triggered mode, a signal registered in the atrium triggers the pulse delivery. Obviously, the control unit must therefore comprise means for detecting cardiac activity. The detection threshold for detecting intrinsic cardiac activity can be determined and adjusted in a conventional manner.

[0020] In a further advantageous embodiment of the invention, the control unit can have means for time-delayed pulse delivery. This makes it possible for the stimulation pulses for the left and right atrium to be delivered with a time delay from one another. The time delay can also be configurable.

[0021] Since the control unit may automatically determine the stimulation pulse amplitude based on the two individually determined pacing thresholds, it is advisable for the display element to display at least one notification message informing the user about the use of a common pulse amplitude for both atria and / or the level of the amplitude used. This notification is particularly useful if the user has specified different pulse amplitudes when determining the pacing threshold. The control unit overwrites these user-configured values ​​with the automatically determined value of the common stimulation pulse amplitude.

[0022] In addition to the external pacemaker, the invention relates to a method for determining the pacing threshold using the external pacemaker or an advantageous embodiment of the pacemaker. According to the method according to the invention, an atrial stimulation pulse delivery is deactivated alternately for the left and right atrium, and the pacing threshold is determined individually for the left and right atrium. In this procedure, the pulse delivery for the left or right atrium is first deactivated, and a low pulse amplitude is set for the activated atrium. This pulse amplitude is gradually increased until effective stimulation can be detected. In particular, effective stimulation is checked and detected using an ECG monitor or ECG recorder. The selected stimulation rate for setting the pacing threshold must necessarily be above the heart's natural frequency.

[0023] Once the pacing threshold for the first atrium has been detected, the other atrium is activated and the pacing threshold is determined in the same way.

[0024] Since the pacing thresholds of the left and right atrium typically differ from each other, according to an advantageous embodiment of the method, a common stimulation pulse amplitude is used for bi-atrial pacing, i.e., for pacing the left and right atrium. In particular, the common pulse amplitude is selected that corresponds to the higher pacing threshold of the individually determined pacing thresholds.

[0025] Furthermore, it may be appropriate to increase the common pulse amplitude for normal operation by a certain buffer amount in order to have a sufficient safety margin to the respective pacing threshold of the left and right atrium.

[0026] The invention further relates to control software stored on a data storage medium for implementing the inventive method on an external pacemaker according to the present invention. The control software obviously has the same advantages and properties as the inventive method or the external pacemaker, which is why a repetitive description will be omitted here.

[0027] Further advantages and features of the invention will be explained in more detail below using an exemplary embodiment illustrated in the figures. They show: Fig. 1, Fig. 2: Sketches of the external pacemaker according to the invention.

[0028] The Fig. 1 and Fig. Figure 2 shows a schematic top view of the external pacemaker 1 according to the invention. The device 1 has a display element 10 located on the left side of the top of the device. The display element 10 serves, among other things, to display the configuration menu, allowing individual settings regarding the pacemaker mode to be used and patient-specific adjustments for the selected mode.

[0029] Both figures show the menu area for atrial-separated pacing threshold determination for bi-atrial pacing modes. The menu area shown is only accessible if the appropriate pacing mode has been selected beforehand, ie, a bi-atrial pacing mode has been selected. The selected mode 11 is displayed in the top line of the display on the left edge of the screen.

[0030] In the lower display area 20, two checkboxes 21 and 22 are available for activation / deactivation. The upper checkbox 21, when checked, activates stimulation of the right atrium, while the lower checkbox, when checked, stimulates the left atrium. Deactivation is achieved by removing the checkbox. Selection and activation / deactivation are performed via the rotary knob 40, which responds to both rotation and pressure.

[0031] When entering the displayed menu, both checkboxes 21, 22 are set by default, ie the pulse delivery is activated for both the left and right atrium.

[0032] The selected stimulation amplitude for the left and right atrium is displayed and configured via fields 23 and 24 below checkboxes 21 and 22. When entering the configuration menu for the first time, the initial value is taken from the "A STIM V" field 25, which indicates the active stimulation pulse amplitude in normal operation of the pacemaker with biatrium stimulation. In the example of Fig. 1 the value is 2.5 V, which is automatically transferred to fields 23, 24 for the amplitudes for determining the stimulation threshold.

[0033] For effective biatrial stimulation using external pacemaker 1, an individual pacing threshold must be determined for each atrium. After selecting a biatrial stimulation mode, displayed in field 11, the user deactivates stimulation of the right atrium by removing the checkmark from checkbox 21. To do so, the user selects checkbox 21 using the rotary knob 40 and removes the checkmark by pressing it. Pressing it again re-enters the checkmark. The corresponding menu display is shown in the Fig. 2.

[0034] The menu indicates to the user that only one pulse will be delivered to the left atrium during the pacing threshold determination. The user initially selects a low pulse amplitude for pacing the left atrium. The stimulation amplitude 24 is selected by pressing the rotary knob 40, which causes the selected field 24 to be displayed inverted. The amplitude can be increased or decreased by rotating the rotary knob 40. The value "---" is displayed in the "A STIM" field 25 during the pacing threshold determination.

[0035] The amplitude for pacing the left atrium is now increased continuously or gradually, while simultaneously monitoring the patient's heart via an external ECG monitor or ECG recorder for effective stimulation when a pacing pulse is triggered. The smallest amplitude value at which effective stimulation is detected defines the pacing threshold. As a prerequisite for determining the pacing threshold, a pacing rate must be selected in field 26 that is above the heart's natural rate.

[0036] Once the appropriate amplitude for the left atrium threshold has been found, in the Fig.2, if this is 4V, stimulation for the right atrium is activated via checkbox 21 and deactivated via checkbox 22 for the left atrium. For safety reasons, deactivating both channels 21 and 22 is not possible, which is why both checkboxes 21 and 22 must always be activated before one of the two checkboxes 21 and 22 can be deactivated again.

[0037] After repeating the described procedure for the right atrium, the determination of the pacing thresholds for both atria is complete. Since the two determined pacing thresholds are usually different, a common pulse amplitude is automatically selected for both atria upon exiting the settings menu. This value is identical to the higher of the two determined pacing thresholds. This value is automatically transferred to field 25 for normal operation.

[0038] Optionally, the pulse amplitude can be automatically increased by a relative or absolute value to provide a safety buffer to account for a subsequent, physiologically induced increase in the pacing threshold. The actual set pulse amplitude is displayed to the user via a message upon exiting the menu, which must be confirmed before resuming regular biatrial pacing. This set amplitude is permanently displayed at a predefined position on the external pacemaker display after exiting the menu.

[0039] The inventive concept of the external pacemaker lies in the ability to deactivate stimulation of the left or right atrium during biatrium stimulation mode. Deactivation can be implemented in both hardware and software. Due to the use of a common pulse amplitude for stimulation of both atria, external pacemakers are suitable. Due to their hardware configuration, they can only set a common pulse amplitude during normal operation, and in which the external pacemaker can only detect the stimulated cardiac activity in one or neither of the two atria due to the properties of the hardware circuit.

Claims

[1] External pacemaker (1) for biatrial stimulation, with a control or regulating unit for delivering at least one stimulation pulse, wherein the stimulation of the left or right atrium can be selectively deactivated, characterized by that the control or regulating unit is designed in such a way that a common stimulation pulse amplitude is set for the stimulation mode for the left and right atrium, and the control or regulating unit is designed in such a way that the common stimulation pulse amplitude is automatically increased by a definable safety amount in the stimulation mode. [2] External pacemaker (1) according to claim 1, characterized by that the stimulation of the left or right atrium can be optionally deactivated for the determination of the pacing threshold. [3] External pacemaker (1) according to one of the preceding claims, characterized bythat the control or regulation unit is designed for individual determination of the pacing thresholds of the left and right atrium. [4] External pacemaker (1) according to claim 3, characterized by that the control or regulating unit automatically uses the stimulation pulse amplitude determined from the stimulation threshold determination and which is greater in magnitude than the determined stimulation pulse amplitudes for the left and right atrium for the biatrial stimulation of the left and right atrium. [5] External pacemaker (1) according to one of the preceding claims, characterized by that it has a display element (10) for displaying a configuration menu, wherein the configuration menu includes a configuration option for the user for activating and deactivating the left and right atrial stimulation. [6] External pacemaker (1) according to claim 5, characterized bythat the configuration menu only allows deactivation of either the left or right atrium. [7] External pacemaker (1) according to one of the preceding claims, characterized by that the control or regulating unit has means for triggered and / or inhibited pulse delivery. [8] External pacemaker (1) according to one of the preceding claims, characterized by that the control or regulating unit has means for the time-delayed stimulation pulse delivery, whereby the stimulation pulses of the left and right atrium can be delivered with a time delay from one another. [9] External pacemaker (1) according to one of the preceding claims, characterized by that the control or regulating unit informs the user of the automatically determined common stimulation pulse amplitude for the biatrial stimulation by notification, in particular by optical and / or acoustic notification, on the display element (10).

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