How it Works
Biotronik
Loading...
CYLOS
Users Manual
175 pgs2.57 Mb0

Biotronik CYLOS Users Manual

1
Table of Contents
Table of Contents.......................................................... 1
Introduction................................................................... 8
NBG Code.................................................. 11
Programmer and Software........................... 11
Indications and Contraindications.............................12
Home Monitoring ........................................................16
Pacing Types – Modes................................................22
Closed Loop Modes
...................................22
2
Summary of the Functions and Timing Intervals
of the Modes...............................................32
Timing Functions ........................................................34
AV Hysteresis............................................. 41
Pacing and Sensing Functions...................................49
3
Continuous Measurement and Recording of Lead
Automatic Lead Check................................. 51
Antitachycardia Functions..........................................63
PMT Management....................................... 71
Rate Adaptation ..........................................................78
Accelerometer-Based Rate Adaptation
Physiologic Rate Adaptation (The CLS Feature)
....................................................79
Individually Adjusting CLS Parameters..... 81
The CLS Safety Feature
.............................82
Automatic Initialization of Closed Loop
Stimulation ...............................................82
Rate Increase..............................................86
......78
4
IEGM Recordings.........................................................92
Diagnostic Memory Functions (Statistics)................96
Timing Statistics .........................................98
Arrhythmia Statistics .................................101
Sensor Statistics .......................................107
Sensing Statistics......................................108
Pacing Statistics........................................109
Follow-up Options .....................................................111
Realtime IEGM Transmission with Markers ...111
IEGM Recordings.......................................112
Analog Telemetry of Battery, Pulse and Lead
Data.........................................................113
Rate and Sensor Trend...............................114
High-Resolution Threshold Test...................114
P/R-Wave Test ..........................................115
Retrograde Conduction Test........................115
External Pulse Control (NIPS)......................115
Temporary Program Activation....................116
Patient Data Memory .................................118
5
Storing Follow-up Data...............................118
Position Indicator for the Programming Wand
...............................................................118
Handling and Implantation ......................................119
Sterilization and Storage ............................119
Opening the Sterile Container......................120
Connecting the Leads.................................120
Follow-up Basics .......................................................124
Battery Status...........................................124
Testing the Pacing Threshold......................125
Sensing Functions .....................................126
Retrograde Conduction...............................126
Rate Adaptation.........................................127
Sensor Gain ..............................................128
Sensor Threshold.......................................128
Battery, Pulse and Lead Data......................129
Replacement Indication............................................130
Expected Time Until ERI.............................130
Remaining Service Time after ERI................132
Cautionary Notes ......................................................133
Medical Complications...............................133
Technical Malfunctioning............................133
Muscle Potentials ......................................133
Electromagnetic Interference (EMI)..............134
Risky Therapeutic and Diagnostic Procedures
...............................................................136
6
Explantation..............................................141
Technical Data ..........................................................142
Pacing Modes ...........................................142
Home Monitoring — Programmable Parameters
...............................................................142
Home Monitoring – Non-Programmable
Parameters/Value Ranges ..........................142
Pulse and Timing Parameters .....................144
Rate Adaptation.........................................150
Parameters at Replacement Indication.........151
Additional Functions ..................................152
Default Programs ......................................153
Materials in Contact with Human Tissue.......157
Programmer .............................................157
Electrical Data...........................................158
Battery.....................................................158
Service Times............................................158
Mechanical Data........................................159
Storage Conditions ....................................159
X-ray Identification.....................................159
Projected Tolerances of Factory Settings......160
Product Line .............................................161
Block Diagram for Cylos DR........................162
Block Diagram for Cylos DR-T .....................163
Block Diagram for Cylos VR ........................164
Federal Communications Commissin Disclosure .......165
Terms and Abbreviations............................................166
7
Index...........................................................................170
Cylos DR
Cylos VR
Cylos DR-T
8 Introduction
Introduction
Cylos is a line of pacemakers that may be used for all indications of bradycardic arrhythmias. There are three pacemakers in the Cylos product group. There are single- and dual-chamber pacemakers that achieve physiological rate adaptation using Closed Loop Stimulation,1 and a third pacemaker that permits external monitoring via a Home Monitoring feature.2
The myocardium contracts differently under different states of load. Closed Loop Stimulation (CLS) uses these variations to provide the patient with a physiologic pacing rate that is specific to his or her needs. The dynamics of the cardiac contractions are evaluated by unipolarly measuring the intracardiac ventricular impedance. Changes in the impedance curves over time are directly proportional to the state of load. By evaluating these changes, the pacemaker then sets the pacing rate. Closed Loop Stimulation uses ventricular sense (VS) and ventricular pace (VP) events in calculating the pacing rate.
A traditional accelerometer is another way Cylos can adapt the pacing rate. With the accelerometer, which is integrated into the hybrid circuit, any patient movement generates an electrical signal. This signal is used as input for controlling how the pacing rate is adapted.
The dual-chamber pacemaker has separate atrial and ventricular leads and is suited for patients who need AV-synchronous pacing.
The single-chamber pacemaker needs just one lead and is only suited for ventricular pacing.
Cylos DR-T features the complete functionality of Cylos DR and is also equipped with the Home Monitoring function. For more information, please see the "Home Monitoring" section.
1
Pacing in a closed loop.
2
An extended telemetry option available in Cylos DR-T
9 Introduction
All the systems have extensive features that allow quick diagnosis and delivery of safe therapy for cases of bradycardic arrhythmia. The guided follow-up functions have been largely automated. Initialization and optimization of Closed Loop Stimulation is also automated. This saves the physician time and eliminates problems in verifying and adjusting the pacemaker.
Even during implantation, the implant can detect any connected leads – one of the key aspects of Auto-initialization.
Cylos features numerous special functions:
• The amplitude control function (which is referred to as ACC, Active Capture Control) continuously monitors the effectiveness of ventricular pacing and continuously adjusts the pacing amplitude to the pacing threshold.
• Closed Loop Stimulation (CLS) is automatically initiated and optimized.
• Statistics tracking intrinsic AV conduction help optimize the programmed AV delay and AV hysteresis.
• Antitachycardia functions provide the patient significant protection from the consequences of tachycardias. Automatic mode conversion or automatic mode switching prevent atrial-controlled pacing in the case of atrial tachycardias.
• A preventive overdrive mode reduces the occurrence of atrial tachycardias by using minimal overdrive pacing of the patient’s intrinsic rate.
• Extensive algorithms help to prevent, recognize, and terminate tachycardia induced by the pacemaker.
10 Introduction
• Innovative rate hysteresis promotes the patient’s own cardiac rhythm and avoids unnecessary overdrive pacing.
• AV hysteresis features support intrinsic conduction and hence the natural contraction process.
• The night program adjusts the pacing rate to the reduced metabolic needs of the patient while resting at night.
• The regular automatic lead impedance check triggers the switch from a bipolar to unipolar pacing mode when values outside the normal range occur.
• Automatic sensor features make it easier to adjust pacemaker parameters to the individual needs of the patient.
• The Rate Fading function ensures that the heart rate does not drop abruptly when the intrinsic rate suddenly decreases. Rather, the rate is gradually reduced until the basic or sensor rate has been reached.
• IEGM recordings provide insight into the events before a tachycardic phase.
• Extensive memory functions (such as the histogram, rate trend, activity chart, etc.) facilitate evaluation of the state of the patient and the pacemaker.
• Atrial and ventricular extrasystoles as well as atrial tachycardias can be analyzed and classified with respect to their complexity and when they occur.
• An external pulse control function is available for terminating atrial tachycardias and for use during electrophysiologic studies. Burst stimulation, with realtime control of the burst rate, and programmed stimulation, with up to 4 extrastimuli, are available.
11 Introduction
• Automatic functions and the storage of follow-up data in the implant simplify and accelerate the follow-up process.
Note: This technical manual describes all the features of
the Cylos line of pacemakers. A special note of any features that apply only to specific Cylos models will be made in the text or margins.
NBG Code
DDDR is the NBG code1 for Cylos DR/DR-T:
D Pacing in both chambers D Sensing in both chambers D Inhibition and triggering of pulses R Rate adaptation
VVIR is the NBG code2 for Cylos VR:
V Pacing in the ventricle V Sensing in the ventricle I Inhibition and triggering of pulses R Rate adaptation
Programmer and Software
The pacemakers can only be programmed with appropriate BIOTRONIK programmers, e.g., ICS 3000 or PMS 1000, along with the current software version. The range of functions and available parameters depend on the software module being used. Therefore, the operation and availability of certain functions can differ from the description in this manual. Specific information pertaining to the programmable options is provided in the user manual of the respective software module.
1
See Bernstein et al., The Revised NASPE/BPEG Generic Code for Antibradycardia,
Adaptive-Rate, and Multisite Pacing. PACE 2002, Vol. 25, No. 2: 260-264
2
See Bernstein et al., The Revised NASPE/BPEG Generic Code for Antibradycardia,
Adaptive-Rate, and Multisite Pacing. PACE 2002, Vol. 25, No. 2: 260-264
12
Indications and Contraindications
Indications and Contraindications
Indications for Closed Loop Stimulation
Closed Loop Stimulation uses ventricular sense (Vs) and ventricular pace (Vp) events in calculating the pacing rate. The indications for Closed Loop Stimulation are summarized in the following: — Patients with intermittent AV conduction disorders or intact AV
conduction. The algorithm is based on an AV hysteresis that can be turned off for patients with high-degree AV blocks.
— Patients with a permanent AV block can be paced in the ventricle
with the required VP parameter set to “yes”.
— Patients with vasovagal syncope can be optimally supported with
the programmable “dynamic runaway protection” parameter.
— Patients who would benefit from a constant AV delay are better
treated when the “CLS dynamics” parameter is turned off.
The following information includes general indications and contraindications for the use of cardiac pacemakers. Please refer to the appropriate medical literature for detailed information. The guidelines of the American College of Cardiology (ACC),1 the American Heart Association (AHA), and the German Society for Cardiology and Cardiovascular Research2 are particularly good sources of information.
1
Guidelines for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices,
Gregoratos et al., ACC/AHA Task Force Report, Circulation 2002; 106: 2145-2151, October 15, 2002
2
Richtlinien zur Herzschrittmachertherapie; Indikationen, Systemwahl, Nachkontrolle.
[Guidelines for Cardiac Pacemaker Therapy; Indications, System Selection, Follow-up Care]. Reports by the Commission for Clinical Cardiology at the German Society for Cardiology - Cardiovascular Research] (DGK), B. Lemke, W. Fischer, H. K. Schulten, Steinkopff Verlag 1996
13
Indications and Contraindications
General Indications
The following conditions are regarded as general indications for pacemaker implantation when they occur together with symptoms such as syncope, dizziness, reduced physical capacity, or disorientation:
• Sinus node arrest and symptomatic bradycardia with or without an AV conduction disorder.
• Intermittent or complete AV block.
• Brady-/tachycardia syndrome or other symptoms of sick sinus
syndrome that result in symptomatic bradycardia.
• Supraventricular reentry tachycardias that can be suppressed by chronic AV-sequential pacing.
• Atrial and ventricular ectopic arrhythmias that can be suppressed by permanent AV-sequential pacing.
In contrast to a single-chamber pacemaker, a dual-chamber pacemaker is indicated for patients who require increased cardiac output. This includes active patients and patients who have experienced, or are likely to experience, pacemaker syndrome.
An atrial-controlled dual-chamber mode (DDD and VDD) is indicated for patients who have an intact spontaneous atrial rhythm. Ventricular­controlled, AV-sequential dual-chamber pacing modes (DDI, DVI and VDI) are indicated for patients in whom ventricular pulse triggering due to spontaneous atrial events is not required or desired. Rate-adaptive pacing is indicated for patients who exhibit chronotropic incompetence and require increased pacing rates with physical activity.
14
The functions "Automatic Mode Conversion" and "Mode Switching" in connection with the pacing modes DDD(R) and VDD(R) are useful in cases of paroxysmal atrial tachyarrhythmia to interrupt any atrial synchronization of ventricular pulses during the phases of atrial tachyarrhythmia. The DDD(R) mode with Mode Conversion is an alternative to the DDI(R) or DVI(R) mode in this case.
The AAI mode is indicated in the presence of symptomatic sinus node dysfunction as long as adequate AV conduction exists. The VVI mode is indicated in cases of symptomatic bradycardia when there is no (longer) significant atrial contribution to hemodynamics.
The demand modes as well as the asynchronous DOO, AOO, and VOO modes (with reduced sensing functions) are indicated in cases of medical/technical complications (e.g., electromagnetic interference, sensing errors, lead fractures, detection of myopotentials, muscle stimulation, etc.).
The triggered pacing modes DDT, DDI/T, VDT, DVT, AAT, and VVT as well as the VDI and OFF modes are indicated for diagnostic purposes.
Indications and Contraindications
General Contraindications
There are no known contraindications for the use of multiprogrammable and multifunctional dual-chamber pacemakers, provided that implantation is preceded by an adequate diagnosis, and
no parameter combinations inappropriate for the patient’s condition
are programmed. In individual cases, it is recommended that the tolerance and effectiveness of parameter combinations are checked by observing the patient for some time after programming. The following are contraindicated:
• Operating modes with atrial control (DDD, VDD, AAI) are contraindicated in the presence of chronic atrial tachycardia as well as chronic atrial fibrillation or flutter.
15
• If slow retrograde conduction is encountered after ventricular pacing, a longer atrial refractory period and/or a shorter AV delay may have to be programmed to prevent pacemaker-mediated tachycardia. Programming DDI, DVI, or VVI modes is rarely required in these instances.
• If elevated rates above the basic rate are not well tolerated by the patient (e.g., the patient has chest pain as a result), a low “upper rate” and lower “maximum sensor rate” should be programmed. In
these cases, atrial-controlled modes and rate-adaptive modes may even be contraindicated.
• If a case of pacemaker syndrome has been observed or is likely to develop, the modes VDD, VVI and VOO are contraindicated. The DDI mode is contraindicated in cases of pacemaker syndrome where sinus rates are above the basic rate.
• Atrial single-chamber pacing is contraindicated in the presence of existing AV conduction disorders or if failing AV conduction can be demonstrated by suitable tests.
• In the presence of competing spontaneous rhythms, modes without sensing and inhibition ability in the chamber affected are contraindicated.
• Unipolar pacing is contraindicated for patients who also have an implanted cardioverter-defibrillator (ICD). There is a risk of ICD inhibition or accidental delivery of pacemaker pulses.
Indications and Contraindications
Cylos DR-T
The Implant
16
Home Monitoring
Home Monitoring
Introduction
With BIOTRONIK's Home Monitoring function, patients can be treated even more effectively. All Home Monitoring implants are equipped with a small transmitter and are designated by the letter "T," e.g., Cylos DR­T and Lumos DR-T.
The Home Monitoring function has no effect on any functions and features of the basic implant, such as pacing and sensing functions, preset parameters, or memory functions.
With Home Monitoring, you as the physician can view the data transmitted by the implant in a comprehensive report called a Cardio Report, allowing you to always be informed about your patient's cardiac status.
A patient device receives messages from the implant and transmits them to the BIOTRONIK Service Center. At the Center, the data are processed and are made available to you via a secure Internet connection.
The implant’s Home Monitoring function can be used for the entire
operational life of the implant or for shorter periods, just a few weeks or months.
The most important components of Home Monitoring are the implant, the patient device, and the BIOTRONIK Service Center.
The power of the implant's transmitter is very low, so that the patient's health is not affected in any way. The resulting short transmission range requires the use of a special patient device to forward the implant data to the BIOTRONIK Service Center.
Patient Device
BIOTRONIK
Service Center
Cardio Report
17
Home Monitoring
The patient's implant data are sent to the patient device at regular intervals. With Home Monitoring, the distance between the implant and the patient device should not be less than 20 centimeters (8 inches) and not more than two meters (6 feet).
The implant can send three different types of messages: trend messages, event messages and patient messages (for pacemakers only). For more information about the message types, see "Types of Implant Messages," on page 17.
The RUC or CardioMessenger® patient device works sim ilarly to a cellular phone and transmit s the messages received from the implant as short messages (SMS) to the BIOTRONIK Service Center via the cellular phone network. The integrated batteries enable battery­operated usage for 15-24 hours, depending on the model. The patient device can, of course, also be used with the included charging station.
At the BIOTRONIK Service Center, the implant messages transmitted by the patient device are processed and then made available to you via the Internet or a fax in the form of a concise report called the Cardio Report.
In the Cardio Report, the transmitted implant data are displayed in graphs and tables. With the online option, you can individually configure the Cardio Report graphs for each patient. For certain events, the Cardio Reports are also sent to you by fax, e-mail, or SMS, in addition to being available for viewing on the Internet.
The title of the Cardio Report indicates the report type. There are three types of Cardio Reports:
• Trend reports
• Event reports
• Patient reports (for pacemakers only)
Programmer
18
On event reports, the title tells you which event triggered that Cardio Report, e.g., Event report – ERI detected.
You must set up the Home Monitoring function in the programmer and register with the BIOTRONIK Customer Service Center.
For more information about act ivating Home Monitoring on the programmer, see the manual of your programmer.
For information about signing up for Home Monitoring, see the manual for the BIOTRONIK Home Monitoring® Service.
Home Monitoring
Types of Implant Messages
Implants with the Home Monitoring function send implant messages at set times or when certain events have occurred. Message transmission can be triggered as follow s:
• Trend message – every day, at a certain time, the message is triggered
• Event message – an event triggers the message
• Patient message – the pacemaker patient triggers the message w ith a special magnet
Trend Message
Using the programmer, you decide the time at which the daily implant message is transmitted to the patient device. It is recommended that a time be chosen during which the patient is sleeping because the patient will t hen be close to the patient device.
The length of the time interval (the monitoring interval) is not programmable: it is preset to "daily." For each monitoring interval, a data set is generated in the implant and the transmission is triggered.
19
Home Monitoring
Event Message
When the implant detects certain cardiac and technical events, an event message is sent to the patient device. For each implant, you decide what kinds of events will trigger a message. You can go to the Home Monitoring Service Center on the Internet and configure whether you also want to receive event reports for these events.
Certain events, e.g., when the battery reaches ERI, can never be omitted. You can find more information about events in the online help section for the Home Monitoring Service Center.
Patient Message
Pacemaker pat ients can apply a special magnet over the pacemaker and trigger a m essage. Please provide your patient with comprehensive information about how to handle the magnet and for which physical symptoms you consider it appropriate for your patient to trigger a message.
Caution! The special magnet may only be distribut ed to
pacemaker patients.
A patient-triggered message does not affect any trend message transmission settings.
For more information about programmer settings with the patient message, see the manual of your programmer.
Home Monitoring
Home Monitoring Parameters
Off, On
You can activate (ON) or deactivate (OFF) the Home Monitoring function with your programmer. Any other partial functions can only be used if Home Monitoring has been previously activated.
Monitoring Interval
Transmission Time
of the Periodic Report
Event Message
Patient Message
20
Home Monitoring
1 day
When you activate the Home Monitoring function, the (daily) interval of the trend message transmission is automatically activated.
Between 0:00 (12:00 a.m.) and 23:50 (11:50 p.m.)
For the trend message, program a time betw een 0:00 (12:00 a.m.) and 23:50 (11:50 p.m.). Selecting a time between 0:00 (12:00 a.m.) and 4:00 (4:00 a.m.) is recommended as that is a time when the patient is usually asleep.
Off, On
The implant detects certain cardiac and technical events that trigger an automatic message transmission. As a default setting, this option is activated.
Off, On
The patient-triggered message can also be programmed. This option is not activated for the default settings.
Criteria for the Use of Home Monitoring
Intended Use
The fundamental medical objective is to make diagnostic information available to physicians. The therapeutic effect of implants that transmit data is not affected because the Home Monitoring Service Center has no direct effect on the implant.
For a specific description of the objective of the Home Monitoring system, see the manual for the BIOTRONIK Home Monitoring® Service.
21
Home Monitoring
Prerequisites
The technical prerequisites for access to Cardio Reports are described in the manual for the BIOTRONIK Home Monitoring® Service.
Indications and Contraindications
The known indications and contraindications for pacemakers and ICDs are applicable regardless of Home Monitoring. There is no absolute indication for the use of the Home Monit oring Service Center.
There are no contraindications for the use of the Home Monitoring Service Center as a diagnostic tool, because it has no effect on the diagnostic or therapeutic functionality of the implant. However, proper use of Home Monitoring requires the complete cooperation of the patient. Moreover, a prerequisite is that the physician has access to the Home Monitoring data (per fax and/or Internet) in order to be able to use the Home Monitoring Service Cent er.
Warnings and Precautions
The known warnings and precautions for pacemakers and ICDs are applicable regardless of Hom e Monitoring. However, there are specific precautions for Home Monitoring.
Please observe the specific warnings and precautions for Home Monitoring in the manual of the BIOTRONIK Home Monitoring® Service and in the manual of the patient device.
Valid for Cylos DR and
Cylos VR
22
Pacing Types – Modes
Pacing Types – Modes
Closed Loop Modes
Cylos achieves physiologic rat e adaptation using Closed Loop Stimulation. Closed Loop Modes work the same way as non-rate­adaptive modes. The only difference is that the basic rate is increased when Cylos senses that the pat ient is under stress. Closed Loop modes are identified by the designation "CLS."
In the DDD-CLS and VVI-CLS m odes, the atrial and/or ventricular refractory period can cover a larger portion of the basic interval with high closed loop pacing rates. As a result, the sensing of spontaneous events may be prevented or im possible.
Valid for
Cylos DR-T
Rate-Adaptive Modes
Rate-adaptive m odes are marked by an "R" (for "rate") in the pacemaker code. Rate-adaptive modes function identically to corresponding non­rate-adaptive m odes, with the exception that the basic rate increases when patient exertion is detected by the motion sensor. The non-rate­adaptive modes are described below. In rate-responsive demand modes (DDDR, DDTR/A, DDTR/V, DDIR, DVIR, VDDR, VVIR, AAIR), it is possible that the atrial or ventricular refractory period can comprise a major portion of the basic interval at high sensor-modulated rates. As a result, sensing of intrinsic actions is limited or completely suspended. For more information, see the "Rate Adapt ation" section.
23
Pacing Types – Modes
Overdrive Modes
Overdrive m odes reduce the probability of atrial tachycardias. In this case, the pacing rate always lies slightly above the intrinsic atrial heart rate. Preventive overdrive is available in m odes DDD(R)+, DDT/(R)A+, DDT/V(R)+, AAI(R)+ and AAT(R)+. For a detailed functional description, see the "Preventive Overdrive Pacing" section.
DDD Mode
In the DDD mode, the basic interval starts w ith an atrial sense (AS) or atrial pace event (Ap) or a ventricular sense event not preceded by an atrial event (VES = "ventricular extrasystole"). If no atrial sense event occurs within the basic interval, atrial pacing takes place at the end of the basic interval (See Figure 1), and the basic interval is restarted.
24
Pacing Types – Modes
Figure 1: AV-sequential pacing in DDD mode without an intrinsic event
In the case of an atrial sensed or paced event, the AV delay starts together with the basic interval. If a ventricular sensed event does not occur within the AV delay, ventricular pacing is triggered at the end of the AV delay. If ventricular sensing (VS) occurs within the AV delay, the ventricular pulse delivery (VP) is inhibited.
Figure 2: An atrial sensed event restarts the basic interval
If atrial sensing occurs, atrial pacing is inhibited and the basic interval is restarted (See Figure 2).
25
Pacing Types – Modes
Figure 3 and Table 1 summarize the timing intervals init iated by sensing or pacing. The table distinguishes between pacing at the end of the AV delay (VP) or pacing at the end of the AV safety delay (VSP) and between sensing within the AV delay (VS) or sensing outside the AV delay (VES).
Figure 3: Start of timing intervals in the DDD mode depending on the events that occur
Event Timing Interval
Ap As Vp Vsp Vs VES
Basic Interval (DDD)
Basic Interval (DDI)
Atrial Refractory Period
Atrial Refractory Period ­Extension
Upper Track ing Rate Interval
Ventricular Refractory Period
• • •
• • • •
• • •
•
• • • •
• • • •
Table 1: Timing intervals initiated by pace and sense events in DDD and DDI modes (Vsp = v entricular safety pacing)
26
Pacing Types – Modes
Event Timing Interval
Ap As Vp Vsp Vs VES
(Dynamic) AV Delay
AV Safety Delay
Interference Interval (A)
Interference Interval (V)
• •
•
•
• •
Blanking Period (A) • • •
Blanking Period (V) • • •
Table 1: Timing intervals initiated by pace and sense events in DDD and DDI modes (Vsp = v entricular safety pacing)
DDI Mode
In contrast to the DDD mode, the basic interval in the DDI mode does not start with a P wave, but rather with ventricular sensed or paced events. The VA interval is started together with the basic interval. If no atrial or ventricular sensing occurs within the VA interval, atrial pacing takes place at the end of the VA interval (See Figure 4).
Figure 4: AV-sequential pacing in DDI mode without an intrinsic event
Upon pacing, the AV delay is restarted. If sensing occurs, atrial pacing is inhibited (See Figure 5). The AV delay does not start with this sense event, but again at the end of the VA interval. Thus, P waves in DDI mode do not trigger ventricular events.
27
Figure 5: Inhibition of atrial pacing in DDI mode by an atrial sensed event occurring within the VA interval. The atrial refractory period restarts at the end of the VA interv al.
Pacing Types – Modes
DVI Mode
The DVI mode is based on the DDI mode. In contrast to the latter, atrial sensing does not occur in DVI mode. Therefore, atrial pacing is forced at the end of the VA delay. Ventricular sensing within the VA interval inhibit s both the atrial and the ventricular pulse. Ventricular sensing within the AV delay inhibits the ventricular pulse.
VDD Mode
The VDD mode is derived from the DDD mode. In contrast to the latter, no atrial pacing takes place. Therefore, the basic interval starts at an atrial sense event, a ventricular extrasystole, or at the end of the preceding basic interval if no sense event occurs.
To prevent pacemaker-mediated reentry tachycardia, the atrial refractory period is also started by ventricular paced events that were not triggered by atrial sensed events (See Figure 6).
28
Pacing Types – Modes
Figure 6: Prevention of pacemaker-mediated tachycardia in VDD mode
AAI Mode, VVI Mode
The AAI and VV I single-chamber pacing m odes are used for atrial or ventricular demand pacing. In each case, pacing and sensing only occur in either the atrium (AAI) or the ventricle (VVI).
The basic interval is started by a sense or pace event. If there is a sense event before the end of the basic interval, pulse delivery is inhibited. Ot herwise, pacing takes place at the end of the basic interval.
AOO Mode, VOO Mode
In these pacing modes, pulses are emitted asynchronously in the atrium (AOO) or ventricle (VOO). When using VOO or AOO mode, the risks associated with asynchronous vent ricular pacing must be considered.
DOO Mode
Asynchronous AV-sequential pulses are delivered in this pacing mode. When using DOO mode, the risks associated w ith asynchronous ventricular pacing must be considered.
29
Pacing Types – Modes
Triggered Pacing
Triggered pacing modes correspond to the respective demand modes, the difference being that detection of an atrial/ventricular event outside the refractory period does not cause pulse inhibition, but rather triggers imm ediate pulse delivery to the respective chamber.
The corresponding pacing m odes are:
Demand: DDD VDD DDI DVI AAI VVI
Triggered: DDT
DDT/A DDT/V
However, the following differences do occur: There is no AV safety delay in the DDT, DDI/T and DVT pacing modes. It is not necessary since ventricular pulse inhibition because of crosstalk (ventricular sensing of the atrial pacing pulse) cannot occur in these modes.
In the DDI/T and DV T pacing modes, the basic interval is not restarted if ventricular sensing occurs within the AV delay.
VDT DDI/T DVT AAT VVT
DDT/A Mode, DDT/V Mode
The DDT/A and DDT/V modes are derived from the DDT mode. In DDT/A mode, the pacemaker delivers a pulse in the atrium after every sensed atrial event and inhibits pacing in the ventricle if required. Similarly, in DDT/V mode, an immediate pulse in the ventricle, and if required pulse inhibition in the atrium, follows every sensed ventricular event.
30
Pacing Types – Modes
VDI Mode
The VDI mode is derived from the VVI mode. In contrast to the latter, the VDI mode allows intra-atrial events to be recorded. The timing corresponds to the VVI mode, however. The VDI mode is designed for measuring ret rograde conduction with the IEGM and/or the marker function. Retrograde conduction time can be determined directly on the programmer, or on an additional ECG recorder, as the length of time between a ventricular pace or sense event and the subsequent atrial sense event.
OFF Mode
In the OFF mode, pacing pulses are not delivered, except when used with external pulse control. Without external pulse control, the OFF mode is used for detection and morphological evaluation of the intrinsic rhythm. With external pulse control, the OFF mode is used for electrophysiologic studies and to combat tachycardia. The OFF mode is only programmable as a temporary program. The pulse and control parameters remain adjustable in the OFF mode. With the use of the external pulse control function, the programmer triggers pacing pulses and sensed events can be transmitted to the programmer. Note that sensing is limited by the refractory period, whereas pacing is not.
Magnet Effect
Placing a magnet (or the programming wand) over the pacemaker causes the built-in magnetic switch in the pacemaker to close. The pacemaker response to magnet application is adjustable.
Note: The following functions are deactivated by magnet
application:
Loading...
+ 145 hidden pages
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use