- Email: [email protected]
Transatlantic flight: Not only jet lag
Accepted Manuscript Transatlantic Flight: Not Only Jet Lag Offir Paz, MD, Nicolay Teodorovich, MD, FHRS, Yonatan Kogan, MD, Moshe Swissa, MD, FHRS PII:
S1547-5271(17)30355-7
DOI:
10.1016/j.hrthm.2017.03.033
Reference:
HRTHM 7094
To appear in:
Heart Rhythm
Received Date: 19 December 2016
Please cite this article as: Paz O, Teodorovich N, Kogan Y, Swissa M, Transatlantic Flight: Not Only Jet Lag, Heart Rhythm (2017), doi: 10.1016/j.hrthm.2017.03.033. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Transatlantic Flight: Not Only Jet Lag
Paz: The Flight from Hell
RI PT
Offir Paz MD, Nicolay Teodorovich MD, FHRS, Yonatan Kogan MD and Moshe Swissa MD, FHRS
SC
Kaplan Medical Center, Rehovot. The Hebrew University, Jerusalem, Israel.
Word count: 1478
Address for Correspondence: Moshe Swissa, M.D .
M AN U
1
P.O. Box 1 Rehovot 76100, Israel
TE D
Heart Institute, Kaplan Medical Center
Phone: +972-8-944-1376, Fax: +972-8-944-1110
EP
Email: [email protected]
AC C
Disclosures for all authors: None
Keywords: ICD; Ventricular fibrillation; Inappropriate shock; Cosmic radiation
1
ACCEPTED MANUSCRIPT Case report A 73 year old man with a history of myocardial infarction, CABG, PCI and symptomatic (NYHA class II) left ventricular dysfunction (LVEF 33%) underwent ICD implantation (Biotronik, 2005) for primary prevention of SCD. An ICD generator change (Lumax 540 HF-T, Biotronik) was performed in 2011 due to
RI PT
approaching ERI. The patient received one appropriate shock for VT in 2013. Three
hours after landing from a 10 hour transatlantic flight he received four inappropriate
shocks (IS). Apart from the shock sensation, the patient had no symptoms at that time. The next day the patient came to our pacemaker clinic, the ICD therapies were
SC
suspended and the patient was hospitalized for further evaluation. The ICD log noted 8 shock charges with 4 shocks delivered and another 4 terminated without shocks
M AN U
(Table 1). The electrogram (IEGM) demonstrated a regular sinus rhythm with no arrhythmia prior to the ICD shock (Figure 1A and supplement file). During the first part of the recording there are no artifacts in the IEGM recordings, and the marker channel correctly allocates markers to the atrial and ventricular sensing and pacing, respectively. Despite that, there are 4 therapy cycles. In each cycle, VF was detected; the device started charging, and after 2.3 to 2.9 seconds it terminated charging without
TE D
therapy (Figure 1A and supplement file). After that, there was an instant redetection of VF with charging of the device and shock delivery (Figure 1A and supplement file). IEGMs and the marker channel continue to correctly identify normal sinus rhythm. After the fourth cycle, an artifact appeared and the marker channel allocated a
EP
VF sign to these lines (Figure 1B and supplement file). The normal electrograms are clearly seen through the artifact. The device did not react in any way to this noise
AC C
because it reached the maximum of 8 consecutive shocks that can be delivered for an arrhythmic event. The ICD diagnosed that the VF episode lasted 5:21:47 hours and ended at 00:04:57. The interrogated information was sent to the device manufacturer. The memory content of the ICD inspection revealed that the device detected a tachycardia during a normal sinus rhythm, thereby confirming the clinical observation. The root cause for the unexpected behavior was determined to be an inconsistent memory content in the device. Furthermore, the analysis revealed that the ICD, during automatic device check process, automatically detected and repaired the inconsistent memory content at night.
2
ACCEPTED MANUSCRIPT Discussion Implantable cardioverter defibrillators are used to treat ventricular arrhythmias and prevent mortality in high risk patients. Unfortunately, sometimes ICDs may deliver inappropriate therapies (3-6%) (1).The most common causes of IS are supraventricular tachycardia and atrial fibrillation (1). Other causes include
RI PT
oversensing of artifacts caused by lead fracture, T wave oversensing, and electromagnetic interference.
Cosmic radiation is a known cause of single event upsets (SEUs) or disruption to
electrical circuits in electronic devices. The error rate for a given circuit is generally
SC
proportional to the relative neutron flux of the operating environment. The neutron
flux for an airplane operating at altitudes near 40,000 feet on near polar flight paths is
M AN U
roughly 600 times that at ground level in New York City. SEUs usually affect device memory. CMOS memory structures such as static RAM cells and flip-flops are susceptible to upset when bombarded with high-energy particles (2). The neutrons from the cosmic radiation can create a high voltage wave that alters the position of a bit or multiple bit components on the integrated circuit board, leading to device software change. These upsets are temporary in nature and can be cleared. The
TE D
susceptibility of memory circuits to SEUs increases with each new generation of devices due to the decrease in process geometries (2). The frequency of these events was reported as 22 events in 579 ICDs over 284,672 device days (3). Safety
EP
mechanisms, internal to each device, perform a critical redundancy check that verifies the integrity of the bits and can correct altered bits or reset the device to its nominal parameters.
AC C
A joint USAF/NOAA statement reported low solar activity and regular geomagnetic activity on October 31 – November 01, 2016. It should be noted, however, that low solar activity may lead to increased cosmic ray penetration of the stratosphere. Cosmic rays intensified by 12.4% from May 2015 to September 2016 due to the decreased solar activity (near Solar Minimum) and possibly weakening of the Earth's magnetic field. Ferrick at al (4) described 3 ICD cases of software electrical resets during air travel. No inappropriate therapies were delivered in any of these cases. In all of the cases the time stamp of the date and time of reset were correlated to time in flight. In our case, 3
ACCEPTED MANUSCRIPT however, the event occurred 3 hours after landing. Additionally, this is the first report where a malfunction of this kind by the device has led to the delivery of a shock. The manufacturer stated that this is the first case of inconsistent memory content which resulted in the ICD shock in this type of device (Lumax 5 family) and estimated a probability of 0.00015%/patient-year. We think that the widespread damaged memory
RI PT
causes software changes that lead to the described different behaviors of the device. In addition, a safety feature for resetting an ICD to VVI backup mode with only a ventricular fibrillation (VF) zone due to software error is associated with ISs (6),
especially for SJM devices (5). Although this report may be considered the first report
SC
of ISs due to memory failure of an ICD, it should be noted that once the modification to the safety mode occurs, the device acts correctly according to the new programmed mode. In our case, however, a global failure was demonstrated in which there is
M AN U
incorrect identification of a normal sinus rhythm as a VF, though the device itself recorded and annotated a normal atrial and ventricular EGM.
In conclusion, this case may demonstrate that the effects of cosmic radiation on
TE D
ICDs, though uncommon, may lead to inappropriate therapies, potentially with lifethreatening complications. This case highlights that additional steps should be considered to prevent possible ICD malfunction. We suggest that check and repair of the inconsistent memory content should be done by the ICD more frequently and
EP
preferably also after any treated tachycardia episode. Because the effect of cosmic radiation can occur with the device of any manufacturer, we suggest that the industry
AC C
develop a common mechanism to address and treat this problem.
4
ACCEPTED MANUSCRIPT References: 1. Moss AJ, Schuger C, Beck CA, et al. Reduction in inappropriate therapy and mortality through ICD programming. N Engl J Med. 2012 Dec 13;367(24):2275-83 2. Single-event upsets and medical devices 2010.
RI PT
http://www.eejournal.com/files/5913/0219/5116/SEU_Medical_WP.pdf
3. Bradley PD and Normand E. Single Event Upsets in Implantable Cardioverter Defibrillators. IEEE Trans Nucl Sci 1998; 45: 2929.
4. Ferrick AM, Bernstein N, Aizer A, Chinitz L. Cosmic radiation induced
SC
software electrical resets in ICDs during air travel. Heart Rhythm 2008;8:1201-1203.
Philbert BT, Tfelt-Hansen J, Jacobsen PK, Pehrson S, Svendsen Jh, Jøns C
M AN U
5.
and Petersen HH. Is modification of the VVI backup mode in implantable cardioverter-defibrillators from St Jude medical required due to increased risk
AC C
EP
TE D
of inappropriate shocks?. Europace 2016. doi:10.1093/europace/euw083.
5
ACCEPTED MANUSCRIPT Table 1: Timeline of inappropriate therapy delivered.
Date and Time (Israel Zone)
Comments
Departure time from NY
November 1st, 2016 - 05:30:00
Cosmic radiation may
Landing time in Tel-Aviv
November 1st, 2016 - 16:05:00
have occurred during
RI PT
Timeline
the flight
November 1st, 2016 - 18:43:10
1st inappropriate shock
November 1st, 2016 - 18:43:23
2nd inappropriate shock
November 1st, 2016 - 18:43:34
3rd inappropriate shock
November 1st, 2016 - 18:43:45
4th inappropriate shock
November 1st, 2016 - 18:43:55
Time of the artifact
November 1st, 2016 - 18:43:55
End of Event
November 2nd, 2016 -
M AN U
SC
First detected VF
AC C
EP
TE D
00:04:47
6
Automatic repair time
ACCEPTED MANUSCRIPT Figure legend:
Figure 1: Detailed episode IEGM and annotations. A. First cycle: VF is incorrectly detected; the device starts charging, and after 2.8 seconds it terminates charging
RI PT
without therapy, proceeds with an instant incorrect redetection of VF as well as charging of the device (9.4 seconds) and a 40J shock delivery. IEGMs and a marker
channel continue to correctly identify normal sinus rhythm with atrial and ventricular sensing. B. This pattern repeated 4 times. At the end of the fourth cycle (the last
shock), an artifact appears which has densely spaced vertical lines covering the whole
SC
IEGM (50 Hz) and a marker channel allocates the VF sign to these lines. The normal
AC C
EP
TE D
M AN U
atrial and ventricular electrograms are clearly seen through the artifact.
7
Termination without shock (2.8 sec)
Second Cycle:
Charging time of 9.4 sec (40J) and delivering shock
RI PT
Figure 1:
ACCEPTED MANUSCRIPT
First Cycle:
SC
Inappropriate shock (40J), and incorrect redetection of VF
M AN U
Incorrect VF detection
EP
A.
TE D
Incorrect VF re-detection
AC C
Fourth cycle ended with Inappropriate shock (40J
B.
Termination without shock (2.5 sec)
S1547-5271(17)30355-7
DOI:
10.1016/j.hrthm.2017.03.033
Reference:
HRTHM 7094
To appear in:
Heart Rhythm
Received Date: 19 December 2016
Please cite this article as: Paz O, Teodorovich N, Kogan Y, Swissa M, Transatlantic Flight: Not Only Jet Lag, Heart Rhythm (2017), doi: 10.1016/j.hrthm.2017.03.033. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Transatlantic Flight: Not Only Jet Lag
Paz: The Flight from Hell
RI PT
Offir Paz MD, Nicolay Teodorovich MD, FHRS, Yonatan Kogan MD and Moshe Swissa MD, FHRS
SC
Kaplan Medical Center, Rehovot. The Hebrew University, Jerusalem, Israel.
Word count: 1478
Address for Correspondence: Moshe Swissa, M.D .
M AN U
1
P.O. Box 1 Rehovot 76100, Israel
TE D
Heart Institute, Kaplan Medical Center
Phone: +972-8-944-1376, Fax: +972-8-944-1110
EP
Email: [email protected]
AC C
Disclosures for all authors: None
Keywords: ICD; Ventricular fibrillation; Inappropriate shock; Cosmic radiation
1
ACCEPTED MANUSCRIPT Case report A 73 year old man with a history of myocardial infarction, CABG, PCI and symptomatic (NYHA class II) left ventricular dysfunction (LVEF 33%) underwent ICD implantation (Biotronik, 2005) for primary prevention of SCD. An ICD generator change (Lumax 540 HF-T, Biotronik) was performed in 2011 due to
RI PT
approaching ERI. The patient received one appropriate shock for VT in 2013. Three
hours after landing from a 10 hour transatlantic flight he received four inappropriate
shocks (IS). Apart from the shock sensation, the patient had no symptoms at that time. The next day the patient came to our pacemaker clinic, the ICD therapies were
SC
suspended and the patient was hospitalized for further evaluation. The ICD log noted 8 shock charges with 4 shocks delivered and another 4 terminated without shocks
M AN U
(Table 1). The electrogram (IEGM) demonstrated a regular sinus rhythm with no arrhythmia prior to the ICD shock (Figure 1A and supplement file). During the first part of the recording there are no artifacts in the IEGM recordings, and the marker channel correctly allocates markers to the atrial and ventricular sensing and pacing, respectively. Despite that, there are 4 therapy cycles. In each cycle, VF was detected; the device started charging, and after 2.3 to 2.9 seconds it terminated charging without
TE D
therapy (Figure 1A and supplement file). After that, there was an instant redetection of VF with charging of the device and shock delivery (Figure 1A and supplement file). IEGMs and the marker channel continue to correctly identify normal sinus rhythm. After the fourth cycle, an artifact appeared and the marker channel allocated a
EP
VF sign to these lines (Figure 1B and supplement file). The normal electrograms are clearly seen through the artifact. The device did not react in any way to this noise
AC C
because it reached the maximum of 8 consecutive shocks that can be delivered for an arrhythmic event. The ICD diagnosed that the VF episode lasted 5:21:47 hours and ended at 00:04:57. The interrogated information was sent to the device manufacturer. The memory content of the ICD inspection revealed that the device detected a tachycardia during a normal sinus rhythm, thereby confirming the clinical observation. The root cause for the unexpected behavior was determined to be an inconsistent memory content in the device. Furthermore, the analysis revealed that the ICD, during automatic device check process, automatically detected and repaired the inconsistent memory content at night.
2
ACCEPTED MANUSCRIPT Discussion Implantable cardioverter defibrillators are used to treat ventricular arrhythmias and prevent mortality in high risk patients. Unfortunately, sometimes ICDs may deliver inappropriate therapies (3-6%) (1).The most common causes of IS are supraventricular tachycardia and atrial fibrillation (1). Other causes include
RI PT
oversensing of artifacts caused by lead fracture, T wave oversensing, and electromagnetic interference.
Cosmic radiation is a known cause of single event upsets (SEUs) or disruption to
electrical circuits in electronic devices. The error rate for a given circuit is generally
SC
proportional to the relative neutron flux of the operating environment. The neutron
flux for an airplane operating at altitudes near 40,000 feet on near polar flight paths is
M AN U
roughly 600 times that at ground level in New York City. SEUs usually affect device memory. CMOS memory structures such as static RAM cells and flip-flops are susceptible to upset when bombarded with high-energy particles (2). The neutrons from the cosmic radiation can create a high voltage wave that alters the position of a bit or multiple bit components on the integrated circuit board, leading to device software change. These upsets are temporary in nature and can be cleared. The
TE D
susceptibility of memory circuits to SEUs increases with each new generation of devices due to the decrease in process geometries (2). The frequency of these events was reported as 22 events in 579 ICDs over 284,672 device days (3). Safety
EP
mechanisms, internal to each device, perform a critical redundancy check that verifies the integrity of the bits and can correct altered bits or reset the device to its nominal parameters.
AC C
A joint USAF/NOAA statement reported low solar activity and regular geomagnetic activity on October 31 – November 01, 2016. It should be noted, however, that low solar activity may lead to increased cosmic ray penetration of the stratosphere. Cosmic rays intensified by 12.4% from May 2015 to September 2016 due to the decreased solar activity (near Solar Minimum) and possibly weakening of the Earth's magnetic field. Ferrick at al (4) described 3 ICD cases of software electrical resets during air travel. No inappropriate therapies were delivered in any of these cases. In all of the cases the time stamp of the date and time of reset were correlated to time in flight. In our case, 3
ACCEPTED MANUSCRIPT however, the event occurred 3 hours after landing. Additionally, this is the first report where a malfunction of this kind by the device has led to the delivery of a shock. The manufacturer stated that this is the first case of inconsistent memory content which resulted in the ICD shock in this type of device (Lumax 5 family) and estimated a probability of 0.00015%/patient-year. We think that the widespread damaged memory
RI PT
causes software changes that lead to the described different behaviors of the device. In addition, a safety feature for resetting an ICD to VVI backup mode with only a ventricular fibrillation (VF) zone due to software error is associated with ISs (6),
especially for SJM devices (5). Although this report may be considered the first report
SC
of ISs due to memory failure of an ICD, it should be noted that once the modification to the safety mode occurs, the device acts correctly according to the new programmed mode. In our case, however, a global failure was demonstrated in which there is
M AN U
incorrect identification of a normal sinus rhythm as a VF, though the device itself recorded and annotated a normal atrial and ventricular EGM.
In conclusion, this case may demonstrate that the effects of cosmic radiation on
TE D
ICDs, though uncommon, may lead to inappropriate therapies, potentially with lifethreatening complications. This case highlights that additional steps should be considered to prevent possible ICD malfunction. We suggest that check and repair of the inconsistent memory content should be done by the ICD more frequently and
EP
preferably also after any treated tachycardia episode. Because the effect of cosmic radiation can occur with the device of any manufacturer, we suggest that the industry
AC C
develop a common mechanism to address and treat this problem.
4
ACCEPTED MANUSCRIPT References: 1. Moss AJ, Schuger C, Beck CA, et al. Reduction in inappropriate therapy and mortality through ICD programming. N Engl J Med. 2012 Dec 13;367(24):2275-83 2. Single-event upsets and medical devices 2010.
RI PT
http://www.eejournal.com/files/5913/0219/5116/SEU_Medical_WP.pdf
3. Bradley PD and Normand E. Single Event Upsets in Implantable Cardioverter Defibrillators. IEEE Trans Nucl Sci 1998; 45: 2929.
4. Ferrick AM, Bernstein N, Aizer A, Chinitz L. Cosmic radiation induced
SC
software electrical resets in ICDs during air travel. Heart Rhythm 2008;8:1201-1203.
Philbert BT, Tfelt-Hansen J, Jacobsen PK, Pehrson S, Svendsen Jh, Jøns C
M AN U
5.
and Petersen HH. Is modification of the VVI backup mode in implantable cardioverter-defibrillators from St Jude medical required due to increased risk
AC C
EP
TE D
of inappropriate shocks?. Europace 2016. doi:10.1093/europace/euw083.
5
ACCEPTED MANUSCRIPT Table 1: Timeline of inappropriate therapy delivered.
Date and Time (Israel Zone)
Comments
Departure time from NY
November 1st, 2016 - 05:30:00
Cosmic radiation may
Landing time in Tel-Aviv
November 1st, 2016 - 16:05:00
have occurred during
RI PT
Timeline
the flight
November 1st, 2016 - 18:43:10
1st inappropriate shock
November 1st, 2016 - 18:43:23
2nd inappropriate shock
November 1st, 2016 - 18:43:34
3rd inappropriate shock
November 1st, 2016 - 18:43:45
4th inappropriate shock
November 1st, 2016 - 18:43:55
Time of the artifact
November 1st, 2016 - 18:43:55
End of Event
November 2nd, 2016 -
M AN U
SC
First detected VF
AC C
EP
TE D
00:04:47
6
Automatic repair time
ACCEPTED MANUSCRIPT Figure legend:
Figure 1: Detailed episode IEGM and annotations. A. First cycle: VF is incorrectly detected; the device starts charging, and after 2.8 seconds it terminates charging
RI PT
without therapy, proceeds with an instant incorrect redetection of VF as well as charging of the device (9.4 seconds) and a 40J shock delivery. IEGMs and a marker
channel continue to correctly identify normal sinus rhythm with atrial and ventricular sensing. B. This pattern repeated 4 times. At the end of the fourth cycle (the last
shock), an artifact appears which has densely spaced vertical lines covering the whole
SC
IEGM (50 Hz) and a marker channel allocates the VF sign to these lines. The normal
AC C
EP
TE D
M AN U
atrial and ventricular electrograms are clearly seen through the artifact.
7
Termination without shock (2.8 sec)
Second Cycle:
Charging time of 9.4 sec (40J) and delivering shock
RI PT
Figure 1:
ACCEPTED MANUSCRIPT
First Cycle:
SC
Inappropriate shock (40J), and incorrect redetection of VF
M AN U
Incorrect VF detection
EP
A.
TE D
Incorrect VF re-detection
AC C
Fourth cycle ended with Inappropriate shock (40J
B.
Termination without shock (2.5 sec)