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Volume 12 No. 05
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Accepted Papers

Sleep Medicine Pearls

Pulseless Electrical Activity during Polysomnography

Safal Shetty, MD1,2; Tam Le, MD1,2; Sairam Parthasarathy, MD1,2
1Center for Sleep Disorders and Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona, Tucson, AZ; 2Department of Medicine, University of Arizona, Tucson, AZ

A 61-year-old male was referred to the sleep laboratory for possible obstructive sleep apnea (OSA). The patient complained of loud snoring, frequent awakenings at night, trouble falling asleep and staying asleep, and excessive daytime sleepiness.

The patient had a significant past cardiac history of ischemic cardiomyopathy and cardiac surgery of a certain nature performed one-year prior, which was unknown at the time of presentation.

On physical examination, the sleep technician was unable to obtain blood pressure or a pulse. Oxygen saturation was 97% on room air. BMI 31.5 kg/m2, neck circumference was 16 inches, and a Mallampati III airway, with a continuous “smooth humming sound” heard on cardiovascular auscultation with normal breath sounds. The sleep technician noted an artifact on the EKG tracing which are shown in the Figure 1. The polysomnography revealed that an overall apnea-hypopnea index (AHI) of 24 per hour, predominantly obstructive events, with optimal titration of CPAP pressure to 12 cm H2O.

10-second epoch from the overnight polysomnogram revealing electrocardiogram (EKG) artifact, best seen on the magnified inset.


Figure 1

10-second epoch from the overnight polysomnogram revealing electrocardiogram (EKG) artifact, best seen on the magnified inset.

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QUESTION: What artifact is seen in Figure 1?

ANSWER: Electrical artifact due to the electromagnetic axial rotor of the left ventricular assist device.


Figure 1 shows a 10-second epoch from the overnight polysomnogram. The inset is a magnification of a fragment of the EKG that reveals the electrical artifact due to the electromagnetic axial rotor of the left ventricular assist device (LVAD). Electrical artifact with 60 Hz/sec and ST elevation are seen on the EKG recording of the polysomnogram in patients with LVAD implantation. As seen in Figure 2, electrical artifact is more prominent on the anterior leads, namely, leads I, III, AVL, and V1 precordial leads. The magnified inset gives a better view of the nature of the electrical artifact. This artifact is a nearly pathognomonic of the post-LVAD EKG.1 Other commonly noted artefacts include, low voltage in limb leads, splintering of the QRS complex, wide QRS complex, ST elevation, and increased ventricular pacing.1

12-lead electrocardiogram (EKG) of the patient with the magnified inset showing a better view of the nature of the electrical artifact.


Figure 2

12-lead electrocardiogram (EKG) of the patient with the magnified inset showing a better view of the nature of the electrical artifact.

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Left Ventricular Assist Device and Heart Failure

There are about 5.1 million Americans have heart failure (HF). The prevalence of HF is estimated to further increase by 46% by 2030. With such rising prevalence of HF, the increased use of left ventricular assist devices (LVAD) is anticipated. LVADs are used to treat patients with advanced heart failure as a bridge to heart transplantation, until recovery of left ventricular function or as destination therapy, where the device remains implanted for the life of the patient. Based on recent retrospective studies, the prevalence of sleep disordered breathing (SDB) was 54% in such individuals. Central sleep apnea (CSA) accounted for 34% and OSA for 20% of the patients with SDB.2 SDB remains under recognized in this population and thereby further contributes mortality and morbidity.3

Does CPAP Therapy Affect LVAD Function?

There are limited case reports on the beneficial effects of PAP therapy on hemodynamics in patients with LVAD. Application of CPAP to patients with severe heart failure with LVAD was associated with an increase in cardiac output measured by the LVAD.4

Our patient had an LVAD placement as a bridge to transplantation. Following diagnosis of obstructive sleep apnea, his CPAP adherence was poor. He underwent an orthotopic heart transplant after and died due to cardiogenic shock.


  1. Recognition of common artifacts seen on polysomnogram is essential for providers in sleep medicine

  2. There are data to suggest that application of CPAP to patients with severe heart failure and LVAD leads to improved cardiac output as measured by the LVAD device.

  3. Evaluation for possible SDB prior to placement of assist devices and PAP therapy might be beneficial in improving the functioning of LVAD devices. The effect of CPAP on cardiac output in patients with severe systolic dysfunction requires further investigation.


This was not an industry supported study. Dr. Parthasarathy was supported by the National Institutes of Health Grants (HL095748 and HL095799); PCORI contract (IHS-1306-2505) during the writing of this manuscript. The funding institutions did not have any role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Dr. Parthasarathy reports grants from NIH/NHLBI, grants from Patient Centered Outcomes Research Institute, grants from US Department of Defense, grants from NIH (National Cancer Institute) NCI, grants from US Department of Army, grants from Johrei Institute, personal fees from American Academy of Sleep Medicine, personal fees from American College of Chest Physicians, non-financial support from National Center for Sleep Disorders Research of the NIH (NHLBI), personal fees from UpToDate Inc., personal fees from Philips-Respironics, Inc., grants from Younes Sleep Technologies, Ltd., grants from Niveus Medical Inc., grants from Philips-Respironics, Inc., outside the submitted work; In addition, Dr. Parthasarathy has a patent UA 14-018 U.S.S.N. 61/884,654; PTAS 502570970 (home breathing device). The abovementioned conflicts including the patent are unrelated to the topic of this paper. Dr. Shetty and Dr. Le do not have any conflicts of interest to disclose. The work was conducted at University of Arizona, Tucson, AZ



body mass index


central sleep apnea




heart failure


left ventricular assist device


obstructive sleep apnea


positive airway pressure


sleep disordered breathing


Shetty S, Le T, Parthasarathy S. Pulseless electrical activity during polysomnography. J Clin Sleep Med 2016;12(5):771–773.



Martinez SC, Fansler D, Lau J, Novak EL, Joseph SM, Kleiger RE, authors. Characteristics of the electrocardiogram in patients with continuous-flow left ventricular assist devices. Ann Noninvasive Electrocardiol. 2015;20:62–8. [PubMed]


Krawczyk M, Flinta I, Garncarek M, et al., authors. Sleep disordered breathing in patients with heart failure. Cardiol J. 2013;20:345–55. [PubMed]


Javaheri S, Caref EB, Chen E, Tong KB, Abraham WT, authors. Sleep apnea testing and outcomes in a large cohort of Medicare beneficiaries with newly diagnosed heart failure. Am J Respir Crit Care Med. 2011;183:539–46. [PubMed]


Kourouklis SP, Vagiakis E, Paraskevaidis IA, et al., authors. Effective sleep apnoea treatment improves cardiac function in patients with chronic heart failure. Int J Cardiol. 2013;168:157–62. [PubMed]