Sleep Apnea and its impact on cardiovascular system

1. Sleep Apnea and its impact
on Cardiovascular System
Dr Syed Raza
MD, MRCP, FRCP, CCT , FESC, FACC, FECVI
Consultant Cardiologist
Awali Hospital
Bahrain

2. Objectives
• 1. Introduction to sleep apnea
• 2. Impact of sleep apnea on cardiovascular system
• 3. Management

3. What is Sleep Apnea ?
• Sleep apnea is a condition marked by abnormal breathing during
sleep.
• People with sleep apnea have multiple extended pauses in breath
when they sleep.
• These temporary breathing lapses cause lower-quality sleep and
affect the body’s supply of oxygen, leading to potentially serious
health consequences.

7. Sleep Apnea - Types

12. Sleep Apnea and CV problems
• 1. Hypertension - difficult to manage
• 2. Arrhythmia
• 3. CAD
• 4. Stroke
• 5. Pulmonary hypertension
• 6. Heart failure

13. Pathophysiology
• 1. Hypoxia
• 2. Negative intrathoracic pressure
• 3. Arousal - increase sympathetic activity

15. Hypertension
• Nearly half of patients with Sleep Apnea have underlying high
blood pressure
• Blood pressure is generally resistant to medications
• Nocturnal hypertension
• Lack of ‘ dipping’ of blood pressure during sleep
• Presence of hypertension in addition to co-existing co-morbidities
increase the risk of CV events as well as mortality.

16. Sleep Apnea and Arrhythmia
• Exact prevalence and pathophysiology is not well known
• Brady-arrhythmia : Severe bradycardia ,sinus pause, 1st degree AV
block, Mobitz Type 1 AV block
• Tachy-arrhythmia – PVCs , SVT, AF x 5 fold , VT (non sustained and
sustained)

17. Pathophysiology –SA and Arrhythmia

18. Management of arrhythmia in Sleep Apnea
• CPAP
• Anti-arrhythmic generally not indicated
• Specific targeted therapy if electrical conduction abnormality
detected
• Atrial overdrive pacing does not help and not recommended

19. Sleep Apnea
and Heart Failure
• Sleep Apnea and Heart Failure
are inter-related
• At least 50% of patients with HF
have OSA or CSA
• Sleep apnea increases the risk of
heart failure by 140%
• The exact prevalence and
pathophysiology of HF in Sleep
Apnea is not known

21. Sleep Apnea in HF patients: common
preponderance
• Age above 60
• Male
• NYHA Class III and IV
• For unknown reason sleep apnea is not seen in female HF
patients

22. Factors influencing HF in Sleep Apnea
• Associated HPN , AF
• Sympathetic overdrive
• Increase pre-load due to decreased intra-thoracic pressure
• Increase afterload leading to increase left ventricular end diastolic
pressure (LVeDP) and impaired LV systolic function
• Increased pulmonary artery pressure pre-dispose to right heart
failure

24. Sudden Cardiac Death in Sleep Apnea
• Obstructive sleep apnea (OSA) raises the risk of sudden
cardiac death (SCD) by 300–400% depending on the severity of
OSA.
• Published reports raised the association between OSA and
SCD but not the mechanism of SCD..

25. Severity of Sleep Apnea and Survival

26. CPAP and CV benefits

27. Using CPAP as management strategy

28. CPAP and CV benefits
• 1. Improve oxygenation
• 2. Reduce oxidative stress
• 3. Reduce endothelial dysfunction
• 4. Reduce pre-load and afterload by increasing intra-thoracic
pressure.
• 5. Reduce sympathetic overdrive
• 6. Reduce HPN , Arrhythmia

37. • Activating the Sympathetic Nervous System
• Each time a person with sleep apnea stops breathing, the level of
oxygen in the blood decreases13. As the body becomes deprived of
oxygen, specialized cells — called chemoreceptors — detect these
changes and activate the sympathetic nervous system to respond,
which is the part of the nervous system responsible for reacting to
stressful or dangerous situations. The sympathetic nervous system
triggers the body to gasp for air, which sometimes wakes a person
out of sleep.
• The sympathetic nervous system also responds to a low level of
oxygen by constricting blood vessels and increasing heart rate and
blood pressure. As the pauses in breath continue throughout the
night, repetitive changes in blood pressure may lead to hypertension
or make existing hypertension worse.

38. • Changes in Pressure Within the Chest
• When a person with obstructive sleep apnea
(OSA) attempts to breathe, they inhale against
a narrowed or closed upper airway. These
unsuccessful, forced inhalations can cause
substantial changes in pressure within the
chest cavity. Over time, these repetitive
changes in intrathoracic pressure can damage
the heart. Intrathoracic pressure changes can
lead to atrial fibrillation (an irregular,
often rapid heartbeat), problems with blood
flow to the heart, and even heart failure.

39. • Oxidative Stress
• After each pause in breath, a person with sleep
apnea once again inhales successfully. This
inhale brings much-needed oxygen back into the
lungs, blood, and body tissues. Unfortunately,
frequent changes in oxygen levels can cause
significant stress on the body, called
oxidative stress. Oxidative stress can promote
systemic inflammation, as well as neurochemical
and physiological reactions that increase the
risk of heart disease.