Saunders, Cardio Flashcards
the Total Volume of Blood Pumped through the heart in 1 Minute. Normal (4-7 L/min). Equals Stroke Volume Multiplied by HR. Can be calculated via the Thermodilution method when the client has a Pulmonary Artery Cather (Swan-Ganz catheter)
Cardiac Output
CO =
SV x HR
the Amount of Blood Ejected from the Left Ventricle w/ each Contraction. Normal (70-130 mL/heartbeat). Can be affected by Preload, Afterload, Contractility, & the Frank-Starling law.
Stroke Volume
the Volume of Blood Stretching the Left Ventricle at the End of Diastole. Is determined by the Total Circulating Blood Volume & is Increased by an Increase in Venous Return to the Heart.
Preload
the Force Against which the Heart has to Pump (Peripheral Resistance) to Eject Blood from Left Ventricle. Factors & Conditions that would Impede Blood Flow Increase Left Ventricular ___.
Afterload
the Inherent Ability of the Myocardium to Alter Contractile Force & Velocity. Sympathetic Stimulation Increases it, so Stroke Volume Increases. Conditions that decreases this Reduce Stroke Volume.
Contractility
the Force Exerted by the Blood Against the Walls of the blood vessels. If it Falls too Low, Blood flow to the Tissues, Heart, Brain, & other Organs becomes Inadequate. If it becomes too High, the Risk of Vessel Rupture & Damage Increases.
BP
Blood Pressure
the Phase of Contraction of the Heart, Especially of the Ventricles, during which Blood is Forced into the Aorta & Pulmonary Artery
Systole
the Maximum Pressure of Blood Exerted Against the Artery Walls when the Heart Contracts
Systolic Pressure
the Phase of the Cardiac Cycle in which the Heart Relaxes between Contractions. Represents the Period of time when the Two Ventricle are DILATED by the Blood Flowing into them.
Diastole
the Force of the blood Exerted Against the Artery Walls when the Heart Relaxes of Fills.
Diastolic Pressure
an Approximate of the Average Pressure in the Systemic Circulation throughout the Cardiac Cycle; Used in Hemodynamic Monitoring. Must be between 60-70 mm Hg for Adequate Organ Perfusion
MAP
Mean Arterial Pressure
the Difference between the Systolic & Diastolic Pressure. Norma (30-40 mm Hg)
Pulse Pressure
the Force Exerted by the blood Against the Vein Walls. Normal are Highest in the Extremities (5-14 cm H2O in the arm), & Lowest Closest to the Heart (6-8 cm H2O in the Inferior Vena Cava)
Venous Pressure
a Blood pressure Decrease of more than 10-15 mm Hg of the Systolic Pressure or a Decrease of more than 10 mm Hg of the Diastolic Pressure & a 10%-20% Increase in HR.
Postural (Orthostatic) Hypotension:
Occurs when the client’s BP is not Maintained adequately when moving from a Lying to a Sitting or Standing Position
Specialized Nerve Endings located in the walls of the Aortic Arch & Carotid Sinuses. They are Affected by Changes in the Arterial BP. Increases in Arterial Pressure Stimulate ___ & the HR & Arterial Pressure Decrease. Decreases in Arterial Pressure lead to a Lessened Stimulation of the Baroreceptors, Vasoconstriction occurs, & the HR Increases.
Baroreceptors (Pressoreceptors)
Nerve Endings located in the Vena Cava & the Right Atrium that Respond to Pressure Changes Affecting Circulatory Blood Volume. When the Blood Pressure Decreases because of Hypovolemia, a Sympathetic Response Occurs, causing an Increased HR & Blood Vessel Constriction. When the BP Increases because of HYPER-Volemia, an Opposite effect occurs.
Stretch Receptors
the measurement obtained during Momentary Balloon Inflation of a Pulmonary Artery catheter; it is Reflective of Left Ventricular End-Diastolic Pressure. Normally ranges between 4-12 mm Hg. A Decrease indicates HypErVolemia, Left Ventricular Failure, or Mitral Regurgitation.
PAWP
Pulmonary Artery Wedge Pressure
the Ability of the Heart Muscle Fibers to Propagate Electrical Impulses Along & Across Cell Membranes.
conductivity
Heard as the atrioventricular valves Close & is heard Loudest at the APEX of the Heart
S1 (first Heart Sound)
Heard when the Semilunar Valves Close & is Heard Loudest ate the BASE of the heart.
S2 (second heart sound)
Heard if Ventricular Wall Compliance is Decreased & Structures in Ventricular Wall Vibrate; Can occur in HF, Valvular Regurgitation. May be norma in individuals <30 y)
S3 (third heart sound)
Heard on Atrial Systole if Resistance to Ventricular Filling is Present; Abnormal Finding; Causes Cardiac Hypertrophy, Disease, or Injury to Ventricular Wall
S4 ( fourth Heart Sound)
Stimulation of ____ releases neurotransmitter Norepinephrine, producing an Increased HR, Increased conduction speed through the Atrioventricular Node, Increased Atrial & Ventricular Contractility, & Peripheral Vasoconstriction.
Sympathetic nerve fibers
Stimulation occurs when a Decrease in Pressure is Detected
Stimulation of ____ Releases Neurotransmitter ACetylCholine, which decreases HR & lessens Atrial & Ventricular Contractility & Conductivity.
Parasympathetic Nerve Fibers
Stimulation occurs when an Increase in Pressure is Detected
___ in Arterial Pressure stimulate Baroreceptors & HR & Arterial Pressure Decrease.
Increases
___ in Arterial Pressure reduce stimulation of Baroreceptors & Vasoconstriction occurs, as does an Increase in HR.
Decreases
Located in the Vena Cava & Right Atrium; Respond to pressure changes that Affect Circulatory Blood Volume
Stretch Receptors
When the BP Decreases as a result of ____, a Sympathetic Resoponse occurs, causing and Increased HR & Blood Vessel Constriction
Hypovolemia
When the BP Increases as a result of ____, Parasympathetic Response occurs, causing a Decrease in HR & lessened atrial & ventricular contractility & conductivity.
Hypervolemia
Influences BP Indirectly by regulating Vascular Volume
Antidiuretic Hormone (Vasopressin)
Increases in blood Volume result in Decreased Antidiuretic Hormone Release, Increasing Diuresis, Decreasing Blood Volume, & thus…
Decreasing BP
Decreases in blood Volume result in Increased Antidiuretic Hormone Release; this promotes an Increase in Blood Volume & therefore …
Increased BP
A potent Vasoconstrictor; causes BP to ..
Increases
Renin Converts Angiotensinogen to Angiotensin I; Angiotensin I is then converted to Angiotensin II in the ..
LUNGS
Angiotensin II Stimulates the Release of ___, which promotes Water & Na+ REtention by the KIDNEYS; this action Increases Blood Volume & BP
Aldosterone
(pacing function) ability of cardiac cells to generate an electrical impulse spontaneously & repetitively; primarily pacemaker cells (SA node)
Automaticity
Ischemia (decreased blood flow), Electrolyte Imbalance, Hypoxia, Drug Toxicity, Infarction (cell death)
conditions creating independent electrical impulses creating dysrhythmias
ability of non-pacemaker heart cell to respond to an electrical impulse beginning in pacemaker cell and depolarize (neg. charged cells develop pos. charge)
Excitability
ability to send an electrical stimulus from cell membrane to cell membrane ; wave of depolarization causes the deflections of ECG waveforms that are recognized as P Wave & QRS complex
Conductivity
ability of Atrial & Ventricular muscle cells to shorten their fiber length in response to electrical stimulation, causing sufficient pressure to push blood forward through the heart. (mechanical activity of the heart)
Contractility
