Cardiovascular Physiology Essentials

This cheat sheet covers the fundamental aspects of cardiovascular physiology, including heart structure, electrical conduction, muscle contraction, and the causes and symptoms of heart failure.

Core Principles

The heart is a four-chambered pump with pulmonary and systemic circuits.
Blood vessels include arteries, capillaries, and veins, forming a closed circulation system.
Critical cardiovascular variables include pressure, volume, contractility, and compliance.
Blood flow is driven by a pressure gradient and influenced by vessel diameter, viscosity, and length.
Cardiac muscle cells are autorhythmic, interconnected by intercalated discs (desmosomes and gap junctions), and possess numerous mitochondria.
Cardiac muscle contraction involves excitation-contraction coupling, modulated by calcium ions and autonomic nervous system input.
Heart failure can be left-sided or right-sided, with distinct causes and symptoms.
Various medical interventions exist for heart failure, including electrical devices, artificial valves, and heart transplantation.

Action Steps

Understand the structure and function of the heart chambers and valves.
Trace the path of electrical conduction through the SA node, AV node, and Purkinje fibers.
Differentiate between systolic and diastolic heart failure.
Identify the key symptoms of left-sided and right-sided heart failure.
Recognize common causes and risk factors for heart failure.
Learn about the indications and types of electrical heart devices.
Familiarize yourself with the evolution and types of artificial heart valves.
Understand the principles of heart transplantation and ventricular assist devices.

Formulas

Flow velocity (v) = Flow rate (Q) / Cross-sectional area (A)

Key Terms

Systolic Heart Failure: Heart failure with reduced ejection fraction (EF).
Diastolic Heart Failure: Heart failure with preserved ventricular function.
Pulmonary Congestion: Fluid buildup in the lungs, a symptom of left-sided heart failure.
Peripheral Edema: Swelling in the extremities, a symptom of right-sided heart failure.
Autorhythmic Cells: Cardiac cells that can generate their own electrical impulses.
Intercalated Discs: Specialized junctions between cardiac muscle cells containing desmosomes and gap junctions.
SA Node: Sinoatrial node, the heart's primary pacemaker.
AV Node: Atrioventricular node, which delays electrical conduction to allow atrial contraction before ventricular contraction.
Ventricular Assist Device (VAD): Mechanical pump implanted to assist a weakened ventricle.

Real World Examples

A patient presents with a persistent cough, crackles in the lungs, and shortness of breath during exertion.: These symptoms are indicative of pulmonary congestion, a hallmark of left-sided heart failure.
A patient experiences significant swelling in their legs and ankles, along with abdominal distension (ascites).: These signs suggest peripheral edema and ascites, common in right-sided heart failure due to fluid backup.
An individual has a history of hypertension and coronary artery disease, leading to impaired ventricular ejection.: This scenario describes a common cause of systolic heart failure.

Timeline

1982-1987: Heart transplantation survival data shows a half-life of 7.7 years.
1988-1992: Heart transplantation survival data shows a half-life of 9.3 years.
1993-1997: Heart transplantation survival data shows a half-life of 9.1 years.
1991: 3.5 million heart failure patients in the US.
2000: 4.7 million heart failure patients in the US.
2001: 4.8 million heart failure patients in the US.
2014: Publication date for Circulation reference on Cardiovascular Mortality.
2016: Publication date for JACC source on artificial heart valves.
2037: Estimated 10 million heart failure patients in the US.

People

Dee Unglaub Silverthorn, Ph.D.: Author of 'Human Physiology: An Integrated Approach'
Dr. Howard D. Booth: Presenter of the PowerPoint® Lecture Slide Presentation
Ashley Barlow PharmD: Creator of the Clinicians Pocket Guide to Vasopressors