Week 6 Cardiac B

Vocabulary flashcards for Cardiac B: Own-Time (week 6) lecture notes focusing on heart failure.

Heart Failure

A debilitating heart condition that affects the heart's ability to pump effectively, resulting in reduced cardiac output.

Primary Manifestations of Heart Failure

Difficulty breathing and fatigue which limits exercise tolerance, and fluid retention, which could result in pulmonary congestion and peripheral oedema.

Cardiac Output (CO)

Volume of blood pumped out of the heart each minute.

Heart Rate (HR)

Number of heart beats per minute.

Stroke Volume (SV)

Volume (mLs) of blood ejected per beat.

Preload

The volume of blood in the ventricles and associated pressure just prior to ventricular contraction; impacted by venous return and ventricular compliance.

Venous Return

The volume of blood returning to the heart.

Ventricular Compliance

The heart’s ability to stretch and accommodate blood.

Afterload

The resistance the ventricle is required to overcome in order to eject blood into the arteries.

Contractility

The force of myocardial contraction.

Ejection Fraction (EF)

How effectively the heart is pumping, usually ranging between 50-70% in a healthy heart.

Prevalence of Heart Failure in Australia

According to the lecture, approximately 0.6% of the Australian population.

New York Heart Association (NYHA) Classification

Classification system for heart failure based on physical activity tolerance.

ACC/AHA Heart Failure Stages

Stages of heart failure identified by the American College of Cardiology and American Heart Association (AHA).

Pathophysiology of Heart Failure

Heart failure is a chronic, progressive condition where the heart is unable to pump enough blood to meet the body's demands. It results from structural or functional abnormalities affecting ventricular filling or ejection of blood.

Pathophysiology Overview

1. Primary Cause:

   • Ischemic heart disease (e.g., myocardial infarction)

   • Hypertension (leading to left ventricular hypertrophy)

   • Valve disorders (e.g., aortic stenosis, mitral regurgitation)

   • Cardiomyopathy (e.g., dilated or restrictive cardiomyopathy)

2. Types of Heart Failure:

   • Heart Failure with Reduced Ejection Fraction (HFrEF):

     • Impaired systolic function, leading to weak ventricular contraction and low cardiac output.

   • Heart Failure with Preserved Ejection Fraction (HFpEF):

     • Impaired diastolic function, causing stiff ventricles and poor ventricular filling.

3. Compensatory Mechanisms (Initially Helpful but Harmful Long-Term):

   • Sympathetic Nervous System (SNS) Activation

     • Releases epinephrine & norepinephrine → increases heart rate & vasoconstriction.

     • Leads to increased myocardial oxygen demand, worsening failure.

   • Renin-Angiotensin-Aldosterone System (RAAS) Activation

     • Renin → Angiotensin II → Aldosterone → vasoconstriction & fluid retention.

     • Causes hypertension, edema, and ventricular remodeling.

   • Ventricular Hypertrophy & Remodeling

     • Chronic pressure overload → enlargement of the heart → worsens contraction ability.

4. Signs & Symptoms (Due to Blood Backup & Insufficient Perfusion):

   • Left-sided heart failure (affects lungs):

     • Pulmonary congestion → dyspnea, orthopnea, crackles, cough.

   • Right-sided heart failure (affects systemic circulation):

     • Peripheral edema, jugular venous distension (JVD), ascites

Preload in Heart Failure

Increased volume/filling prior to systole.

Afterload in Heart Failure

Increased workload on the heart, such as in hypertension

Left-Sided and Right-Sided Heart Failure

Failure of either the left or right side of the heart to meet the cardiac output demands for perfusion.

Afterload

Increased workload on the heart.

Heart Failure with REDUCED Ejection Fraction (HFrEF)

Occurs when the left ventricular systolic function reduces leading to poor contraction and emptying of the left ventricle during systole.

Heart Failure with PRESERVED Ejection Fraction (HFpEF)

Characterized by heart failure symptoms however with a preserved ejection fraction of 50% or higher indicating decreased compliance of the left ventricle and poor filling.

Right-Sided Heart Failure

Results from impaired contractility of the right ventricle (RV) caused by increased pressure, volume overload, intrinsic myocardial contractility dysfunction and/or cardiac arrhythmias.

Sympathetic Nervous System Activation (Compensatory Mechanism)

Increases heart rate and blood pressure.

Neurohormonal Responses (Compensatory Mechanism)

Releases hormones that cause blood vessels to narrow and retain fluids.

Ventricular Dilation (Compensatory Mechanism)

The heart stretches to hold more blood.

Ventricular Hypertrophy (Compensatory Mechanism)

The heart muscle thickens to pump harder.

Ventricular Remodeling (Compensatory Mechanism)

Changes in heart size and shape that can worsen heart failure.

Clinical Manifestations of HFrEF

Includes fatigue, dyspnoea, orthopnoea, cough (with frothy sputum), decreased urine output and oedema.

Clinical Manifestations of HFpEF

Includes dyspnoea on exertion, fatigue and pulmonary oedema (venous congestion in the lungs).

Chronic Heart Failure

A progressive decline in ventricular function coupled with chronic neurohormonal activation resulting in ventricular remodeling.

Medications to Prevent Heart Failure

ACE inhibitors, Beta blockers, Sodium-glucose cotransporter 2 (SGLT2) inhibitors for patients with T2 diabetes.

SGLT2 Inhibitors

Dagagliflozin and Empagliflozin.

Loop Diuretics

Furosemide and Bumetanide.

Potassium Sparing Diuretics

Spironolactone.

Angiotensin Receptor Neprilysin Inhibitor (ARNI)

Sacubitril with Valsartan

Key Aspects of Heart Failure Self-Management Education

Medication adherence, diet, exercise, and recognizing worsening symptoms.