Electrocardiography and Pulmonary Function Testing

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CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 52 Electrocardiogr aphy and Pulmonary Function Testing

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52. Electrocardiography and Pulmonary Function Testing. Learning Outcomes. 52.1Describe the anatomy and physiology of the heart. 52.2 Explain the conduction system of the heart. 52.3Describe the basic patterns of an electrocardiogram (ECG). - PowerPoint PPT Presentation

Transcript of Electrocardiography and Pulmonary Function Testing

CHAPTER

© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

52Electrocardiography

and Pulmonary Function Testing

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52-2

Learning Outcomes

52.1 Describe the anatomy and physiology of the heart.

52.2 Explain the conduction system of the heart.

52.3 Describe the basic patterns of an electrocardiogram (ECG).

52.4 Identify the components of an electrocardiograph and what each does.

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Learning Outcomes (cont.)

52.5 Explain how to position the limb and precordial electrodes correctly.

52.6 Describe in detail how to obtain an ECG.

52.7 Identify the various types of artifacts and potential equipment problems and how to correct them.

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Learning Outcomes (cont.)

52.8 Identify how the ECG is interpreted.

52.9 Identify common arrhythmias.

52.10 Summarize exercise electrocardiography.

52.11 Explain the procedure of Holter monitoring.

52.12 Describe forced vital capacity.

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Learning Outcomes (cont.)

52.13 Describe the procedure of performing spirometry.

52.14 Describe the procedure for obtaining a performing peak expiratory flow rate.

52.15 Describe the procedure for performing pulse oximetry testing.

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Introduction

• Patients often have cardiovascular or respiratory problems

• Medical assistant– Perform screening and/or diagnostic

testing– Understand the anatomy and physiology of

the heart and respiratory system

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The Medical Assistant’s Role

• Electrocardiography – Graphic recording of the

electrical impulses of the heart

– Uses• Evaluate symptoms of heart

disease• Check effectiveness or side

effects of medications• General examination

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The Medical Assistant’s Role (cont.)

• Pulmonary function tests – Measure and evaluate a

patient’s lung capacity and volume

– Uses• Help detect and diagnose

pulmonary problems• Monitor respiratory

disorders• Evaluate effectiveness of

treatments

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Anatomy of the Heart

• Muscular double pump– Right – receives blood from the body, sends it

to the lungs– Left – receives blood from the lungs, sends it

out to all parts of the body

• Four chambers– Two atria– Two ventricles

• Valves

• Septum

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Physiology of the Heart

• Systole – contraction phase

• Diastole – relaxation phase

• Cardiac cycle – sequence of contraction and relaxation

• Cardiac muscle fibers are interconnected so when one is stimulated to contract, all fibers in the group contract.

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Conduction System of the Heart

• Cardiac cycle – Controlled by

specialized tissues in the heart wall that transmit electrical impulses

– Impulses cause muscle to contract and relax

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Bundle Branches

Bundle of HisSA Node

Purkinje Fibers

AV Node

Pacemaker of the heart

Sets rhythm of contractions

Bottom of right atrium

Impulse delayed slightly

Located in septum between ventricles

Relay impulse to Purkinje fibers

Located in ventricle walls

Contraction of ventricles

Conduction System of the Heart (cont.)

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Conduction System of the Heart (cont.)

• Electrocardiography– Transmission, magnitude,

and duration of electrical impulses of the heart

• Polarity– Having a positive and

negative pole– Resting cell

• Positive outside

• Negative inside

• Depolarization – Impulse that initiates a

contraction

• Repolarization – Period of electrical

recovery following depolarization

– Prior to polarized (resting) state

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Conduction System of the Heart (cont.)

• Basic pattern of the ECG– Waves (deflections) are labeled P, Q, R, S,

T, U

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Apply Your Knowledge

True or False

___ The AV node is the heart’s pacemaker.

___ The medical assistant does not perform ECGs or PFTs.

___ The bundle branches relay impulses to the Purkinje fibers in the ventricles.

___ The heart is resting in the polarized state.

___ Depolarization initiates contractions of atria and ventricles.

___ Repolarization occurs before depolarization. F

ANSWER:

T

T

T

F

F

following

may

SA

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The Electrocardiograph

• Electrical impulses are detected through the skin– Measures– Amplifies – signal

is increased– Records using the

stylus

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The Electrocardiograph (cont.)

• Types of electrocardiographs– Standard machine –

12-lead, which records

12 different views at once

– Single channel – one lead and records only one view

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The Electrocardiograph (cont.)

• Electrodes and electrolyte products– Electrolyte – enhances

transmissions of electric current

– Electrodes• Ten areas of the body

– Right and left arms– Right and left legs– Six locations on the

chest

• Enables physician to pinpoint origin of problems

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The Electrocardiograph (cont.)

• Leads– Provide different images of electrical activity

– Marked automatically on the ECG

– Limb leads • Three standard – I, II, III• Three augmented – AVF, AVR, AVL

– Precordial leads – V1 through V6

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The Electrocardiograph (cont.)

• ECG paper

– Single or multichannel

available

– Heat- and pressure-

sensitive

– Standardized to permit

uniform interpretation

– Vertical axis – strength

of impulse (millivolt)

– Horizontal axis – time

0.04 sec

5 mm(0.5 mV)

1 mm(0.1 mV)

1 mm5 mm

0.2 sec

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The Electrocardiograph (cont.)

• Controls– Standardization

control

– Speed selector – 25mm/sec standard

– Sensitivity control – adjusts height of tracing

– Lead selector – enables selection of a single lead

– Centering control – adjusts position of stylus

– Line control – adjusts darkness of line

– On/Off switch

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Apply Your Knowledge

Matching:

___ Adjusts position of stylus A. Vertical axis

___ Adjusts height of tracing B. Sensitivity control

___ Adjusts darkness of tracing C. Precordial leads

___ Measures strength of impulse D. Horizontal axis

___ Measures time E. Limb leads

___ AVF, AVR, AVL F. Amplification

___ V1 through V6 G. Centering control

___ Increases signal H. Stylus temperature control

ANSWER:

H

G

F

E

D

C

B

A

Superbly Matched!

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Preparing to Obtain an ECG

• Proper technique essential

• Preparing the room and equipment– Other electrical equipment turned off– Quiet room, comfortable temperature– Check machine

• Warm up• Adequate paper

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Preparing to Obtain an ECG (cont.)

• Preparing the patient

– Introduce yourself

– Explain the procedure

– Answer questions

– Ensure patient comfort

– Perform ECG procedure

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Applying the Electrodes and the Connecting Wires

• Electrodes – disposable are most common

• Positioning electrodes – Use consistent

technique– Limb electrodes –

place at same level – Precordial electrodes

– specific intercostal spaces

Precordial Lead Placement

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Applying the Electrodes and the Connecting Wires (cont.)

• Attaching wires– Numbers and letters

correspond to those for electrodes

– Connect limb wires first

– Precordial in same sequence as electrodes

– Avoid tension on wires

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Operating the Electrocardiograph

• Standardize

• Run the ECG– Automatic– Manual– Multiple-channel

• Check the tracing– Clear/free from

artifact

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Apply Your Knowledge

1. In addition to making sure the room is comfortable for the patient and the ECG machine is ready, what else should you do to prepare for performing an ECG?

ANSWER: All other electrical equipment in the room should be turned off.

2. Electrodes are placed at how many positions on the body?

ANSWER: Ten: four limb and six chest positions.

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Apply Your Knowledge

3. What should you do just prior to running the ECG to see if the machine needs adjusting? What should you do upon completion of the test?

ANSWER: Standardize the electrocardiograph prior to running the tracing. Upon completion of the ECG, you should check the tracing to be sure is it clear and free from artifact.

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Troubleshooting Artifacts

• Causes– Improper technique

– Poor conduction

– Outside interference

– Improper handling

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Troubleshooting Artifacts (cont.)

• Wandering baseline – somatic interference or mechanical problems

• Flat line – loose or disconnected wire

• Extraneous marks – careless handling

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Troubleshooting Artifacts (cont.)

• Causes – AC interference –

machine picks up current from other electrical equipment

– Somatic interference – muscle movement

• Identifying source of interference– Check tracings for

leads I, II, and III

– If unable to identify source, stop and notify supervisor of problem

– Leave patient connected

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Completing the Procedure• Acceptable tracing

– Label properly– Disconnect wires from

electrodes– Remove

electrodes/wipe off electrolyte

– Assist patient up– Prepare room

appropriately

• Mount tracing if necessary

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Apply Your Knowledge

1. What are four general causes of artifacts?

ANSWER: They are improper technique, poor conduction, outside interference, and improper handling of the tracing.

2. What should you after running an ECG?

ANSWER: After making sure the tracing is acceptable, you should label it properly, disconnect wires from electrodes, remove electrodes and wipe off electrolyte, assist patient up, and prepare the room appropriately for the next patient.

Bravo!

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Interpreting the ECG

• Not a medical assistant responsibility

• Knowing how they are interpreted will enable you to recognize a problem requiring immediate attention

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Interpreting the ECG (cont.)

• Heart rhythm– Regularity of the heartbeat

– Distances between complexes and waves is normally consistent

– Rhythm strip obtainedfrom lead II

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Interpreting the ECG (cont.)

• Heart rate – If regular – count QRS complexes in a 6-

second strip and multiply by 10

– Irregularities • Conduction abnormalities• Reaction to medication

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Interpreting the ECG (cont.)

• Intervals and segments– Variations in length and position

• Conduction disturbances• Myocardial infarctions• Electrolyte disturbances

• Wave changes – normally similar in each lead

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Interpreting the ECG (cont.)

• Cardiac arrhythmias – irregularities in heart rhythm

– Ventricular fibrillation – life-threatening with no cardiac output

– Premature ventricular contractions – heartbeats that originate from the ventricles

– Bundle branch blocks – impulse through the heart is slowed or blocked

– Atrial fibrillation – electrical disturbance in the atria and/or AV node

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Apply Your Knowledge

Matching (may be used more than once):

___ Number of QRS complexes in 6 sec x 10 A. V-fib

___ Cannot identify “P” waves B. Heart rhythm

___ Produces no cardiac output C. Bundle branch block

___ Originates in ventricles D. Atrial fibrillation

___ Slows or stops impulse E. Heart beat

___ Multiple impulses from sites outside SA node F. PVC

___ “Saw-tooth” image

___ Regularity of heart beat

___ Due to irritable of ventricular heart muscleF

F

E

D

A

A

D

C

B

ANSWER:

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Exercise Electrocardiography• Stress test – measures

the heart’s response to a constant or increasing workload

• Uses– Determine how a diseased

heart is functioning– Screen a patient for heart

disease– Determine patient’s ability

to start an exercise program

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Ambulatory Electrocardiography

• Resting ECG may not show abnormalities

• Holter monitor– Monitors heart over a

24-hour period of normal activity

– Uses• Diagnosis • Evaluate status post-MI

• Patient education– Record activities– What to avoid– How to check monitor

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Ambulatory Electrocardiography (cont.)

• Connecting the patient

– 3 or 5 electrodes

– Prep skin prior to placing

– Tape in place to eliminate tension and ensure that electrodes stay in place for entire time of testing

– Put fresh battery in the machine

– Check tape

– Ensure that machine is turned on

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Apply Your Knowledge

What is the purpose for stress testing and Holter monitor testing?

ANSWER: Stress testing is used to measure the heart’s response to a constant or increasing workload. A Holter monitor is used to obtain a tracing over a period of time when a resting ECG shows no abnormalities. Both are used for diagnosing cardiac conditions or for monitoring current treatments and medications.

Correct!

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Anatomy of the Respiratory System

• Nose

• Pharynx

• Larynx

• Trachea

• Two bronchi

• Bronchioles

• Alveoli

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Physiology of the Respirator System

• External respiration – alveoli – Ventilation

• Inspiration• Expiration

– Diffusion

• Internal respiration (perfusion) – exchange of O2 and CO2 between blood and tissues

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Pulmonary Function Testing

• Evaluates lung volume and capacity

• Uses– Evaluate of shortness

of breath – Detect and classify of

pulmonary disorders– Evaluate effectiveness

of treatments

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Spirometry• Measures air taken in by

and expelled by the lungs

• Forced vital capacity (FVC) – greatest volume of air that can be expelled with a rapid, forced expiration

• Types of spirometers:– Computerized – Mechanical

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Performing Spirometry• Technique similar for all types – be consistent

• Patient preparation– Inform the patient about conditions and activities

that could affect the test accuracy– Explain procedure and its purpose– Explain the need for a nose clip– Be sure patient forms a tight seal around the

mouthpiece – Position the patient properly– Demonstrate correct procedure

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Performing Spirometry (cont.)

• Performing the maneuver

– Urge patient to blow hard and to continue

blowing

– Provide feedback on performance

– Obtain three acceptable maneuvers

– Observe the patient’s symptoms

– Notify physician immediately if symptoms

occur

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Performing Spirometry (cont.)

• Determining effectiveness of medications

– Perform test before patient takes medication for day

– Repeat after patient takes the medication

• Special considerations

– Uncooperative patients

– Patients who do not understand

– Patients who cannot follow directions

– Patients who cannot perform the procedure

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Performing Spirometry (cont.)

• Calibration – Daily – keep logbook– Calibration syringe –

standardized measuring instrument

– Detect leaks – check time/volume graph

• Results– Evaluate ventilatory

function– Screening for pulmonary

disorders– Severity of problems– Response to therapy or

medication

• Infection control– Clean equipment after

each patient– Discard disposable

supplies appropriately– Wash hands before and

after each use

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Peak Expiratory Flow Rate

• Determines amount of air that can be quickly forced from the lungs

• Peak flow meter

• Reveals narrowing of airways before an asthma attack

• Peak flow zones– Different for each

patient– Green zone – good

control of asthma– Yellow zone – large

airways are beginning to narrow

– Red zone – medical emergency

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Pulse Oximetry

• Non-invasive measurement of the oxygen saturation in arterial blood– Hemoglobin absorbs infrared light– Measures amount of light absorbed– Hypoxemia – less than 95%

• Uses – Pulmonary and cardiac conditions– Postoperatively– Sleep apnea

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Apply Your Knowledge

1. What is the purpose of PFTs?

ANSWER: To evaluate lung volume and capacity.

2. What is FVC?

ANSWER: It is forced vital capacity: the greatest volume of air that can be expelled with a rapid, forced expiration. It is the measurement of the volume of air expelled and amount of time taken to expel it.

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Apply Your Knowledge

3. Joey Jackson called to ask about taking his asthma medicine. He said he has been using his peak flow meter and the readings have been in his yellow zone. What do you tell him?

ANSWER: This means that his large airways are beginning to narrow and that he should take his medication as prescribed.

4. Joey decided to come to the office and you check his oxygen saturation with the pulse oximeter. The reading was 93%. What does this mean and what should you do?

ANSWER: Joey is hypoxemic. You need to notify the physician and document findings.

YIPPEE!4 for 4

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In Summary

52.1The heart is a muscular pump that circulates blood throughout the body. There are two upper chambers (atria) and two lower chambers (ventricles). Contraction of the atria followed by contraction of the ventricles moves the blood.

52.2The conduction system of the heart is responsible for the electrical pathway that occurs during a heartbeat. The pathway begins with the SA node and travels through the AV node – bundle of HIS – right and left bundle branches and ends with the Purkinje fibers.

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In Summary (cont.)

52.3The electrical impulses are represented in wave forms or deflections. Each deflection is labeled by letters PQRSTU and represents a part of the pattern.

52.4The electrocardiograph consists of the following components: electrodes, which detect and conduct electrical impulses to the electrocardiograph; amplifier, which increases the signal, making the heartbeat visible; stylus, which records the movement on the ECG paper; leads, combinations of electrodes, each providing different views of the electrical activity of the heart; and ECG paper, special heat-sensitive paper used for recording the ECG tracing.

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In Summary (cont.)

52.5The limb leads are placed on the fleshy part of the upper arms and lower legs. The precordial leads are placed across and down the left side of the chest in the 4th and 5th intercostal space. All leads must be placed in a standard and concise manner.

52.6The steps in obtaining an accurate ECG include: identifying the patient; properly placing the limb and chest electrodes; attaching the lead wires; entering the patient data into the ECG machine; running the tracing; checking the tracing for artifacts; disconnecting the patient from the lead wires and removing electrodes; and assisting the patient as required.

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In Summary (cont.)

52.7Artifacts that can occur during ECG testing include:

AC interference – Caused by small amounts of electricity given off by other pieces of equipment in the room and picked up by the ECG machine. This can be corrected by turning off or unplugging other appliances in the room.

Flat line – Caused by a loose or disconnected wire, or two wires that are switched. This can be corrected by checking and correcting lead placement.

Somatic interference – Caused by patient muscle movement. This can be corrected by reminding the patient to remain still, keeping the patient warm, and placing the limb electrodes closer to the trunk of the body.

Wandering baseline – Caused by somatic interference, mechanical problems, or improper electrode application. This can be corrected by reminding the patient to remain still, removing any oil or lotion from the patient’s skin before applying the electrodes, reapplying the electrodes, or uncrossing any crossed electrodes.

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In Summary (cont.)

52.8 The ECG is interpreted by assessing the heart rhythm, heart rate, the length and position of intervals and segments and any wave changes that occur.

52.9 A medical assistant should recognize abnormal heart rhythms such as premature ventricular contractions, ventricular fibrillation, and atrial fibrillation.

52.10 Exercise electrocardiography is referred to as stress testing. This measures the efficiency of the heart during constant or increasing workload.

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In Summary (cont.)

52.11 A Holter monitor is used to measure the heart’s activity over a 24-hour period and when the patient has intermittent chest pain or discomfort and a normal ECG and stress test.

52.12 Forced vital capacity is the measurement of the greatest volume of air expelled when a patient performs a rapid, forced expiration. The lung’s ability to function is measured by the volume of air expelled and the time taken to perform maneuver.

52.13 Accurate spirometry testing requires proper patient positioning, coaching the patient during the procedure, obtaining three acceptable maneuvers, and recording the results in the patient’s chart.

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In Summary (cont.)

52.14 A peak expiratory flow rate is obtained by having the patient sit or stand using good posture, take in as deep a breath as possible, and blow out through the peak flow meter as fast and as hard as possible three times. The highest reading of the three is the peak flow rate and should be recorded in the patient’s chart.

52.15 Pulse oximetry testing is performed by applying the pulse oximeter to the patient’s finger or toe, attaching the sensor cable to the oximeter, turning the oximeter on, setting the alarm limits for high and low oxygen saturations, and reading the patient’s oxygen saturation levels. The oxygen saturation levels should be recorded in the patient’s chart.

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End of Chapter 52

As the arteries grow hard, the

heart grows soft.

~ H. L. Mencken