Diagnosis of Heart Failure

Introduction

We know that when a patient comes to the doctor, patient will come with complaints; giving doctor symptoms like puzzles to be solved with a diagnosis. Sometimes, the symptoms include complaints from several systems in the body so that as physicians, we need to understand the correlation between each system to establish right diagnosis.

In this trigger, we learn about Congestive Heart Failure which is most likely to be caused by hypertension. However, it should be noted that there are several steps (algorithm) to help us in diagnosing patient so that we do not miss anything. Meanwhile, diagnosis of patient with suspected CHF includes history taking/anamnesis, physical examination, and such supporting diagnostic testing as electrocardiogram (ECG), thorax X-ray, echocardiogram, and laboratory test.

 

Discussion

There are several clinical approaches need to be taken to be able to diagnose patient with heart failure. 1 Algorithm below shows the steps of diagnosing patient with suspected heart failure [Figure 1].

Picture1

Figure 1. Algorithm for evaluation and diagnosis of heart failure.

King M, Kingery J, Casey B. Diagnosis and evaluation of heart failure. American Family Physician. 2012. 85(12): 1161-8.

 

History Taking

History taking / anamnesis (including alloanamnesis if the patient is unconscious) can be taken to points out possible etiologies and risk factors of heart failure in the patient. Most common etiologies and risk factors are the history or current illness of having coronary artery disease, hypertension, idiopathic cardiomyopathy, and valvular heart disease. History taking can also functions to know possible complication related to severity that the patient is having. 2,5

 

Physical Examination

Physical condition of the patient should be taken for identifying symptoms and characteristics of heart failure in the patient. Similar to other system’s physical examination, this examination includes inspection, palpation, auscultation, and percussion. 2

There are several criteria to diagnose heart failure. One of them which is widely used is Framingham criteria which is classified into 2 criteria, major and minor criteria. These criteria might be used to establish a diagnosis taken from symptoms gotten from physical examination session. These Framingham criteria includes: 1

  • Major criteria:
    • Acute pulmonary edema
    • Cardiomegaly
    • Hepatojugular reflex
    • Neck vein distension
    • Paroxysmal nocturnal dyspepsia or orthopnea
    • Rales
    • Third heart sound gallop
  • Minor criteria:
    • Ankle edema
    • Dyspnea on exertion
    • Hepatomegaly
    • Nocturnal cough
    • Pleural effusion
    • Tachycardia (>120 beats per minute)

Diagnosis of heart failure is taken when two major criteria or one major and two minor criteria of Framingham are met. 1

 

Electrocardiogram (ECG)

ECG is a tool to capture and observe electrical activity of the heart which is interpreted two-dimensionally (looking at the vector of heart movement). As we know, heart is a three-dimensional organ which moves three-dimensionally, too. 3 Thus, several leads are needed in each unique perspective to really interpret the movement of the heart two-dimensionally. There are twelve leads in ECG, which are then classified into several groups: 3

  • 3 standard limbs: 3
    • lead I: making the left arm the positive electrode and right arm negative electrode with angle of orientation 0 degree.
    • lead II: making legs the positive electrode and right arm negative electrode with angle of orientation 60 degrees.
    • lead III: making legs the positive electrode and left arm negative electrode with angle of orientation 120 degrees.
  • 3 augmented limbs: 3
    • lead aVL: making left arm positive and other limbs negative with angle of orientation -30 degrees
    • lead aVR: making right arm positive and other limbs negative with angle of orientation -150 degrees
    • lead aVF: making legs positive and other limbs negative with angle of orientation +90 degrees
  • 6 precordial leads: 3
    • V1: placed in the 4th intercostal space to the right of sternum
    • V2: placed in the 4th intercostal space to the left of sternum
    • V3: placed between V2 and V4
    • V4: placed in the 5th intercostal space in the midclavicular line
    • V5: placed between V4 and V6
    • V6: placed in the 5th intercostal space in the midaxillary line

Normally, heart pumps to anteriorly, slightly to the left, and downwards. Thus, these leads capture heart’s electrical activity in each’s own unique perspective. When the electrical activity of the heart moves towards the positive electrode of a lead, the lead will interpret a positive deflection in ECG result. On the other hand, when the electrical activity of the heart does not move towards the positive electrode of a lead (moves further apart), the lead will interpret a negative deflection in ECG result. For example, due to the fact that the electrical activity of the heart moves in different direction than lead aVF, ECG result in lead aVF will normally be negative deflection. 3,4

Picture2

Figure 2. Waves, intervals, and segments in ECG

Sherwood L. Human physiology from cells to systems. 9th ed. Boston: Cengage Learning; 2016.

 

In ECG, there are P, QRS, T, and U waves which contribute to PR interval, PR segment, QRS interval, ST segment, QT interval. 3 Each of them represents different electrical activity of the heart. 3

  • P wave represents atrial depolarization.
  • PR interval represents the time from the start of atrial depolarization to the start of ventricular depolarization (normally lasts from 0.12-0.2 seconds).
  • PR segment represents time from the end of atrial depolarization to the beginning of ventricular depolarization.
  • QRS wave represents ventricular depolarization.
  • QRS interval represents duration of QRS complex, normally lasts from 0.06-0.1 seconds.
  • T represents ventricular repolarization.
  • ST segment represents the time from the end of ventricular depolarization to the start of ventricular repolarization, which is usually horizontal or slightly upsloping in all leads (isoelectric).
  • QT interval represents the time from the beginning of ventricular depolarization to the end of ventricular repolarization.
  • TP segment represents duration between the end of ventricular repolarization and the beginning of atrial depolarization. 4

Hypertrophy and Enlargement of the Heart

It should be taken into account that hypertrophy and enlargement is different. Hypertrophy accounts for an increase in muscle mass while enlargement means dilation of a particular chamber in the heart. 3

Picture3

Figure 3. Hypertrophy and Enlargement of Left Ventricle

Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015.

Any changes in heart chamber (decreasing size due to increasing heart muscle mass and increasing size due to dilation) also affect ECG result by increasing time to depolarize, increasing amplitude since chamber generates more current and voltage, and eventually change the electrical axis of the heart. Normal mean electrical axis of the heart is usually between -30° to +90° while heart usually pumps between 0° to +90°, reflecting the electrical dominance of much larger left ventricle over the right ventricle. 3

As explained before, any changes of the heart can change mean electrical axis of the heart. Hypertrophy of the heart might change electrical axis of the heart accordingly to the hypertrophied side. For instance, if the mean electrical axis of the heart is shifted to -30° to -90°, the person is experiencing left axis deviation. On the other hand, right axis deviation is experienced when the mean electrical axis is shifted to +90° until +180°. 3

Picture4

Figure 4. Axis of the Heart

Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015

 

Ventricular Hypertrophy

Ventricular hypertrophy may happen in both left ventricle and right ventricle. Each of them gives different ECG interpretation and different complication. Left ventricular hypertrophy might cause left-sided heart failure, systemic hypertension, and valvular disease. Meanwhile, right ventricular hypertrophy will also cause right-sided heart failure, congenital heart disease, and pulmonary disease. 3,5

Right ventricular hypertrophy induces right axis deviation, a swift of QRS complex axis to +90° and +180°. Other distinct characteristics of right ventricular hypertrophy is seen when: 3

  • Lead I have a negative deflection of QRS complex axis
  • R wave is larger than S wave in lead V1
  • S wave is larger than R wave in lead V6

Picture5

Figure 5. Example of ECG Interpretation with Right Ventricular Hypertrophy

Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015.

On the other hand, the diagnosis of left ventricular hypertrophy is more complicated than right ventricular hypertrophy. In left ventricular hypertrophy, R wave amplitude should increase in leads overlying left ventricle while S wave amplitude should increase in leads overlying the right ventricle. There are several criteria needed to establish left ventricular hypertrophy diagnosis: 3

  • Precordial leads 3
    • R wave amplitude in lead V5 or V6 plus the S wave amplitude in lead V1 or V2 exceeds 3.5mV
    • R wave amplitude in lead V5 exceeds 2.6mV
    • R wave amplitude in lead V6 exceeds 2mV
    • R wave amplitude in lead V6 exceeds R wave amplitude in lead V5
  • Standard and augmented (limb) leads 3
    • R wave amplitude in lead aVL exceeds 1.1mV
    • R wave amplitude in lead aVF exceeds 2mV
    • R wave amplitude in lead I exceeds 1.3mV
    • R wave amplitude in lead I plus S wave amplitude in lead III exceeds 2.5mV

Picture6

Figure 6. Example of ECG Interpretation with Left Ventricular Hypertrophy

Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015.

 

Atrial Enlargement

Both right and left ventricle hypertrophy can result in right and left atrium enlargement due to the pressure exceeds by hypertrophied ventricles might make atrioventricular valves insufficiency; inducing regurgitation to respective atria. Furthermore, atrial enlargement can also be caused by severe lung disease. 3,5

Right atrial enlargement will strengthen electrical activity of right atrium due to the fact that sinoatrial node (SA node) is located in the upper part of right atrial wall. Thus, there will be an increase P wave amplitude in lead II (we see lead II to observe P wave clearly due to the fact that lead II is located in the direction of normal electrical axis of the heart). Right atrial enlargement is commonly caused by severe lung disease – with electrocardiographic picture is commonly known as P pulmonale. 3

Picture7

Figure 7. Example of ECG Interpretation with Right Atrial Enlargement

Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015.

 

On the other hand, due to fact that electrical activity of the heart travels from right atrium to left atrium, enlargement in left atrium might slower down electrical transmission. Thus, there will be an increase in duration of transmission, increase in amplitude of the second portion P wave, slowly drop to more than 0.1mV below the isoelectric line in lead V1. Left atrial enlargement is usually caused by mitral valve disease (the electrocardiographic picture is called P mitrale). 3

Picture8

Figure 8. Example of ECG Interpretation with Left Atrial Enlargement

Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015.

 

Conclusion

In relation to the trigger, the man was experiencing difficulty in breathing, swollen feet (pitting edema), left margin of the heart shifted to anterior axillary line, jugular vein fully filled, increased heart sound 2, S3 gallop, wet rales in lung fields. According to the 5 major criteria and 3 minor criteria of Framingham; suggesting that the man was experiencing congestive heart failure. High possibility of this heart failure is caused by uncontrolled hypertension, causing left ventricular hypertrophy. This hypertrophied left ventricle of the heart is also supported by ECG result which shows:

  • Summation of R wave in lead V5 and S wave in V1 exceeds 3.5mV
  • R wave exceeds 2.6mV in lead V5
  • R wave exceeds 2mV in lead V6
  • R wave in lead I exceeds 1.3mV
  • Summation of R wave in lead I and S wave in lead III exceeds 2.5mV

 

 

References

 

  1. King M, Kingery J, Casey B. Diagnosis and evaluation of heart failure. American Family Physician. 2012. 85(12): 1161-8.
  2. Harrison TR, Resnick BF, Wintrobe MM, et al. Harrison’s principles of internal medicine. 19th New York: McGraw-Hill Education; 2015: 1500-5.
  3. Thaler MS. The only EKG book you’ll ever need. 8th ed. New York: Wolters Kluwer; 2015: 32-103.
  4. Sherwood L. Human physiology from cells to systems. 9th Boston: Cengage Learning; 2016: 312.
  5. Kumar V, Abbas AK, Aster JC. Robbins basic pathology. 9th ed. Philadelphia: Elsevier; 2013: 367-8.
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