- abnormal heart beats
The human heart is the organ
responsible for pumping blood to all parts of the body. The efficiency of
the pumping action is related to three primary factors. These factors
include the strength of the muscular contractions, the amount of
resistance to blood flow across valves in the heart, and the coordinated,
rhythmic pumping of each of the chambers of the heart. Specialized muscle
cells that act as electrical conduits through the heart and natural
pacemakers determine the rhythm of the heart. The graphical representation
of the heartís electrical activity is called an electrocardiogram or ECG.
Pilots applying for First Class medical certification are required to
submit an ECG with the first application after their 35th birthday and
annually with subsequent evaluations after the 40th birthday. The ECG must
be submitted electronically to the FAA ECG Library by the AME at the time
of the physical examination, or by a company medical doctor within the 60
days prior to the physical by the AME.
This article explains at a basic level the physiology of heart rhythms,
some common abnormal rhythms, possible treatments and aeromedical
certification implications. There are many other types of arrhythmias not
discussed here as well as evaluation and treatment options available to
cardiologists and electrophysiologists.
The "normal" electrical signals
within the heart are defined in terms of the rate of signals and the
rhythm of the signals. The normal heart rate is between 60 and 100 beats
per minute in the average adult. Rates slower than 60 beats per minute (bpm)
are termed "bradycardia" while rates faster than 100 bpm are termed
"tachycardia." Heart rates outside the "normal range" indicate a healthy
response of the heart or may reflect malfunction and disease. For example,
the resting heart rate of an aerobically conditioned athlete may be in the
40ís or 50ís, while the appropriate heart rate response to exercise may be
an elevation to rates above 150 beats per minute.
Medications and disease conditions will affect the heart rate. Slow heart
rates (bradycardia) can be caused by some blood pressure medications such
as beta-blockers or diseases such as hypothyroidism (low thyroid
activity). Heart disease can also manifest as an abnormally slow rate.
Tachycardia (fast heart rate) may also reflect the effects of medications
(decongestants, diet pills, thyroid medication, etc.), exercise,
non-cardiac diseases such as adrenal tumors, hyperthyroidism, lung
disease, imbalances of the bloodís electrolytes, dehydration, anemia (low
blood count) and many others.
Irregular heart rates, termed "arrhythmias" or "dysrhythmias" generally
require a more extensive evaluation to exclude underlying heart diseases,
the most common cause. Some cases of dysrhythmias are not associated with
any significant disease or are transient in nature. ECGís or more extended
monitors of heart rhythm are useful in diagnosing arrhythmias.
Disturbances of the heart rhythm are generally categorized as "brady-"
(slow) or "tachy-" (fast) arrhythmias. This categorization is frequently
important in determining treatment as well as providing clues to possible
As mentioned above, a wide variety
of non-cardiac conditions and medications can affect the heart rate and
rhythm. The common element in most of these conditions is the effect they
have on nerves going to the heart. This portion of the nervous system is
called the autonomic nervous system and has two major components. Nerves
of the sympathetic nervous system generally stimulate the heart to beat
faster and may stimulate irregularities in the heart beat. Nerves of the
parasympathetic nervous system, primarily the vagus nerve, act to slow the
Disease of the coronary arteries, which supply blood to the heart muscle
(myocardium), may cause damage to the rate- and rhythm-setting electrical
myocardial fibers. Congenital anatomical defects of the heart and diseases
of the heart itself, such as myocarditis, sarcoid and pericarditis may
cause dysrhythmias. In many cases of dysrhythmias, no specific cause is
ever discovered, particularly in younger individuals.
Heart's Electrical Conduction System
The heartís electrical conduction
system is responsible for setting the rate and rhythm to all sections of
the heart and coordinating the activity for the most efficient operation
of the four chambers of the heart. While all muscles, including the heart,
have some intrinsic electrical properties, the heart has several portions
of very specialized, electrically active myocardial cells.
The two upper chambers of the heart, called the right atrium and left
atrium, receive blood returning from the body (right) or the lungs. They
are relatively thin walled and do not pump very forcefully, as they only
have to pump blood to the adjacent lower chambers of the heart, called the
right and left ventricles. The right ventricle is of medium thickness and
it is responsible for pumping blood a short distance to the lungs where
the blood is re-oxygenated. The left ventricle is a thick walled structure
that must pump the oxygen rich blood returning from the lungs via the left
atrium, to the entire body. The wall of myocardium between the two
ventricles, called the septum, is very thick also since it participates in
pumping blood to both the lungs and the body.
In normal individuals, the heart
rate is usually set by a collection of heart muscle with electrical
properties near the top of the right atrium, called the sino-atrial or SA
node. Depending on the individualís physiology, the SA node serves as an
electrical capacitor that discharges 60-100 times per minute. As mentioned
above, many factors may affect the rate at which the SA node fires. On an
ECG, the discharge of the SA node is represented by the "P wave." The
electrical signal from the SA node diffuses across both atria, causing
different portions of the atria to contract sequentially as the discharge
spreads from the SA node like ripples in a pond. The sequential
contraction of the atria is not as efficient as a simultaneous contraction
of all the myocardial fibers of atria would be, but occurs in less than
0.2 seconds and is adequate to pump blood to the ventricles.
The atrioventricular node acts as
a second electrical capacitor that is located at the junction of the two
atria and two ventricles. Essentially, the AV node collects the electrical
signal diffusing across the atria and holds it until ready for discharge.
This is represented graphically on an ECG by the "P-R interval." In the
absence of a signal from the SA node, the AV node has an intrinsic rate of
discharge of 40-60 per minute. Because the SA node sends signals at a
faster rate, the AV node usually discharges at the same rate as the SA
Unlike the atria which contract
sequentially in response to diffusion of an electrical signal across the
chambers, all portions of the ventricles must contact nearly
simultaneously for efficient pumping action. To accomplish this, the AV
nodes discharges its signal into a high speed conduction pathway called
the His-Purkinje system. The His-Purkinje system uses three conduits to
send electrical signals rapidly to both ventricles and allows the signal
to spread across the thickness of the ventricular walls, rather than
diffusing down the length and width of the ventricles.
There are two pathways sending signals to the thicker left ventricle,
called the left anterior (front) fascicle/bundle and the left posterior
(back) fascicle/bundle. There is a single pathway on the right. The ECG
representation of this discharge down the His-Purkinje bundles and into
the ventricles is called the "QRS complex." This entire sequence is
usually less than 0.12 seconds.
The ventricles depolarize electrically when they contact. This is also
represented on the ECG by the QRS complex. Immediately after
depolarization, they cannot discharge until they repolarize and the
electrolytes in the heart muscles, sodium, potassium and calcium, return
to their normal resting balance. The period of time when they cannot
discharge is called the refractory period is represented by the ST segment
of the ECG. The length of the ST segment is not important in most cases,
but deviations from itsí baseline may represent decreased blood flow to
the heart ("ST depression with exercise") or injury such as an early heart
attack ("ST elevation"). Please see the VFS article on Coronary Heart and
Artery Disease for a full description of exercise stress testing. The
repolarization, or resetting of the baseline electrical state of the
ventricles, is represented by the "T-wave" on the ECG.
The various types of arrhythmias
can be broken into several subcategories: benign, bradyarrhthmias (too
slow) and heart blocks, and tachy-arrhythmias (too fast). Bradyarrhythmias
(slow) generally arise from some type of failure of the conducting system
to conduct signals in the normal sequence or through normal pathways.
Frequently, these failures to conduct signals are termed "heart blocks."
Alternatively, tachy-arrhythmias result from various aberrant conduction
This condition is sometimes found
as an annotation on computer generated ECG interpretations. It does not
represent an abnormal condition and does not require further evaluation.
Sinus arrhythmia is defined as a variability in the resting heart rate,
often associated with breathing in (slows heart rate) and exhaling (speeds
heart rate) due to the change in the rates the chambers of the heart fill
with blood at different phases of respiration. The Guide to Aviation
Medical Examiners specifically states this finding does not require
evaluation and is eligible for First Class certification.
Conditions-Atrial Premature Complexes (APC, APB, PAC)
If atrial premature contractions (APCs)
are noted on an FAA ECG, the pilot may receive a letter from the FAA
several weeks to months after the physical requiring a cardiovascular
evaluation with a Holter monitor. Because up to several APCs a minute may
be normal, but ECGs only evaluate a six second interval, one or more APCs
on a six second ECG may represent significantly more frequent occurrences.
The Holter monitor (continuous, 24-hour ambulatory ECG recording) would
detect all APCs and give an hourly average. Pilots who are directed by the
FAA to undergo a cardiovascular evaluation may continue to fly during the
evaluation unless more serious conditions are discovered.
Occasionally, APCs may set up a re-entry cycle between the atria and
ventricles. This would result in a tachyarrhythmia as noted below and has
more significant implications for certification.
Conditions-Ventricular Premature Complexes (VPC, VPB, PVC)
Like APCs, over 60% of normal
adults will have ventricular premature contractions (VPCs) on a 24 hour
Holter monitor study. Greater than six Ventricular Premature Complexes per
minute are abnormal. The symptoms of VPCs are similar to those of APCs,
although the pause after a premature beat tends to be longer and the
subsequent contraction is more forceful. VPCs may occur in isolation, in
pairs or triplets, alternating with regular beats (bigeminy) or in other
regular sequences with normal beats. The VPCs may arise from a single
location in the ventricle (isomorphic) or from several different locations
(polymorphic) . The ECG representation is a wide QRS complex of greater
than 0.12 seconds.
"Runs" of VPCs greater than three consecutive complexes is termed
ventricular tachycardia (see below). This is a serious and potentially
life threatening condition. More frequent and polymorphic ventricular
premature beats (VPBs) also represent more significant heart conditions
that should be evaluated without delay. Pilots with ventricular
tachycardia are disqualified from flying pending evaluation and treatment.
Those with a single isolated VPB on ECG may continue to hold a medical
certificate, but should expect to receive a requirement from the FAA for a
cardiovascular evaluation as noted in the section above.
and Heart Blocks
Bradyarrhythmias (slow) generally
arise from some type of failure of the conducting system to conduct
signals in the normal sequence or through normal pathways. Frequently,
these failures to conduct signals are termed "heart blocks."
and Heart Blocks-First Degree Heart Block
First degree heart block is
generally a benign condition that does not require treatment and does not
have any symptoms associated with it. The electrical signal is delayed in
the AV node prior to being propagated to the ventricles. Electrically, it
is characterized by a P-R interval of greater than 0.2 seconds. Many
aerobically conditioned athletes will have 1st degree heart block at
resting heart rates. With minimal exercise, the heart rate will increase,
shortening the duration of each phase of electrical activity. When the PR
interval is less than 0.12 seconds, the 1st degree heart block is not
present. Pilots who have slow resting pulses who are concerned about this
normal variant in the ECG on their FAA physical can usually eliminate this
finding by jogging in place for about 30 seconds prior to taking their ECG.
First degree heart block has no effect on FAA medical certification.
and Heart Blocks-Second Degree Heart Blocks Ė Type 1 and Type 2
There are two types of 2nd degree
heart block, called Type 1 and Type 2. Both are manifestations of
intermittent failure to conduct the atrial electrical signals to the
ventricles. Type 1 is also called "Wenckebach". The 2nd degree, Type 1
heart block manifests by a progressive lengthening of the PR interval
followed by a skipped ventricular contraction or "missed beat". The
implications of the two different types of 2nd degree heart block are
Wenckebach is similar to 1st degree heart block in that it generally
represents a benign condition that does not require further evaluation in
an individual without heart symptoms. Like 1st degree heart block, there
is a delay in the conduction through the AV node. In second degree Type 1
block, the delayed conduction is progressively longer with each beat until
a beat is not conducted to the ventricles, or "blocked". The Guide to
Aviation Medical Examiners specifies a cardiovascular evaluation if 2nd
degree, Type 1 heart block shows on a pilotís ECG. If no evaluation is
done and the certificate is issued, the FAA may request a cardiovascular
evaluation, but would not ground the pilot during the evaluation.
Second degree, Type 2 heart block is a more serious condition that may
represent significant heart disease. It is characterized by delays in the
AV node and randomly dropped ventricular beats (as opposed to
progressively longer PR intervals). Individuals may get lightheaded, have
chest pain, anxiety, loss of consciousness (Adams-Stokes attacks) or chest
pain if the number of dropped beats is significant. It may progress to
Third Degree (complete) heart block. This condition generally precludes
FAA medical certification until the underlying cause is corrected. Often,
a cardiac pacemaker is indicated to prevent possible loss of consciousness
or sudden cardiac death. Pilots with cardiac pacemakers may be waived for
any class of medical certificate, if no other underlying heart disease is
and Heart Blocks-Third Degree (Complete) Heart Block
Complete heart block is a very
serious medical condition that generally requires immediate placement of a
cardiac pacemaker as a life saving intervention. In this condition, the
atria and ventricles function independently because of a complete
breakdown in the heartís electrical conduction system. Because of the slow
intrinsic rate of the ventricles, usually 20-40 beats per minute, the
individual can not produce enough blood flow to maintain consciousness in
most situations, and may even have the heart stop beating. This condition
is obviously disqualifying for FAA certification, but correction with a
pacemaker may allow a Special Issuance medical certificate in rare
and Heart Blocks-Bundle Branch Blocks
Bundle branch blocks are delays in
the electrical conduction system below the level of the AV node, in the
His-Purkinje system. In most cases, bundle branch blocks are not serious
in themselves, but may indicate more serious underlying disease. Delay of
signal conduction down the right bundle of the His-Purkinje system is
termed "right bundle branch block". The Guide to Aviation Medical
Examiners does not disqualify right bundle branch blocks unless they are
"newly acquired". New right bundle branch blocks require evaluation with
radionuclide stress test, since standard stress tests are uninterpretable.
In most cases, they are benign and pilots may fly with this finding.
Because the left sided conducting system has dual bundles, it is possible
to get a left "hemiblock" of the anterior or posterior bundle. The new
onset of a left bundle branch block may represent an early warning sign of
coronary artery disease. If found on an FAA ECG, it is disqualifying until
underlying heart disease is excluded.
and Heart Blocks-Sick Sinus Syndrome
Sick Sinus Syndrome (SSS) is not a
single ECG finding, but rather a constellation of findings that indicate a
failing sino-atrial node (the natural pacemaker) and the atrio-ventricular
node (natural back-up pacemaker). SSS is characterized by very slow and
very rapid heart rates (tachy-brady syndrome), irregular heart rates and a
variety of symptoms in individuals. Symptoms may range from fainting,
dizziness, chest pain and skipping beats. People with SSS may experience
strokes, heart attacks and sudden death. The treatment for SSS is
implanting a cardiac pacemaker. See American Family Physician for an
excellent article and information handout on the subject.
Syndrome - Wolff-Parkinson-White (WPW)
The most common syndrome that
predisposes people to tachyarrhythmias is termed WPW syndrome. It is
caused by the presence of by-pass electrical conduction pathways around
the AV node. This signal is characterized by an upsloping "delta wave" on
the ECG just prior to the QRS complex. Normally, the electrical signal to
the ventricles dissipates and the next signal originates from the SA node.
In WPW, the electrical discharge of the ventricles is conducted back
through the by-pass tracts and around the AV node to set up what is termed
a retrograde re-entrant arrhythmia. These tend to cause very fast
arrhythmias. In 5% of WPW, the signals travel from the atria around the AV
node through the by-pass tracts to the ventricles. The QRS complex is
widened and the rate is also fast.
Several treatment options exist for people with WPW. Many individuals with
WPW will not have any arrhythmia and do not require any treatment. The FAA
Guide to Aviation Medical Examiners does not disqualify pilots with WPW
who have not had a significant arrhythmia from holding any class of
medical certificate. Those with arrhythmias will require control of the
condition before medical certification.
The first treatment is with oral medications to slow electrical conduction
across the by-pass tracts. These medications include beta blockers,
calcium channel blockers, quinidine or flecanide. A second option involves
ablation, or destruction, of the by-pass tract using a radiofrequency
catheter. If successful, this procedure offers a potential permanent cure
to WPW caused arrhythmias, usually without the need for medications.
Complications of the procedure are rare, but may require placement of a
pacemaker. FAA medical certification is possible with both treatment
Tachyarrhythmias-Atrial Fibrillation and Atrial Flutter
The most common arrhythmia in
pilots requiring an FAA mandated cardiovascular evaluation is atrial
fibrillation. Up to 2 million Americans are afflicted with atrial
fibrillation each year. Approximately 4% of the adult population will
experience atrial fibrillation in their lifetime. In this phenomenon, the
upper chambers of the heart (atria) fibrillate, or quiver, rather than
contracting sequentially. The AV node receives multiple inputs from many
locations in the atria and sends irregular and frequent signals to the
ventricles to contract. If the signals are transmitted rapidly, the
resultant ventricular rate is very rapid and blood flow to the body is
reduced because the left ventricle contracts before it can fill with
The ECG representation of atrial fibrillation is the absence of a distinct
P wave and "irregularly irregular" (random timing of heart beats) QRS
complexes. An individual may note a very irregular heart rate, usually
somewhat fast. In more serious cases, an individual may get lightheaded,
have extreme fatigue, feel extreme anxiety, have chest pain or lose
consciousness. Atrial fibrillation also puts and individual at risk for
clots forming in the heart and causing strokes when they break loose into
Atrial flutter is very similar to atrial fibrillation, but is
distinguished by a very rapid atrial rate (about 300 beats per minute) and
a variable ventricular response. The ventricular response may be regular
or irregular and frequently has a rate of about 150 beats per minute. The
clinical implications and symptoms of atrial fibrillation and flutter are
Tachyarrhythmias-Atrial Fibrillation and Atrial Flutter-Treatment
Atrial fibrillation (AF) and
flutter can be treated in several ways, often depending on associated
heart conditions, tolerance of the arrhythmia and response to medications.
Each of the treatment options is acceptable for waiver by the FAA, once
control of the arrhythmia and exclusion of underlying heart disease are
documented. An editorial on treatment strategies for atrial fibrillation
in available in the May 10, 2001 issue of the New England Journal of
Medicine. Also see an excellent article in American Family Physician
"Acute Management of Atrial Fibrillation: Part I. Rate and Rhythm Control"
July 15, 2002 and an editorial May 15, 2004 on Management of Newly
Detected Atrial Fibrillation and the Practice Guidelines on the same
subject for the most current evidence based medicine on the subject.
The first treatment option is to
allow the atrial fibrillation to spontaneously convert to a normal sinus
rhythm. Many instances of atrial fibrillation are short-lived, minutes to
hours, and then return to a normal state. Often no medication is required
to sustain the normal rhythm.
A second procedure is termed
pharmacological cardioversion. Treatment with single doses of intravenous
or oral forms of medication may convert AF to NSR. If this treatment is
successful, often long term medication for control is not required as
above. For the individual with recurrent bouts of AF, many medications can
be used to control this rate and/or the rhythm. (see Medications below)
If the AF results in a very fast
ventricular rate, an individual may experience lightheadedness, dizziness,
loss of consciousness, chest pain or a heart attack. In these instances,
there is a sense of urgency in conversion to a normal rhythm to eliminate
or reduce symptoms. The use of direct electrical current, with or without
medication, is the fast way to return the heart to a normal rhythm. This
procedure is called electrical cardioversion. Situations requiring
electrical cardioversion usually are treated with long term medication to
suppress future episodes of AF. The FAA requires a three-month observation
period following electrical cardioversion before returning to flying
At times, the individual with AF may not
experience significant symptoms with the condition , or may not convert to
NSR with medications, but have a controlled ventricular rate (less than
90-100) with the use of alternate medications. In these situations, the
recommended course of treatment may be short-term (several weeks)
anticoagulation with a blood thinning mediation, usually Coumadin, while
pursuing an investigation of possible provocative factors. The reason for
anticoagulation is to prevent clots from forming in blood stagnating in
the atria. These blood clots could break loose and travel to the brain
causing a stroke or to the lungs (pulmonary embolus).
Once achieving adequate anticoagulation and the documentation of the
absence of any atrial clots (thrombi), an elective electrical
cardioversion is done under controlled circumstances. With the use of
anti-arrhythmic medications before the cardioversion, one or two
electrical shocks may be enough to achieve a normal sinus rhythm in a
previously refractive AF. If the NSR is sustained for several weeks on
anti-arrhythmic mediation, the anticoagulation is discontinued and blood
clotting times return to normal in one to two weeks.
Atrial Fibrillation with
Occasionally, all of the above
treatment options fail to convert the AF to NSR. Three additional options
exist. If the heart rate can be maintained at normal rates (60-80 bpm
range) with medication, permanent anticoagulation to reduce the risk of
strokes and emboli may be necessary. Because the anti-clotting medication,
Coumadin, is very sensitive to many foods and medications, regular
monitoring of the blood thinning effects is necessary. The laboratory
reports followed are the prothrombin time (PT) or International Normalized
Ratio (INR) with the dose of Coumadin adjusted to keep the PT/INR in a
range of two to three times greater than that of the normal individual who
is not anticoagulated.
Even those people who convert from atrial fibrillation to normal sinus
rhythm are often placed on aspirin, a weak anticoagulant, designed to
reduce the risk of stroke if the atrial fibrillation were to recur. This
decision of whether to use aspirin or Coumadin depends on the risk factors
present in the individual with atrial fibrillation. See an excellent
article in American Family Physician Acute Management of Atrial
Fibrillation: Part II. Prevention of Thromboembolic Complications July 15,
2002 for more specifics.
Mapping the electrical conduction
pathways of the heart is increasingly common in the evaluation of
arrhythmias. The electrical procedure, termed an electrophysiologic (EP)
study, involves the use of a wire catheter inserted into the blood vessels
of the inner thigh and guided into the heart. If an accessory tract, or
alternate pathway, that may conduct electrical signal abnormally through
the heart is discovered, the electrophysiologist will attempt to eliminate
the pathway. The accessory tract is initially stimulated to determine if
the stimulation will trigger an arrhythmia. If the arrhythmia is
"inducibleí, a radiofrequency ablation of the tract may be possible. A
successful ablation procedure permanently eliminates one potential source
of the arrhythmia by inducing an electrically dead area in the heart,
analogous to a road block for the arrhythmia. Not all ablation attempts
eliminate the arrhythmia, but those that do generally allow the individual
to discontinue use of anti-arrhythmic mediation. The FAA currently
requires a three-month observation period following ablation before
requesting a Special Issuance medical certificate.
A third alternative treatment to
suppress symptomatic arrhythmias is to insert a pacemaker. The electrical
pacemaker "over drives" the heart to beat at a fixed rate, making it less
susceptible to the multiple stimuli originally causing the arrhythmia.
This technique employed with increasing frequency, and is potentially
waiverable by the FAA. A comprehensive review of the subject of pacing and
defibrillation for atrial arrhythmias was published in the New England
Journal of Medicine in June 2002, Current Concepts: Implantable Devices
for the Treatment of Atrial Fibrillation, J.M. Cooper et al.
Some newer pacemakers have an Automatic Internal Cardiac Defibrillator as
an elective component of the device. Current FAA policy does not allow
certification for any rhythm if an AICD is used, no matter how good the
control. This policy is being reviewed, and to date there are a handful of
A recent development in the
treatment of refractory, symptomatic atrial fibrillation is a surgical
approach called the Maze procedure. This open heart surgery involves
making a long incision in the heart and sewing it back together. The
healing incision blocks the irregularly conducted heart beats to stop the
atrial fibrillation. A newer form of the Maze procedure does not include
open-heart surgery, but uses a radiofrequency ablation catheter to achieve
the same results. The FAA has granted waivers to pilots who have undergone
the Maze procedure to control atrial fibrillation successfully.
Control Atrial Arrhythmias
Several categories of medications
are used to control rates of arrhythmias or suppress the arrhythmias. In
most cases, the same medication used to control atrial fibrillation may be
used to control other atrial arrhythmias or supraventricular tachycardias.
Digoxin, from the foxglove or digitalis plant, slows conduction of
electrical signals across the AV node, thus giving a slower ventricular
rate in atrial fibrillation. Digoxin may also suppress the atrial
fibrillation. Digoxin may obscure the ECG interpretation of a plain stress
test, thus leading to the possibility of a radionuclide stress test to
rule out underlying coronary heart disease as a cause of the atrial
Another class of mediation that slows the ventricular heart rate in atrial
fibrillation, but does not suppress the fibrillation, is beta-blockers.
These include propranolol (Inderal) and metoprolol (Lopressor).
This class of medication is sometimes used in combination with digoxin to
control the ventricular rate and eliminate most symptoms of AF that have
not responded to pharmacological or chemical cardioversion attempts.
Most people who experience atrial fibrillation that does not spontaneously
convert are offered one of several classes of anti-arrhythmic medications.
Some commonly used medications include mexilitene, flecanide, amiodorone,
sotalol, verapamil and diltiazem.
The goal for these medications is to sustain a normal sinus rhythm after
chemical or electrical cardioversion. Often, if an individual has episodes
of AF, but is free of any further recurrences for 6-12 months, the
medication may be discontinued. After stopping the medication, an
individual is monitored closely for further occurrence. If there are no
further episodes, the anti-arrhythmic medication is permanently
discontinued. Recurrences trigger resumption of the medication, usually on
a permanent basis.
The FAA Aeromedical Certification Division does not dictate what
medication regimens must be used in individual cases to qualify for a
waiver. All treatment decisions remain between the pilot and treating
physician. The FAA does not even require an evaluation by a cardiologist,
although specialists may be able to arrange evaluations more conveniently
than other physicians without immediate access to testing equipment.
Assuming documentation of the arrhythmia control and the absence of other
types of hear disease is complete, FAA follow-up reports can easily be
completed by most primary care physicians. The overwhelming majority of
pilots who experience uncomplicated atrial fibrillation can expect
clearance by the FAA after a complete evaluation and continued medical
certification in the future.
Like atrial arrhythmias,
ventricular arrhythmias generally represent the non-coordinated beating of
heat muscle resulting in inefficient pumping of blood through the heart.
Unlike most atrial arrhythmias, ventricular arrhythmias are generally very
serious and may have life threatening implications. Other than the second
and third degree heart blocks, previously noted, there are two basic types
of ventricular arrhythmias.
Ventricular tachycardia (VT or V
Tach) is the rapid beating of the heart at rates greater than 100 beats
per minute, paced by a ventricular source rather than the SA node or
atria. The QRS complex of the ECG is wide (greater than 0.12 seconds) and
often inverted from the standard pattern. Some people may survive short
periods of VT (up to several minutes), but blood flow to the body and
brain is rapidly compromised followed by loss of consciousness in most
sustained episodes. Short bursts of VT (several seconds duration),
frequently represents strings of consecutive PVCs, that may spontaneously
revert to NSR. However, VT may degenerate into ventricular fibrillation, a
rapidly fatal condition.
Ventricular fibrillation (VF or V
fib) is the usual mechanism for loss of consciousness and death in "heart
attacks." The treatment for VF is rapid (within 3-4 minutes) electrical
countershock back into a more life sustaining rhythm. Following successful
countershock, immediate stabilization with oxygen, anti-arrhythmic
medication and treatment of the underlying cause, is required. People who
are successfully resuscitated from VF are termed "sudden cardiac death
The most common underlying cause of VF is coronary artery disease (see VFS
section on this topic). Other causes include electrocution, hypoxia and
other forms of heart disease including Arrhythmogenic Right Ventricular
Dysplasia. In correctable causes of VF, the risk of sudden cardiac death
can be minimized.
The traditional, long term treatment for ventricular arrhythmia involve
correcting the underlying cause and preventing future occurrence with
medication. After an appropriate observation period following successful
correction of the cause, many pilots may be returned to flying through the
Special Issuance provisions of the FAR 67.401 on medication.
One increasingly common "treatment" for ventricular arrhythmias is the
surgical placement of an Automatic Internal Cardiac Defibrillator, or AICD.
This implanted device monitors the rhythm with sensors on the heart. If a
ventricular arrhythmia is sensed, the AICD delivers a shock directly to
the heart muscle through two "paddles" implanted on the heart. The shock
is designed to reset the heart electrical state so that a sinus rhythm can
take over. If no spontaneous rhythm is generated, the AICD works with a
pacemaker to attempt to generate a life-sustaining rhythm. AICDs can be
"interrogated" periodically to see if any abnormal rhythms have occurred,
whether shocks were delivered and whether the pacer was required. The
March 21, 2002 issue of the New England Journal of Medicine has both a
review and an editorial on the use of AICDs.
The current FAA policy does not permit AICDs for any class of
certification, nor is any major change in this policy anticipated in the
foreseeable future. This non-certification policy for pilots with AICDs is
true even for pilots who have had the devices placed prophylactically, but
never discharged, as in conditions such as Arrhythmogenic Right
Ventricular Dysplasia (ARVD). As previously noted, however, there have
been a select few certifications in exceptional cases.
A third type of abnormal
ventricular rhythm is asystole, the absence of any rhythm or heart beat.
This condition is rapidly fatal in the absence of CPR and usually is seen
in the seconds before death in an unsuccessful attempt at resuscitating
other ventricular arrhythmias. FAA certification is not relevant.
Overall, the FAA has a relatively
liberal policy of certifying pilots with many types of arrhythmias,
excepting those with AICDs. Most treatments, including coronary
revascularization, anti-arrhythmic medications and pacemakers, may be
considered for Special Issuance medical certification by the FAA. After
stabilization with treatment prescribed by the pilotís treating physician,
submission of complete documentation to the FAA is critical for favorable
certification decisions. Periodic follow-up reports are routinely required
for pilots maintained on anti-arrhythmic medications or with pacemakers.
The FAA requires any pilot with a history of atrial and ventricular
arrhythmias to complete a cardiac evaluation before a certification
(waiver) decision is considered. Favorable certification decisions result
when the arrhythmia is well controlled or eliminated and no evidence of
other heart disease exists. The evaluation is relatively standard for all
types of arrhythmias.
The routine evaluation required by the FAA involves completing the tests
in the FAA Specifications for Cardiovascular Evaluation, FAA Form 8500-19.
The documentation should include an evaluation of any cardiac history,
risk factors for cardiovascular disease, a focused physical examination
and laboratory studies. Risk factors for heart arrhythmias that can be
eliminated, such as stimulants, medications, caffeine, tobacco, alcohol
and herbal products (ma huang/ephedra) found in many weight loss products,
should be halted. The lab studies include a fasting blood sugar,
cholesterol, triglycerides, electrolytes and a complete blood count.
Because hyperthyroidism is a relatively common cause of arrhythmias,
laboratory studies of thyroid hormones is routine. Other labs tests may be
indicated based on historical or physical factors.
Cardiac specific studies required include an echocardiogram to exclude
structural heart abnormalities, as well as clots. After the arrhythmia is
controlled, an exercise stress test and a 24-hour Holter monitor are
required. The stress test (treadmill) detects evidence of coronary artery
disease as a possible cause of the arrhythmia. If the stress test is
abnormal, further, more definitive studies are required such as a
radionuclide stress test or coronary angiography. (See VFS Section on
Coronary Artery Disease).
The Holter monitor should demonstrate control of the atrial fibrillation
or other arrhythmias, either by elimination of the abnormal rhythm for the
routine 24-hour period or by continuous control of the rate of ventricular
beats to less than approximately 100 bpm (60-80 bpm is the desirable
range). Resting heart rates greater than 100 bpm and non-resting heart
rates greater than 130-140 as disqualifying for certification, as are
pauses longer than 3.0 seconds.
If anticoagulated with blood thinners such as Coumadin, control of the PT
or INR to 2-3 times normal on at least three consecutive reports is
required for certification. It may take several months to find a dosage
schedule of Coumadin to keep the PT in the therapeutic range. For
continued certification, 80% of INRs need to be in the therapeutic range.
Pilots treated with electrical cardioversion may be considered for Special
Issuance Authorizations after a three-month observation period.
Pilots undergoing radiofrequency ablation of an arrhythmia-inducing
electrical tract can be considered for waiver after a three month
observation period and a Holter monitor showing no further arrhythmias.
Generally, follow-up reports are not required after initial waiver.
If a pilot has a pacemaker, monthly pacer checks for two months will also
be required before the FAA will consider recertification. Occasionally, an
electrophysiologic study, or electrical map of the heart, may be conducted
by a cardiologist in refractory cases of arrhythmias. If done, the FAA
will request the results of these studies. Other tests may be required
depending on the nature of the condition. Follow up of pacemaker
surveillance depends of the type of pacer (single or dual chamber) and age
of the pacemaker.
Go to the 'FAA Guide to Aviation Medical Examiners' on heart
conditions provides additional information on evaluations required.
Pilots with arrhythmias may obtain the required documentation from their
treating physicians and mail it to the FAA Aeromedical Certification
Aeromedical Certification Division, AAM-300
Civil Aeromedical Institute, FAA
P.O. Box 26080
Oklahoma City, OK 73126-0080
However, without careful review, direct submittal often can result in
significant delays in certification while the FAA asks for clinical
clarification. Often well-meaning specialists who are not trained in
aerospace medicine fail to address all the aeromedically important aspects
of a particular case. As a result, the case is returned without action
pending further documentation, or worse the pilot receives a potentially