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uncommon finding in younger pilots.
Patients with sinoatrial disease may remain relatively or completely free of symptoms for many years or
may become symptomatic quite rapidly. For this reason, regular review with exercise ECG (seeking
chronotropic incompetence — an attenuated exercise heart-rate response) and Holter monitoring1 is
justified. Echocardiography should confirm the continuing structural integrity of the heart. Restriction to
multi-crew operation is preferable, unless the disturbance is no more than minor and the pilot is
asymptomatic. Once symptoms occur, certification to fly should be denied.
Atrial tachyarrhythmia
The abrupt onset of rhythm disturbances may be both alarming and distracting and is a cause of
incapacitation, subtle or obvious. If the rate is very rapid, then systemic hypotension may occur and lead
to altered consciousness. If there is structural abnormality of the heart, such as myocardial hypertrophy
with associated impairment of diastolic function, the disturbance may be tolerated poorly. With increased
atrial or ventricular internal diameters, the risk of thromboembolic stroke increases. The disturbance,
underlying structural abnormality (or non-structural cause) and outcome all need to be considered in the
context of certification.
Atrial fibrillation (AF) is the most common rhythm disturbance causing intermittent or persisting
symptoms. It is often associated with structural abnormality of the heart and has as its basis continuous
wave fronts of depolarisation arising mainly in the left atrium. It has a prevalence in the population of 0.4
per cent in those < age 60 years, two to four percent in those aged 60 to 80 years, and > ten per cent in
1 Holter monitor: an ambulatory ECG device for monitoring and recording heart activity for 24 hours or more. After
Norman J. Holter, American biophysicist (1914-1983).
ICAO Preliminary Unedited Version — October 2008 III-1-22
those > age 80 years. It may be associated with cardiovascular disease, there may be an extra-cardiac
cause (i.e. secondary to hyperthyroidism), or it may be “lone” - without obvious pathology. Common
causes of atrial fibrillation are shown in Table 2 and an example in fig 4.
Table 2.— Common causes of atrial fibrillation (AF)
AF with cardiovascular disease
AF with extra-cardiac disease
Lone AF
Hypertension
Infection
Coronary artery disease
Alcohol abuse
Valvar heart disease
Thyrotoxicosis
Myocardial disease
Electrolyte disturbance
Congenital heart disease
Pulmonary disease
Cardiac surgery (recent and remote)
Pericarditis
The clinical management of atrial fibrillation involves identification of cause with reversion to sinus
rhythm, if possible, either pharmacologically or by DC shock. The European Atrial Fibrillation
Consensus Conference in 2003 suggested that management be directed towards the maintenance of sinus
rhythm or regulation of the heart rate. Anticoagulation will be required > age 65 years, and/or in the
presence of structural abnormality of the heart, hypertension and/or enlargement of the left atrium.
Anticoagulation disqualifies from all classes of medical certification in many States, but not all.
The following presentations of atrial fibrillation are seen:
• Single episode with a defined cause, e.g. vomiting
• Paroxysmal atrial fibrillation, defined as more than one self-terminating episode, usually of <24
hours’ duration.
• Persistent atrial fibrillation, in which the return to sinus rhythm occurs only following therapeutic
intervention. The duration is > seven days.
• Permanent atrial fibrillation, in which a return to sinus rhythm cannot be accomplished or has not
been attempted. The duration is >12 months.
The condition commonly comes to light in one of two ways in the aviation scene: the rhythm is
uncovered by ECG at routine examination or the aviator presents with symptoms. In general,
pharmacological cardioversion with an agent such as flecainide is most likely to be successful if
undertaken in the first few hours after the onset of the episode. A DC shock may be needed. Overall, 50 to
80 per cent will return to sinus rhythm by such means in the first attack, depending on the presence or
absence of other pathology, and the duration of the attack. All attempts at cardioversion require
anticoagulation with warfarin and the maintenance of the international normalized ratio (INR) at 2.5 to
3.0 for one month. This is required beforehand and afterwards, unless undertaken within 24 hours of onset
or if the left atrial appendage is demonstrably free of thrombus at trans-oesophageal echocardiography
(TOE). Before attempting cardioversion, the thyroid-stimulating hormone (TSH) level should be
　
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