Download case report1

Title: chest pain with intermittent LBBB in athlete.
Dr.I Berekat MRCP, S.Duggan MBBCH, Dr. A Azzu MRCP, Dr. M Payne FRCP.
Cardiology Department, Gwynedd Hospital, Bangor, UK LL57 2PW
Keywords: LBBB in Athlete people.
Introduction
Most athletes have a normal electrocardiogram, However ECG abnormalities can
occur in this group of people which reflects cardiac remodelling rather than
pathology. Amongst the most frequent changes in the surface ECG of athletes is
incomplete right bundle branch block which is usually due to increase in muscle mass
of the right ventricle. The occurrence of left bundle branch block is a rare finding
(And here we want to discuss this finding in more details).
Case Report
A 35-year-old fit and well gentleman was admitted to the coronary care unit (on the
10thJuly 2008) with a history of retro-sternal tightness chest pain for 20 minutes. He
had no significant past medical history and no family history of any cardiac illness.
He is a very active man, running 50 miles per week for almost 10 years.
Clinical examination showed blood pressure 117/68 mmHg, Pulse 68 bpm,
Temperature 37oC. Cardiac examination revealed audible first heart sound, normal
second heart sound and no murmur. Respiratory examination was clear. Abdominal
and neurological examinations showed no abnormalities.
His ECG in the Emergency Department at the time of admission as shown
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Dr.I Berekat MRCP
Figure 1: ECG in figure 1 shows he is in intermittent LBBB
Figure 2: is a repeated ECG taken approximately one hour later from the first ECG.
This shows he is back to normal QRS duration with high voltage in LV leads.
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Dr.I Berekat MRCP
The laboratory investigations including full blood count, urea & electrolytes, glucose
and liver function tests were normal. The creatinine kinase was 115 u/L, the
cholesterol measured 5.3, HDL 1.6 and LDL 3.4.
Given the history of chest pain and ECG changes, he was treated as a case of ST
elevation Myocardial Infarction and thrombolysed with Tenectoplase and
subsequently received; aspirin, Clopidogrel, ß-blocker, ACE inhibitor and a statin.
Both initial and 12hr troponin T were (<0.01) normal.
He underwent a treadmill exercise tolerance test where he completed 12 minutes of a
Bruce protocol with no pain or ECG changes or recurrence of LBBB.
Echocardiogram and coronary angiogram, both of which were normal. Hence he was
discharged.
Discussion:
ECG changes in athletes are a subject of great interest. ECG changes are mostly seen
in people who are participating in regular training. These ECG changes depend on the
types of sport and the intensity of training. There are usually no symptoms and any
symptoms that do occur are reversible when the training is stopped. With prolonged
training several structural changes in the athletic heart occur, including an increase in
the internal diameter of the left ventricular cavity of up to 10% in athletes doing
dynamic sports. A lesser dilatation (2.5%) is seen in those doing strength training.
Also left ventricular wall thickness appear to increase in all type of sport.
Predominantly eccentric hypertrophy in sport with high dynamic exercise and
concentric hypertrophy in strength athletes.5This wall thickness can increase to 29%
and 19% in sports with high dynamic and high static demand respectively.1
Both systolic and diastolic function is normal in athlete at rest whereas diastolic
function seems to be enhanced in the exercise endurance athlete.1
The ECG changes commonly seen in athletes are sinus bradycardia, which usually
results from an increase in vagal tone and decrease in sympathetic activity.2-4 Sinus
pause of more than 2 seconds are seen in more than one third of athletes.2 Various
degrees of heart block can occur including; Prolongation of P-R interval, Second
degree AV block ( Wenckeback phenomena ) and non- sinus escape rhythms.3 these
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Dr.I Berekat MRCP
normally do not require any attention as long as the athletes are asymptomatic and not
showing pauses exceeding 4 seconds.
Incomplete right bundle branch block is commonly seen, occurring in up to 14% of
all athletes. Left bundle branch and fascicular blocks are extremely rare.6
Increased pericardial ST segment elevation, and increased T wave amplitude is the
most frequent finding. Diphasic and inverted T wave and prominent U waves are
found in 30% of cases, ST segment elevation or early repolarization changes mainly
in the anterior leads.
Simple ventricular premature beats occur among athletes with the same frequency as
the general population, but usually disappear with exercise.2
The occurrence of complex ventricular arrhythmias is always pathological and should
prompt cardiovascular examination and investigation to find the underlying cause.2
Horizontal ST segment depression is extremely rare in athletes, and should be taken
as being pathological. Exercise induced sudden cardiac death in athletes is unusual
without pre-existing heart disease.6
The occurrence of LBBB is an extremely rare and when present it is considered an
abnormal finding in athletes.3Several studies has shown close relationship between
the development of coronary artery disease and transient LBBB induced by treadmill
exercise. Up to 50% of patient with exercise induced LBBB are thought to have
coronary artery diseases,7 and Rate dependent LBBB may be a reflection of
underlying myocardial dysfunction, intrinsic disease of the cardiac conduction tissue
or a compromised coronary circulation.8
There is a close relation between the heart rate at the onset of LBBB and the presence
or absence of CAD. In all patients with CAD LBBB developed at a heart rate of less
than 125 beats/min and Exercise induced LBBB at a heart rate of 125 beat/ min or
greater was more likely to develop in patients without CAD.8
Therefore the presence of normal coronary arteries can be predicted with increase
specificity by examining the exercise heart rate at the onset of aberrant conduction.8
Furthermore, Patients with normal coronary angiograms, chest pain and LBBB found
to have reversible anteroseptal perfusion defect on thallium-201 scintigraphy. The
authors have suggested that the perfusion defect in these patients could be due to
abnormal septal movement and thus represents functional ischaemia. It’s possible that
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the Presence of LBBB by itself can cause functional myocardial ischaemia
(microcirculatory ischeamia) through an increase in extra vascular coronary resistance
determined by the action of the asynchronously contracting septum on its coronary
branches.9
The prognosis in patients with LBBB and normal coronary artery is usually good.
However, group of patients may progress into permanent LBBB and very rarely into
atrioventricular block with the consequent need for permanent pacemaker
implantation.10
In summary we report an unusual case of a highly trained athlete who presented with
chest pain and conduction abnormalities on ECG. Initially treated as ST elevation
myocardial infarction. All his subsequent investigations were normal including
coronary angiography. The exact cause of his chest pain is not well understood but
most likely caused by the phenomenon of cardiac dyssynergy. It’s important to
exclude coronary artery disease as a cause for his chest pain and intermittent LBBB;
especially in his case he developed LBBB at heart rate of less than 125 beat/ minute,
as his subsequent management and long term prognosis is completely different. The
clinical significance and long term squeals of this changes remain to be determined.
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References:
1. Impact of different sport and training on cardiac structure and function.
Fagard
RH.
2. American Heart Journal.1990 Jun; 119(6): 1378-91. ECG variant and cardiac
Arrhythmias in athletes: clinical relevance and prognostic importance.
Zehender
M, Meinertz T, Keul J, Just H.
3. Sport Med. 1984 Sep-oct; 1(5): 390-403. The electrocardiogram and the
athlete.
Ferst JA, chaitman BR
4. Electrocardiographic alterations associated with the hearts of athlete’s. Holly
RG,
Shaffrath JD, Amsterdam EA.
5. The power athlete. Longhurst JC, Stebbins CL.
6. Rev Esp Cardiol, 1998 may; 51(5): 356-68. The athlete’s heart: most common
electrocardiographic finding. Boraita Perez A, Serratosa Fernandez L.
7. Exercise-induced left bundle branch block in treadmill exercise test: clinical
significance and prognosis]
Aoki T, Nishikawa H, Motoyasu M, Shimizu Y, Ono N, Unno M, Kakuta Y,
Konishi T, Nakano T.
8. Exercise-induced left bundle branch block and its relation to coronary artery
disease. Vasey C, O'Donnell J, Morris S, McHenry P.
9. Assessment of myocardial perfusion with thallium-201 scintigraphy in exerciseinduced left bundle branch block: diagnostic value and clinical significance.
La Canna G, Giubbini R, Metra M, Arosio G, Curnis A,
Cicogna R, Visioli O.
10. Exercise-Induced Left Bundle-Branch Block in Patients with
Coronary Artery
Disease versus Patients with Normal Coronary Arteries. Jaume Candell
Rieraa, Guillermo Oller Martíneza, Juan Vegaa, Enrique Gordilloa, Ignacio
Ferreiraa, Carlos Peñaa, Joan Castella, Santiago Aguadéa y Jordi Soler Solera.
aServicios de Cardiología y Medicina
Nuclear. Hospital Universitari Vall
d'Hebron. Barcelona. España.
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