Stephen J Pettit [1], Giles Roditi [2], Scott
Davidson [3]
Department of Cardiology [1], Department of Radiology [2],
Department of Respiratory Medicine [3], Glasgow Royal Infirmary,
Glasgow, G4 0SF, United Kingdom
Correspondence to:
Dr Scott Davidson
E-mail: scott.davidson@sgh.scot.nhs.uk
Key words:
Heart block, Cardiac Metastasis, Lung Neoplasms
ABSTRACT
We report the case of a 73 year old female who presented with recurrent
short-lived episodes of loss of consciousness.
She had complete heart block due to a cardiac metastasis within the
interventricular septum from a probable primary carcinoma of the lung.
This metastasis was not detected on echocardiography but was identified
on computed tomography imaging. Cardiac
metastases are an uncommon clinical problem, but are present at post mortem
examination in up to 25% of patients who die of malignant disease.
Detailed assessment of cardiac anatomy should be considered when
individuals present with complete heart block and possible malignant disease.
INTRODUCTION
Cardiac metastases are present in up to 25% of patients who die of
malignant disease in published series of post-mortem examinations.[1]
The most common primary tumours are carcinomas of lung, breast and
oesophagus, melanoma, lymphoma and leukaemia.
However, cardiac metastases rarely contribute to the clinical
presentation or progression of malignant disease.
We report the case of an elderly female that presented with complete
heart block and was found to have a cardiac metastasis within the
interventricular septum from a probable primary carcinoma of the lung.
CASE
REPORT
A 73-year-old female patient with a past history of epilepsy and
hypertension was admitted with recurrent short-lived episodes of loss of
consciousness. Significant
bradycardia was noted in the emergency department. Continuous electrocardiogram monitoring showed complete heart
block with a broad QRS escape rhythm (figure one). Periods of asystole, lasting 5-10 seconds and associated with
a transient loss of consciousness, were observed. The patient was treated with intravenous atropine and a
temporary pacing line was inserted.
Transthoracic echocardiography showed a small rim of pericardial fluid,
hypokinesia of the inferior wall but no structural cardiac abnormality.
A chest radiograph showed a cavitating mass in the left upper zone.
She was treated with broad-spectrum antibiotics.
Sputum and blood was sent for microscopy and culture.
Further periods of asystole, up to 20 seconds in duration, were witnessed
and a permanent pacing system was implanted.
Intravenous contrast enhanced helical computed tomography (CT, 4 detector
row) scan of thorax and abdomen was subsequently performed.
This confirmed a large cavitating pulmonary mass in the left upper lobe.
There were eleven sub-centimetre pulmonary nodules and two intra-hepatic
masses. A 2.5cm cardiac mass was
revealed within the basal interventricular septum, hypoattenuating with respect
to normally enhancing myocardium and protruding into the cavity of the right
ventricle (figure two). These
findings were consistent with a primary cavitating lung neoplasm with cardiac,
hepatic and lung parenchymal metastases. Malignant
cells were not identified by sputum microscopy. Bronchoscopy was performed, but did not yield a histological
diagnosis. The patient declined
CT-guided biopsy and was discharged with the support of her family.
She died several months later and did not undergo a post mortem
examination.
DISCUSSION
Cardiac involvement in malignant disease has been described in several
autopsy series.[2-5] In the largest
series, Lam et al reviewed 12485 consecutive autopsies and reported the
frequency of cardiac tumours. They
identified primary cardiac malignancy in 0.056% of cases and secondary cardiac
malignancy in 1.23% of cases.[3] Several
smaller autopsy series have reported evidence of cardiac metastases in up to 25%
of patients who had died of malignancy.[1]
Metastases have been identified from several histological types of
tumour. In a review of four large
autopsy studies, the most common primary tumours were carcinomas of the lung,
breast and oesophagus, melanoma, lymphoma and leukaemia.[1]
The incidence of lung carcinoma differed in each autopsy series, but was
the primary tumour in 7.4% to 36.4% of patients with cardiac metastases.[2-5]
Secondary cardiac malignancy may present with cardiac tamponade, cardiac
failure or conduction abnormalities. However,
cardiac metastases are usually clinically silent. There are three published case
reports of lung cancer presenting with complete heart block caused by cardiac
metastases.[6-8] Buckberg et al
described a 42 year-old male who presented with dyspnoea, haemoptysis and
complete heart block in the era before echocardiography and CT imaging.
A clinical diagnosis of bronchial carcinoma with probable cardiac
infiltration was confirmed at post mortem examination.[6]
Matturi et al described a patient who presented with complete heart block
and was implanted with a permanent pacemaker.
Transthoracic echocardiography was unremarkable.
The patient died unexpectedly and a bronchial carcinoma with metastases
in the bundle of His was identified at post mortem examination.[7]
Mocini et al described a 44 year-old male who presented with syncope and
complete heart block. Transthoracic
echocardiography and CT imaging showed a small pericardial effusion, bilateral
pleural effusions and widespread lymphadenopathy.
This patient also died unexpectedly and a bronchial carcinoma with
cardiac metastases was identified at post mortem examination.[8]
In all three case reports, the cardiac metastases were only identified at
post mortem examination and not diagnosed ante mortem as the cause of the
conduction abnormality. There are
published case reports of ante mortem identification of cardiac metastasis of
other histological types of tumour, which have enabled diagnosis of patients who
have presented with complete heart block. Aleksic
et al described a 59 year-old female who presented with dyspnoea, fever, malaise
and complete heart block. Transoesophageal echocardiography and CT imaging showed a
retrocardiac tumour with extensive direct cardiac invasion.
Diagnostic thoracotomy was performed and histology revealed a B-cell
lymphoma.[9]
The limitation of this case report is that we were unable to obtain a
histological diagnosis, either ante or post mortem. An appropriate differential diagnosis for this case includes
Wegener’s granulomatosis, cavitating pneumonia, septic embolisation and
alternative primary tumours. The CT
findings of a single large ill-defined cavitating pulmonary mass and eleven
smaller discrete pulmonary nodules suggests primary lung cancer with pulmonary
metastases. No alternate primary
tumour was identified within the thorax or abdomen.
No organism was cultured from blood, sputum and broncho-alveolar lavage.
No clinical response to antibiotic therapy was seen.
Renal function and urine dipstick testing were normal. It is not possible to exclude our differential diagnoses but
we believe that a primary lung cancer is the most likely diagnosis.
We report the case of a 73-year-old female who presented with complete
heart block and was found to have cardiac metastases from a probable primary
carcinoma of the lung. This is the
first case in which lung cancer has presented with complete heart block and the
complete diagnosis was made ante mortem. The
myocardial metastasis within the interventricular septum was identified by CT
scanning but not by transthoracic echocardiography.
CT technology is evolving with faster gantry rotation times and thinner
collimation. Routine thoracic CT
studies now reveal cardiac pathology, such as myocardial infarction and
intraventricular thrombus, not previously seen due to motion blurring and
partial volume averaging.[10] Radiologists need to be alert to cardiac pathology that will
be revealed on routine CT studies. Detailed
assessment of cardiac anatomy should be considered when individuals present with
complete heart block and suspected malignant disease.
LEARNING
POINTS
Cardiac
metastases are a rare clinical problem
Locally
invasive or metastatic tumours can cause conduction abnormalities
Cardiac
metastases should be considered when individuals present with complete heart
block and suspected malignant disease
Modern CT scanning may reveal cardiac pathology not previously identified by echocardiography