Atrial Fibrillation in a Patient With Lung Cancer

Lung cancer is the most frequent cause of malignant pericardial effusion, accounting for 35% of reported cases.1 Pericardial effusions secondary to pericardial invasion can cause shortness of breath, orthopnea, tachycardia, chest pain and physical signs of tamponade.1 This article describes a rare case of metastatic squamous cell lung cancer causing a malignant pericardial effusion, which ultimately led to acute-onset atrial fibrillation with rapid ventricular rate.

Atrial fibrillation (AF) has been reported in patients who have undergone lobectomy for non-small cell lung cancer.2 We propose that atrial fibrillation may also be caused by extrinsic compression of the heart by the rapidly expanding tumor.

Figure 1: EKG demonstrating atrial fibrillation. All images courtesy the authors.

Presentation

 

A 68-year-old white man with a recently diagnosed lung mass and esophageal narrowing secondary to extrinsic compression of the esophagus presented to the emergency department with complaints of palpitations and shortness of breath for 3 days associated with a cough productive of yellow sputum.

On admission, the patient was found to have AF with a rapid ventricular rate. He began to acutely decompensate and required emergent intubation. A routine chest x-ray demonstrated a suspicious mass in the chest cavity. The patient was transferred to the medical intensive care unit and upon further evaluation with a computed tomography (CT) scan and an echocardiogram, a malignant pericardial effusion was identified. This likely accounted for his presenting symptoms of palpitations and shortness of breath.

SEE ALSO: E-Cigarettes: A Policy Statement

Lung cancer is the leading cause of cancer-related deaths in the United States and worldwide. The high rate of mortality results from both the high incidence and the late stage of disease at diagnosis,3 as seen with this patient, who also had a significant history of smoking. More than 70% of patients will be diagnosed with advanced disease that is not amenable to curative therapy.4 Only 15% of patients diagnosed with lung cancer survive 5 years.4

Lung Cancer Types

Non-small cell lung cancer (NSCLC) accounts for the greatest number of deaths from cancer in patients older than 60.4 As early as the 1950s, the causal relationship between tobacco smoke and lung cancer was well established. The relative risk for lung cancer in current smokers is approximately 11 to 17 times higher than that for people who have never smoked, although there is evidence for a dose-response relationship between smoking and lung cancer.4 Risk depends on the duration and amount smoked.4

Squamous cell carcinoma (SCC) is the second most common subtype of NSCLC, accounting for 34% of NSCLC.5 Of all the subtypes of NSCLC, the squamous cell variety has the strongest association with smoking. This tumor arises most frequently in the proximal bronchi. With time, these tumors tend to cause bronchial obstruction, with resultant atelectasis, pneumonia or pericardial effusions.

The signs and symptoms of lung cancer are related to the specific locations of tumor masses and the occurrence of paraneoplastic syndromes. The symptoms of centrally located lesions include cough, hemoptysis, wheezing, stridor, dyspnea and postobstructive pneumonia. Peripheral lesions can cause pain due to pleural or chest wall invasion, cough or restrictive dyspnea.6

AF is a common arrhythmia and its prevalence increases with age. It is usually associated with underlying heart disease (from almost any cause), complicated by heart failure and atrial enlargement. The most common underlying disorders are hypertensive heart

Figure 2: CT study from 1 month prior to presentation, showing likely tumor infiltration into the pericardium (CT Scout Film).

disease, coronary artery disease, valvular heart disease, hyperthyroidism and alcoholism.4 The majority of AF episodes are triggered by atrial ectopic beats from muscle fibers extending from the left atrium into the pulmonary veins.4

A Physical Examination

In addition to the symptoms described earlier, the patient reported an unintentional 50-pound weight loss in the prior month. He also complained of dysphagia and was only able to take in a liquid diet. The patient is a 50-pack year smoker. His past medical history is significant for deep venous thrombosis and recently diagnosed non-small cell lung cancer, squamous type, diagnosed 10 days prior to arrival to the ED. The patient was supposed to begin radiotherapy the day of the admission, but he was not able to keep the appointment due to the worsening symptoms.

The physical examination revealed an elderly man in respiratory distress. His vitals upon arrival were blood pressure 128/80 mm Hg, pulse 153 beats per minute, respiratory rate of 24 breaths per minute and an O2 saturation of 90% on room air. He displayed significant temporal wasting and had somewhat dry oral mucosa. His extremities exhibited trace pitting edema; weakened distal pulses were noted in the upper extremities.

The patient exhibited no clear evidence of jugular venous distension or carotid bruits, and his trachea was midline. His lungs revealed diffuse rhonchi. He had an irregularly irregular rhythm and a rapid ventricular rate, along with the EKG demonstrating AF (Figure 1).

Figure 3: Chest x-ray demonstrating an increased amount of opacification in the right lower lung, which included the known mass as well as probable new or accumulating pleural fluid and increasing atelectasis.

The patient was admitted to the medical intensive care unit and eventually required a left subclavian central venous line to maintain cardiovascular functions. He remained on mechanical ventilation due to acute hypoxic respiratory failure. Digoxin and amiodarone drip were initiated to control his atrial fibrillation and rapid ventricular rate.

A chest x-ray performed in the ED demonstrated an increased amount of opacification in the right lower lung, which included the known mass as well as probable new or accumulating pleural fluid and increasing atelectasis (Figure 2). A CT scan of the chest demonstrated massive lymphadenopathy within the mediastinum and hila, which had progressed from the prior study. A conglomerate mass in the subcarinal and right hilar space measured 11.9 x 10.1 cm (Figure 3), previously 9.4 x 8.0 cm (Figure 4). This resulted in narrowing of the right thoracic central airways with right lower lung atelectasis and a large right effusion. Echocardiography revealed a right-sided malignant pericardial effusion with a left ventricular systolic dysfunction (ejection fraction 23% (Figure 5).

As a result of the rapid and extensive growth of the tumor, neither surgery nor chemotherapy was indicated; they were unlikely to alter the prognosis of the patient. As per the family’s wishes to not allow the patient to suffer further, the patient was terminally extubated with palliative care measures in place on day five of admission. He went into asystole 90 minutes later.

Figure 4: CT scan of the chest demonstrating a right lower lobe mass that has increased in size compared to the month before.

Discussion

Metastases to the heart and pericardium can occur in 18% of patients with an underlying malignancy.7 Carcinoma of the lung is the most common source of metastases, largely due to the proximity of the heart.1 Dysrhythmias are often the presenting manifestations of cardiac metastases. They often arise from autonomic instability, involvement of the coronary vasculature or extrinsic compression of the heart. Metastases most commonly involve the pericardium and epicardium, suggestive of lymphatic invasion. In the case of direct extension of the tumor, lymphatic drainage of the heart can easily be obstructed, resulting in a malignant pericardial effusion.7

Malignant pericardial effusion can lead to chest discomfort, dyspnea, tachycardia, hypotension and cardiogenic shock, but some patients may be asymptomatic until death. This was the case with our patient because of the rapid progression of the cancer. Symptoms and effects of the effusion on the heart depend more on the rate of fluid accumulation than on the amount of total fluid trapped in the pericardium.8 Some causes of pericardial effusions, including hypothyroidism, penetrating trauma or pericarditis, cause more insidious effusions that allow the heart to accommodate the extra fluid before hemodynamic compromise occurs. In some cases nearly 2 liters of fluid may accumulate without instability. In these circumstances, emergent pericardiocentesis would not be indicated due to the patient’s hemodynamic stability. On the other hand, in cases of myocardial rupture or malignancy, the fluid may accumulate rapidly in the pericardium and even slight fluid accumulations may trigger cardiac tamponade.8

Early Diagnosis Needed

Figure 5: Echocardiogram of the heart.

Squamous cell lung cancer, commonly seen in smokers, can have a variety of presentations. In the case of our patient, the delay in cancer diagnosis allowed for rapid cardiac involvement leading to an acute onset of atrial fibrillation. Although atrial fibrillation can be a rare complication of tumor metastases, it can quickly lead to hemodynamic instability if not recognized and treated early.

Priti Patel is a fourth-year medical student at St. George’s University School of Medicine in the West Indies, and Sean Khorami is also a fourth-year medical student in the program. John Hallenbeck is an attending physician in the Emergency Trauma Department at Hackensack University Medical Center in Hackensack, N.J. Gordon Huie is a physician assistant who is research coordinator for the Emergency Trauma Department, and Chinwe Ogedegbe is the director of research for the department.

References

1. DeCamp MM, et al. Malignant effusive disease of the pleura and pericardium. Chest. 1997;112(4 Suppl):2915-2955.

2. Cardinale D, et al. Atrial fibrillation after operation for lung cancer: clinical and prognostic significance. Ann Thoracic Surg. 1999;68(5):1827-1831.

3. Jemal A, et al. Cancer statistics, 2009. CA Cancer J Clin. 2009;59(4):225-249.

4. Kamangar F, et al. Patterns of cancer incidence, mortality, and prevalence across five continents: defining priorities to reduce cancer disparities in different geographic regions of the world. J Clin Oncol 2006;24(14):2137-2150.

5. Morgensztern D, et al. Improving survival for stage IV non-small cell lung cancer: a surveillance, epidemiology, and end results survey from 1990 to 2005. J Thorac Oncol. 2009;4(12):1524-1529.

6. Kantarjian HM, et al. Non-small cell lung cancer. In: The MD Anderson Manual of Medical Oncology. 2nd ed. McGraw Hill; 2001.

7. Chiles C, et al. Metastatic involvement of the heart and pericardium: CT and MR imaging. Radiographics. 2011;21(2):438-449.

8. Bois JP, et al. 78-year-old man with metastatic squamous cell carcinoma, dyspnea, and hypotension. Mayo Clin Proc. 2010;85(11): e78-e81.

9. Goldstraw P, et al. The IASLC Lung Cancer Staging Project: proposals for the revision of the TNM stage groupings in the forthcoming (seventh) edition of the TNM Classification of malignant tumours. J Thorac Oncol. 2007;2(8):706-714.

10. Chen SA, et al. Initiation of atrial fibrillation by ectopic beats originating from the pulmonary veins: electrophysiological characteristics, pharmacological responses, and effects of radiofrequency ablation. Circulation. 1999;100(18):1879-1886.

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