To the Editor: Patients admitted to the hospital with community-acquired pneumonia are more likely to be elderly, with major risk factors for cardiovascular diseases. These patients have significantly higher risk of acute coronary syndromes during their hospital stay. The estimated incidence of acute myocardial infarction is between 3% and 7%.1,2 An elderly patient who was admitted with community-acquired pneumonia to the hospital and developed silent acute myocardial infarction during his hospital stay is reported. This case highlights the difficulties related to the diagnosis of acute coronary events in older patients admitted to the hospital with pneumonia. Telemetry monitoring can help identify these events and should be used more often in this population during hospitalization.
A 70-year-old Caucasian man was admitted to the hospital with right lower lobe community-acquired pneumococcal pneumonia. He had a history of hypertension, obstructive sleep apnea, and type 2 diabetes mellitus. He did not have chest pain, shortness of breath, or palpitations. He was admitted to a telemetry unit (Figures 1A and 2A). He was started on levofloxacin 500 mg po daily and enoxaparin 40 mg subcutaneous daily. His troponin T was mildly elevated (0.1 ng/mL) on admission. This was presumed to be secondary to pneumonia. At 3 a.m., ST segment elevation was noticed on the telemetry monitor while he was asleep (Figures 1B and 2B). This finding was considered to be nonspecific initially because the patient was sleeping and asymptomatic, with normal vital signs (blood pressure 130/70 mmHg, heart rate 90 beats/minute) and oxygen saturation (93% on room air). The on-call team decided to obtain a 12-lead electrocardiogram (ECG), which revealed 2-mm ST segment elevation in leads V3 and V4, although the patient was still asymptomatic. Cardiac enzymes were ordered, and nitroglycerin infusion was started (5 μg/minutes). The patient developed dyspnea and tachycardia 30 minutes later and was transferred to the cardiac catheterization unit. His coronary angiogram revealed total thrombotic occlusion of the left anterior descending artery, and primary coronary intervention with stenting was performed. Follow-up ECG revealed biphasic T waves in the anterior leads with no pathological Q waves. His echocardiogram revealed normal left ventricular systolic function before his discharge. The patient reported no cardiac symptoms at his follow-up visits.
The diagnosis of an acute coronary event in an elderly hospitalized patient with multiple comorbidities is challenging. Elderly patients may have atypical or few symptoms of coronary events during their hospital stay. Some cases can even occur without any symptoms because of the reduction of pain perception during sleep3 or the effect of analgesic drugs. More specifically, patients with pneumonia can be easily overlooked because of the inherent association of pneumonia with chest pain. Alternatively, acute coronary syndromes can mimic acute clinical deterioration of pneumonia because both conditions can present with dyspnea, hypoxemia, and hypotension. Serum troponin T or I may be high in patients with Streptococcus pneumoniae infection.4 Furthermore, negative troponin tests do not exclude unstable angina pectoris or the early phase of acute myocardial infarction.
Beyond arrhythmia recognition, ST segment monitoring with telemetry can predict and detect cardiac events,5 particularly in high-risk patients. This benefit may reduce mortality in patients whose chest pain is atypical. Telemetry can indicate an acute coronary syndrome when chest pain is multifactorial and alert the physician to investigate a cardiac event. ST segment monitoring using a 12-lead ECG has a high sensitivity (100%) for acute myocardial infarction.6 The sensitivity is lower in patients with unstable angina pectoris or single vessel coronary artery disease. The specificity of ST segment monitoring was higher than typical chest pain (84% vs 73%) in adults evaluated for acute coronary syndrome has been demonstrated.7 Although ST segment monitoring can detect asymptomatic ischemic episodes, it has been underused in many hospitals, even in patients admitted with acute coronary syndromes.8 Currently, the indications for the use of telemetry monitoring in patients hospitalized with pneumonia are unclear and usually left to the physician's decision.
The American Heart Association Scientific Statement on Practice Standards for Electrocardiographic Monitoring in Hospital Settings stated that ST monitoring is a class I indication in cases of acute coronary syndrome, possible acute coronary syndrome, and possible variant angina pectoris and after a complicated coronary intervention.9 These indications are not based on randomized controlled trials, but rather on expert opinion. Elderly patients with coronary risk factors admitted with pneumonia were not included in this statement. Although pulmonary diseases are common causes of hospital admissions, the indications for ST segment monitoring of these patients are unclear. Arrhythmia monitoring has been the main focus for most patients who are placed on telemetry. Observational studies of telemetry have demonstrated that patients at low risk for cardiac complications do not benefit from telemetry monitoring,10 but it is possible that older patients with major coronary risk factors and at high risk for cardiac events admitted to the hospital with pneumonia would have a mortality benefit from ST segment monitoring.
Older patients with high-risk features for cardiovascular disease may be at risk for acute coronary syndromes during their hospital admissions with pneumonia. Chest pain in patients with pneumonia may be attributed to the pleural inflammation, and a coronary event may be overlooked. The use of telemetry monitoring for ST segment changes seems helpful in identifying acute coronary syndromes in these asymptomatic patients. Randomized controlled studies are needed to investigate the prognostic utility of ST segment monitoring in patients with cardiac risk factors admitted to general wards with pneumonia.
Conflict of Interest: The editor-in-chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper.
Author Contributions: Elsayed Abo-salem: design, acquisition of data, preparation of letter. Cihan Cevik: preparation of letter. Kenneth Nugent: supervision of writing, editing, data analysis.
Sponsor's Role: No sponsor.