Use of point-of-care ultrasound by internists to rapidly diagnose acute decompensated heart failure

Abstract

Dyspnea is a common presenting complaint seen by hospitalists. The differential is broad, including life-threatening and less urgent etiologies. We report a 43-year-old male presenting to an inpatient medicine service with dyspnea in the setting of asthma, tobacco and occupational exposures, and no prior cardiac history. Use of point-of-care ultrasound (POCUS) immediately confirmed diagnosis of acute decompensated heart failure, allowing prompt decision making and care. Use of POCUS is widespread among emergency physicians and intensivists; however, use among medical students, internal medicine residents, and hospitalists remains variable. Increased use of POCUS by hospitalists may increase speed and accuracy of diagnosis.

1. Background

Point-of-care ultrasound (POCUS) is performed by the clinician, at the point of care, to obtain real-time dynamic images to be directly correlated with the patient's presenting signs and symptoms [1]. POCUS reduces time spent to acquire diagnoses, increases accuracy of diagnoses, and decreases overall costs [2]. Use of POCUS is recommended by the American College of Physicians in patients presenting with dyspnea and diagnostic uncertainty [3]. Interest in POCUS among internal medicine physicians is rapidly expanding, but internists' training and use of POCUS remains variable. Furthermore, POCUS use is not considered a core competency in internal medicine graduate medical education [4], and only 25% of internal medicine residency programs report an active POCUS curriculum [5]. Here we present a case of a young, athletic patient with dyspnea admitted to the inpatient internal medicine service where POCUS was used to quickly diagnose acute decompensated heart failure with cardiogenic shock, facilitating immediate treatment of a life-threatening condition.

2. Case description

A 43-year-old male with history of asthma was admitted to the inpatient medicine service due to ten days of worsening dyspnea. He had a non-productive cough, paroxysmal nocturnal dyspnea, and orthopnea. He developed a rash on his forehead 10 days prior to admission. He had no chest pain, fevers, or gastrointestinal symptoms. He was prescribed an albuterol rescue inhaler, which he used three times per day without relief of dyspnea. He was a former college athlete that worked in a shipyard and smoked two packs of cigarettes per day. He lived out of state but was on extended travel for work.

Physical exam was pertinent for heart rate 108 bpm, blood pressure 100/53 mmHg, oxygen saturation 90% on room air, and BMI 23 kg/m². There were multiple scalloped erosions isolated to the forehead and bilateral cheeks. Cardiovascular exam revealed bibasilar crackles, tachycardia with regular rhythm and no murmurs or gallops, and pitting edema to mid-calves bilaterally. Pertinent labs included white blood count 5 K/cumm, hemoglobin 16.7 g/dL, creatinine 1.3 mg/dL from unknown baseline, high-sensitivity troponin 61 ng/L, BNP 2979 pg/mL, and lactate 3.3 mmol/L. EKG revealed sinus tachycardia, left atrial enlargement, and left axis deviation. Portable AP chest x-ray was concerning for enlarged cardiac silhouette and cephalization of pulmonary vasculature with no pleural effusion or interstitial opacities (Fig. 1). CT chest demonstrated no pulmonary embolism and non-specific bilateral ground glass opacities.

Fig. 1.

Portable AP chest x-ray demonstrated concern for cardiomegaly and cephalization of pulmonary vasculature with no clear pulmonary edema.

On arrival to the inpatient medicine service, lung ultrasound demonstrated multiple diffuse bilateral B-lines (Fig. 2), indicating alveolar-interstitial syndrome [6,7]. Cardiac POCUS revealed severely reduced left ventricular ejection fraction (LVEF) using qualitative assessment of endocardial excursion and septal motion of the anterior mitral valve leaflet (Fig. 3) and LVEF 19% using quantitative assessment of E-point septal separation (EPSS) (Fig. 4) [8]. There was no evidence of pericardial effusion. POCUS findings of diffuse bilateral B-lines and reduced LVEF, in conjunction with physical exam findings and elevated lactate, confirmed a diagnosis of acute decompensated heart failure with cardiogenic shock. The patient was immediately initiated on therapy with 7 L diuresis within 12 hours and normalization of lactate.

Fig. 2.

Lung ultrasound demonstrated vertical hyperechoic reverberation artifacts originating from the pleural line and extending to the periphery, known as B-lines. The presence of multiple B-lines indicated alveolar-interstitial syndrome [6,7].

Fig. 3.

Cardiac ultrasound from parasternal long axis view demonstrated diminished endocardial excursion with poor movement toward the center of the left ventricle chamber during systole, as well as diminished mitral valve excursion with increased distance between the anterior leaflet of the mitral valve and interventricular septum. Both findings indicated reduced left ventricular systolic function [15].

Fig. 4.

Cardiac ultrasound from parasternal long axis view using M-mode revealed EPSS of 22.6 mm. LVEF of 19% was estimated using the formula LVEF = 75.5 – (2.5 x EPSS), with EPSS in millimeters [8].

Formal transthoracic echocardiogram performed the next day confirmed severe dilated cardiomyopathy with LVEF 17%, thin myocardium, and global LV hypokinesis without regional wall motion abnormalities. HSV-1 PCR returned positive from skin lesions and was thought to be unrelated to his cardiomyopathy. The patient was started on valaciclovir with resolution of rash.

After 17 L of diuresis, the patient underwent right heart catheterization, revealing normal right atrial pressure of 7 mmHg, elevated pulmonary capillary wedge pressure of 22 mmHg, and reduced cardiac index of 1.0 L/min/m². Cardiac MRI demonstrated four-chamber cardiomegaly with normal cardiac viability and no evidence of delayed myocardial enhancement. Further investigation led to suspicion for genetic cardiomyopathy; the patient's father suffered an ischemic stroke at age 50, underwent ICD placement in his 50s, and per patient, died from a “rare heart condition” at age 63. The patient declined genetic testing.

Ultimately, the patient was unable to tolerate full dose goal-directed-medical-therapy. He was started on advanced therapies with dobutamine continuous infusion and discharged with cardiology follow up in his home state for transplant evaluation.

3. Discussion

This case represents a young, athletic male with new diagnosis of acute decompensated heart failure, which was confirmed within minutes by focused POCUS. Notably, POCUS identified cardiogenic pulmonary edema that was not present on chest x-ray. The sensitivity and specificity for lung ultrasound to diagnose pulmonary edema are 0.88 and 0.90, respectively. The sensitivity and specificity for chest x-ray to diagnose pulmonary edema are 0.73 and 0.90, respectively [9]. Chest x-ray may fail to detect smaller volumes of fluid, leading to delays in diagnosis and treatment [10].

Use of POCUS facilitated diagnosis of decompensated heart failure complicated by cardiogenic shock and allowed immediate treatment and stabilization of our patient. Further investigation led to presumed diagnosis of genetic cardiomyopathy. HSV-2 has been shown to cause rare cases of fulminant heart failure [11]; however, normal myocardial enhancement on cardiac MRI made viral myocarditis an unlikely etiology. The patient's HSV skin lesions likely appeared secondarily in the setting of stress and acute decompensated heart failure [10]. Thin myocardium on transthoracic echocardiogram suggested chronic heart failure, which was previously compensated likely due to the patient's age and physical conditioning. His chronic dyspnea may have been falsely, or at least over-attributed, to asthma. Given the limits of physical exam in this case, earlier use of POCUS or transthoracic echocardiogram may have led to earlier diagnosis and initiation of therapy for heart failure. Early recognition and initiation of therapy improves outcomes and reduces morbidity and mortality in heart failure [12,13].

POCUS may reveal life-threatening diagnoses that are not apparent on primary assessment [14], and this case report highlights the importance of using POCUS to make an accurate and timely diagnosis in patients presenting with undifferentiated dyspnea. Although we used endocardial excursion and EPSS, we recommend adding myocardial thickening as well when focusing on a qualitative approach [15]. Use of POCUS is widespread among emergency medicine physicians, and numerous studies report the ability of emergency medicine physicians to detect LVEF with high degrees of accuracy using our quantitative approach of EPSS [16,17], but this method has been rarely studied among internal medicine providers [18]. Management of hospitalized medicine patients is dynamic, often with undifferentiated disease processes that are rapidly changing, despite initial management in the emergency department. Although interest in POCUS among hospitalists is increasing, use of POCUS among internal medicine physicians remains highly variable with no standardized curriculum. Compared to other specialties, research remains limited on the use of POCUS by internists [19]. This case demonstrates that internists can and should effectively use POCUS to rapidly assess, diagnose, and manage a patient presenting with undifferentiated dyspnea, emphasizing the need for widespread training and use of POCUS among internists.

4. Conclusion

• •Use of lung and cardiac POCUS by trained providers is effective for rapidly diagnosing and managing patients presenting with acute decompensated heart failure.
• •Widespread training and use of POCUS among internal medicine physicians is needed and may improve speed and accuracy of diagnosis.

Declaration of competing interest

Please check the following as appropriate:

All authors have participated in (a) conception and design, or analysis and interpretation of the data; (b) drafting the article or revising it critically for important intellectual content; and (c) approval of the final version.

This manuscript has not been submitted to, nor is under review at, another journal or other publishing venue.

The authors have no affiliation with any organization with a direct or indirect financial interest in the subject matter discussed in the manuscript.

The following authors have affiliations with organizations with direct or indirect financial interest in the subject matter discussed in the manuscript:

Appendix A. Supplementary data

The following is the Supplementary data to this article: