Being an outstanding physician and lifelong learner requires stoking the flames of clinical curiosity. In Chiefs’ Inquiry Corner (CIC) we attempt to succinctly answer actual clinical questions that have been raised on the wards and in the clinics of NYU’s teaching hospitals. Our answers are not meant to be all encompassing or practice changing but rather to serve as springboards for further exploration. For those of us with short attention spans, we hope CIC satisfies that craving for a morsel of knowledge in a digestible format.
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[Q] Bellevue Clinic: What is the significance of and work-up for asymptomatic, ectopic heartbeats in the outpatient setting?
[A] It can be difficult to diagnose arrhythmias based solely on exam in the outpatient setting, but auscultating or palpating an irregular rhythm in an asymptomatic patient is an important catch. Patients may have ectopic beats such as premature atrial or ventricular contractions (PACs or PVCs), and at high frequency, these can lead to significant morbidity. In one study, over 1100 patients with normal cardiac function were monitored with a 24-hour Holter, along with echocardiography at baseline and after 5 years. Patients in the highest quartile of PVC burden had a significantly higher risk of left ventricular dysfunction at 5 years. They also had a higher risk of clinical heart failure and mortality on follow-up (median of 13 and 15 years later, respectively). Aside from an in-office EKG and standard lab work-up (including BMP, TSH), it’s important to refer patients for at least 24-hour monitoring to assess PVC burden and check for other potential arrhythmias.
[Q] Bellevue Hospital: What are the different types of proteinuria?
[A] Proteinuria can be broken down into four basic mechanistic types. Glomerular proteinuria occurs when there is increased filtration of proteins through the glomerulus (this largely consists of macromolecules such as albumin). Tubular proteinuria occurs from decreased protein absorption in the tubules due to tubulointerstitial diseases (this largely consists of smaller proteins, such as beta2-microglobulin or immunoglobulin light chains). Overflow proteinuria occurs due to increased overproduction of proteins (such as in multiple myeloma) such that the filtration load exceeds the reabsorption capacity. Post-renal proteinuria occurs in the setting of urinary tract inflammation and protein excretion, although the exact mechanism is unclear.
[Q] NYU Brooklyn: How do BNP levels correspond to NT-proBNP levels?
[A] B-type natriuretic peptide (BNP) is a physiologically active compound released from the ventricular myocardium in response to wall stress. It has a half life of 20 minutes. After release it is neutralized into inactive N-terminal pro-BNP, which is renally cleared after 120 minutes. Thus, NT-proBNP levels are typically around six times higher than BNP values. However, there are many different assays for each test which are not comparable, so there is no standard conversion factor for the comparison of BNP to NT-proBNP.