Chiefs’ Inquiry Corner-3/21/22

March 21, 2022

Chief residents of the NYU Langone Internal Medicine Residency give quick-and-easy, evidence-based answers to interesting questions posed by house staff, both in their clinics and on the wards.

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 The de Winter ECG pattern was actually first described by Dr. William Dressler in 1947 in a study of patients experiencing myocardial infarction who underwent early ECG (ranging from 1h 15 imins-12 hours) after onset of symptoms. It was later reported in a case series by Dr. de Winter in 2008, whereby it was observed in 2% of patients with acute left anterior descending occlusions.  The de Winter ECG pattern is characterized by :
  • up-sloping ST-segment depression at the J point,
  • tall, peaked, symmetrical T-waves in the precordial leads, and
  • ST-segment elevation in aVR
Given that this ECG pattern has a high specificity for acute LAD occlusion, it is considered to be an ST-elevation myocardial infarction (STEMI) equivalent, and thus requires urgent coronary intervention. Of note, the the electrophysiologic mechanism explaining the absence of classic ST-elevation findings in a LAD occlusion remains unclear, although it has been documented that some de Winter-ECG patterns have evolved to STEMI ECG patterns on serial ECG exams.

References: Chest pain: The importance of serial ECGs
 While compression therapy to prevent infection among chronic LE edema patients has long been suggested by various society guidelines, until recently there has been limited data from trials to support the practice. A 2020 RCT published in the NEJM compared compression plus education to education alone in 84 patients with at least 3 months of LE edema (from any cause) and at least 2 episodes of cellulitis in the preceding 2 years. Follow up took place every 6 months, and if a non-compression patient developed cellulitis, they were permitted to cross-over to the compression cohort. The trial was stopped early for efficacy and found that compression therapy resulted in a significantly lower incidence of recurrent cellulitis compared to the control, 15% vs 40%, respectively. 88% of the participants in the compression group reported during a follow-up interview that they wore the garments >3d/week, and 73% wore the garments >4d/week. While the mechanism isn’t definitively known, investigators postulated that compression therapy could decrease the risk of cellulitis by lessening edema, improving immune response and skin integrity, and providing physical protection for the skin.

References: Compression Therapy to Prevent Recurrent Cellulitis of the Leg
 Diuresis is a cornerstone of managing patients with symptomatic heart failure. Many experts start oral therapy with furosemide, and switch to torsemide or bumetanide if the patient cannot effectively be diuresed with high-dose furosemide (i.e., total daily dose 200mg or greater). This is based on the effectiveness of furosemide in most patients, familiarity of dosing with most health care providers, and ease of conversion between intravenous and oral forms. However, its bioavailability is only approximately 50%, compared to torsemide and bumetanide, with their bioavailability of 80-100%; such pharmacologic properties make it reasonable to try switching to either of these latter agents if an adequate diuretic response is not achieved with furosemide.  However, there are few high-quality studies that have actually analyzed the comparative efficacy of the various loop diuretics. One meta-analysis evaluated for differences among loop diuretics (furosemide, torsemide, bumetanide, and azosemide) on all-cause mortality, cardiovascular mortality, heart failure-related hospitalization, hypokalemia, and acute renal failure. The study did not find any significant differences among the loop diuretics with regard to all-cause mortality, cardiovascular mortality or hypokalemia, although torsemide use was associated with the lowest risk of heart failure-related hospitalization and a trend towards less acute renal failure. However, this study admittedly was limited by the component trials having diverse methodologies, and most being conducted prior to the year 2000. There is a need for newer, methodologically sound and robust studies to better elucidate differences, if any, among the loop diuretics. For now, however, it is reasonable to use them interchangeably and guide selection based on clinical response.

References: READY: relative efficacy of loop diuretics in patients with chronic systolic heart failure-a systematic review and network meta-analysis of randomized trials