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We appreciate the thoughtful comments of Dr. Shiber regarding our case report and literature review (1Walsh B.M. Tobias L.A. Low-pressure pericardial tamponade: case report and review of the literature.J Emerg Med. 2017; 52: 516-522Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar). We welcome the opportunity to discuss 2 of the points he has raised. First, although Dr. Shiber suggests that appropriate fluid loading should address hypotension associated with low-pressure tamponade, Spodick has cautioned that treating low-pressure tamponade with fluid boluses may actually provoke overt tamponade hemodynamics (2Spodick D.H. Acute cardiac tamponade.N Engl J Med. 2003; 349: 684-690Crossref PubMed Scopus (530) Google Scholar). In 9 case reports we cite, fluid therapy did not improve symptoms or hemodynamics of low-pressure tamponade (references 10–16, 23, and 24 in our article), and apparently converted low-pressure tamponade to typical tamponade physiology in 2 other cases (1Walsh B.M. Tobias L.A. Low-pressure pericardial tamponade: case report and review of the literature.J Emerg Med. 2017; 52: 516-522Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar, 3Labib S.B. Udelson J.E. Pandian N.G. Echocardiography in low pressure cardiac tamponade.Am J Cardiol. 1989; 63: 1156-1157Abstract Full Text PDF PubMed Scopus (18) Google Scholar, 4Falzone E. Libert N. Hoffmann C. et al.Tamponnade à pression basse mimant une cholécystite.Ann Fr Anesth Reanim. 2012; 31: 911-913Crossref PubMed Scopus (3) Google Scholar). Second, Dr. Shiber attributes our patient's failure to manifest pulsus paradoxus to right ventricular hypertrophy (RVH). We must emphasize, however, that like other “classic” signs of tamponade, pulsus is of limited diagnostic utility, even in the absence of RVH. It has a sensitivity for tamponade that ranges from 12–75% (5Argulian E. Messerli F. Misconceptions and facts about pericardial effusion and tamponade.Am J Med. 2013; 126: 858-861Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar). Moreover, while RVH may indeed have had a role in our patient's lack of pulsus, many other conditions can attenuate this finding (2Spodick D.H. Acute cardiac tamponade.N Engl J Med. 2003; 349: 684-690Crossref PubMed Scopus (530) Google Scholar). Lastly, we should emphasize that a lack of pulsus does not equate to a lack of respiratory variation in cardiac output. Our patient did indeed show echocardiographic evidence of decreased cardiac output during inspiration. Figure 5 in our article shows significant mitral valve inflow variation, which is considered the echocardiographic correlate of pulsus paradoxus (1Walsh B.M. Tobias L.A. Low-pressure pericardial tamponade: case report and review of the literature.J Emerg Med. 2017; 52: 516-522Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar). In a second letter, Dr. Jolobe notes that hypoadrenalism can be considered in the differential diagnosis of low-pressure tamponade. While this appears to be a rare etiology, we agree that appropriate testing should be pursued if the clinical context warrants. Comments on: Walsh and Tobias, “Low-Pressure Pericardial Tamponade: Case Report and Review of the Literature”Journal of Emergency MedicineVol. 54Issue 1PreviewI enjoyed the article by Walsh and Tobias on low-pressure pericardial tamponade in the April issue of Journal of Emergency Medicine, but would like to make a few comments (1). Pericardial tamponade occurs when the filling pressure of the cardiac chambers is lower than the pericardial pressure, thereby inhibiting chamber filling (2). When a low-pressure pericardial effusion exists, it becomes symptomatic when the central venous pressure (CVP) drops and becomes lower than the pericardial pressure; right atrial filling is then reduced because “water doesn't flow uphill.” The patient described had end-stage renal disease and was on peritoneal dialysis, but clearly still made a fair amount of urine because she was on furosemide. Full-Text PDF In Reply to ShiberJournal of Emergency MedicineVol. 54Issue 1PreviewWe appreciate the thoughtful comments of Dr. Shiber regarding our case report and literature review (1). We welcome the opportunity to discuss two of the points he has raised. Full-Text PDF