Pulsus Paradoxus

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Pediatr Cardiol. 2007 Sep-Oct;28(5):358-62.
Sensitivity and specificity of echocardiographic evidence of tamponade: implications for ventricular interdependence and pulsus paradoxus.
Guntheroth WG.
Department of Pediatrics (Cardiology), University of Washington School of Medicine, Box 356320, Seattle, WA 98185, USA wgg@u.washington.edu

The reported sensitivity of the echocardiographic finding of right atrial collapse for the diagnosis of tamponade ranges from 50% to100%; specificities have ranged from 33% to 100%. Its sensitivity in identifying right ventricular collapse ranges from 48% to 100% whereas the specificity ranges from 72% to 100%. Collapse of either the right atrium or right ventricle is not reliable except in cases where the risk of tamponade is high, consistent with Bayes' theorem. If the patient has hypotension, tachycardia, dyspnea, increased venous pressure, and a pericardial effusion, the diagnosis of tamponade will likely be sustained. To explain pulsus paradoxus, most echocardiographic reports have invoked Dornhorst's theory that inspiratory filling of the right ventricle actively collapses the left ventricle by successfully competing for a fixed total pericardial space ("ventricular interdependence"). However, the pericardial space is not fixed in tamponade but increases with inspiration, and the right heart is much more likely to collapse than the left, given their relative thickness. Pulsus paradoxus depends on the inspiratory surge to the right heart, exaggerated by the small stroke volume of both ventricles induced by tamponade, and vascular coupling between the pulmonary and systemic beds, with a transit time of one to two heart beats.

Dynamics. 2007 Fall;18(3):16-8.
Pulsus paradoxus in ventilated and non-ventilated patients.
Wong FW.
Clinical Neuroscience Unit, Foothills Medical Centre, Calgary, Alberta. 1wong@telus.net

Human physiology changes are often amplified in disease states and may be altered when a patient is mechanically ventilated. Normally, systolic blood pressure is slightly lower during inspiration than expiration due to the change in intrathoracic pressure. Pulsus paradoxus is a phenomenon in which the difference in systolic blood pressure (BP) between inspiration and expiration is more than 10 mmHg. When a patient is mechanically ventilated, the pattern of changes observed in pulsus paradoxus is reversed; that is, the systolic BP is higher during inspiration than expiration. In this article, the airway pressure and respiratory impedance tracings are used to demonstrate the inspiratory and expiratory phase of the respiratory cycle. Then BP can be determined with each respiratory phase. The difference in presentation of pulsus paradoxus in patients who are breathing spontaneously and with mechanical ventilation is described. A case study is also included to illustrate the presentation and treatment of pulsus paradoxus in a mechanically ventilated patient.

Clin Cardiol. 2003 May;26(5):215-7.
Pulsus paradoxus in cardiac tamponade: a pathophysiologic continuum.
Swami A, Spodick DH.
Department of Medicine and Division of Cardiovascular Medicine, Saint Vincent Hospital-Worcester Medical Center, Worcester, Massachusetts 01608, USA.

Pulsus paradoxus has interested physicians for more than a century. Since McGregor's comprehensive New England Journal of Medicine article in 1979, there have been no updated reviews; accordingly, we review pulsus paradoxus based on the clinical and physiologic literature and personal experience.

Rev Esp Cardiol. 1995 Jun;48(6):443-5.
Cardiac tamponade with the absence of a paradoxical pulse. The practical utility of echocardiography.
Zamorano J, Vilacosta I, Almería C, Alonso L, Batlle E, Conde A, Castillo JA, Peral V, Sánchez-Harguindey L.
Servicio de Cardiología, Hospital Clínico San Carlos, Madrid.

A patient with cardiac tamponade but without hypotension and pulsus paradoxus is reported. In this patient, echocardiography confirmed the diagnosis of cardiac tamponade, showing diastolic collapse of the right ventricle and also the presence of an atrial septal defect (ostium secundum) that explains the absence of pulsus paradoxus. The role of echocardiography in those rare clinical situations that in the presence of cardiac tamponade showed no pulsus paradoxus are discussed.

Echocardiography. 1994 Sep;11(5):477-87.
The paradoxical pulse in tamponade: mechanisms and echocardiographic correlates.
Hoit BD, Shaw D.
Division of Cardiology, University of Cincinnati Medical Center, OH 45267-0542, USA.

Pulsus paradoxus is an exaggerated fall in systolic blood pressure with inspiration (usually greater than 10 mm). Understanding the accuracy of pulsus paradoxus for a diagnosis of cardiac tamponade requires a consideration of the mechanisms underlying its genesis, and a knowledge of its presence in other conditions and its variable absence in cardiac tamponade with associated disease states. Echocardiography (M-mode, 2-D, and Doppler) has aided considerably our understanding of pulsus paradoxus. Inspiratory increases in right heart filling and output are widely accepted as necessary for pulsus paradoxus to occur; inspiration causes increases in right ventricular dimensions and pulmonic and tricuspid velocities, and decreases in left ventricular (LV) dimensions and aortic and mitral velocities and LV diastolic compliance. Doppler studies of pulmonary venous inflow confirm that an inspiratory fall in left atrial filling is necessary for pulsus paradoxus. Pulsus paradoxus is complex and multifactorial in origin; it may be absent in cardiac tamponade when certain conditions (e.g., LV dysfunction) coexist and may accompany disease states other than cardiac tamponade (e.g., obstructive airway disease). Thus, the significance of pulsus paradoxus (and its Doppler echo correlates) must be considered in the clinical context.

Schweiz Rundsch Med Prax. 1994 Feb 8;83(6):158-62.
Paradoxical pulse
Mooser V, Regamey C, Stauffer JC.
Clinique de médecine interne, Hôpital cantonal, Fribourg.

Pulsus paradoxus is one of the cardinal signs of cardiac tamponade and must be looked for at bedside examination of any patient who presents a clinical picture of low cardiac output. This paper reviews the definition of pulsus paradoxus and the way to measure it noninvasively. We then discuss the physiological fluctuation of systemic blood pressure during respiration and the various mechanisms which lead to an exaggeration of this phenomenon during tamponade. The sensitivity and specificity of this sign are also discussed. Finally, the role of echocardiography in the diagnosis of cardiac tamponade is shortly presented, as this method appears to be very accurate and sensitive in evaluating the hemodynamic embarrassment associated with pericardial effusion.

J Am Soc Echocardiogr. 1991 Jul-Aug;4(4):408-12.
Pulsus paradoxus: a definition revisited.
Santoro IH, Neumann A, Carroll JD, Borow KM, Lang RM.
Department of Medicine, University of Chicago Medical Center, IL 60637.

Pulsus paradoxus is associated with many clinical conditions and is defined as a greater than 10 mm Hg end-inspiratory decrease in systolic blood pressure. Kussmaul's original definition of pulsus paradoxus is presented, along with an explanation of his choice of the term "pulsus paradoxus." A case of pulsus paradoxus is graphically described using simultaneoustwo-dimensional targeted M-mode, Doppler echocardiographic, and high-fidelity pressure recordings.

J Am Coll Cardiol. 1986 Sep;8(3):706-9.
Doppler-detected paradoxus of mitral and tricuspid valve flows in chronic lung disease.
Hoit B, Sahn DJ, Shabetai R.

An echocardiographic Doppler study in a patient with pulsus paradoxus of respiratory origin demonstrated a large inspiratory increase of tricuspid flow velocity and a corresponding decrease of mitral flow velocity. This "flow paradoxus" is therefore not specific for cardiac tamponade, and provides evidence that decreased left ventricular filling is an important mechanism of pulsus paradoxus observed in severe chronic lung disease.

Circulation. 1985 Apr;71(4):829-33.
The relative merits of pulsus paradoxus and right ventricular diastolic collapse in the early detection of cardiac tamponade: an experimental echocardiographic study.
Klopfenstein HS, Schuchard GH, Wann LS, Palmer TE, Hartz AJ, Gross CM, Singh S, Brooks HL.

An inspiratory decline in systolic arterial blood pressure exceeding 10 mm Hg has been used clinically to identify hemodynamically significant pericardial effusions. Recently, the echocardiographic sign of right ventricular diastolic collapse (RVDC) has been shown to occur early in the course of cardiac tamponade in association with a hemodynamically important decline in cardiac output. This study was undertaken to compare the relative merits of pulsus paradoxus and the onset of RVDC in the early detection of cardiac tamponade in an unanesthetized canine preparation. We studied six chronically instrumented, conscious dogs with two-dimensional echocardiography during cardiac tamponade induced by continuous infusion of saline into the pericardial space. We recorded intrapericardial pressure, cardiac output (electromagnetic flowmeter), aortic (catheter-tip transducer) and right atrial blood pressures, heart rate, and respiration. None of the dogs had RVDC when the pericardial space was empty, but all dogs showed RVDC during cardiac tamponade. We found that RVDC was strongly related to all of the cardiac parameters evaluated (intrapericardial pressure, cardiac output, aortic blood pressure, heart rate, and stroke volume) and provided information on each that was independent of that provided by pulsus paradoxus. Furthermore, RVDC appeared to be more strongly related to most cardiac parameters than was pulsus paradoxus and to be more sensitive and specific than pulsus paradoxus in detecting changes in intrapericardial pressure early in cardiac tamponade.

J Cardiogr. 1981 Mar;11(1):147-60
Echocardiographic findings of pulsus paradoxus: cardiovascular changes due to respiration
Anno Y, Matsuzaki M, Sada K, Sasada T, Fukagawa K, Sasaki T, Ogawa H, Kusukawa R, Takahashi Y, Nakashima A.

Echocardiographic studies were performed in two cases with pulsus paradoxus
(Case 1: a 13-year-old boy, acute viral pericarditis with massive pericardial effusion; Case 2: a 25-year-old woman, status asthmaticus) and in a normal subject when his intra-airway pressure rapidly fell on a deep negative level, e.g., during Mueller maneuver. During inspiration in both clinical cases, the anterior mitral leaflet showed a diminished diastolic excursion, and the right ventricular dimension increased accompanied by a reciprocal decrease in the left ventricular dimension. In Case 2, in addition, an abrupt downward motion of the ventricular septum was present in early diastole during inspiration. In experimental study of a normal subject, similar respiratory changes in mitral ans septal motions and the similar respiratory interaction between the right and left ventricles were also observed during Mueller maneuver. Our observations suggest left ventricular filling and left ventricular end-diastolic volume decrease during inspiration in the presence of pulsus paradoxus. These are compatible with the pulmonary pooling hypothesis, and also support the hypothesis that pulsus paradoxus may be caused by competition of the ventricles for filling within a relatively fixed pericardial space. The mechanism of the abrupt downward septal motion in early diastole was also discussed.

Circulation. 1977 Dec;56(6):951-9.
Echocardiographic study of cardiac tamponade.
Settle HP, Adolph RJ, Fowler NO, Engel P, Agruss NS, Levenson NI.

We studied 14 patients with cardiac tamponade and pulsus paradoxus; 11 were studied after relief of tamponade by pericardiocentesis. Right ventricle diastolic diameter increased during inspiration in each of 12 patients; left ventricle diastolic diameter decreased during inspiration in each of 13. Mitral valve DE amplitude decreased with inspiration in 13 of 14 patients. Mitral valve E-F slope could be measured in eight patients, and was rounded and not measurable in six. Six of the eight showed inspiratory decrease in mitral E-F slope. Similar changes were observed in two other patients with pulsus paradoxus who had chronic obstructive airway disease. Twenty patients with large pericardial effusions and no tamponade did not show these changes. These results suggest inspiratory augmentation of right ventricular filling and inspiratory diminution of left ventricular filling, not only in cardiac tamponade, but in obstructive airway disease associated with pulsus paradoxus.

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