Left ventricular diastolic collapse in low-pressure cardiac tamponade

Low-Pressure Pericardial Tamponade: Case Report and Review of the Literature

BACKGROUND

Focused cardiac ultrasound (FoCUS) is accurate for determining the presence of a pericardial effusion. Using FoCUS to evaluate for pericardial tamponade, however, is more involved. Many experts teach that tamponade is unlikely if the inferior vena cava (IVC) shows respiratory variation and is not distended.

CASE REPORT

A 53-year-old woman presented to the emergency department (ED) with severe orthostatic hypotension, exertional dyspnea, and hypoxia. The evaluation did not reveal an acute cardiopulmonary etiology, but FoCUS demonstrated a pericardial effusion, with several signs consistent with tamponade. The IVC, however, was not distended. She was believed to be hypovolemic, but fluid therapy provided minimal benefit. The patient's condition improved only after aspiration of the effusion. The patient's presentation was likely a "low-pressure" pericardial tamponade. Patients with this subset of tamponade often do not have significant venous congestion, but urgent pericardial aspiration is still indicated. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Pericardial tamponade may not manifest with IVC plethora on ultrasound. Patients with low-pressure tamponade do not present with the most florid signs of tamponade, but they nonetheless fulfill diagnostic criteria for tamponade. If a non-plethoric IVC is used to rule out tamponade, the clinician risks delaying comprehensive echocardiography or other tests. Furthermore, the potential for deterioration to frank shock could be discounted, with inappropriate disposition and monitoring.

Isolated left ventricular collapse in rheumatic heart disease with tamponade

Echocardiography in a 23-year-old woman with chronic rheumatic heart disease revealed severe mitral and tricuspid stenosis, severe tricuspid regurgitation with severe pulmonary hypertension, and mild-to-moderate pericardial effusion that resulted in cardiac tamponade with isolated left ventricular collapse. The left ventricle became the victim as this was the only low pressure chamber. This report emphasizes the role of echocardiography in the diagnosis and early recognition of atypical clinical and hemodynamic manifestations of cardiac tamponade.

Hemodynamic Effects of Volume Expansion in Patients With Cardiac Tamponade

Background— Volume expansion has been proposed as an alternative treatment for cardiac tamponade; however, the scientific evidence for this recommendation is very poor.

Methods and Results— Forty-nine unselected patients (23 males; age 55±16 years) with large pericardial effusion and hemodynamic tamponade underwent fluid overload with intravenous administration of 500 mL of normal saline over 10 minutes. Cardiac index and intrapericardial, left ventricular end-diastolic, right atrial, and right ventricular end-diastolic pressures were measured during basal state (tamponade), after fluid overload, and after pericardiocentesis. Twenty-eight patients (57%) had physical signs of tamponade, and 10 (20%) were hypotensive. Size of pericardial effusion was 31±13 mm. Initial mean arterial pressure was 88±21 mm Hg, and cardiac index was 2.46±0.80 L · min −1 · m −2 . Intrapericardial pressure was 8.31±5.98 mm Hg. Volume expansion caused a significant increase in mean arterial pressure (from 88±21 to 94±23 mm Hg, P =0.003) and cardiac index (from 2.46±0.80 to 2.64±0.68 L · min −1 · m −2 , P =0.013), as well as in intrapericardial pressure (from 8.31±5.98 to 11.02±6.27 mm Hg, P =0.0001), right atrial pressure (from 9.76±5.91 to 12.82±6.34 mm Hg, P =0.0001), and left ventricular end-diastolic pressure (from 14.21±5.97 to 19.48±6.19 mm Hg, P =0.0001). Cardiac index increased by >10% in 23 patients (47%), remained unchanged in 11 (22%), and decreased in 15 (31%). No patient developed clinical complications. Predictors of this favorable response were systolic blood pressure <100 mm Hg and low cardiac index.

Conclusions— Approximately one half of patients with cardiac tamponade develop a significant increase in cardiac output after volume overload. Low systolic blood pressure (<100 mm Hg) at baseline was the simplest clinical finding that was predictive of this favorable response.

Low-Pressure Cardiac Tamponade

BACKGROUND

Low-pressure cardiac tamponade is a form of cardiac tamponade in which a comparatively low pericardial pressure results in cardiac compression because of low filling pressure. This syndrome is poorly characterized because only isolated cases have been reported. We conducted a study of its clinical and hemodynamic profiles.

METHODS AND RESULTS

From 1986 through 2004, we evaluated all patients at our institution with combined pericardiocentesis and cardiac catheterization. We identified those patients who fulfilled catheterization-based criteria of low-pressure cardiac tamponade and compared their clinical and catheterization data with those of patients with classic tamponade. A total of 1429 patients with pericarditis were evaluated, 279 of whom underwent combined pericardiocentesis and catheterization. Criteria of low-pressure cardiac tamponade were met in 29, whereas 114 had criteria of classic cardiac tamponade. Patients with low-pressure tamponade less frequently had clinical signs of tamponade, but the rate of constitutional symptoms, use of diuretics, and echocardiographic findings of tamponade were similar in both groups. Patients with low-pressure tamponade showed a significant increase in cardiac output after pericardiocentesis, but they usually had less severe cardiac tamponade compared with patients with classic tamponade. Prognosis was related mainly to the underlying disease.

CONCLUSIONS

Low-pressure cardiac tamponade was identified in 20% of patients with catheterization-based criteria of tamponade. Clinical recognition may be difficult because of the absence of typical physical findings of tamponade in most patients. Although some patients are critically ill, most show a stable clinical condition. However, these patients obtain a clear benefit from pericardiocentesis.