Effect of acute cardiac tamponade on left ventricular pressure-volume relations in anaesthetised dogs

• Published in: Cardiovascular research 1990-08, Vol.24 (8), p.633-640
• Main Authors: Johnston, William E, Vinten-Johansen, Jakob, Klopfenstein, H Sidney, Santamore, William P, Little, William C
• Format: Article
• Language: English
• Subjects: Acute Disease; Animals; Biological and medical sciences; Blood Pressure - physiology; cardiac tamponade; Cardiac Tamponade - physiopathology; Cardiology. Vascular system; Diseases of the pericardium; Dogs; end systolic pressure-volume relations; experimental; Heart; Hemodynamics - physiology; Medical sciences; myocardial contractile function; Myocardial Contraction - physiology; preload recruitable stroke work; Stroke Volume - physiology; Ventricular Function, Left - physiology
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1093/cvr/24.8.633

Study objective – The aim was to determine whether depressed myocardial contractility is responsible for the decline in stroke volume that occurs with cardiac tamponade. Design – Left ventricular contractile performance was assessed before and after β adrenergic blockade using the end systolic pressure-volume relation, the left ventricular dP/dtmax-end diastolic volume relation, and the left ventricular stroke work-end diastolic volume relation during acute cardiac tamponade in dogs. Experimental material — In eight pentobarbitone anaesthetised dogs (15.7-24.8 kg), transducer tipped and volume impedance catheters were positioned in the left ventricle. Through a median sternotomy incision, a pericardial catheter was inserted to produce varying stages of cardiac tamponade. By the use of transient bicaval occlusions, variably loaded pressure-volume loops were recorded. Measurements and results – Incremental tamponade reduced mean arterial pressure from 105(SEM 3) to 89(2) mm Hg (mild tamponade), 75(2) mm Hg (moderate tamponade), and 59(10) mm Hg (severe tamponade). The slope of the end systolic pressurevolume relation was 6.3(1.2) mm Hg·ml−1 at baseline and increased slightly to 7.7(1.8), 8.5(1.3), and 9.2(1.5) mm Hg·ml−1 with the progressive levels of tamponade (NS). The role of autonomic reflexes was assessed by repeating the tamponade sequence after β adrenergic blockade with 10 mg of metoprolol intravenously. The slope of the end systolic pressure- volume relation was reduced by metoprolol, at 4.9(1.0) mm Hg·ml−1 (p