Cardiac tamponade is that situation where increase in pericardial fluid raises the intrapericardial pressure which interferes with diastolic filling. This leads to decreased ventricular filling resulting in low cardiac output.
Pathophysiology
Progressive increase in pericardial fluid results in progressive increase in intrapericardial pressure, till a critical volume is reached beyond which small increases result in significant increase in intrapericardial pressure. The compliance of the pericardium and rate of accumulation of fluid decides the critical volume. The increase in intrapericardial pressure results in decreased
ventricular distension and decreased ventricular filling. This results in decrease in stroke volume.
In order to maintain cardiac output, there will be sinus tachycardia. In severe cardiac tamponade,this compensatory mechanism will be inadequate resulting in low output, hypotension,hypoperfusion, and shock state. The reduction in coronary circulation can further reduce the myocardial performance.
Clinical Features
The clinical presentation will be that of a low output state with anxiety, restlessness, dyspnoea,sweating, cold extremities and drowsiness.Signsa) Elevated Jugular venous pressure (JVP)-With the increase in intrapericardial pressure the JVP also gets elevated with prominent ‘X’ descent and reduced or absent ‘Y’ descent.
b) Tachypnoea.
c) Sinus tachycardia to compensate the low stroke volume.
Pulsus Paradoxus is a Feature of Cardiac Tamponade: Pulsus paradoxus is diagnosed if decline in systolic pressure during normal inspiration exceeds 10 mm. of Hg. (Pulsus paradoxus is an exaggerated normal response). In extreme cases, the pulse may not be felt during inspiration. Though pulsus paradoxus can be detected by palpation of pulse, blood pressure recording during inspiration and expiration and demonstrating the decline of more than 10 mm. of Hg. in systolic pressure during inspiration confirms this physical finding.
Mechanism: During inspiration there is increase in systemic venous return to the right side of the heart resulting in greater right ventricular filling. Because of the elevated intra-pericardial pressure in cardiac tamponade, in order to accommodate the extra volume of blood during inspiration in the right ventricle, the interventricular septum is pushed to the left ventricle resulting in reduced left ventricular filling. The decreased pulmonary venus return during inspiration adds on to the reduced left ventricular volume which results in reduced stroke volume and reduced systolic pressure.
Pulsus paradoxus can occur in other conditions like effusive constrictive pericarditis and obstructive pulmonary disease.
Investigations
Electrocardiogram (ECG)
Low voltage complexes with electrical alternanes, especially total electrical alternanes, is a feature of cardiac tamponade.
2 Dimensional Echocardiogram (2DE) The 2 DE features of cardiac tamponade are:
1) Massive pericardial effusion.
2) Swinging heart motion in the pericardial fluid.
3) Right ventricular (RV) early diastolic collapse—This is seen in the anterior free wall of RV as a depression during early diastolic and is best seen in parasternal long and short axis views. This sign is highly sensitive in detecting cardiac tamponade. Increase in RV volume and or pressure as in pulmonary arterial hypertension or RV infarction can delay or negate the occurrence of RV diastolic collapse.
4) Right atrial diastolic collapse is also a highly sensitive sign of cardiac tamponade. This is best detected in apical 4 chamber view.Fig. 4.6: Note the prominent right atrial collapse (arrow) in a case of cardiac tamponade. LA – Left Atrium, LV – Left Ventricle, PE – Pericardial Effusion, RA – Right Atrium, RV – Right Ventricle.
5) Respiratory variation of atrioventricular valve flow patterns – expiratory increase in flow across mitral valve and inspiratory increase in flow across tricuspid valve are features of cardiac tamponade. Mitral E decrease of 25 per cent during inspiration is highly suggestive of cardiac tamponade.
6) Inferior vena cava plethora – Lack of normal inspiratory collapse of 50 per cent in the proximal inferior vena cava is a feature of cardiac tamponade.Transoesophageal Echocardiography is not indicated in Cardiac tamponade.Haemodynamic Studies: With the availability of accurate diagnosis by 2DE, there is no indication for cardiac catheterization to confirm the diagnosis of cardiac tamponade.
Treatment
Percutaneous Pericardiocentesis
Cardiac tamponade is an acute emergency and percutaneous pericardiocentesis must be done as immediately as possible. Ideally this should be done under 2DE guidance with haemodynamic monitoring. The percutaneous pericardiocentesis can be done from the subxiphoid region with needle directed towards the 2nd left costochondral junction. Fluid should be removed slowly. Removal of even small quantity of fluid can relieve the tamponade. Complications are damage to coronary arteries and laceration to heart and lungs.See also under cardiac emergencies.
Surgical Pericardial Drainage
Surgical drainage of the pericardial fluid is considered in recurrent pericardial effusion. Surgical drainage gives an opportunity for pericardial biopsy which can confirm the etiology of PE.Pericardial window can be created for drainage of PE to left pleural cavity. This is done for recurrent large PE.
Specific Treatment
Depending upon the etiology of PE, specific treatment must be given.
Pathophysiology
Progressive increase in pericardial fluid results in progressive increase in intrapericardial pressure, till a critical volume is reached beyond which small increases result in significant increase in intrapericardial pressure. The compliance of the pericardium and rate of accumulation of fluid decides the critical volume. The increase in intrapericardial pressure results in decreased
ventricular distension and decreased ventricular filling. This results in decrease in stroke volume.
In order to maintain cardiac output, there will be sinus tachycardia. In severe cardiac tamponade,this compensatory mechanism will be inadequate resulting in low output, hypotension,hypoperfusion, and shock state. The reduction in coronary circulation can further reduce the myocardial performance.
Clinical Features
The clinical presentation will be that of a low output state with anxiety, restlessness, dyspnoea,sweating, cold extremities and drowsiness.Signsa) Elevated Jugular venous pressure (JVP)-With the increase in intrapericardial pressure the JVP also gets elevated with prominent ‘X’ descent and reduced or absent ‘Y’ descent.
b) Tachypnoea.
c) Sinus tachycardia to compensate the low stroke volume.
Pulsus Paradoxus is a Feature of Cardiac Tamponade: Pulsus paradoxus is diagnosed if decline in systolic pressure during normal inspiration exceeds 10 mm. of Hg. (Pulsus paradoxus is an exaggerated normal response). In extreme cases, the pulse may not be felt during inspiration. Though pulsus paradoxus can be detected by palpation of pulse, blood pressure recording during inspiration and expiration and demonstrating the decline of more than 10 mm. of Hg. in systolic pressure during inspiration confirms this physical finding.
Mechanism: During inspiration there is increase in systemic venous return to the right side of the heart resulting in greater right ventricular filling. Because of the elevated intra-pericardial pressure in cardiac tamponade, in order to accommodate the extra volume of blood during inspiration in the right ventricle, the interventricular septum is pushed to the left ventricle resulting in reduced left ventricular filling. The decreased pulmonary venus return during inspiration adds on to the reduced left ventricular volume which results in reduced stroke volume and reduced systolic pressure.
Pulsus paradoxus can occur in other conditions like effusive constrictive pericarditis and obstructive pulmonary disease.
Investigations
Electrocardiogram (ECG)
Low voltage complexes with electrical alternanes, especially total electrical alternanes, is a feature of cardiac tamponade.
2 Dimensional Echocardiogram (2DE) The 2 DE features of cardiac tamponade are:
1) Massive pericardial effusion.
2) Swinging heart motion in the pericardial fluid.
3) Right ventricular (RV) early diastolic collapse—This is seen in the anterior free wall of RV as a depression during early diastolic and is best seen in parasternal long and short axis views. This sign is highly sensitive in detecting cardiac tamponade. Increase in RV volume and or pressure as in pulmonary arterial hypertension or RV infarction can delay or negate the occurrence of RV diastolic collapse.
4) Right atrial diastolic collapse is also a highly sensitive sign of cardiac tamponade. This is best detected in apical 4 chamber view.Fig. 4.6: Note the prominent right atrial collapse (arrow) in a case of cardiac tamponade. LA – Left Atrium, LV – Left Ventricle, PE – Pericardial Effusion, RA – Right Atrium, RV – Right Ventricle.
5) Respiratory variation of atrioventricular valve flow patterns – expiratory increase in flow across mitral valve and inspiratory increase in flow across tricuspid valve are features of cardiac tamponade. Mitral E decrease of 25 per cent during inspiration is highly suggestive of cardiac tamponade.
6) Inferior vena cava plethora – Lack of normal inspiratory collapse of 50 per cent in the proximal inferior vena cava is a feature of cardiac tamponade.Transoesophageal Echocardiography is not indicated in Cardiac tamponade.Haemodynamic Studies: With the availability of accurate diagnosis by 2DE, there is no indication for cardiac catheterization to confirm the diagnosis of cardiac tamponade.
Treatment
Percutaneous Pericardiocentesis
Cardiac tamponade is an acute emergency and percutaneous pericardiocentesis must be done as immediately as possible. Ideally this should be done under 2DE guidance with haemodynamic monitoring. The percutaneous pericardiocentesis can be done from the subxiphoid region with needle directed towards the 2nd left costochondral junction. Fluid should be removed slowly. Removal of even small quantity of fluid can relieve the tamponade. Complications are damage to coronary arteries and laceration to heart and lungs.See also under cardiac emergencies.
Surgical Pericardial Drainage
Surgical drainage of the pericardial fluid is considered in recurrent pericardial effusion. Surgical drainage gives an opportunity for pericardial biopsy which can confirm the etiology of PE.Pericardial window can be created for drainage of PE to left pleural cavity. This is done for recurrent large PE.
Specific Treatment
Depending upon the etiology of PE, specific treatment must be given.
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