cardiac tamponade

Examples of cardiac tamponade in the following topics:

• Pericarditis

  • Other physical signs include a patient in distress, positional chest pain, diaphoresis (excessive sweating), and possibility of heart failure in form of precardial tamponade causing pulsus paradoxus, and the Beck's triad of hypotension (due to decreased cardiac output), distant (muffled) heart sounds, and JVD (jugular vein distention).
  • Pericarditis can progress to pericardial effusion and eventually cardiac tamponade.
  • This can be seen in patients who are experiencing the classic signs of pericarditis but then show signs of relief, and progress to show signs of cardiac tamponade which include decreased alertness and lethargy, pulsus paradoxus (decrease of at least 10 mmHg of the systolic blood pressure upon inspiration), hypotension (due to decreased cardiac index), JVD (jugular vein distention from right sided heart failure and fluid overload), distant heart sounds on auscultation, and equilibration of all the diastolic blood pressures on cardiac catheterization due to the constriction of the pericardium by the fluid.
  • In such cases of cardiac tamponade, EKG or Holter monitor will then depict electrical alterans indicating wobbling of the heart in the fluid filled pericardium, and the capillary refill might decrease, as well as severe vascular collapse and altered mental status due to hypoperfusion of body organs by a heart that cannot pump out blood effectively.
  • The diagnostic test for cardiac tamponade, is trans-esophageal echocardiography (TEE) although trans-thoracic echocardiography (TTE) can also be utilized in cases where there is a high suspicion of aortic dissection and high blood pressure, or in patients where esophageal probing is not feasible.

• The Complement System and Heart Disease

  • In autoimmune heart diseases, the body's immune defense system mistakes its own cardiac antigens as foreign, and attacks them.
  • Autoimmune heart diseases result when the body's own immune defense system mistakes cardiac antigens as foreign, and attacks them, leading to inflammation of the heart as a whole, or in parts.
  • Acutely, it can cause pericardial effusion leading to cardiac tamponade and death.
  • After healing, there may be fibrosis and adhesion of the pericardium with the heart, leading to constriction of the heart and reduced cardiac function.
  • Therapy will involve intensive cardiac care and immunosuppressives, including corticosteroids, which are helpful in the acute stage of the disease.

• Cardiac Cycle

  • The cardiac cycle describes the heart's phases of contraction and relaxation that drive blood flow throughout the body.
  • Heart rate is a term used to describe the frequency of the cardiac cycle.
  • Every single heartbeat includes three major stages: atrial systole, ventricular systole, and complete cardiac diastole.
  • Complete cardiac diastole occurs after systole.
  • Blood pressure is a regulated variable that is directly related to blood volume, based on cardiac output during the cardiac cycle.

• Types of Muscle Tissue

  • The function of muscles is movement, but the types of movement elicited differ between skeletal, cardiac, and smooth muscle.
  • There are three kinds of muscle tissue: skeletal, smooth, and cardiac.
  • Cardiac muscle is found in the walls of the heart.
  • Although cardiac muscle is involuntary in nature, it is structurally different from smooth muscle.
  • Cardiac muscle is striated, similar to skeletal muscle, but beats involuntarily.

• Characteristics of Muscle Tissue

  • The three types of muscle tissue are skeletal, smooth, and cardiac.
  • Cardiac muscle tissue is found only in the heart where cardiac contractions pump blood throughout the body and maintain blood pressure.
  • Cardiac muscle can be further differentiated from skeletal muscle by the presence of intercalated discs which control the synchronized contraction of cardiac tissues.
  • Both cardiac and smooth muscle are involuntary while skeletal muscle is voluntary.
  • Differentiate among the structure and location of skeletal, smooth, and cardiac muscles

• Microscopic Anatomy

  • Cardiac muscle appears striated due to the presence of sarcomeres, the highly-organized basic functional unit of muscle tissue.
  • Cardiac muscle, like skeletal muscle, appears striated due to the organization of muscle tissue into sarcomeres.
  • While similar to skeletal muscle, cardiac muscle is different in a few ways.
  • Cardiac muscles are composed of tubular cardiomyocytes, or cardiac muscle cells.
  • A sarcomere is the basic unit of muscle tissue in both cardiac and skeletal muscle.

• Mechanism and Contraction Events of Cardiac Muscle Fibers

  • Cardiac muscle fibers undergo coordinated contraction via calcium-induced calcium release conducted through the intercalated discs.
  • In cardiac, skeletal, and some smooth muscle tissue, contraction occurs through a phenomenon known as excitation contraction coupling (ECC).
  • Similarly to skeletal muscle, the influx of sodium ions causes an initial depolarization; however, in cardiac muscle, the influx of calcium ions sustains the depolarization so that it lasts longer.
  • The actual mechanical contraction response in cardiac muscle occurs via the sliding filament model of contraction.
  • Calcium in the cytoplasm then binds to cardiac troponin-C, which moves the troponin complex away from the actin binding site.

• Anatomy of the Heart

  • The heart is an organ responsible for pumping blood through the blood vessels using rhythmic contractions of cardiac muscle.
  • The heart has its own self-sustaining conduction system that sends nervous  impulses to cardiac tissue.
  • The middle layer of the heart, the myocardium, and contains specialized cardiac muscle tissue responsible for contraction.
  • Cardiac tissue is permanent tissue that does not heal or regenerate when damaged.
  • The position of valves ensures proper directional flow of blood through the cardiac interior.

• Role of the Cardiovascular Center

  • The cardiovascular center forms part of the autonomic nervous system and is responsible for regulation of cardiac output.
  • The cardioaccelerator center stimulates cardiac function by regulating heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve.
  • The cardioinhibitor center slows cardiac function by decreasing heart rate and stroke volume via parasympathetic stimulation from the vagus nerve.
  • Changes in diameter affect peripheral resistance, pressure, and flow, which in turn affect cardiac output.

• Muscle Tissues and Nervous Tissues

  • There are three types of muscle in animal bodies: smooth, skeletal, and cardiac.
  • Smooth muscle tissue is also called non-striated as it lacks the banded appearance of skeletal and cardiac muscle .
  • Cardiac muscle is found only in the heart.
  • An added feature to cardiac muscle cells is a line that extends along the end of the cell as it abuts the next cardiac cell in the row.
  • Cardiac muscle tissue also has intercalated discs, specialized regions running along the plasma membrane that join adjacent cardiac muscle cells and assist in passing an electrical impulse from cell to cell.