The heart is a complex three-dimensional structure with mechanical properties that are inhomogeneous, non-linear, time-variant and anisotropic. These properties affect major physiological factors within the heart, such as the pumping performance of the ventricles, the oxygen demand in the tissue and the distribution of coronary blood flow.
During the cardiac cycle the heart muscle tissue is deformed as a consequence of the active contraction of the muscle fibers and their relaxation respectively. A mapping of this deformation would give increased understanding of the mechanical properties of the heart. The deformation induces strain and stress in the tissue which are both mechanical properties and can be described with a mathematical tensor object.
This is a preview of Biomedical Project Ideas: Visualization tool for Myocardial Strain Tensors. Read the full post (172 words, 1 image, estimated 41 secs reading time)
Electrical Activity and EKG
The Cardiac Action Potential Has a Prolonged Refractory Period
- Heart action potential has a prolonged spike (depolarized)
- Membrane is refractory for a long time
- This prevents summation and gives the heart time to fill
All Parts of the Heart Beat Spontaneously
- Heart muscle does not require stimulation by a nerve
- Nerves usually inhibit the heart beat; cutting the nerves -> heart speeds up
- Beat originates as a depolarization in the heart muscle cell itself (self stimulation)
- All parts of the heart can beat spontaneously
This is a normal rhythm, and is not of diagnostic significance unless the rate, which ranges from 60 to 100 beats per minute, is not appropriate for the clinical setting.
This rhythm differs from normal sinus rhythm only in that the rate is above 100 beats per minute. The differential diagnosis is extensive. Common causes are anxiety; physiological stress such as hemorrhage, dehydration, sepsis, and fever; and hyperthyroidism. Correction of the underlying cause, if necessary, is recommended.
This is a preview of Electrocardiographic Rhythms-Biomedical terminology of ECG. Read the full post (4223 words, 1 image, estimated 16:54 mins reading time)
Atrial fibrillation (AFib) is one of the prominent causes of stroke, and its risk increases with age. We need to detect AFib correctly as early as possible to avoid medical disaster because it is likely to proceed into a more serious form in short time. If we can make a portable AFib monitoring system, it will be helpful to many old people because we cannot predict when a patient will have a spasm of AFib.
This is a preview of Atrial fibrillation detection by heart rate variability in Poincare plot. Read the full post (360 words, 1 image, estimated 1:26 mins reading time)