| RV | random variable; rat virus; Rauscher virus; rectovaginal; reinforcement value; renal vein; residual ... |
|---|---|
| RVA | re-entrant ventricular arrhythmia; right ventricle activation; right vertebral artery |
| RVF | renal vascular failure; Rift Valley fever; right ventricular failure; right visual field |
| VR | right arm [electrode]; valve replacement; variable ratio; vascular resistance; venous reflux; venous... |
| RL | radial line; radiation laboratory; reduction level; renal dysplasia-limb defects [syndrome]; resisti... |
| intra-atrial | Within one or both of the atria of the heart. (05 Mar 2000) |
|---|---|
| intra-atrial block | Impaired conduction through the atria, manifested by widened and often notched P waves in the electrocardiogram. (05 Mar 2000) |
| intra-atrial conduction | Conduction of the cardiac impulse through the atrial myocardium, represented by the P wave in the electrocardiogram. (05 Mar 2000) |
| intra-atrial conduction time | The total duration of electrical activity of the atria in one cardiac cycle. (05 Mar 2000) |
| tachycardia, ectopic atrial | A tachycardia originating in the atrial myocardium and characterised by rates between 135 and 175 beats per minute. (12 Dec 1998) |
| tachycardia, paroxysmal atrial | Bouts of rapid, regular heart beating originating in the atrium (upper chamber of the heart). Often due to abnormalities in the av node relay station that lead to rapid firing of electrical impulses from the atrium which bypass the av node under certain conditions. These conditions include alcohol excess, stress, caffeine, overactive thyroid or excessive thyroid hormone intake, and certain drugs. Pat is an example of an arrhythmia where the abnormality is in the electrical system of the heart, while the heart muscle and valves may be normal. (12 Dec 1998) |
| fibrillation, atrial | An abnormal irregular heart rhythm whereby electrical signals are generated chaotically throughout the upper chambers (atria) of the heart. Although many persons with atrial fibrillation have no symptoms, the most common symptom is palpitations, an uncomfortable awareness of the rapid and irregular heartbeat. Atrial fibrillation can cause blood clots that travel from the heart to the brain, causing stroke. Treatment of atrial fibrillation involves controlling the risk factors, medications to slow the heart rate and/or convert the heart to normal rhythm, and preventing complications of blood clotting. (12 Dec 1998) |
| lateral atrial vein | A vein draining deep portions of the temporal and parietal lobes; it runs in the lateral wall of the lateral ventricle to terminate in the superior thalamostriate vein. Synonym: vena ventriculi lateralis lateralis, lateral atrial vein, lateral vein of lateral ventricle. (05 Mar 2000) |
| aberrant ventricular conduction | Abnormal intraventricular conduction of a supraventricular beat, especially where surrounding beats are normally conducted. Synonym: ventricular aberration. (05 Mar 2000) |
| arrhythmias, ventricular | Abnormal rapid heart rhythms (arrhythmias) that originate in the lower chambers of the heart (the ventricles). Ventricular arrhythmias include ventricular tachycardia and ventricular fibrillation. Both are life threatening arrhythmias most commonly associated with heart attacks or scarring of the heart muscle from previous heart attack. (12 Dec 1998) |
| bidirectional ventricular tachycardia | Ventricular tachycardia in which the QRS complexes in the electrocardiogram are alternately mainly positive and mainly negative; many such cases may represent ventricular tachycardia with alternating forms of aberrant ventricular conduction. (05 Mar 2000) |
| ventricular | <anatomy> Pertaining to a ventricle. (18 Nov 1997) |
| ventricular aberration | Abnormal intraventricular conduction of a supraventricular beat, especially where surrounding beats are normally conducted. Synonym: ventricular aberration. (05 Mar 2000) |
| ventricular afterload | Formerly, the arterial pressure or some other measure of the force that a ventricle must overcome while it contracts during ejection, contributed to by aortic or pulmonic artery impedance, peripheral vascular resistance, and mass and viscosity of blood; now, more rigorously expressed in terms of the wall stress, i.e., the tension per unit cross-sectional area in the ventricular muscle fibres (calculated by an expansion of Laplace's law utilizing pressure, internal radius, and wall thickness) that is required to produce the intracavitary pressure required during ejection. (05 Mar 2000) |
| ventricular aneurysm | Aneurysm of the ventricular portion of the membranous septum, an aneurysm that bulges toward the right in systole, often consisting of the anterior leaflet of the tricuspid valve. Synonym: cardiac aneurysm. (05 Mar 2000) |