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Normal sinus rhythm and ectopic beats - premature ventricular contractions (PVC) and premature atrial contractions (PAC) shown on an EKG. PVCs may be found incidentally on cardiac tests such as a 12-lead electrocardiogram (ECG/EKG) performed for another reason. In those with symptoms suggestive of premature ventricular complexes, the ECG/EKG is ...
Ventricular escape beats occur when the rate of electrical discharge reaching the ventricles (normally initiated by the heart's sinoatrial node (SA node), transmitted to the atrioventricular node (AV node), and then further transmitted to the ventricles) falls below the base rate determined by the rate of Phase 4 spontaneous depolarisation of ventricular pacemaker cells. [1]
The second Cardiac Arrhythmia Suppression Trial (CAST II) modified the enrollment criteria to include patients at higher risk for serious arrhythmia. [4] This included 1) patients enrolled within 4 to 90 days of a previous MI, 2) a left ventricular ejection fraction lower than 40%, 3) prior to enrollment, suppression of PVCs had occurred with the drugs (vs. placebo) using a double-blinded ...
Pulse pressure is calculated as the difference between the systolic blood pressure and the diastolic blood pressure. [3] [4]The systemic pulse pressure is approximately proportional to stroke volume, or the amount of blood ejected from the left ventricle during systole (pump action) and inversely proportional to the compliance (similar to elasticity) of the aorta.
The normal range has since been revised in textbooks to 50–90 bpm for a human at total rest. Setting a lower threshold for bradycardia prevents misclassification of fit individuals as having a pathologic heart rate. The normal heart rate number can vary as children and adolescents tend to have faster heart rates than average adults.
This may also be called standard range. In contrast, optimal (health) range or therapeutic target is a reference range or limit that is based on concentrations or levels that are associated with optimal health or minimal risk of related complications and diseases. For most substances presented, the optimal levels are the ones normally found in ...
In normal individuals, during ventricular systole, the pressure in the ascending aorta and the left ventricle will equalize, and the aortic valve is open. In individuals with aortic stenosis or with HCM with an outflow tract gradient, there will be a pressure gradient (difference) between the left ventricle and the aorta, with the left ...
The ventricular beats typically have a right axis deviation. Multiple morphologies of ventricular tachycardia may be present in the same individual, suggesting multiple arrhythmogenic foci or pathways. Right ventricular outflow tract (RVOT) tachycardia is the most common VT seen in individuals with ACM.