Rate-dependent left ventricular filling time: A critical factor for adequate cardiac output

In patients with heart failure and in the elderly, changes in ventricular rate are a major determinant of cardiac output. In these patients, the range of effective ventricular contractions is markedly reduced than in young and normal adults in whom faster heart rates are well tolerated and contribute to increased cardiac output, particularly in conditions characterized by high adrenergic tone. The picture becomes even more complex when atrial fibrillation develops. The loss of atrial contraction, which reduces ventricular filling and the occurrence of left ventricular desynchronization often induced by fast ventricular rates, may result in further deterioration of cardiac function, particularly when ventricular volume is increased and the strength –length relationship is beyond the physiological range.
Source: Heart Rhythm - Category: Cardiology Authors: Source Type: research