What is meant by a "controlled" ventricular rate in atrial fibrillation?

Abstract

Reduction of a rapid ventricular rate in atrial fibrillation results in a longer diastolic filling period and a higher left ventricular stroke volume but this is offset by reduced contractility and fewer beats per minute; the net effect on cardiac output is uncertain. Sequences of stroke distances were measured by Doppler ultrasound in 60 resting patients with atrial fibrillation to determine the relation between ventricular rate and linear cardiac output. The slope of the cardiac output/ventricular rate relation was positive in all 20 patients with a ventricular rate less than 90 beats per minute and negative in 16 (40%) of 40 patients with a ventricular rate greater than 90 beats per minute. In atrial fibrillation the ventricular rate can be regarded as "controlled" when the cardiac output/ventricular rate slope is positive and "uncontrolled" when the slope is negative--that is when reduction of ventricular rate would lead to increased cardiac output. As so defined, ventricular rate at rest was controlled in every patient when the ventricular rate was less than 90, controlled in 44 (73%) patients when the ventricular rate was 90-140 beats per minute, and uncontrolled in every case when it was greater than 140 beats per minute. Achieving a target ventricular rate of 90 beats per minute in patients with atrial fibrillation at rest would result in control with the least compromise of cardiac output.

Guidelines for Pharmacotherapy of Atrial Fibrillation (JCS 2013)

“…In order to prevent the development of congestive heart failure, it is important to control the heart rate during AF to ≤130 bpm. 114 In the RACE II (Rate Control Efficacy in Permanent Atrial Fibrillation: a Comparison between Lenient versus Strict Rate Control II) study, the incidence rates of symptoms and adverse events and the severity of heart failure did not differ between patients receiving lenient rate control with a target resting heart rate of <110 bpm and those receiving strict rate control with a target resting heart rate of <80 bpm and a target heart rate of <110 bpm during moderate exercise. 115 However, this finding does not mean that a target resting heart rate of 100~109 bpm is sufficient.…”

Hizli Ventrikul Cevapli Atri̇al Fi̇bri̇lasyonlu Olgularda İntravenöz Di̇lti̇azem Ve Di̇goksi̇ni̇n İsti̇rahat Ve Kisa Süreli̇ Egzersi̇z Sonrasi Etki̇nli̇ği̇

“…İstira-hat halindeki atrial fibrilasyonlu bir kalbin optimal vuru sayısı normalden yüksek olabilir. Hemodinamik açıdan ideal atım sayısı ortalama dakikada 90 dolaylarındadır (3). Atrial fibrilasyonda ventrikül hı-zını kontrol etmek amacıyla digoksin önceden beri kullanılmaktadır.…”

The drug treatment of atrial fibrillation.

“…Anti-arrhythmic drugs in the classes Ia, Ic and III have this property. Digoxin, however, which is widely used in established fibrillation to slow atrioventricular conduction, actually shortens atrial refractory period and is ineffective in preventing atrial fibrillation developing and actually prolongs the duration of bouts of atrial fibrillation (Rawles et al, 1990).…”

“…More usually the ventricular rate is fast and this is associated with short diastolic filling periods and low cardiac output. Rawles (1990) recently showed that the optimum ventricular rate at rest in atrial fibrillation was about 90 beats min-' rather than 70 beats min-' which is the optimum in sinus rhythm. He hypothesised that the higher rate was required in atrial fibrillation to compensate for the loss of effective atrial contraction.…”

“…He hypothesised that the higher rate was required in atrial fibrillation to compensate for the loss of effective atrial contraction. The contribution of atrial systole to left ventricular filling increases with exercise (Channer & Jones, 1989) and Rawles (1990) predicted that the loss of atrial systole in atrial fibrillation would be compensated for by an increase in heart rate during exercise. One method of examining variations in heart rate is by using 24 h ambulatory electrocardiography.…”