Does a pacemaker increase cardiac output?
This clinical study tests the hypothesis that the respiratory-dependent pacemaker (RDP) is able to increase CO by an increase in HR. A multiprogrammable RDP (BIOrate RDP 2, Alpha, Köln, West Germany) was implanted in 21 patients (16 men and 5 women) for ventricular pacing.
Is cardiac output decreased with atrial fibrillation?
Atrial fibrillation (AF) can lead to a fall in cardiac output that is often clinically significant. Potential consequences include a fall in blood pressure, decreased exercise capacity, and pulmonary congestion, all of which are manifestations of heart failure (HF).
How can cardiac rhythm affect cardiac output?
Tachycardia of atrial or ventricular origin reduces stroke volume and cardiac output particularly when the ventricular rate is greater than 160 beats/min. The stroke volume becomes reduced because of decreased ventricular filling time and decreased ventricular filling (preload) at high rates of contraction.
What is pacing induced cardiomyopathy?
Pacing induced cardiomyopathy (PICM) is most commonly defined as a drop in left ventricle ejection fraction (LVEF) in the setting of chronic, high burden right ventricle (RV) pacing.
What is pacing and sensing in pacemakers?
Pacing refers to depolarization of the atria or ventricles, resulting from an impulse (typically 0.5 msec and 2 to 5 volts) delivered from the generator down a lead to the heart. Sensing refers to detection by the generator of intrinsic atrial or ventricular depolarization signals that are conducted up a lead.
What are signs of decreased cardiac output?
A decrease in cardiac output is characterized by the following manifestations:
- Abnormal heart sounds (S3, S4)
- Angina.
- Anxiety, restlessness.
- Change in level of consciousness.
- Crackles, dyspnea, orthopnea, tachypnea.
- Decreased activity tolerance.
- Decreased cardiac output.
How does atrial flutter affect cardiac output?
The symptoms of atrial flutter relate to tachycardic heart rate either causing palpitations or decreased overall cardiac output (from loss of atrial contraction and fast ventricular rates) resulting in congestive heart failure.
What factors increase cardiac output?
The determinants of cardiac output are:
- Heart rate. A higher heart rate increases cardiac output as it multiplies by stroke volume.
- Stroke volume, which is in turn determined by preload, afterload and cardiac output.
- Preload. Increased preload leads to an increase in the stroke volume.
- Afterload.
- Cardiac contractility:
Does pacing increase cardiac output?
It is the latter that is the most effective in generating an increased cardiac output. Pacing per se is unable to influence contractility (although it is arguable that the benefits of resynchronisation pacing is a manifestation of improved contractile coordination, and with remodelling, improved contractility).
What is the difference between atrial pacing and ventricular pacing?
If the atrial rate exceeds the baser rate of the pacemaker but ventricular rate does not, then atrial pacing is inhibited, but ventricular pacing is triggered. DDI pacemaker offers pacing and sensing in the atria and ventricles and can also be inhibited if spontaneous activity occurs. Atrial activity will not trigger ventricular pacing.
Does pacing mode affect the outcome of atrial fibrillation?
Longer follow‐up is being undertaken and is required to exclude the possibility of a delayed effect of pacing mode on atrial fibrillation, heart failure and other outcomes. Studies of benefits of dual chamber pacing using right ventricular pacing suggest: little or no impact on mortality reduction
What are the different methods of pacemaker pacing?
1 Sensing. The pacemaker can record intrinsic cardiac activity and response appropriately. 2 Base rate. The base rate is the lowest heart rate allowed by the pacemaker; intrinsic cardiac activity below the base rate will trigger pacing. 3 Triggering.