Cardiac Rhythm Management Cardiac Rhythm Management (sometimes called by its initials, CRM) is the area that Admittance works in. This area can be divided into two major classes of devices:

1) a pacemaker, which paces your heart when it’s going too slow, and

2) a defibrillator, which shocks your heart to reset it when it’s going too fast.

When these devices have three leads, including the one in yellow in the diagram, they are called Cardiac Resynchronization Therapy devices, or CRTs. CRT devices have been proven to be effective in improving heart failure patients by synchronizing the two main chambers in the heart.

Admittance is an instrumentation design company that can take advantage of the technology already implanted in patients, with the goal of improving their care.

Example of instrumentation implanted in a heart.

Example of instrumentation implanted in a heart.

At its most basic level, the heart is a pump. When the heart is adequately pumping blood to the body, we feel fine. The amount of blood the heart pumps with each stroke is called the Stroke Volume (SV). When doctors or medical professionals have to decide whether to shock (or defibrillate) a patient who is in the hospital, they consider stroke volume (or a proxy for stroke volume such as blood pressure) along with ECG readings. However, when a patient has an implantable defibrillator and is not in the hospital, current implantable defibrillators only have access to ECG data and not SV in order to determine when to shock. Knowing the stroke volume could assist the implantable defibrillator in evaluating the condition of the heart to make more appropriate shock decisions. .

CardioVol™ uses a proprietary algorithm and current waveforms to determine relative volume in the heart using leads already implanted in patients with CRT devices. This is what CardioVol™ measures compared to a standard of volume (Sonomicrometry crystals, or Sono SV):

The stroke volume of the heart for each beat is the span of the volume each heartbeat. Measured by a highly invasive standard (black) and measured using pacemaker leads and CardioVol™ (blue).

The stroke volume of the heart for each beat is the span of the volume each heartbeat. Measured by a highly invasive standard (black) and measured using pacemaker leads and CardioVol™ (blue).

A heart in normal sinus rhythm (left) and then in fibrillation (right). When the heart is in fibrillation, the patient can lose consciousness in a matter of seconds. It is a very dangerous situation where a pacemaker must intervene with a shock. However, up to 1/3 of the time a pacemaker shocks, a patient did not need to be shocked. This is where CardioVol™ could help.

Cessation of stroke volume, which can happen during fibrillation (abnormal beating) looks like this. A heart in normal sinus rhythm (left) and then in fibrillation (right). When the heart is in fibrillation, the patient can lose consciousness in a matter of seconds. It is a very dangerous situation where a pacemaker must intervene with a shock. However, up to 1/3 of the time a pacemaker shocks, a patient did not need to be shocked. This is where CardioVol™ could help.

And when the SV changes, CardioVolTM can pick it up too. The SV was changed in this study by overdrive pacing to reduce SV, and then dopamine infusion to increase SV:

On the left, the stroke volume is being changed in one experiment. On the right, the stroke volume from CardioVol™ (SV from Gb) is plotted vs. the standard (Stroke Volume).

On the left, the stroke volume is being changed in one experiment. On the right, the stroke volume from CardioVol™ (SV from Gb) is plotted vs. the standard (Stroke Volume).