Indications



OVATIO CRT 6750 is indicated for ventricular antitachycardia pacing and ventricular defibrillation for automated treatment of life threatening arrhythmias.


The device is also indicated for the reduction of heart failure symptoms in NYHA Functional Class III and IV patients with left ventricular ejection fraction of 35% or less, and a QRS duration of 150 ms or longer.

In some cases of retrograde ventricular conduction, the use of atrial- triggered modes (DDD, VDD) can often activate the protection mechanism against pacemaker-mediated tachycardia. It is therefore advisable to evaluate carefully the most appropriate atrial refractory period or to select a non- synchronized pacing mode e.g. DDI, which is specifically indicated for bradytachy syndrome.



Contraindications


Implantation of OVATIO CRT 6750 is contraindicated in patients:


- whose ventricular tachyarrhythmias may have transient or reversible causes such as: acute myocardial infarction, digitalis intoxication, drowning, electrocution, electrolyte imbalance, hypoxia, sepsis, or unstable ischemic episodes,
- who present incessant tachyarrhythmia,
- who have an internal pacemaker,
- whose primary disorder is bradyarrhythmias, or atrial tachyarrhythmias,

Dual-chamber and single chamber atrial pacing is contraindicated in patients with chronic refractory atrial tachyarrhythmias.


Warnings and precautions


The patient should be warned of the potential risks of defibrillator malfunction if he is exposed to external magnetic, electrical, or electromagnetic signals.

These potential interference sources may cause conversion to inhibited mode (because of noise detection), erratic delivery of VT or VF therapies, nominal programming, or much more rarely, irreversible damage to the device’s circuits.

The main sources of high magnitude electrical interference are: powerful radiofrequency equipment (radar), industrial motors and transformers, induction furnaces, resistance and arc-welding equipment, and high power loudspeakers.

Be aware that the changes in the patient’s condition, drug regimen, and other factors may change the defibrillation threshold (DFT) which may result in non-conversion of the arrhythmia post-operatively. Successful conversion of ventricular fibrillation or ventricular tachycardia during arrhythmia conversion testing is no assurance that conversion will occur post-operatively.

Resuscitation Availability. Do not perform device testing unless an external defibrillator and medical personnel skilled in cardiopulmonary resuscitation (CPR) are readily available.

Electrical Isolation. Do not permit the patient to contact grounded equipment that could produce hazardous leakage current. Ensuing arrhythmia induction could result in the patient’s death.

Disable the ICD During Handling. Program Shock Therapy to OFF during surgical implant and explant or post mortem procedures. The device can deliver a serious high energy shock should accidental contact be made with the defibrillation electrodes.

Antitheft gates. Since antitheft devices at the entrance to stores are not subject to any safety standards, it is advisable to spend as little time as possible in their vicinity.

Airport detection systems. Since airport detection systems are not subject to any safety standards, it is advisable to spend as little time as possible in their vicinity.

High voltage power transmission lines. High voltage power transmission lines may generate enough EMI to interfere with defibrillator operation if approached too closely.

Communication equipment. Communication equipment such as microwave transmitters, linear power amplifiers, or high-power amateur transmitters may generate enough EMI to interfere with defibrillator operation if approached too closely.

Home appliances. Home appliances that are in good working order and properly grounded do not usually produce enough EMI to interfere with defibrillator operation. There are reports of device disturbances caused by electric hand tools or electric razors used directly over the device implant site.

Cellular phones. Radiofrequency signals can interfere with the functioning of OVATIO CRT 6750 if the handset is placed too close to the defibrillator. It is advisable to maintain a minimum distance of 30 cm (12 inches) between the cellular telephone and the implanted device, when the telephone is turned on.

CAUTION : Do not tap sharply on the ICD can after implant, because the ICD's sensing circuits can detect this as P-waves or R-waves, and such oversensing could result in inappropriate pacing, inhibition, or therapy. Normal activities after implant do not result in such oversensing.