Dr.S.Venkatesan MD

Pacemaker lead implantation is basically a blind procedure .We are supposed to pace the RV apex . It is akin to anchor a ship in the sea bed. Screwing leads are preferred in permanent pacing  ,but tined leads have few unique advantages as well .

Can we combine the advantage of both ?

It is believed displacements are more common with tined leads . May be yes . . . or  is it really so ?

It is not the tines  or screws that is going to  determine the early displacement , rather ,  it is the expertise , commitment and the time spent during the implantation that matters . I have witnessed equal number of  early lead dislodgement in both .

One issue often goes unreported is that , when screwing lead is used operator is subconsciously complacent.While cardiologists who implant  tined lead is more cautious , make sure it is well trapped in RV.

Screwing leads.

• Screwing leads should not be positioned in the same place as tine leads.
• This is because , RV apex is rich in trabeculae. Screws can enter one of the trabeculae or it may even enter  inter  trabecular  space. or poke  thin trabeculae which may  break in near future.(Realise ,how blind we are !)
• Screwing  should be done in area where there is least  trabeculae  ideally in  lower end of septum. Since we do it blindly , we can’t be sure where exactly we have screwed .
• Please note , pacing parameters are less  reliable than anatomy One may get surprisingly good pacing threshold even in trabecular pacing.
• RV non apical pacing is possible only with screwing leads . However , the superiority of RVOT, para hisian pacing is yet to established in patients with normal LV function (Note  90 % of individuals who require PPM have normal LV function )

Tined leads

• In contrary,tined leads are best placed where there is dense trabeculae.
• It is natural entrapment.
• The expertise of screwing  in a best place of RV is not required.
• Whether screwing  predispose   to septal perforations in long term follow up is not known. Logic would suggest it may  !  (The Initial of few mm  of IVS tunneling  is done by us ! )
• Diaphragmatic twtiching is more common with screwing leads.
• Explantation  issues  is similar in both .

What does experienced cardiologists say ?

Cardiologists before the era of EPs were using  only tined leads  without any major hitch . I know electrophysiologists rarely use tined leads now . In our institute ,  with a  cumulative experience of over 3000  pacemakers  over 30 years( 99% are with tined leads ) , we  have no reason to believe they are vastly superior technique.

However there are few definite Indication for screwing lead

• Abnormal RV anatomy
• Loss of RV trabeculae
• Marked Tricuspid regurgitation
• Pulmonary hypertension
• Second lead in RV
• LTGV

* Note all atrial based pacing are screw based as atria lack trabeculae.

A suggestion

Final message

I would believe ,there is no major difference in both short and long term outcome between these two system of leads.Each has it’s own advantage.

After thought

Why can’t  we accrue  the benefits of both ? I think we have good scientific reason to request the pacemaker industry   to  design  a lead which  can have both tines and screws to  provide  double safety .Simple isn’t ?