cardiac implantable electronic devices ( cieds ) have become increasingly important in cardiac disease management worldwide .
in fact , pacemakers , implantable cardioverter defibrillators ( icds ) , and cardiac resynchronization therapy ( crt ) have been used and developed since the 1960s . with the increase in the number of patients with cieds ,
the number of the cied - related complications , including infection , has also been increasing . from 1996 to 2003 , the rates of hospitalization for cied infection reportedly increased faster than the rates of cied implantation . in patients with cied infection , complete removal of all hardware , regardless of location ( subcutaneous , transvenous , or epicardial ) , is the recommended treatment .
various tools ( traction devices , mechanical sheaths , laser sheaths , electrosurgical sheaths , rotating threaded tip sheath , and telescoping sheaths ) and methods ( femoral approach , internal jugular approach , and a hybrid method with both , transvenous and surgical methods ) have been developed for lead removal , and favorable results have been reported , .
however , data to determine the optimal duration of antimicrobial therapy for cied infection are limited .
further , data on appropriate management after cied removal are also not available , although management of arrhythmic support after cied removal is needed until a new cied is implanted . in the present review ,
before a cied can be removed , the consequences of removal need to be ascertained .
patients dependence on pacemakers , the risk of tachyarrhythmia , and requirement of crt must be determined , and the strategy for antiarrhythmic management should be determined on the basis of these investigations .
second , until the new cied is implanted , temporary pacing should be set up , especially in patients completely dependent on a pacemaker , using tools such as passive fixation leads , active fixation leads , and epicardial leads . in their prospective , controlled study , braun et al .   reported that transvenous pacing with active fixation is safe and is associated with a significantly lower rate of pacing - related adverse events than the standard technique of transvenous pacing using a passive external pacing catheter .
forty - nine patients with systemic infection and hemodynamic - relevant bradyarrhythmia were temporarily paced using either a conventional pacing wire / catheter ( n=26 , reference group ) or a permanent bipolar active pacing lead , which was placed transcutaneously in the right ventricle and connected to an external pacing generator ( n=23 , external lead group ) .
the sensing values in the two groups were almost identical , but the median pacing threshold was significantly higher in the reference group ( 1.0  v vs. 0.6  v , p<0.05 ) . within comparable durations of pacing ( median : 8.2 vs. 7.7 days ) , there were 24 pacing - related adverse events ( including dislocation , resuscitation due to severe bradycardia , and local infection ) in the reference group but only one in the external lead group ( p<0.01 ) .
active fixation of temporary leads was only introduced in japan in 2013 . moreover , a 2-week gap is generally observed between cied removal and new cied implantation in patients with pocket infection and a 46-week gap in patients with systemic infection .
therefore , especially in patients completely dependent on pacing , permanent active fixation of leads permitting bipolar stimulation has been used for temporary pacing ( fig .
these leads carry a very low risk of percutaneous infection and lead dysfunction for a couple of weeks .
no clinical trial data are available for determining the optimal duration of antimicrobial therapy for cied infection . however , therapy for 1014 days after device removal is considered reasonable when cied infection is limited to the pocket site , while at least 24 weeks of parenteral therapy after extraction of the infected device is recommended for patients with bloodstream infection . only one study has reported simultaneous contralateral ( side - to - side ) replacement of an infected cied .
a one - stage exchange was performed in 68 consecutive patients over a 14-year period by a single cardiologist , and dual - chamber devices were used in two - thirds of these patients .
clinical presentations included device erosion ( 41% ) , cellulitis or abscess ( 35% ) , and endocarditis ( 24% ) .
fifty - nine patients ( 87% ) were followed up for more than 1 year , and 9 patients were lost to follow - up at 110 months after the one - stage contralateral device exchange , with no newly identified cied infections . additional experience with one - stage contralateral device exchange is needed before it can be recommended for routine use .
the patient had cied infection on both sides , and open chest surgery was needed to remove all cieds .
no re - infection was noted in the 2year follow - up period . in the other case ,
early re - implantation was performed because the patient experienced dementia and restlessness 3 days after cied removal . in this case
as well , no re - infection was noted in the 2-year follow - up period .
patients with high - energy cieds are more likely to develop an infection than patients with a pacemaker .
patients with a high risk of tachyarrhythmia should be temporarily managed using tools such as wearable cardioverter defibrillators ( wcds ) and catheter ablation .
healy et al .   reported on the cost effectiveness of using wcds ( fig .
the incremental cost effectiveness of wcds was $ 20,300 per life - year or $ 26,436 per quality - adjusted life - year ( qaly ) as compared to discharge to home without a wcd .
discharge to a skilled nursing facility and in - hospital monitoring resulted in higher costs and poorer clinical outcomes .
the incremental cost - effectiveness ratio was as low as $ 15,392/qaly if the wcds successfully terminated 95% of sudden cardiac arrest ( sca ) events and exceeded the $ 50,000/qaly willingness - to - pay threshold if their efficacy was < 69% .
use of wcds remained cost effective , assuming a 2-month sca risk of 5.6% , as long as the time to reimplantation was at least 2 weeks .
conducted a retrospective study on all wcd patients who underwent icd removal because of cardiac device infections at two referral centers .
the median daily wcd use was 20  h / day and the median duration of use was 21 days .
two patients had four episodes of sustained ventricular tachycardia ( vt ) , which were successfully terminated by the wcd .
this previous study concluded that the wcd can prevent sudden cardiac death until icd reimplantation is possible in patients from whom the cied has been removed because of cied infection . in japan , because most patients with cied infection are not discharged until a new cied is implanted and are monitored by a telemetry device , the rate of sudden death during the waiting period is low .
however , wcd seems to be safer than only monitoring , even when the patients are hospitalized .
s - icds are beneficial because they carry no risk of vascular injury , have a low risk of systemic infection , and have no need for fluoroscopy .
although s - icds are not a temporary system , they may be suitable for early reimplantation in patients at a high risk of tachyarrhythmia .
we encountered one case of successful ablation before removal of an infected crt - d .
the patient was a 72-year - old woman with complete av block , sustained vt , and cardiac sarcoidosis .
the vt was controlled using amiodarone and pilsicainide , but a vt storm occurred after pilsicainide was withdrawn . because the lv ejection fraction was less than 30%
the vt was finally eliminated by catheter ablation , and it did not recur after implantation of a new cied . thus , catheter ablation may be another useful method for managing tachyarrhythmia during the waiting period .
in patients dependent on crt , it is very difficult to maintain hemodynamics by using temporary vvi pacing after cied removal . to our knowledge ,
we encountered two cases in which temporary sequential pacing was used during the waiting period .
the first was that of a 77-year - old man who suffered from a complete av block , sustained vt , and cardiac sarcoidosis .
vvi pacing instead of crt aggravated the hemodynamic state ( cardiac index [ ci]=2.27  l  min  m in ddd with biv pacing ; 1.76  l  min  m in vvi with rv pacing ) .
the hemodynamic state was maintained for 2 weeks , and a new crt - d was successfully implanted after the infection disappeared .
the other case was that of a 72-year - old woman with complete av block , sustained vt , and cardiac sarcoidosis .
her pacemaker was upgraded to crt - d at the time of mitral valve replacement , and the lv lead was an epicardial lead ( fig .
vvi pacing instead of crt aggravated the hemodynamic state ( ci=1.95  l  min  m in ddd with biv pacing ; 1.74  l  min  m in ddd with only rv pacing ; 1.45  l  min  m in vvi with rv pacing ) .
the lateral chest wall was opened to remove the lv epicardial lead , but because of adhesion of the left lung , the lv lead was only partially removed .
temporary epicardial atrial and lv leads were implanted . a temporary rv lead ( with a permanent active fixation lead )
the hemodynamic state was maintained for 2 weeks , and a new crt - d was successfully implanted after infection disappeared .
we have never used a temporary transvenous lv lead , which may be required in some cases .
various methods can be used for arrhythmic management during the waiting period before new cied implantation .
the aim should be to use an appropriate method to prevent the occurrence of arrhythmic events .
 arrhythmic management is needed after removal of cardiac implantable electronic devices ( cieds ) . 
 patients completely dependent on cieds need temporary device back - up until new cieds are implanted . 
 various methods are available for device back - up , and the appropriate management varies among patients . 
 the duration from cied removal to implantation of a new cied also differs among patients . 
 temporary pacing is needed for patients with bradycardia , a wearable cardioverter defibrillator ( wcd ) or catheter ablation is needed for patients with tachyarrhythmia , and sequential pacing is needed for patients dependent on cardiac resynchronization therapy . 
 the present review focuses on arrhythmic management after cied removal . 