premature beats arising from foci other than pulmonary veins have been related to its pathogenesis . a 64-year - old female underwent superior vena cava ( svc ) isolation after triggers were identified originating from the svc following pulmonary vein isolation ; immediately after svc isolation , she developed junctional rhythm with symptomatic hypotension requiring emergent management . apical motion abnormalities were noticed in the echocardiography suggesting stress - induced cardiomyopathy which resolved 48 hours later . although received a dual chamber pacemaker , intact sinus node function returned 2 weeks later . superior vena cava isolation in those with trigger mediated atrial fibrillation following pulmonary vein isolation ( pvi ) is performed to enhance long - term outcomes . we present the first case of time course of recovery of sinus node function , injured during svc isolation . atrial fibrillation ( af ) is the most common sustained arrhythmia ; its incidence increases with aging . this condition could increase morbidity and mortality due to its high potential to cause heart failure , thromboembolic events and the related conditions associated to its treatment such as bleeding . the cornerstones for the management of atrial fibrillation are anticoagulation to prevent embolic events , control symptoms and avoid deterioration of heart function . af arising from the pulmonary veins ( pv 's ) was recognized by haissaguerre et  al . , in a study that showed 94% of the time pvs are implicated . however , there is some evidence showing that non - pulmonary veins ( npv 's ) premature beats could trigger af in up to 28% of cases . the most common npv foci include the left atrial posterior wall ( 38% ) and superior vena cava  svc (37% ) . other areas acting as npv include crista terminalis , coronary sinus , ligament of marshall and interatrial septum . catheter techniques looking for the electrical isolation of pv antrum and other atrial tissue originating premature beats has emerged as therapeutic option for symptomatic patients with atrial fibrillation , providing symptomatic benefit . we present a clinical case of a patient who developed a transient sinus node block as a complication during pvi and superior vena cava isolation ( svci ) . , although patient did receive a dual chamber pacemaker , two weeks later , sinus node function returned back to baseline , identifying the time course of recovery of sinus node function . a 64 year - old female with drug refractory af and atrial flutter underwent pvi and cavotricuspid isthmus(cti ) ablation . basal measurements and conduction study were considered normal . during the isoproterenol testing the patient developed recurrent episodes of recurrent atrial tachycardia ( at ) , left bundle branch block ( lbb ) and rapid ventricular response af ( cycle length up to 410 msec ) . pvi was carried out with irrigated radiofrequency ( rf ) ablation and lesions were tagged on geometry created using carto 3d sound system ( biosense webster , diamond bar , ca , usa ) ; we did a wide area circumferential ablation on all four pv 's including carinal ablations , with evidence of entrance block . however , triggered af was inducible with isoproterenol , and triggers in vein of marshall was successfully ablated . further testing revealed svc origination of npv triggers and svci was performed ( see fig .  1 , fig .  2 ) . during immediate observation , junctional rhythm at 36 bpm ( fig . 3 ) with hypotension requiring emergency administration of epinephrine and temporary transvenous pacemaker insertion was needed . an echocardiogram showed apical motion abnormalities , and coronary angiogram was negative for coronary artery disease . patient was implanted with a permanent pacemaker after failure of recovery of sinus node function at 48 hours . on weekly observations in clinic , recovery of sinus node function yamaguchi et  al . showed that in those patients with npv foci pvi alone is not enough to reach long term responses suggesting that they should always be addressed during the index ablation procedure . controversies still exist about the npv foci management especially with svc triggers and conflicting evidence exists based on randomized control trials ( rct ) . . showed in 2003 that there were no difference between patients randomly assigned to pvi versus pvi  +  svci regarding af recurrence after ablation . however in a more recent clinical trial evaluating 2 randomly assigned groups to pvi compared to pvi  +  svci , the authors found that those patients who underwent both procedures were significantly less prone to paroxysmal af after 12 months of follow - up . the most common are svc stenosis , phrenic nerve damage with diaphragmatic paralysis and sinus node injury ( sni ) . described 6 patients who developed sni after svci , in this clinical study 5 patients had transient junctional rhythm that resolved in the first 48 hours postprocedure and just one patient required permanent pacemaker implantation . probably the sni is due to the damage to the atrial muscle sleeve that extends into the svc and contains sinus node pacemaker activity . to the best of our knowledge ours is the first report of sni associated with pvi  +  svci where time course of recovery of sinus node function was noted . identification of npv triggers and subsequent successful ablation is performed in order to get higher responses in the long term follow up after the index procedure . premature beats arising from svc triggering af is infrequent but when present has to be approached cautiously due to proximity of phrenic nerve and inadvertent sinus node injury .
introductionatrial fibrillation is the most common sustained heart arrhythmia . 
 premature beats arising from foci other than pulmonary veins have been related to its pathogenesis.methods and resultsa 64-year - old female underwent superior vena cava ( svc ) isolation after triggers were identified originating from the svc following pulmonary vein isolation ; immediately after svc isolation , she developed junctional rhythm with symptomatic hypotension requiring emergent management . 
 apical motion abnormalities were noticed in the echocardiography suggesting stress - induced cardiomyopathy which resolved 48 hours later . although received a dual chamber pacemaker , intact sinus node function returned 2 weeks later.conclusionsuperior 
 vena cava isolation in those with trigger mediated atrial fibrillation following pulmonary vein isolation ( pvi ) is performed to enhance long - term outcomes . 
 sinus node injury has been related previously to this procedure . 
 we present the first case of time course of recovery of sinus node function , injured during svc isolation .