Home monitoring of implantable cardioverter-defibrillators: interpretation reliability of the second-generation "IEGM Online" system.

AIMS: Intracardiac electrograms (IEGMs) are essential for the assessment of implantable cardioverter-defibrillator (ICD) function. The Biotronik Home Monitoring systems transmit an 'IEGM Online' that is shorter than the full-length programmer IEGM due to technical constrains. The aim of this study was to evaluate the accuracy of the physician's classification of the underlying rhythm based on the second-generation IEGM Online. METHODS AND RESULTS: In total, 1533 patients treated with single- and dual-chamber ICDs and cardiac resynchronization therapy defibrillators were enrolled at 67 investigational sites and followed for 15 months. The investigators classified the rhythm shown in IEGM Online as ventricular tachycardia, ventricular fibrillation, atrial fibrillation, other supraventricular tachyarrhythmia, oversensing due to lead failure, T-wave oversensing, or other rhythm. At the next in-office follow-up, the investigators classified independently the rhythm seen in the corresponding programmer IEGM. The two rhythm classifications were compared thereafter. Both IEGM Online and programmer IEGM were available in 2099 arrhythmic or oversensing events, of which 146 (7.0%) were classified as other rhythm or artefacts and were excluded as inconclusive or atypical. The remaining 1953 events, affecting 352 patients (23.0%), were classified correctly in 1803 cases (92.3%). The accuracy of rough rhythm classification as ventricular, supraventricular, or oversensing was 97.2%. CONCLUSION: The Lumax and IEGM Online HD Evaluation study demonstrates that remote IEGM analysis is reasonably accurate in a remote monitoring system that transmits shorter IEGM than the full-length programmer IEGM for the sake of frequent, fully automatic data transmission.

Clinical, anatomical, and technical risk factors for postoperative pacemaker or defibrillator lead perforation with particular focus on myocardial thickness.

BACKGROUND: Postoperative lead perforation is a life-threatening complication of cardiac pacing. Identification of precipitating factors for this serious complication may help to anticipate a specific risk profile and to minimize the incidence. METHODS: We conducted a retrospective tertiary referral center analysis to clarify clinical, anatomical, and technical characteristics related to pacemaker (PM) and cardioverter/defibrillator lead perforation. We examined the baseline characteristics and the symptoms. In a subgroup, we investigated the myocardial thickness on contrast-enhanced cardiac computed tomography. RESULTS: We enrolled 26 patients. Female gender appears to put patients at slightly increased risk for lead perforation. In a majority active fixation leads were used. Symptoms occurred in 72%. Pericardial effusion and tamponade were present in 38% and 19%, respectively. Sensing was compromised in 65%. A high pacing threshold or exit block occurred in 92%. Myocardial thickness did not differ between patients with or without perforation. In 96%, the perforation was treated by transvenous withdrawal. CONCLUSION: Chest pain, phrenic stimulation, bad sensing, or exit block early after PM implantation must prompt radiological and echocardiographic evaluation. A missing pericardial effusion particularly late after implantation does not rule out a perforation. Especially active fixating leads have a higher risk of perforation. With cardiac surgery in standby transvenous withdrawal is a safe way to treat lead perforation.

Complete atrioventricular block after TAVI: when is pacemaker implantation safe?

INTRODUCTION: Atrioventricular (AV) block is a frequent complication of transcatheter aortic valve implantation (TAVI). TAVI is routinely performed under anticoagulation using heparin, which potentially may lead to an increased bleeding rate in patients who undergo permanent pacemaker (PPM) implantation immediately after TAVI. As the number of TAVI procedures continues to rise, data on the optimal management of TAVI-related AV block are needed. Therefore, the aim of our study was to analyze PPM implantation-related complications after TAVI. METHODS: We retrospectively collected data on PPM implantations after TAVI in our center from January 2010 to December 2012. In total, we included 30 patients who received a PPM for TAVI-related AV block. Twelve patients (group A) underwent PPM implantation on the day of TAVI. In 18 patients (group B), PPM implantation was performed at least 1 day after TAVI (3.8 ± 4.5 days). Since all patients undergoing TAVI receive dual antiplatelet therapy (DA-therapy), we compared all implantations after TAVI with a historic patient cohort that underwent PPM implantation under DA-therapy. RESULTS: Procedure times, fluid loss via drainage systems, and drainage times were neither significantly different between groups A and B nor between all PPM implantations after TAVI compared to the historic control group. CONCLUSION: PPM implantation immediately after TAVI is safe and can be performed without increased rate of complications.

Pacing-induced cardiomyopathy in patients with right ventricular stimulation for >15 years.

AIMS: The prevalence of pacing-induced cardiomyopathy (PiCMP) has been reported to be 9% 1 year after implantation. As long-term data are sparse, the aim of our study was to evaluate the prevalence of PiCMP in a cohort of patients with at least 15 years of right ventricular (RV) pacing. METHODS AND RESULTS: Inclusion criteria were RV stimulation for at least 15 years due to atrioventricular block III° and absence of structural heart disease at the time of initial implantation. All patients were examined by echocardiography and spiroergometry. Pacing-induced cardiomyopathy was pre-defined as left ventricular (LV) ejection fraction (LVEF) ≤45%, dyskinesia during RV pacing and absence of other known causes of cardiomyopathy. Twenty-six patients from our outpatient department met the inclusion criteria. Pacing-induced cardiomyopathy was diagnosed in four patients (15.4%). Echocardiography showed significant LV remodelling in PiCMP patients [LVEF 41.0 ± 4.5%, LV end-diastolic diameter (LVEDD) 54.0 ± 2.7 mm] compared with patients with preserved LVEF (LVEF 61.2 ± 5.8%, P = 0.002, LVEDD 45.6 ± 4.0 mm, P= 0.004). There were no significant differences regarding age, gender, duration of RV pacing, heart rate, interventricular mechanical delay, QRS duration or prevalence of sinus rhythm, and arterial hypertension between both groups. The longest intraventricular delay was significantly shorter in patients with preserved LVEF (65.5 ± 43.0 ms) compared with PiCMP patients (112.5 ± 15.0 ms, P= 0.043). Exercise capacity and quality of life did not differ significantly between both groups. CONCLUSION: Considering the very long duration of RV stimulation in our study population (24.6 ± 6.6 years), the prevalence of PiCMP was remarkably low. Pacing-induced cardiomyopathy was associated with more pronounced intraventricular dyssynchrony.

Dyssynchrony parameter-guided interventricular delay programming.

AIMS: Interventricular (VV) delay optimization for cardiac resynchronization therapy (CRT) is recommended by current guidelines and several algorithms have been proposed. So far, however, no gold standard has been established in the clinical routine. We hypothesized that dyssynchrony parameter assessment might guide VV delay optimization and investigated whether dyssynchrony parameter changes induced by sequential biventricular pacing follow a predictable pattern. METHODS AND RESULTS: We determined intra- and interventricular dyssynchrony in 80 CRT patients by echocardiographic quantification of the interventricular mechanical delay and the septal-lateral time to peak systolic velocity delay. Dyssynchrony parameters were assessed during simultaneous biventricular pacing as well as during sequential biventricular pacing with a right ventricular (RV) or left ventricular (LV) preactivation of 40 ms. Simultaneous biventricular pacing significantly improved inter- and intraventricular dyssynchrony parameters compared with preoperative baseline measurements. In general, dyssynchrony parameter changes induced by sequential biventricular pacing showed high interindividual variance and did not follow a predictable pattern. Intra- or interventricular dyssynchrony persisted during simultaneous biventricular pacing in 39 and 19% of our patients, respectively. Neither RV nor LV preactivation significantly decreased the number of patients with persistent intraventricular dyssynchrony. In contrast, LV preactivation significantly reduced the prevalence of interventricular dyssynchrony by 80%. CONCLUSIONS: Left ventricular preactivation effectively ameliorates interventricular dyssynchrony, which persists in almost one in five CRT patients. Assessment of interventricular dyssynchrony and consecutive programming of LV preactivation in patients with persistent interventricular dyssynchrony may represent a pragmatic and time-effective approach to improve CRT in patients with inferior response.

Remote monitoring of implantable-cardioverter defibrillators: results from the Reliability of IEGM Online Interpretation (RIONI) study.

AIMS: Intracardiac electrograms (IEGMs) recorded by implantable cardioverter-defibrillators (ICDs) are essential for arrhythmia diagnosis and ICD therapy assessment. Short IEGM snapshots showing 3-10 s before arrhythmia detection were added to the Biotronik Home Monitoring system in 2005 as the first-generation IEGM Online. The RIONI study tested the primary hypothesis that experts' ratings regarding the appropriateness of ICD therapy based on IEGM Online and on standard 30 s IEGM differ in <10% of arrhythmia events. METHODS AND RESULTS: A total of 619 ICD patients were enrolled and followed for 1 year. According to a predefined procedure, 210 events recorded by the ICDs were selected for evaluation. Three expert board members rated the appropriateness of ICD therapy and classified the underlying arrhythmia using coded IEGM Online and standard IEGM to avoid bias. The average duration of IEGM Online was 4.4±1.5 s. According to standard IEGM, the underlying arrhythmia was ventricular in 135 episodes (64.3%), supraventricular in 53 episodes (25.2%), oversensing in 17 episodes (8.1%), and uncertain in 5 episodes (2.4%). The expert board's rating diverged between determinable IEGM Online tracings and standard IEGM in 4.6% of episodes regarding the appropriateness of ICD therapy (95% CI up to 8.0%) and in 6.6% of episodes regarding arrhythmia classification (95% CI up to 10.5%). CONCLUSION: By enabling accurate evaluation of the appropriateness of ICD therapy and the underlying arrhythmia, the first-generation IEGM Online provided a clinically effective basis for timely interventions and for optimized patient management schemes, which was comparable with current IEGM recordings.

Is antiarrhythmia device implantation safe under dual antiplatelet therapy?

BACKGROUND: Device implantations in patients on dual antiplatelet-therapy (DA-therapy) continue to rise. The aim of our study was to compile and analyze data on complications of antiarrhythmia device implantation under DA-therapy. METHODS: We prospectively collected data on all device implantations in our department from January 2008 until February 2009. The control group was comprised of patients on acetylsalicylic acid alone or no antiplatelet medication at all (318 subjects). The DA-therapy group consisted of 109 patients of whom 71 were analyzed retrospectively (implantations from 2002 to 2007). RESULTS: Procedure times were significantly longer in DA-therapy patients receiving a pacemaker for the first time. In contrast, procedure times did not differ significantly between the two study groups for implantable cardioverter defibrillator (ICD) implantations and for pacemaker replacements. Fluid losses via drainage systems and drainage times were significantly increased in the DA-therapy group as compared with the control group after pacemaker but not after ICD implantations. Importantly, there were no significant differences in complication rates, particularly the hematoma rate, between the DA-therapy and the control group. CONCLUSIONS: When drainage systems are used, antiarrhythmia device implantation is safe and can be performed without significantly increased risk of clinically relevant hematoma in patients on continued DA-therapy. (PACE 2010; 394-399).

Should we use the rate-adaptive AV delay in cardiac resynchronization therapy-pacing?

AIMS: Recommendations for programming the rate-adaptive AV delay in CRT. METHODS AND RESULTS: In cases of continual biventricular pacing, the optimal AV delay in CRT (AVD(opt)) is the net effect of the pacemaker-related interatrial conduction time (IACT), duration of the left-atrial electromechanical action (LA-EAC(long)), and the duration of the left-ventricular latency period (S(V)-EAC(short)). It can be calculated by AVD(opt) = IACT+LA-EAC(long)-S(V)-EAC(short). We measured these three components in 20 CRT-ICD patients during rest and submaximal ergo metric exercise (71 +/- 9 W) resulting in a 22.5 +/- 9.6 bpm rate increase. IACT and S(V)-EAC(short) did not reveal significant differences. LA-EAC(long), however, varied significantly by -10.7 +/- 16.1 ms (P = 0.008) during exercise. In contrast to AVD(optVDD), there was a significant difference in AVD(optDDD) of -8.8 +/- 14.5 ms (P = 0.014) between the resting and submaximal exercise conditions. In DDD pacing, AVD(opt) was shortened by 2.6 ms/10 bpm. CONCLUSION: In consideration of the findings of the studies performed to date, the rate-adaptive AV delay should be deactivated.

Circumferential 2D-strain imaging for the prediction of long term response to cardiac resynchronization therapy.

BACKGROUND: Cardiac Resynchronization Therapy (CRT) leads to hemodynamic and clinical improvement in heart failure patients. The established methods to evaluate myocardial asynchrony analyze longitudinal and radial myocardial function. This study evaluates the new method of circumferential 2D-strain imaging in the prediction of the long-term response to CRT. METHODS AND RESULTS: 38 heart failure patients (NYHA II-III, QRS > 120 ms, LVEF < 0.35) received CRT and echocardiographic evaluation with a mean follow-up of 9.4 months. 18 (47.4%) of the patients were hemodynamic responders to long-term CRT. In the responder group, the maximum delay in the circumferential 2D-strain in the basal segments decreased (246 +/- 94 to 123 +/- 92 ms, p < 0.001). In the non-responder group there was no significant change (pre CRT: 195 +/- 86, post CRT 135 +/- 136 ms, p = 0.84). This was paralleled by a reduction of the maximum delay in the radial and longitudinal 2D strain in the basal segments. In ROC analysis, the baseline delay of circumferential 2D strain (AUC 0.66 (+/- 0.14)) does not predict a long-term response to CRT (p = 0.37). CONCLUSION: There is a significant decrease in the circumferential 2D-strain derived delays after CRT, indicating that resynchronization induces improvement in all three dimensions of myocardial contraction. However, the resulting predictive values of 2D strain delays are not superior to longitudinal and radial 2D-strain or TDI delays.

Implementation of seven echocardiographic parameters of myocardial asynchrony to improve the long-term response rate of cardiac resynchronization therapy (CRT).

BACKGROUND: Cardiac resynchronization Therapy (CRT) is an effective therapy for chronic heart failure with beneficial hemodynamic effects leading to a reduction of morbidity and mortality. The responder rates, however, are low. There are various and contentious echocardiographic parameters of myocardial asynchrony. Patient selection by echocardiographic assessment of asynchrony is thought to improve responder rates. METHODS: In this small single-center pilot-study, seven established parameters of myocardial asynchrony were used to select patients for CRT: (1) interventricular electromechanical delay (IMD, cut-off > or = 40 ms), (2) Septal-to-posterior wall motion delay (SPWMD, > or = 130 ms), (3) maximal difference in time-to-peak velocities between any two of twelve LV segments (Ts-12 > or = 104 ms), (4) standard deviation of time to peak myocardial velocities (Ts-12-SD, > or = 34.4 ms), (5) difference between the septal and basal time-to-peak velocity (TDId, > or = 60 ms), (6) left ventricular electromechanical delay (LVEMD, > 140 ms) and (7) delayed longitudinal contraction (DLC, > 2 segments).16 chronic heart failure patients (NYHA III-IV, LVEF < 0.35, QRS > or = 120 ms) at least two out of seven parameters of myocardial asynchrony received cardiac resynchronization therapy (CRT-ICD). Follow-up echo examination was after 6 months. The control group was a historic group of CRT patients (n = 38) who had not been screened for echocardiographic signs of myocardial asynchrony prior to device implantation. RESULTS: Based on reverse remodeling (relative reduction of LVESV > 15%, relative increase of LVEF > 25%), the responder rate to CRT was 81.2% in patients selected for CRT according to our protocol as compared to 47.4% in the control group (p = 0.04). At baseline, there were on average 4.1 +/- 1.6 positive parameters of asynchrony (follow-up: 3.7 [+/- 1.6] parameters positive, p = 0.52). Only the LVEMD decreased significantly after CRT (p = 0.027). The remaining parameters showed a non-significant trend towards reduction of myocardial asynchrony. CONCLUSION: The implementation of different markers of asynchrony in the selection process for CRT improves the hemodynamic response rate to CRT.

Influence of the atrio-ventricular delay optimization on the intra left ventricular delay in Cardiac Resynchronization Therapy.

BACKGROUND: Cardiac Resynchronization Therapy (CRT) leads to a reduction of left-ventricular dyssynchrony and an acute and sustained hemodynamic improvement in patients with chronic heart failure. Furthermore, an optimized AV-delay leads to an improved myocardial performance in pacemaker patients. The focus of this study is to investigate the acute effect of an optimized AV-delay on parameters of dyssynchrony in CRT patients. METHOD: 11 chronic heart failure patients with CRT who were on stable medication were included in this study. The optimal AV-delay was defined according to the method of Ismer (mitral inflow and trans-oesophageal lead). Dyssynchrony was assessed echocardiographically at three different settings: AVDOPT; AVDOPT-50 ms and AVDOPT+50 ms. Echocardiographic assessment included 2D- and M-mode echo for the assessment of volumes and hemodynamic parameters (CI, SV) and LVEF and tissue Doppler echo (strain, strain rate, Tissue Synchronisation Imaging (TSI) and myocardial velocities in the basal segments) RESULTS: The AVDOPT in the VDD mode (atrially triggered) was 105.5 +/- 38.1 ms and the AVDOPT in the DDD mode (atrially paced) was 186.9 +/- 52.9 ms. Intra-individually, the highest LVEF was measured at AVDOPT. The LVEF at AVDOPT was significantly higher than in the AVDOPT-50 setting (p = 0.03). However, none of the parameters of dyssynchrony changed significantly in the three settings. CONCLUSION: An optimized AV delay in CRT patients acutely leads to an improved systolic left ventricular ejection fraction without improving dyssynchrony.

Tissue Doppler echocardiography and biventricular pacing in heart failure: patient selection, procedural guidance, follow-up, quantification of success.

Asynchronous myocardial contraction in heart failure is associated with poor prognosis. Resynchronization can be achieved by biventricular pacing (BVP), which leads to clinical improvement and reverse remodeling. However, there is a substantial subset of patients with wide QRS complexes in the electrocardiogram that does not improve despite BVP. QRS width does not predict benefit of BVP and only correlates weakly with echocardiographically determined myocardial asynchrony. Determination of asynchrony by Tissue Doppler echocardiography seems to be the best predictor for improvement after BVP, although no consensus on the optimal method to assess asynchrony has been achieved yet. Our own preliminary results show the usefulness of Tissue Doppler Imaging and Tissue Synchronization Imaging to document acute and sustained improvement after BVP. To date, all studies evaluating Tissue Doppler in BVP were performed retrospectively and no prospective studies with patient selection for BVP according to echocardiographic criteria of asynchrony were published yet. We believe that these new echocardiographic tools will help to prospectively select patients for BVP, help to guide implantation and to optimize device programming.

Not left ventricular lead position, but the extent of immediate asynchrony reduction predicts long-term response to cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is an effective treatment for a large subgroup of chronic heart failure patients. Various attempts to improve the high non-responder rate of 30 % by preoperative asynchrony assessment have failed. We hypothesized that superior response to CRT is correlated with greater acute reduction of asynchrony and that a concordant left ventricular (LV) lead is beneficial compared to a discordant lead. Hundred and eight consecutive CRT patients from our center were prospectively included. Clinical status and asynchrony parameters were assessed before, 1 day and 6 months after CRT implantation. Super-response was defined as an increase of the LV ejection fraction by ≥15 % and a decrease in LV end systolic volume (LVESV) by ≥30 %. When the criteria for super-response were not met, average response was given with a decrease of baseline LVESV ≥15 %. Sixty eight patients were classified as responders (63 %). Comparing super- (n = 19) and average (n = 49) responders, we found that greater acute reduction of LV asynchrony (change of asynchronous segments under CRT: -1.3 vs. -0.4, p < 0.05; decrease of LV intraventricular delay: -34 ms vs. -16 ms, p < 0.05) is associated with superior reverse remodeling after 6 months. Importantly, asynchrony parameters of super-, average and non-responders were almost identical at baseline. A concordant LV lead (n = 63) was not associated with improved LV reverse remodeling compared to a discordant lead (n = 28): LVEF: +8.6 % vs. +7.8 %, p = 0.91; LVESV: -30.5 ml vs. -23.8 mL, p = 0.84. A greater immediate reduction of LV asynchrony predicts superior response. Preoperative asynchrony parameters do not correlate with outcome. A concordant LV lead is not superior to a discordant lead.

Evaluation of longitudinal and radial two-dimensional strain imaging versus Doppler tissue echocardiography in predicting long-term response to cardiac resynchronization therapy.

INTRODUCTION: Cardiac resynchronization therapy (CRT) leads to hemodynamic and clinical improvement in patients with heart failure. This study compares the new technique of 2-dimensional (2D) strain imaging with Doppler tissue imaging (DTI) in the prediction of the long-term response to CRT. METHODS: In all, 38 patients with heart failure (New York Heart Association II-III, QRS > 120 milliseconds, left ventricular ejection fraction < 0.35) received CRT and echocardiographic evaluation with a mean follow-up of 9.4 months. RESULTS: Of the patients, 47.4% were hemodynamic responders to long-term CRT. In the responder group, the maximum delay in the longitudinal and radial 2D strain in the basal segments and the maximum delay in the DTI peak systolic myocardial velocities but not DTI strain decreased. In receiver operating characteristic analysis, the baseline delay of DTI peak velocities predicts improvement after CRT, whereas baseline 2D- and DTI-strain measurements fail to predict a long-term response to CRT. CONCLUSION: Although there is a significant decrease in longitudinal and radial 2D strain-derived delays after CRT, the resulting predictive value is not superior to DTI.

Autocapture enhancements: unipolar and bipolar lead compatibility and bipolar pacing capability on bipolar leads.

Beat-by-beat Autocapture maximizes device longevity by minimizing stimulus amplitude while assuring patient safety. Currently, Autocapture permits use of only bipolar leads. The authors have devised a detection method that operates with unipolar and bipolar leads and covers all pacing and sensing combinations (but bipolar pace and sense simultaneously). This new detection method for unipolar sensing uses the integral of the negative portion of the unipolar evoked response as a robust capture detection feature. When using bipolar leads, the method provides the flexibility of bipolar or unipolar pacing. In this study, unipolar ventricular intracardiac electrograms (EGMs) were recorded in 71 patients, 73.7 +/- 9.9 years of age; 9 with high polarization, 62 with low polarization. High polarization had polished platinum or activated carbon electrodes. Low polarization had TiN, platinized platinum, or IrOx electrodes. The intracardiac EGMs were recorded 544 +/- 796 days after implant. The pacemakers performed an automatic capture threshold test while the intracardiac EGM signals were recorded in a programmer. These digitized signals were saved for off-line analysis. The unipolar evoked response was calculated at up to six (depending on capture threshold) pacing voltages and the polarization integral at 4.5 V and at loss of capture. An automatic calibration algorithm determined if the signal-to-noise ratio was adequate for Autocapture operation. Autocapture was possible with 60 of 62 of the low polarizations, and with 6 of 9 of the high polarizations. The average values form the data collected were: average unipolar evoked response--4.1 +/- 2.1 mV, average peak negative voltage--10.0 +/- 3.7 mV, average polarization 0.3 +/- 0.34 mV, and average signal-to-noise ratio (unipolar evoked response/ polarization) 38 +/- 71. In all cases the algorithm correctly determined the appropriateness of using Autocapture with the electrodes tested and the unipolar evoked response threshold to be used.