Do gender differences exist in pacemaker implantation?--results of an obligatory external quality control program

AIMS

The aim of the study was to evaluate the effects of patient gender onto primary pacemaker implantation, evaluating the database of the Institute of Quality Assurance Hessen in the federal state of Hessen, Germany.

METHODS AND RESULTS

The database of the obligatory external quality control program for the years 2003-2006 was evaluated retrospectively. In 72 centres, 17 826 patients undergoing stationary primary pacemaker implantation have been registered. Male patients had more AV blocks when compared with women and less sick sinus syndrome and atrial fibrillation with bradycardia. In patients being 80 years and older, men received significantly more dual-chamber devices than women for the indications: AV block and sick sinus syndrome. In women, atrial pacing thresholds were significantly higher and P-wave amplitudes were significantly lower. Women had, independent from age or pacing system implanted, significantly more acute complications than men, with significant differences for pneumothorax and pocket haematoma.

CONCLUSION

This large-scale real-life patient cohort of primary stationary pacemaker implantation showed that gender has an impact onto pacemaker implantation, with less favourable outcomes for women.

[Pacemaker ECG Quiz No. 20. Multiple ventricular extrasystoles with a little extra]

A patient with ischemic heart disease and dual-chamber pacing for binodal disease, exhibiting a complex pacemaker ECG, is presented.

[Pacemaker ECG quiz: AV sequential pacing--what is happening?]

The present case of a 55-year-old patient with heart failure displays a complex pacemaker ECG.

[Fast heart rate after a ventricular premature beat--what is the mechanism?]

A 61-year-old patient with sinus node disease and intermittent AV block presented with palpitations and the feeling of an intermittent fast heart beat. A 24 h Holter recording documented repetitive fast heart rates starting after a premature ventricular beat. This case underlines that sometimes profound knowledge of the implanted pacemaker system is necessary to optimize device therapy.

[Sandwiched between the single- and triple-chamber ICD: do we still need the dual-chamber ICD?]

Since it has been shown that adverse events are more frequent with dual-compared to single-chamber ICDs in patients with heart failure, and since the importance of prevention of unnecessary right ventricular pacing and the success of biventricular pacing have been demonstrated in numerous studies, the need for dual-chamber ICD systems has to be reassessed. The development of these systems was accompanied by expectations of improved hemodynamics in patients with bradycardia, a reduced incidence of atrial fibrillation, inappropriate therapies, and bradycardia-associated ventricular tachyarrhythmias. Single-chamber ICDs should be used restrictively and with great caution in patients with (sinus-) bradycardia and heart failure, since a relevant proportion of these patients is at risk of hemodynamic deterioration. Even if the proportion of patients with proven pacemaker syndrome is so small that it does not reach the level of statistical significance in large studies, a small percentage of patients with hemodynamic deterioration due to VVI pacing is still clinically (and economically) intolerable. Since the development of bradycardia or symptomatic chronotropic incompetence (e.g., due to amiodarone) is difficult to predict, it seems reasonable to use the indication for dualchamber systems liberally. However, the systematic prevention of unnecessary right ventricular pacing is crucial if dual-chamber ICDs are used. If advanced tachycardia discrimination algorithms and careful, individual programming are used, dual-chamber ICDs are superior in the prevention of inappropriate therapies. Additionally, dualchannel electrograms allow a more reliable interpretation of stored tachycardia episodes. In summary, dual-chamber systems represent a valuable improvement of ICD therapy but require thorough programming to convey their advantage.

[17th part: Transvenous pacemaker implantation in corrected Fallot tetralogy with heart failure]

Implantation of transvenous pacemaker leads can be particularly--and unexpectedly--difficult in patients with corrected congenital heart disease. If the operation has been performed a long time ago, there are frequently no more reports about the exact intervention available. The present case illustrates the importance of the ECG and fluoroscopy during implantation in complex congenital heart disease.

[16th part: ventricular lead position]

This case illustrates how the ventricular lead position can be defined exactly if different fluoroscopic views and a 12 lead ECG are available.

Stroke complicating congenital sick sinus syndrome

We report the case of a patient with congenital sick sinus syndrome complicated by atrial fibrillation and embolic stroke 23 years after the initial diagnosis, at the age of 34 years. Treatment with a dual-chamber pacemaker and oral anticoagulation were initiated; further follow-up was uneventful but pacemaker diagnostics constantly documented asymptomatic recurrences of paroxysmal atrial fibrillation.

Non-invasive risk stratification: prognostic implications of exercise testing

The interpretation of exercise ECGs is frequently limited to an assessment of the ST segment for evaluation of ischemia. However, exercise testing represents a simple test of the complex interactions of the autonomous nervous system and provides a multitude of information with independent prognostic information. This overview summarizes available studies on the significance of chronotropic incompetence, exercise capacity, heart rate recovery after exercise, and the incidence of ventricular premature activity during or after exercise. These parameters express subclinical pathophysiological changes which cannot be identified by other means, e. g., coronary angiography or echocardiography. A reduced maximal heart rate under exercise may indicate a "blunted" sympathetic reaction as a protective myocardial reaction to an increase in left ventricular wall stretch in preclinical forms of heart failure. A reduced exercise capacity, measured in metabolic equivalents, METs, is one of the strongest predictors of cardiac and all cause mortality. A reduced heart rate recovery after exercise indicates an increased sympathetic tone or lack physiological increase in vagal tone; increased ventricular ectopy potentially identifies preclinical cardiomyopathy. This summary of study results aims at providing a new view on exercise testing that should lead to an improved understanding of relevant information included in the exercise ECG.

Use of telemedicine in the diagnosis of paroxysmal atrial fibrillation and to monitor the effect of antiarrhythmic drug therapy

We present the case of a patient with highly symptomatic tachyarrhythmias for 2 years without any arrhythmia documentation despite numerous ECG and Holter registrations. By means of telemedicine, it was possible to document the arrhythmia--in this case atrial fibrillation--within 10 days and to start antiarrhythmic drug treatment with flecainide and metoprolol. This case demonstrates the diagnostic potential of telemedicine in patients with recurrent episodes of tachyarrhythmias in whom episodes are not sufficiently frequent to allow diagnosis by Holter monitoring. Telemedicine may also be advantageous for ECG monitoring during the early phase after cardioversion or initiation of specific antiarrhythmic pharmacotherapy in order to detect potential drug-induced proarrhythmic changes.

[Progression of heart failure during cardiac resynchronization therapy: what is the cause?]

A 74 year old patient with cardiac resynchronization therapy (CRT) since 12 months presents with cardiac decompensation and dyspnea NYHA III-IV after improvement of cardiac symptoms for 9 months. Her history is remarkable for left ventricular hypertrophy, aortic valve replacement 14 years earlier, a left ventricular ejection fraction of 35-40%, and permanent third degree AV block. The 12 lead standard ECG reveals the cause of cardiac deterioration which is confirmed by telemetry. This case demonstrates the importance of optimized programming of CRT systems which differs from conventional programming of dual-chamber devices in some aspects.

[Cardiac resynchronization therapy in patients with permanent atrial fibrillation--with or without atrial lead?]

A 59-year-old patient received a biventricular defibrillator for cardiac resynchronization therapy (CRT) due to severe heart failure and a left bundle branch block. He had suffered from mitral stenosis and had received valve replacement 16 years earlier. Because he had permanent atrial fibrillation since that time, no atrial lead was implanted. His symptoms improved with CRT until he received adequate shock therapy for a rapid ventricular tachyarrhythmia. After that his symptoms deteriorated again severely. The ECG recorded during an unscheduled follow-up visit 1 week after the shock explains the reason.

[Difficult AV optimization in a patient with a biventricular implantable cardioverter defibrillator]

This quiz presents the case of a patient who deteriorated clinically after AV delay optimization of a biventricular implantable cardioverter defibrillator. It illustrates that these complex devices require profound knowledge of their function.

[Indication for cardiac resynchronization therapy: Consensus 2005]

The indication for cardiac resynchronization therapy (CRT) using biventricular pacing or ICD systems has to be highly differentiated to optimize the proportion of patients who derive significant symptomatic benefit from this therapy, on the one hand, and to avoid this invasive treatment in patients with a low probability of clinical success of CRT, on the other hand. As a consensus in 2005, it can be put forward that there is sufficient evidence for an indication for CRT from clinical studies for the following characteristics: 1) Heart failure in NYHA functional class III or IV (if cardiac recompensation to class III is at least temporarily successful), 2) left ventricular ejection fraction < or =35%, 3) QRS duration >130 ms, particularly if left bundle branch block is present, 4) sinus rhythm. In addition, available data also suggest an indication for CRT in patients with atrial fibrillation if the other criteria listed above are met. The indication for CRT is unclear in patients with other intraventricular conduction delay (particularly right bundle branch block) while patients with left bundle branch block and a QRS duration of 120-130 ms seem to benefit if echocardiographic criteria demonstrate ventricular dyssynchrony. Since a multiplicity of echocardiographic criteria of ventricular dyssynchrony exists which is neither standardized nor evaluated in large-scale randomized trials, ventricular dyssynchrony on echocardiography alone cannot be regarded as an established indication for CRT without a QRS complex > or =120 ms. Similarly, whether heart failure in functional state NYHA II should be regarded as a CRT indication is currently being investigated in the randomized RAFT and MADIT-CRT trials.

[Technical requirements for early defibrillation: what are the capabilities of automated external defibrillators]

Modern automated external defibrillators (AEDs) offer a variety of technical improvements which increase the efficacy of early defibrillation, facilitate the application by not or minimally trained persons and improve safety. The development of biphasic shocks allows better myocardial protection, the use of lithium batteries, and a marked decrease of AEDs, in size. Microprocessors realize complex acoustic and visual prompts which lead the user through all steps of cardiopulmonary resuscitation (CPR) according to current guidelines. The design of AEDs has been simplified; many devices provide only a single button which can be used for all active processes. Memory functions record the whole CPR with all details which can be transferred to other computers and analyzed off-line. The introduction of AEDs has reduced the delay between collapse and defibrillation to less than 4 min in several studies thus increasing the success of CPR and the proportion of patients dismissed from hospital alive and without neurological deficit. Up to 93% of untrained volunteers were able to successfully complete defibrillation with the use of an AED, sixth-form pupils without experience in CPR were only few sec slower with an AED than staff of emergency medical services. The ability to perform CPR after defibrillation guided by the AED depends primarily on the clarity of acoustic prompts which have to consider the terms and abbreviations of the respective language. Currently available AEDs surpass performance goals of the AHA. However, all devices exhibit advantages and disadvantages which will be discussed in this review.

Incremental programming of atrial anti-tachycardia pacing therapies in bradycardia-indicated patients: effects on therapy efficacy and atrial tachyarrhythmia burden

AIMS

Efficacy of pace-termination of atrial arrhythmias (ATP) may depend on atrial cycle length and regularity. Whether device programming of ATP therapies can improve ATP efficacy and alter atrial tachyarrhythmia burden is unknown.

METHODS AND RESULTS

ATP efficacy was evaluated in 61 patients (39 males; 66 +/- 10 years) with a standard indication for pacing, 95% with a history of AT/AF. Each patient was implanted with a novel DDDRP pacemaker capable of delivering ATP therapy. ATP efficacy and AT/AF frequency and burden were compared within each patient during a period of nominal ATP programming (NP) followed by a period of aggressive incremental programming (IP). Adjusted ATP-termination efficacy was higher during IP than during NP (54.8% vs 37.9%, P < 0.05). No differences in AT/AF frequency (3.3 +/- 5.9 vs 3.2 +/- 6.9 day(-1)) or burden (18 +/- 28% vs 18 +/- 29%) were observed comparing NP with IP. The majority of episodes during both the NP (81%) and IP (77%) periods terminated within 10 min. Episodes lasting 24 h or more accounted for only 0.4% of the episodes in both groups. but accounted for 38% of the average burden during NP and 51% during IP.

CONCLUSIONS

Device programming of ATP therapies can influence the number of treated episodes and the efficacy of ATP therapies although arrhythmic frequency and burden may not change. Total atrial arrhythmia burden is disproportionately influenced by long (>24 h) episodes.

Prediction of early recurrence of atrial fibrillation after external cardioversion by means of P wave signal-averaged electrocardiogram

BACKGROUND

Therapy of atrial fibrillation by electrical cardioversion (CV) is limited by the high rate of recurrences. Early recurrence of atrial fibrillation (ERAF) occurs in a subgroup of patients whose characteristics are poorly defined. This prospective study was performed to evaluate if the P wave signal-averaged ECG (PSAECG) is able to identify patients with an increased risk of ERAF after CV.

METHODS

Patients with an indication for elective external CV were enrolled. After successful CV, PSAECGs were recorded at 0.5, 1, 24 h and 1 week. The ability of PSAECG parameters (signal-averaged P wave duration, PWD; root-mean-square of the voltage of the terminal 20, 30, and 40 ms of the signal-averaged P wave; RMS20, RMS30, RMS40) to predict ERAF (prospectively defined as AF recurrence within 4 h after CV) was assessed.

RESULTS

Of 111 consecutive patients, 7 experienced ERAF, 30 patients had AF recurrence later during the 1-week follow-up. Patients with ERAF had a significantly prolonged signal-averaged PWD compared to patients who remained in SR (194+/-16 ms vs 139+/-3 ms at 0.5 h, p<0.001). As ROC analysis revealed, a PWD >/=154 ms at 30 min after CV had the highest predictive accuracy for ERAF (sensitivity 100%, specificity 82%, positive predictive value 33%, negative predictive value 100%). Other parameters of the PSAECG did not reveal significant differences between patients with and without ERAF.

CONCLUSIONS

The PSAECG provides a sensitive noninvasive tool for detection of patients at risk of ERAF. Thus identified, tailored pharmacological therapy is conceivable to prevent ERAF.

Single-lead VDD-pacing system incorporating high impedance stimulation: a multicentre study

AIM

The purpose of this study was to evaluate the performance of a new VDD pacing system incorporating a high impedance, single-pass VDD lead. The new lead is a bipolar, steroid-eluting, high impedance lead with a full-ring atrial dipole.

METHODS AND RESULTS

The system was implanted in 46 patients with high degree atrioventricular (AV) block. Patients were followed at pre-discharge, 6 weeks, and 3 months. The mean measured P-wave amplitude was stable, with values between 1.18 and 1.43 mV. Atrial sensing was reliable during short-term evaluation at rest and in the sitting position, with AV-synchronous stimulation between 98.79 +/- 6.90% and 99.73 +/- 1.47%. Holter recordings after 6 weeks demonstrated AV-synchronous stimulation in 99.57 1.03% of all P-waves. Lead impedance was stable during follow-up, with mean values between 1000 and 1167 Q. Mean ventricular pacing thresholds (at 0.5 ms) were 0.47 V at implant, 0.49 V at pre-discharge, 0.74 V at 6 weeks, and 0.72 V at 3 months. R-wave amplitude remained stable between 14.9 and 16.7 mV during follow-up.

CONCLUSION

This new single-pass VDD lead system provided reliable atrial sensing and stable high impedance stimulation during a 3-month follow-up period.