Myopotential inhibition of unipolar demand pacemakers: utility of provocative manoeuvres in assessment and management

Recommendations for participation in leisure-time physical activity and competitive sports of patients with arrhythmias and potentially arrhythmogenic conditions. Part 2: ventricular arrhythmias, channelopathies, and implantable defibrillators

This paper belongs to a series of recommendation documents for participation in leisure-time physical activity and competitive sports by the European Association of Preventive Cardiology (EAPC). Together with an accompanying paper on supraventricular arrhythmias, this second text deals specifically with those participants in whom some form of ventricular rhythm disorder is documented, who are diagnosed with an inherited arrhythmogenic condition, and/or who have an implanted pacemaker or cardioverter defibrillator. A companion text on recommendations in athletes with supraventricular arrhythmias is published in the European Journal of Preventive Cardiology. Since both texts focus on arrhythmias, they are the result of a collaboration between EAPC and the European Heart Rhythm Association (EHRA). The documents provide a framework for evaluating eligibility to perform sports, based on three elements, i.e. the prognostic risk of the arrhythmias when performing sports, the symptomatic impact of arrhythmias while performing sports, and the potential progression of underlying structural problems as the result of sports.

High incidence of diaphragmatic myopotential oversensing by a specific implantable cardioverter defibrillator

INTRODUCTION

Diaphragmatic myopotential oversensing (dMPO) by implantable cardioverter defibrillators (ICDs) is thought to be a rare condition that can be misdiagnosed as lead failure and lead to unnecessary lead replacement. We observed several cases of dMPO in patients with Sorin/LivaNova ICDs (MicroPort Sci.). We sought to systematically assess the incidence of dMPO in patients with Sorin/LivaNova ICDs.

METHODS AND RESULTS

A predefined number of 100 consecutive patients with Sorin/LivaNova ICDs were prospectively included in the device clinic of our center. Stored arrhythmia episodes were checked for spontaneous dMPO. In addition, we performed provocation maneuvers by Valsalva. At least one episode of spontaneous or provoked dMPO was seen in 12 (12%) of the 100 patients included in the study (86% males, median age: 66 years). Nine of 89 patients (10%) with true bipolar and 3 of 11 patients (27%) with integrated bipolar sensing configuration were affected. Spontaneous dMPO was observed in 7 of 58 patients (12%) with sensitivity programmed to 0.4 mV and in 2 of 42 patients (5%) with sensitivity programmed to 0.6 mV (not significant). In three patients, dMPO could be provoked with no spontaneous episodes recorded. In two nonpacemaker-dependent patients with a CRT-D, ventricular pacing was temporarily inhibited. No antitachycardia therapy was triggered by dMPO in any patient.

CONCLUSIONS

DMPO is frequent in patients with Sorin/LivaNova ICDs, especially with sensitivity programmed to 0.4 mV. It also frequently occurs with true bipolar sensing configuration. DMPO should not be misinterpreted as lead failure to avoid unnecessary lead replacement.

Influence of myopotential interference on the Wavelet discrimination algorithm in implantable cardioverter-defibrillator

Background

Wavelet is a morphology-based algorithm for detecting ventricular tachycardia. The electrogram (EGM) source of the Wavelet algorithm is nominally programmed with the Can-RV coil configuration, which records a far-field ventricular potential. Therefore, it may be influenced by myopotential interference.

Methods

We performed a retrospective review of 40 outpatients who had an implantable cardioverter-defibrillator (ICD) with the Wavelet algorithm. The percent-match score of the Wavelet algorithm was measured during the isometric chest press by pressing the palms together. We classified patients with percent-match scores below 70% due to myopotential interference as positive morphology change, and those with 70% or more as negative morphology change. Stored episodes of tachycardia were evaluated during the follow-up.

Results

The number of patients in the positive morphology change group was 22 (55%). Amplitude of the Can-RV coil EGM was lower in the positive morphology change group compared to that in the negative group (3.9±1.3 mV vs. 7.4±1.6 mV, P=0.0015). The cut-off value of the Can-RV coil EGM was 5 mV (area under curve, 0.89). Inappropriate detections caused by myopotential interference occurred in two patients (5%) during a mean follow-up period of 49 months, and one of them received an inappropriate ICD shock. These patients had exhibited positive morphology change.

Conclusions

The Wavelet algorithm is influenced by myopotential interference when the Can-RV coil EGM is less than 5 mV.

Recommendations for participation in leisure-time physical activity and competitive sports in patients with arrhythmias and potentially arrhythmogenic conditions Part I: Supraventricular arrhythmias and pacemakers

This document by the Study Group on Sports Cardiology of the European Society of Cardiology extends on previous recommendations for sports participation for competitive athletes by also incorporating guidelines for those who want to perform recreational physical activity. For different supraventricular arrhythmias and arrhythmogenic conditions, a description of the relationship between the condition and physical activity is given, stressing how arrhythmias can be influenced by exertion or can be a reflection of the (patho)physiological cardiac adaptation to sports participation itself. The following topics are covered in this text: sinus bradycardia; atrioventricular nodal conduction disturbances; pacemakers; atrial premature beats; paroxysmal supraventricular tachycardia without pre-excitation; pre-excitation, asymptomatic or with associated arrhythmias (i.e. Wolff-Parkinson-White syndrome); atrial fibrillation; and atrial flutter. A related document discusses ventricular arrhythmias, channelopathies and implantable cardioverter defibrillators.

[Sport for pacemaker patients]

Sport activity is an important issue in many patients with a pacemaker either because they performed sport activities before pacemaker implantation to reduce the cardiovascular risk or to improve the course of an underlying cardiovascular disease (e.g. coronary artery disease, heart failure) by sports. Compared to patients with an implantable cardioverter defibrillator (ICD) the risks from underlying cardiovascular disease (e.g. ischemia, heart failure), arrhythmia, lead dysfunction or inappropriate therapy are less important or absent. Sport is contraindicated in dyspnea at rest, acute heart failure, new complex arrhythmia, acute myocarditis and acute myocardial infarction, valvular disease with indications for intervention and surgery and comorbidities which prevent physical activity. Patients with underlying cardiovascular disease (including hypertension) should preferably perform types and levels of physical activity that are aerobic (with dynamic exercise) such as running, swimming, cycling instead of sport with high anaerobic demands and high muscular workload. In heart failure, studies demonstrated advantages of isometric sport that increases the amount of muscle, thereby preventing cardiac cachexia. Sport with a risk of blows to the chest or physical contact (e.g. boxing, rugby, martial arts) should be avoided. Implantation, programming and follow-up should respect specific precautions to allow optimal physical activity with a pacemaker including implantation of bipolar leads on the side contralateral to the dominant hand, individual programming of the upper sensor and tracking rate and regular exercise testing.

Approach to patients with implanted pacemaker and scheduled surgical or diagnostic procedure

Application of cardiac electrostimulation in strictly defined indications has been on the increase over the last few decades. Frequent use of this therapy as well as the fact that it is applied predominantly in patients in the seventh decade of life, implies possible signifficant comorbidities and need for various diagnostic and surgical procedures. These are the reasons we decided to point out certain specific features in approaching this patient group in preparation and implementation of these procedures. Preoperative approach starts with usual patient history, with additional information on the type of pacemaker, last pacemaker check and electrocardiogram. This general approach is not substantialy different for pacemaker or ICD patients. What is specific is the possible interferrence caused by devices used in diagnostic or therapeutic procedures (diathermy, lithotripsy). Complications that may arise are usually related to the underlying disease rather than the pacemaker malfunction, but still, careful approach and pacemaker check are warranted, especially in the group marked as "pacemaker dependent". Adequate preoperative assessment, only slightly different from the usual, represents a sufficient guarantee for safe procedures diagnostic, therapeutic or surgical.

Unipolar sensing in contemporary pacemakers: using myopotential testing to define optimal sensitivity settings

Bipolar lead use has increased due to oversensing concerns with older unipolar systems. Data on contemporary unipolar devices with improved hardware design and greater programming flexibility is lacking. Using a randomized crossover design, unipolar and bipolar sensing characteristics of 22 atrial and 16 ventricular leads were compared in 34 patients who had pulse generators of programmable polarity. Unipolar and bipolar intracardiac electrogram amplitudes, pacing and sensing thresholds at rest were similar. Provocative maneuvers were used to assess for myopotential inhibition. At atrial sensitivities of 0.625-1.50 mV, myopotential inhibition occurred in 11 (50%) atrial leads in the unipolar mode compared to 1 (5%) in the bipolar mode (p < 0.001). At sensitivities of > 1.50 mV myopotential inhibition occurred in only 1 ventricular (unipolar) lead. An optimal sensitivity setting for each polarity was derived using clinic test results and assessed by ambulatory ECG (AECG). At these optimal settings, oversensing occurred in 1 (6%) atrial and 1 (8%) ventricular unipolar lead during AECG monitoring, whereas oversensing was not seen in any leads programmed to the bipolar mode. Undersensing occurred in 5 (29%) atrial unipolar versus 1 (6%) bipolar lead (p = 0.08). Undersensing was not observed in any of the ventricular leads. Myopotential inhibition may be frequently provoked by provocative maneuvers at higher sensitivity settings in atrial unipolar leads. The frequency of oversensing can be significantly reduced by defining an optimal sensitivity setting using simple isometric maneuvers. Given present day concerns over bipolar lead longevity, increased utilization of unipolar ventricular leads should be considered.