Per Ivar Hoff

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

This consensus paper on behalf of the Study Group on Sports Cardiology of the European Society of Cardiology follows a previous one on guidelines for sports participation in competitive and recreational athletes with supraventricular arrhythmias and pacemakers. The question of imminent life-threatening arrhythmias is especially relevant when some form of ventricular rhythm disorder is documented, or when the patient is diagnosed to have inherited a pro-arrhythmogenic disorder. Frequent ventricular premature beats or nonsustained ventricular tachycardia may be a hallmark of underlying pathology and increased risk. Their finding should prompt a thorough cardiac evaluation, including both imaging modalities and electrophysiological techniques. This should allow distinguishing idiopathic rhythm disorders from underlying disease that carries a more ominous prognosis. Recommendations on sports participation in inherited arrhythmogenic conditions and asymptomatic gene carriers are also discussed: congenital and acquired long QT syndrome, short QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, arrhythmogenic right ventricular cardiomyopathy and other familial electrical disease of unknown origin. If an implantable cardioverter defibrillator is indicated, it is no substitute for the guidelines relating to the underlying pathology. Moreover, some particular recommendations for patients/athletes with an implantable cardioverter defibrillator are to be observed.

Long-term assessment of electrocardiographic and echocardiographic findings in Norwegian elite endurance athletes.

Objectives: The long-term outcome and clinical significance of athlete’s heart has been debated and more longitudinal data are needed. We present a prospective 15 years’ follow-up study of ECG and echo findings in elite endurance athletes following the end of their competitive career. Methods: Clinical evaluation, ECG, ambulatory Holter recording and echocardiography were performed in 30 top-level endurance athletes with a mean age of 24 years with follow-up 15 years later. All had then ended their competitive career, but still performed recreational sports activities. Results: No clinical events were reported. Average resting heart rate was unchanged (53.5 ± 10 at baseline and 55.4 ± 11 at follow-up, p = n.s.), complex ventricular arrhythmias did not occur and the number of ventricular premature beats (VPBs) were 0.4 ± 0.8/h at baseline and 3.8 ± 10/h at follow-up (p = n.s.). In a subgroup of 4 subjects with >100 VPBs per hour at follow-up left ventricular mass was increased compared to the others (p < 0.03). Furthermore, regression of sino-atrial (SA) and atrioventricular (AV) blocks was shown. There were no cases of atrial flutter or fibrillation. There was a slight reduction in mean left ventricular wall thickness (9.9 ± 1.2 vs. 9.5 ± 1.4 mm, p < 0.05) and a highly significant reduction of relative wall thickness (0.38 vs. 0.35, p < 0.001). Left ventricular end-diastolic volume (68 ± 6 vs. 70 ± 7 ml ml/m2, p = n.s.) and left ventricular mass (109 ± 19 vs. 107 ± 19 g/m2, p = n.s.) were unchanged when corrected for body surface area and ejection fraction (EF) increased (60 ± 7 vs. 67 ± 6%, p < 0.01). Parameters of left ventricular diastolic function were normal both at baseline and follow-up. Conclusions: There was no evidence of deleterious cardiac effects of previous top-level endurance athletic activity at 15 years’ follow-up.

Global Right Atrial Mapping Delineates Double Posterior Lines of Block in Patients with Typical Atrial Flutter

Introduction: The crista terminalis (CT) has been shown to be a barrier to transverse conduction during typical atrial flutter (AFL). However, some studies have demonstrated the presence of functional block in the sinus venosa region but not at the CT. The aim of this study was to define these regions of block in the right atrium using a three‐dimensional noncontact mapping system.

Clinical Performance of Steroid‐Eluting Pacing Leads with 1.2‐mm2 Electrodes

To raise pacing impedance and reduce battery current drain, new tined steroid‐eluting leads were developed with 1.2‐mm2 hemispherical electrodes, instead of conventional 5–8 mm2. Twenty‐two unipolar J‐shaped atrial leads and 25 unipolar ventricular leads (models 4533 and 4033, respectively) were implanted in 33 consecutive patients and followed for a mean of 25 months (range 18–29). Handling characteristics of atrial leads were found favorable. The leads slipped easily into the right atrial appendage and were easy to position. Handling characteristics of ventricular leads were satisfying, but more efforts had to be applied to cross the tricuspid valve. Special care was taken to avoid perforation of the myocardium due to the small lead tip. Following implantation, four ventricular and one atrial lead exhibited instability of pacing thresholds that resolved spontaneously within 1–3 days of implantation. Except for this, no lead malfunctioned. The reoperation rate was zero. The mean electrogram amplitudes of 15 mV (ventricle) and 4 mV (atrium), and the mean chronic pacing threshold of 0.085 ms at 1.6 V (app. 0.43 Vat 0.5 ms) were comparable with the best values seen in the literature on passive fixation leads. The rest of the electrophysiological parameters were enhanced: mean pacing impedances were 984 Ω (acute) and 900 Ω (chronic), mean slew rates 3.26 V/s (ventricle) and 1.75 V/s (atrium), mean acute voltage threshold at 0.5 ms was 0.25 V, mean current and energy thresholds calculated at 0.5 ms were 260 μA and 32 nJ (acute) and 478 μA and 103 nJ (chronic). The electrical characteristics of these leads provide for increased pacemaker longevity in combination with substantial safety margins for pacing and sensing.

AN ALGORITHM FOR AUTOMATIC MEASUREMENT OF STIMULATION THRESHOLDS : CLINICAL PERFORMANCE AND PRELIMINARY RESULTS

We have developed an algorithmic method for automatic determination of stimulation thresholds in both cardiac chambers in patients with intact atrioventricular (AV) conduction. The algorithm utilizes ventricular sensing, may be used with any type of pacing leads, and may be downloaded via telemetry links into already implanted dual‐chamber Thera® pacemakers. Thresholds are determined with 0.5 V amplitude and 0.06 ms pulse‐width resolution in unipolar, bipolar, or both lead configurations, with a programmable sampling interval from 2 minutes to 48 hours. Measured values are stored in the pacemaker memory for later retrieval and do not influence permanent output settings. The algorithm was intended to gather information on continuous behavior of stimulation thresholds, which is important in the formation of strategies for programming pacemaker outputs. Clinical performance of the algorithm was evaluated in eight patients who received bipolar tined steroid‐eluting leads and were observed for a mean of 5.1 months. Patient safety was not compromised by the algorithm, except for the possibility of pacing during the physiologic refractory period. Methods for discrimination of incorrect data points were developed and incorrect values were discarded. Fine resolution threshold measurements collected during this study indicated that: (1) there were great differences in magnitude of threshold peaking in different patients; (2) the initial intensive threshold peaking was usually followed by another less intensive but longer‐lasting wave of threshold peaking; (3) the pattern of tissue reaction in the atrium appeared different from that in the ventricle; and (4) threshold peaking in the bipolar lead configuration was greater than in the unipolar configuration. The algorithm proved to be useful in studying ambulatory thresholds.

Electrophysiologic and clinical effects of flecainide for recurrent paroxysmal supraventricular tachycardia

The antiarrhythmic effects of flecainide acetate were evaluated in 9 patients with paroxysmal atrioventricular (AV) nodal tachycardia and 17 patients with AV tachycardia. An electrophysiologic study was performed before and after intravenous flecainide acetate, 2 mg/kg body weight, was infused over 15 minutes and was followed by a maintenance infusion of 1.6 mg/kg given over 1 hour to 26 patients and during oral treatment to 15. Treatment with oral flecainide acetate was continued for 14 +/- 5 months. Intravenous flecainide acetate terminated AV nodal tachycardia by blocking the retrograde fast pathway conduction in 7 of 7 patients and AV tachycardia by blocking retrograde conduction in the extranodal pathway in 10 of 10 patients. AV nodal tachycardia and AV tachycardia were noninducible in 8 of 9 patients (90%, p less than 0.001) and 11 of 17 patients (65%, p less than 0.001), respectively. Long-term treatment with oral flecainide acetate suppressed AV nodal tachycardia and AV tachycardia in 8 of 9 patients (90%, p less than 0.001) and 11 of 17 patients (65%, p less than 0.001), respectively. A favorable outcome was associated with block in the accessory pathway after intravenous flecainide acetate and noninducibility during oral treatment. Recurrences preferentially occurred in the younger patients. Flecainide acetate is effective in the acute and long-term management of paroxysmal supraventricular reentry tachycardia by suppressing conduction through the retrograde fast limb of the tachycardia circuit. The clinical effect can be predicted by electrophysiologic testing.

Treatment of atrial fibrillation by silencing electrical activity in the posterior inter-pulmonary-vein atrium

AIMS The recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation is still a challenge. We investigated a new approach to treating AF patients by silencing electrical activity in the posterior inter-pulmonary-vein atrium (PIA). METHODS AND RESULTS Three ablation steps are required to obtain PIA electrical silence: electrical PV isolation, the creation of two lines of lesions between the two superior and inferior PVs and the abolition of residual electrical signals within the PIA. The endpoint was the electrical silence and the inability to pace in the PIA. The posterior inter-pulmonary-vein atrium silence was obtained in 42 AF patients (56 +/- 9 years, four women). Recurrence of AF and atrial flutter was observed in 14 (33.3%) patients after the first procedure. Freedom from atrial arrhythmias after the second procedure was displayed by 94.4, 85.7, and 60.0% of patients with paroxysmal, persistent, and permanent AF, respectively. The left atrium (LA) volume was larger, and the percentages of the silent area of the LA surface and voltages were lower in patients with AF recurrence than in recurrence-free patients. CONCLUSION Posterior inter-pulmonary-vein atrium electrical silence can greatly decrease the AF recurrence. The clinical AF recurrence may be related to an enlarged LA, a low percentage of electrically silent area, and low voltage in the LA.

Prospective European Survey on Atrial Fibrillation Ablation: Clinical Characteristics of Patients and Ablation Strategies Used in Different Countries

Atrial fibrillation (AF) ablation is widely adopted. Our aim was to conduct a prospective multicenter survey to verify patients’ characteristics, approaches, and technologies adopted across Europe.

Evaluation of the appropriateness and outcome of in-hospital telemetry monitoring.

The American Heart Association classifies monitored patients into 3 categories. The aims of this study were to (1) investigate how patients are assigned according to the American Heart Association classification, (2) determine the number and type of arrhythmic events experienced by these patients, and (3) describe subsequent changes in management. A prospective observational study design was used. All patients assigned to telemetry during a 3-month period were consecutively enrolled in our study. Data were collected 24/7. Only arrhythmias that might require a change in management were recorded. Monitor watchers at the central monitoring station completed a standard data sheet assessing 64 variables. These data, as well as medical records, were reviewed by the investigator. Overall, 1,194 patients were included. Eighteen percent of the patients were assigned to American Heart Association class I (monitoring indicated), 71% to class II (monitoring may be of benefit), and 11% to class III (monitoring not indicated). The overall arrhythmia event rate was 33%. Forty-three percent of class I patients, 28% of class II patients, and 47% of class III patients experienced arrhythmia events. Change in management occurred in 25% of class I patients, 14% of class II patients, and 29% of class III patients. Although the number of class III indications should have been reduced, nearly 1/2 of class III patients experienced arrhythmia events and 1/3 of them received management changes. This outcome challenges existing guidelines. In conclusion, most patients in this study were monitored appropriately, according to class I and II indications.

Three‐Dimensional Noncontact Mapping Defines Two Zones of Slow Conduction in the Circuit of Typical Atrial Flutter

CHEN, J, et al.: Three‐Dimensional Noncontact Mapping Defines Two Zones of Slow Conduction in the Circuit of Typical Atrial Flutter. The cavotricuspid isthmus (CTI) is a slow conduction area in the circuit of typical atrial flutter. However, conventional methods are limited by the inaccuracy of measurements of distance on the surface of the heart. The aim of the study was to define the conduction properties of the atrial flutter circuit along the tricuspid annulus by using a three‐dimensional noncontact mapping system. In 34 atrial flutter patients (30 men, 4 women; mean age 54 ± 14; 27 counter‐clockwise, 4 clockwise, and 3 both), a noncontact multielectrode array was used to reconstruct electrograms in the right atrium. Isochronal and isopotential propagation mapping was performed during atrial flutter. The conduction velocity was calculated by dividing conduction time by surface distance. The right atrium along the tricuspid annulus was divided into five regions: lateral wall, superior right atrium, septum, septal CTI, and lateral CTI. Conduction velocities were 0.99 ± 0.85, 1.67 ± 1.21, 1.58 ± 1.05, 0.82 ± 0.72 , and 1.68 ± 1.00  m/s in counter‐clockwise and 0.81 ± 0.71, 2.61 ± 1.90, 1.52 ± 0.91, 0.91 ± 0.80 and 1.91 ± 0.83  m/s in clockwise, respectively. Conduction velocities were significantly slower in the septal CTI and lateral wall than in the lateral CTI, the septum, and the superior right atrium (P < 0.05). No significant difference was found between the septal CTI and the lateral wall. Conduction within the septal CTI was slower in patients treated with antiarrhythmic agents than in untreated patients (P < 0.05). The septal part of the CTI (but not the lateral CTI) and the lateral wall are slow conduction zones in the atrial flutter circuit, and both may, therefore, be mechanically important for the development of atrial flutter. (PACE 2003; 26[Pt. II]:318–322)