Kai Sonne

Non-invasive assessment of fibrillatory activity in patients with paroxysmal and persistent atrial fibrillation using the Holter ECG

OBJECTIVE Automatic analysis of the frequency content of the fibrillatory baseline on the surface ECG accurately reflects the average rate of atrial fibrillation (AF). This frequency measurement correlates with the behavior of AF and predicts the response to administration of ibutilide, a new antiarrhythmic drug. Neither the temporal pattern of fibrillatory frequency in spontaneous paroxysmal or persistent AF, nor its response to chronic antiarrhythmic medication has been studied so far. METHODS AND RESULTS Holter ECG recordings were made in 20 patients during AF. One minute ECG segments were selected for analysis. The frequency content of the fibrillatory baseline was then quantified using digital signal processing. After high-pass filtering, the QRST complexes were subtracted using a template matching algorithm. The resulting fibrillatory baseline signal was subjected to Fourier transformation, displayed as a frequency power spectrum and the peak frequency (f) was determined. In 11 patients (7 male, 4 female, age 62 +/- 10 years) 31 paroxysmal AF episodes were analyzed. Duration ranged from 1 min to 665 min (115 +/- 175 min). Initial mean peak f measured 5.1 +/- 0.7 Hz (range 3.9 to 6.9 Hz). There was a positive correlation between f and AF duration (R = 0.53, p = 0.002). AF of less than 15 min duration (n = 13) showed a lower f (4.8 +/- 0.6 Hz) when compared with longer lasting episodes (n = 18, 5.3 +/- 0.7 Hz, p = 0.03). In short AF episodes f was constant, whereas in longer-lasting episodes f increased to 5.8 +/- 0.5 Hz (p < 0.001) within 5 min. In 9 patients (9 male, age 58 +/- 8 years) with persistent AF oral antiarrhythmic drugs (amiodarone n = 5, sotalol n = 3, flecainide n = 1) were given prior to electrical cardioversion for prophylaxis of AF recurrence. Frequency measurements were obtained at baseline and 3 to 5 days after initiation of drug administration. At baseline mean f measured 6.9 +/- 0.4 Hz. Frequency was reduced by antiarrhythmic drugs to 5.8 +/- 0.4 Hz (p < 0.001). CONCLUSIONS (1) The duration of paroxysmal AF episodes can be predicted using spectral analysis of ECG recordings of AF episodes. (2) An increase in fibrillatory frequency is associated with AF persistence. (3) This technique can be used to monitor the response to antiarrhythmic medication.

Circadian variations in atrial fibrillatory frequency in persistent human atrial fibrillation.

Atrial fibrillatory frequency reflects the atrial refractory period during AF. This study was conducted to investigate noninvasively the diurnal fluctuations of fibrillatory frequency in persistent human atrial fibrillation and to determine the relationship between changes in ventricular rate and fibrillatory frequency. Ambulatory ECGs were recorded in 30 patients (18 men, 12 women, mean age 60 ± 11 years) with persistent AF (< 24 hours). AF frequency was measured in 1‐minute ECG segments by subtracting averaged QRST complexes and applying Fourier analysis to the resulting signals at 4 pm, 10 pm, 4 am, and 10 am. Peak frequency was determined in the 3–12 Hz frequency band. Mean fibrillatory frequency measured 6.6 ± 0.6 Hz (range 5.0–7.8 Hz). Two different frequency patterns were distinguished comparing maximal diurnal versus nocturnal fibrillatory frequency. In six (20%) patients an increase (P = 0.045) in nocturnal fibrillatory frequency (type I) was found. In the remaining 24 (80%) patients a decrease (P < 0.001) in fibrillatory frequency occurred (type II). Type I AF showed a strong inverse correlation between relative changes (percent) in ventricular rate and fibrillatory frequency obtained from two consecutive measurement points (r = −0.88 to −.97, P < 0.01), whereas in type II AF a moderate positive correlation (r = 0.36 to 0.41, P < 0.05) was detected. These data indicate a circadian pattern in AF frequency that concurs with ventricular rate changes suggesting a modulating influence of the autonomic nervous system on atrial electrophysiology in persistent human AF.

Left Atrial Appendage Flow in Nonrheumatic Atrial Fibrillation: Relationship With Pulmonary Venous Flow and ECG Fibrillatory Wave Amplitude

OBJECTIVE This study was conducted (1) to examine the relationship between left atrial appendage (LAA) flow velocity and pulmonary venous flow (PVF) variables during nonrheumatic atrial fibrillation (AF), and (2) to determine whether a reduction in LAA flow is reflected by the fibrillatory wave amplitude on the surface ECG. BACKGROUND Although LAA Doppler echocardiographic signals provide information regarding the velocity and direction of flow only for a localized narrow sample, systolic PVF represents in part the global left atrial function, mainly relaxation. Controversy exists about whether the amplitude of fibrillatory waves recorded on the surface ECG correlates with LAA flow velocity during AF. MEASUREMENTS AND RESULTS Thirty-three patients (20 men, 13 women; mean [+/- SD] age, 61 +/- 11 years) with nonrheumatic AF undergoing transthoracic and transesophageal echocardiography were studied. A correlation between LAA flow velocity and systolic PVF variables (peak systolic velocity, R: = 0.450, p = 0.009; velocity-time integral of systolic flow, R = 0.491, p = 0.004; systolic fraction of PVF, R: = 0.627, p < 0.0001) was observed. Patients with a low LAA flow profile (< 25 cm/s) had a reduced systolic PVF. Longer AF duration and the occurrence of moderate mitral regurgitation were related to reduced LAA flow. AF was subdivided into coarse (peak-to-peak fibrillatory amplitude > or = 1 mm) or fine (< 1 mm) in standard ECG lead V1. There was no association between the coarseness of AF and the LAA flow profile. CONCLUSION In patients with nonrheumatic AF, a reduction in LAA flow velocity correlates with a reduction in systolic PVF. These hemodynamic changes are not reflected by the ECG fibrillatory wave amplitude.

Clinical InvestigationsCardiologyLeft Atrial Appendage Flow in Nonrheumatic Atrial Fibrillation: Relationship With Pulmonary Venous Flow and ECG Fibrillatory Wave Amplitude

OBJECTIVE This study was conducted (1) to examine the relationship between left atrial appendage (LAA) flow velocity and pulmonary venous flow (PVF) variables during nonrheumatic atrial fibrillation (AF), and (2) to determine whether a reduction in LAA flow is reflected by the fibrillatory wave amplitude on the surface ECG. BACKGROUND Although LAA Doppler echocardiographic signals provide information regarding the velocity and direction of flow only for a localized narrow sample, systolic PVF represents in part the global left atrial function, mainly relaxation. Controversy exists about whether the amplitude of fibrillatory waves recorded on the surface ECG correlates with LAA flow velocity during AF. MEASUREMENTS AND RESULTS Thirty-three patients (20 men, 13 women; mean [+/- SD] age, 61 +/- 11 years) with nonrheumatic AF undergoing transthoracic and transesophageal echocardiography were studied. A correlation between LAA flow velocity and systolic PVF variables (peak systolic velocity, R: = 0.450, p = 0.009; velocity-time integral of systolic flow, R = 0.491, p = 0.004; systolic fraction of PVF, R: = 0.627, p < 0.0001) was observed. Patients with a low LAA flow profile (< 25 cm/s) had a reduced systolic PVF. Longer AF duration and the occurrence of moderate mitral regurgitation were related to reduced LAA flow. AF was subdivided into coarse (peak-to-peak fibrillatory amplitude > or = 1 mm) or fine (< 1 mm) in standard ECG lead V1. There was no association between the coarseness of AF and the LAA flow profile. CONCLUSION In patients with nonrheumatic AF, a reduction in LAA flow velocity correlates with a reduction in systolic PVF. These hemodynamic changes are not reflected by the ECG fibrillatory wave amplitude.

Patients with persistent atrial fibrillation taking oral verapamil exhibit a lower atrial frequency on the ECG

Background: While there is agreement that verapamil attenuates the AF‐ induced refractory period shortening when given before AF induction, controversy exists regarding its effects when given after the onset of persistent AF. This study aimed to compare atrial fibrillatory frequency obtained from the surface ECG in patients with persistent atrial fibrillation (AF) with oral verapamil treatment to those without this treatment.

Progression From Esophageal Thermal Asymptomatic Lesion to Perforation Complicating Atrial Fibrillation Ablation: A Single-Center Registry

Background— Up to 40% of patients demonstrate endoscopically detected asymptomatic esophageal lesions (EDEL) after atrial fibrillation ablation. Methods and Results— Patients undergoing first atrial fibrillation ablation and postinterventional esophageal endoscopy were included in the study. Occurrence of esophageal perforating complications during follow-up was related to documented EDEL (category 1: erythema/erosion; category 2: ulcer). In total, 1802 patients underwent first atrial fibrillation ablation procedure between January 2013 and August 2016 at our institution. Out of this group, 832 patients (506 male patients, 61%; 64.0±10.0 years) with symptomatic paroxysmal (n=345; 42%) or persistent atrial fibrillation underwent postprocedural esophageal endoscopy. Patients were ablated using single-tip ablation with conventional or surround flow irrigation and circular ablation catheters with open irrigation (nMARQ). In 295 of 832 patients (35%), a temperature probe was used. EDEL occurred in 150 patients (18%; n=98 category 1 EDEL, n=52 category 2 EDEL). In 5 of 832 patients (0.6%), an esophageal perforation (n=3) or an esophagopericardial or atrioesophageal fistula (n=2) occurred 15 to 28 days (19±6 days) after ablation. Two patients (1 atrioesophageal fistula and 1 esophagopericardial fistula) died. Esophageal perforation occurred only in patients with category 2 lesions (absolute risk, 9.6%). In a logistic regression analysis, ulcers were identified to be a significant predictor for esophageal perforating complications. Conclusions— Postablation endoscopy seems to identify patients at high risk of esophageal perforating complications only occurring in patients with category 2 EDEL. One out of 10 postablation esophageal ulcers progressed to perforation, and no patient without esophageal thermal ulcers showed the occurrence of perforating esophageal complications.

Electrocardiographic Characteristics in Patients with Nonrheumatic Atrial Fibrillation and Their Relation to Echocardiographic Parameters

BOLLMANN, A., et al.: Electrocardiographic Characteristics in Patients with Nonrheumatic Atrial Fibrillation and their Relation to Echocardiographic Parameters. The aim of this study was to determine the relation between (1) ECG fibrillatory wave amplitude and left atrial diameter and left atrial appendage (LAA) flow velocity using different ECG recording techniques, and (2) ECG fibrillatory frequency and frequency of LAA contractions in patients with nonrheumatic AF. In 36 patients (22 men, 14 women, mean age 61 ± 11 years) with persistent AF, ECG recordings were performed using a standard 12‐lead ECG and an orthogonal ECG lead system using a high gain, high resolution ECG. AF was classified as coarse (fibrillatory amplitude ≥ 1 mm) or fine (fibrillatory amplitude < 1 mm) in leads I, aVF, V1 and corresponding leads X, Y, and Z. Fibrillatory frequency from the ECG was determined by subtracting averaged QRST complexes and applying a Fourier analysis to the resulting signal. Doppler flow was obtained from LAA during transesophageal echocardiography and LAA emptying velocity was determined. Fourier analysis was also applied to the Doppler signal generating the frequency of LAA contractions. Coarse AF was observed in 0, 9, and 18 patients in leads I, aVF, and V, respectively. It was more often (P < 0.05) detected in corresponding leads X (n = 13), Y (n = 31), and Z (n = 23). Fine AF in lead X was associated with a reduced LAA velocity (33 ± 16 cm/s in coarse AF vs 22 ± 13 cm/s in fine AF, P = 0.05). There was neither a relation between AF coarseness in any other ECG lead and LAA flow velocity, left atrial diameter, or echo contrast. In 25 patients with an active LAA flow, the mean frequency of LAA contractions was 6.8 ± 0.8 Hz. The corresponding mean frequency obtained from the ECG was 6.7 ± 0.7 Hz (r = 0.85, P < 0.001). The mean difference between these two measures was 0.04 Hz, and the 95% confidence limits were 0.90 and – 0.82 Hz using the Bland‐Altman method. In conclusion, AF coarseness and its relation to LAA flow velocity depend on the ECG recording technique used. LAA contractions represent one mechanical correlate of the electrical fibrillatory activity in AF.

Current developments in cardiac rhythm management devices

Endocardial pacing has experienced a tremendous evolution since the 1960s. A lot of challenges associated with pacemaker and ICD devices have already been successfully targeted. However, a relevant number of problems have not been solved to date. Not all patients with accepted indication for biventricular pacing have benefited from cardiac resynchronisation therapy (CRT) despite extensive efforts to reduce the rate of non-responders. Current strategies to optimize lead position, multipolar left-ventricular (LV) pacing leads, new strategies to gain access to the left-ventricle (atrial transseptal or ventricular transseptal access) or alternative right-ventricular (septal, His bundle pacing) pacing sites, and “leadless” LV pacing have the potential to increase response to device-based heart-failure treatment. The opportunity of pacemaker and ICD remote monitoring led to relevant improvements in therapy management by timely detection of events requiring medical or invasive interventions (e.g., external cardioversion of atrial fibrillation, increasing effective biventricular pacing, catheter ablation of ventricular tachycardias, or changes in heart-failure medication). Two completely endocardial leadless “all-in-one” pacemaker systems recently became available. Besides these innovations, new “synergistic” therapy concepts combining catheter ablation and device therapy proved to affect clinical endpoints (e.g., ATAAC study and CASTLE-AF study).

Tachykardie mit breitem QRS-Komplex unter antiarrhythmischer Therapie mit Flecainid

Recent prospective trials of pacing in atrial fibrillation are inconclusive. A substantial suppression of atrial tachyarrhythmias has been observed in patients with brady-tachy-syndrome and high rate of paced vs. intrinsic beats. An improvement in prognosis, incidence of thromboembolism, rehospitalization and improvement in heart failure have been controversally described in different trials. The quality of life improves in most studies in physiologic pacing. This paper presents a short overview on published and ongoing trials in pacing of atrial fibrillation.Summary Recent prospective trials of pacing in atrial fibrillation are inconclusive. A substantial suppression of atrial tachyarrhythmias has been observed in patients with brady-tachy-syndrome and high rate of paced vs. intrinsic beats. An improvement in prognosis, incidence of thromboembolism, rehospitalization and improvement in heart failure have been controversally described in different trials. The quality of life improves in most studies in physiologic pacing. This paper presents a short overview on published and ongoing trials in pacing of atrial fibrillation.Zusammenfassung Die prospektiven Studien zur Herzschrittmachertherapie bei Patienten mit paroxysmalem Vorhofflimmern zeigten keine übereinstimmenden Befunde. Eine Suppression der Vorhoftachyarrhythmien gelingt am ehesten bei Patienten mit Bradykardie-Tachykardie-Syndrom und hoher Stimulationsrate. Hinsichtlich einer Verbesserung der Prognose, der Häufigkeit von Thromboembolien, der Rehospitalisierung und einer Verringerung der Herzinsuffizienz sind die Aussagen verschiedener Untersuchungen kontrovers. Die Lebensqualität ist in einigen Studien bei vorhofbeteiligter Stimulation verbessert. Die vorliegende Arbeit gibt einen Überblick über vorliegende und gegenwärtig laufende Studien.