[The athlete's ECG : What is normal or abnormal?] / Das EKG beim Leistungssportler und Athleten : Was ist normal und was nicht?

BACKGROUND: The electrocardiogram (ECG) has become a mobile and cost-effective routine assessment tool to risk stratify leisure-time and professional athletes during preparticipation screening. A central goal is the reduction of sudden cardiac death in sports through early recognition of the most prevalent underlying cardiac pathologies, e.g., hereditary cardiomyopathies or primary arrhythmias. METHODS: Continuous evolution of the first ECG criteria for athletes, presented in 2010 by the European Society of Cardiology (ESC), has helped to improve the specificity of the criteria to both detect cardiac pathologies in early stages and differentiate from physiologic adaptation of the athlete's heart. Thus, the risk of false-positive findings and erroneous stigmatizations of athletes has been successfully reduced. CONCLUSION: This review article intends to trace back the changes of the ECG criteria in the light of a growing body of scientific evidence over the last 15 years, to present the key messages of the current International ECG criteria from 2017 and to identify some of the remaining challenges that wait to be answered by physicians in the field of sports medicine and sports cardiology.

[Cardiac contractility modulation]. / Kardiale Kontraktilitätsmodulation.

Heart failure (HF) will be one of the biggest medical challenges in the coming years, with increasing prevalence in an aging society. It is associated with a poor prognosis and impaired quality of life-despite steadily improving medical therapy which has resulted in a steady decrease in mortality and an increase in quality of life. In medically refractory patients with impaired left ventricular (LV) function, left bundle branch block and wide QRS complex (≥130 ms) cardiac resynchronization therapy (CRT) in addition to medical therapy has become the gold standard. Additionally, other therapeutic modalities such as vagal stimulation are being clinically tested but as yet have no general therapeutic recommendation. Overall, CRT patients represent only one-third of all HF patients and about 25% are "non-responders" who do not benefit from CRT.In HF patients with an LVEF between 25 and 45% and a QRS duration <130 ms who are not suitable for CRT, cardiac contractility modulation (CCM) is currently a therapeutic option that has been shown in several randomized trials to be efficacious and safe. It reduces the frequency of HF hospitalizations and improves HF symptoms, functional capacity, and quality of life. The goal of this article is to present mechanisms of action, major clinical studies, current indications, and recent developments of CCM for the treatment of patients with chronic HF.

Positive impact of pulmonary vein isolation on biventricular pacing in nonresponders to cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is less effective in patients with atrial fibrillation (AF) because of impaired ventricular CRT capture. OBJECTIVE: We investigated the effects of catheter ablation in patients with AF and previous nonresponse to CRT. METHODS: Consecutive patients with AF and CRT nonresponse who underwent catheter ablation for AF were analyzed. CRT nonresponse was defined as one of the following: (1) reduced biventricular capture <95% due to rapidly conducted AF, (2) <1 point improvement in New York Heart Association (NYHA) class after CRT implantation, or (3) insufficient increase in left ventricular ejection fraction (LVEF; ≤5%) after CRT implantation. RESULTS: Thirty-eight patients (8 women [21%]; mean age 68 ± 10 years; LVEF 30% ± 7%, biventricular capture 88.0% [25th, 75th percentile 75.3%, 98.5%]) underwent catheter ablation. One major and 1 minor complication occurred (1 lethal atrioesophageal fistula and 1 hemodynamically nonrelevant pericardial effusion). The Kaplan-Meier estimates for arrhythmia-free survival after single and multiple ablation procedures were 29% (95% confidence interval 16%-51%) and 67% (95% confidence interval 53%-86%) after 24 months. After a median follow-up of 817 days (25th, 75th percentile 179, 1741 days), biventricular capture and LVEF were significantly higher (median [25th, 75th percentile] 99% [96%, 99%], difference 8% [0.2%, 3.75%], P < .0001; mean 32.1% ± 9.1%, difference 2.2% ± 7.1%, P = .0225) and patients had a significantly lower functional NYHA class (28 of 37 patients with improvement of at least 1 point; P < .0001). CONCLUSION: Catheter ablation of AF significantly improves CRT response in patients with heart failure and concomitant AF in terms of increased biventricular capture and LVEF and improved functional NYHA class.

Right heart function prediction of outcome in heart failure patients after catheter ablation for recurrent ventricular tachycardia.

OBJECTIVES: This study sought to determine the relevance of echocardiographic assessment focusing on right ventricular (RV) function to estimate prognosis in patients with heart failure (HF) and low left ventricular ejection fraction (LVEF) after ablation of ventricular tachycardia (VT). BACKGROUND: Recurrent VT is a marker of increased mortality in HF. Decision making remains challenging as some patients have a poor outcome despite successful catheter ablation of VT due to progressive biventricular HF. METHODS: Retrospective analysis was performed on data from 320 consecutive patients with HF and LVEF ≤40% who underwent ablation for recurrent VT between 1999 and 2008. Baseline clinical and echocardiographic data were analyzed in relation to survival. RESULTS: Among the 320 patients included, the mean age was 63 years, and 86% were male. During follow-up (median: 36 months) 127 patients (40%) died. RV dysfunction (hazard ratio [HR]: 1.4) and tricuspid regurgitation (TR) (HR: 1.7), together with age, New York Heart Association (NYHA) class, and serum creatinine, were independent predictors of death in a Cox regression model. Mortality was more than 2-fold higher in patients with at least moderate RV dysfunction and TR (HR: 2.6; p < 0.001). In patients with at least moderate RV dysfunction, TR, and estimated pulmonary arterial pressure ≥45 mm Hg, mortality was 61% at 2 years, compared with 16% in patients with good RV function without pulmonary hypertension (p < 0.0001). CONCLUSIONS: Despite low LVEF, patients with recurrent VT who had good RV function without elevated pulmonary pressures had a good prognosis after VT ablation. RV dysfunction, TR, and elevated pulmonary pressures identified a high-risk group of VT survivors in whom additional interventions may be necessary to improve survival.

Impaired heart rate responses and exercise capacity in heart failure patients with paced baseline rhythms.

BACKGROUND: Conduction system disease and beta-blocker therapy are both common among heart failure (HF) patients and contribute to increasing reliance on paced rhythms. We hypothesized that many HF patients dependent on pacing have suboptimal heart rate responses and associated limitations in exercise capacity. METHODS AND RESULTS: We studied 122 HF patients (left ventricular ejection fractions ≤40%) referred for cardiopulmonary exercise testing, comparing those with pacing at baseline with those with native rhythms. The paced group (PG) had lower resting (71 ± 9 vs 75 ± 15 beats/min; P = .048) and peak heart rates (103 ± 22 vs 127 ± 27 beats/min; P < .0001). Although beta-blockers were prescribed with similar frequency in both groups (90% vs 85%), average dose was higher in the PG. Inotropic reserve (oxygen pulse) was similar in both groups (11.1 ± 3.3 vs 11.1 ± 3.4 mL/beat; P = .94), consistent with equivalent stroke volumes, but chronotropic incompetence was higher (95% vs 71%, P = .001) and peak VO(2) was lower (12.2 ± 3.4 vs 14.2 ± 4.1 mL/kg/min; P = .004) in the PG. CONCLUSIONS: Chronotropic incompetence and exercise capacity are worse in HF patients depending on paced heart rate responses. This has implications for quality of life as well as advanced therapy choices based on exercise capacity. Reevaluating beta-blocker dosing and optimizing pacemaker programming may therefore benefit the growing population of HF patients with device-dependent rhythms.

Pulmonary vein conduction is the major finding in patients with atrial tachyarrhythmias after intraoperative maze ablation.

INTRODUCTION: Electrophysiological (EP) data from patients with recurrent atrial tachyarrhythmias (ATa) after intraoperative maze ablation are limited. Furthermore, the clinical course after accomplishing pulmonary vein (PV) isolation using the double lasso technique (DLT) is unknown. METHODS AND RESULTS: EP study and catheter ablation (CA) was guided by a three-dimensional electroanatomic mapping system (3-D EA, CARTO, Biosense-Webster) combined with simultaneous ipsilateral PV mapping using the DLT. Defined endpoints were: (1) identification of conduction gaps within the ipsilateral PVs, (2) elimination of all PV spikes, and (3) ablation of clinical ATas. CA was performed in eight patients (four females, 62 +/- 5 years, LA: 50 +/- 6 mm) with drug refractory ATa (9.1 +/- 6.3 years) despite non-"cut and sew" maze operation. Electrical PV conduction was demonstrated in the majority of patients (7/8). All endpoints were achieved. Repeat ablations were required in three patients. Second ablation was due to typical atrial flutter (n = 1) and atrial fibrillation (n = 2). One patient required three ablations due to a left atrial macroreentrant tachycardia. During a mean follow-up of 15.5 +/- 4.8 months, 7/8 patients were free of ATa recurrences. CONCLUSION: Incomplete lesions after non-"cut and sew" maze operation are associated with PV conduction and recurrence of ATas. Electrical isolation of ipsilateral PVs and completion of linear lesions guided by 3-D EA mapping is feasible and successful in maintaining sinus rhythm during mid term follow-up. Completeness of linear lesions using EP endpoints should be confirmed during the initial surgical procedure to minimize ATa recurrences.

Remote-controlled catheter ablation of accessory pathways: results from the magnetic laboratory.

AIMS: This study evaluates feasibility, safety, and efficacy of magnetic remote-controlled accessory pathway (AP) ablation. METHODS AND RESULTS: The novel magnetic navigation system (MNS) (Niobe, Stereotaxis) creates a steerable magnetic field (0.08 T) controlling the distal magnetic tip of an ablation catheter. In conjunction with a catheter advancer system (Cardiodrive, Stereotaxis) remote catheter ablation is enabled. Conventional electrophysiology study identified AP conduction in 59 patients (37 males, 36+/-14 years, 60 APs). First generation 1-magnet tip (1-M) (group I, n=18), second generation bipolar 3-magnet tip (3-M) (group II, n=27), and third generation quadripolar 3-magnet tip catheters (3-M quad.) (group III, n=14) were used for magnetic remote-controlled ablation. Successful AP ablation was achieved in 67% (group I), 85% (group II), and 92% (group III). A significant decrease of median [IQR: Q1-Q3] fluoroscopy time and dosage was observed: 21.2 [12.1-33.8] min, 1110 [395-3234] microGym2 (group I); 6.5 [4.4-15.4] min, 290 [129-489] microGym2 (group II), and 4.9 [3.4-8.0] min, 129 [74-270] microGym2 (group III). Mean procedure time (217+/-67 min; 182+/-68 min, and 172+/-90 min) significantly decreased in group III. Median number [Q1-Q3] of radiofrequency current applications in groups I, II, and III was 4 [2-9], 4 [2-6], and 2 [2-4], respectively. No complications occurred. CONCLUSION: Remote AP ablation is safe and feasible using the novel MNS. Introduction of the 3-magnet quadripolar ablation catheter significantly improved the efficacy of the procedure.

A single pulmonary vein as electrophysiological substrate of paroxysmal atrial fibrillation.

INTRODUCTION: It has been demonstrated that pulmonary veins (PVs) play an important role in initiation and maintenance of paroxysmal atrial fibrillation (AF). However, it is not clearly known whether a single PV acts as electrophysiological substrate for paroxysmal AF. METHODS AND RESULTS: This study included five patients with paroxysmal AF. All patients underwent complete PV isolation with continuous circular lesions (CCLs) around the ipsilateral PVs guided by a three-dimensional mapping system. Irrigated radiofrequency (RF) delivery was performed during AF on the right-sided CCLs in two patients and on the left-sided CCLs in three patients. The incomplete CCLs resulted in a change from AF to atrial tachycardia (AT), which presented with an identical atrial activation sequence and P wave morphology. Complete CCLs resulted in AF termination with persistent PV tachyarrhythmias within the isolated PV in all five patients. PV tachyarrhythmia within the isolated PV was PV fibrillation from the left common PV (LCPV) in two patients, PV tachycardia from the right superior PV (RSPV) in two patients, and from the left superior PV in one patient. All sustained PV tachyarrhythmias persisted for more than 30 minutes, needed external cardioversion for termination in four patients and a focal ablation in one patient. After the initial procedure, an AT from the RSPV occurred in a patient with PV fibrillation within the LCPV, and was successfully ablated. CONCLUSION: In patients with paroxysmal AF, sustained PV tachyarrhythmias from a single PV can perpetuate AF. Complete isolation of all PV may provide good clinical outcome during long-term follow-up.