In sepsis, systemic inflammatory response syndrome (SIRS), and multiorgan dysfunction syndrome (MODS), a severe prognostically relevant cardiac autonomic dysfunction exists, as manifested by a strong attenuation of sympathetically and vagally mediated heart rate variability (HRV). The mechanisms underlying this attenuation are not limited to the nervous system. They also include alterations of the cardiac pacemaker cells on a cellular level. As shown in human atrial cardiomyocytes, endotoxin interacts with cardiac hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels, which mediate the pacemaker current I f and play an important role in transmitting sympathetic and vagal signals on heart rate and HRV. Moreover, endotoxin sensitizes cardiac HCN channels to sympathetic signals. These findings identify endotoxin as a pertinent modulator of the autonomic nervous regulation of heart function. In MODS, the vagal pathway of the autonomic nervous system is particularly compromised, leading to an attenuation of the cholinergic antiinflammatory reflex. An amelioration of the blunted vagal activity appears to be a promising novel therapeutic target to achieve a suppression of the inflammatory state and thereby an improvement of prognosis in MODS patients. Preliminary data revealed therapeutic benefits (increased survival rates and improvements of the depressed vagal activity) of the administration of statins, β-blockers, and angiotensin-converting enzyme inhibitors in patients with MODS.
Abstract Background This retrospective observational study investigated the relationship between heart rate variability (HRV) and atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) by cryoballoon or radiofrequency ablation (RF). Methods We enrolled 497 patients who underwent PVI using first-generation cryoballoon (CB1), second-generation cryoballoon (CB2), or RF. We analyzed HRV as a surrogate for modulation of the intrinsic autonomic nervous system using 24‑h Holter recordings 1 or 2 days after the procedure and compared the recurrence and non-recurrence group with regard to ablation methods. Furthermore, we calculated recurrence-free survival (RFS) below/over HRV cut-off values for the whole study population and separately for each ablation method. Results All except one of the five time-based HRV parameters analyzed were significantly lower in the non-recurrence group than in the recurrence group after CB2. Only a trend toward lower HRV for the non-recurrence group was found after RF and no remarkable differences were detected after CB1. The HRV parameters below their calculated cut-off were associated with a significantly higher RFS rate 2 years after CB2. This also applied to root mean sum of squared distance (rMSSD) and the percentage of adjacent NN interval differences greater than 50 ms (pNN50) after RF. No differences were found regarding CB1. Concerning rMSSD, the sensitivity, specificity, and difference in RFS increased when using cut-offs that were calculated including only CB2 patients. Multivariate cox regression analysis showed that low rMSSD values could independently predict AF recurrence after adjusting for covariates (hazard ratio: 0.50; p < 0.001). Conclusion Low values of rMSSD early after a PVI could independently predict AF recurrence, especially after CB2.
It was the purpose of this study to determine the incidence of more than two AV nodal pathways in patients with AVNRT.In 78 consecutive patients with AV-nodal reentrant tachycardias (AVNRT) (50 females, 28 males, mean age 52.8 +/- 14.6 years), the number of sudden AH increases by 50 ms or more (AH-jump) was analysed during atrial extrastimulation. The incidence of two AV nodal pathways was accepted to be present in patients with AVNRT without an AH-jump ('smooth curve'). The following forms of tachycardia were induced: a typical AVNRT (slow-fast) in 67 patients, an atypical AVNRT (fast-slow) in 12 patients and a slow-slow-AVNRT in 4 patients. Five patients had two forms of AVNRT. 47 patients (60.3%) showed two AV nodal pathways, 27 patients (34.6%) had three AV-nodal pathways and 4 patients (5.1%) exhibited four AV-nodal pathways. For successful catheter ablation of AVNRT in patients with more than two pathways, more radiofrequency energy applications were required (9.2 +/- 6.3) compared with patients with only two pathways (6.7 +/- 4.8). Furthermore, in patients with more than two AV-nodal pathways, the catheter intervention resulted more frequently in a modulation of slow pathway conduction than in an ablation of the slow pathway(s).The incidence of more than two AV-nodal pathways in patients with AVNRT was unexpectedly high at about 40%. Thus, these tachycardias require a meticulous electrophysiological evaluation for successful ablation.
A 46-year-old woman was admitted to hospital due to dyspnoea. Chest X-ray, serological parameters, and spirometry ruled out pulmonary reasons or infection as its cause.
Transthoracic echocardiography revealed a moderately impaired left ventricular (LV) contractility (ejection fraction 42% calculated according to Simpson's rule); there were no relevant valvular pathologies. In the …
Facing an increasing number of radiofrequency ablation (RF) and cryoballoon ablation (CB) procedures for treatment of AF radiation exposure and its reduction is a focus point for interventional electrophysiologists.
Objectives: Atrial fibrillation is associated with stroke events, progressive heart failure and severely reduced quality of life. In cases of unsuccessful catheter interventions surgery might be an alternative.
Diagnostik und Therapie bradykarder Herzrhythmusstörungen stellen in der Notfallmedizin einen wichtigen Teilbereich dar, denn diese erfordern sofortiges Handeln. Die bradykarden Rhythmusstörungen lassen sich in Reizbildungsund Reizleitungsstörungen einteilen. Beim Sinusknotensyndrom treten neben tachykarden atrialen Arrhythmien sowohl der Sinusknotenstillstand als auch der sinuatriale Block auf. Erregungsleitungsstörungen lassen sich in unterschiedliche Grade des AV-Blocks und in die verschiedenen Schenkelblockierungen unterteilen. Die Ursachen bradykarder Rhythmusstörungen sind vielfältig. Neben primären, degenerativen Ursachen kommen als sekundäre Ursachen der akute Myokardinfarkt, pharmakologische und toxische Ursachen, reflexvermittelte Bradykardien, neurologische Ursachen, Infektionen, rheumatologische und andere Erkrankungen infrage. Zur Klärung der zugrundeliegenden Störung ist die Anamnese von entscheidender Bedeutung. Hiervon ist die Entscheidung zu weiteren diagnostischen Maßnahmen abhängig. Die medikamentöse Therapie akuter symptomatischer Bradykardien besteht aus Atropin sowie Katecholaminen. Zuverlässiger ist die passagere Schrittmachertherapie, von denen die transvenöse Schrittmachertherapie zwar die aufwendigste ist, aber sie ist zuverlässiger als die transkutane und transgastrale Schrittmachertherapie. Bei Persistenz symptomatischer Bradykardien ist die Indikation zur Implantation eines permanenten Schrittmachersystems gegeben.
