Infectious endocarditis caused by Helcococcus kunzii in a vascular patient: a case report and literature review.

BACKGROUND: Helcococcus kunzii is a facultative anaerobic bacterium that was first described by Collins et al. in 1993, and was initially considered as a commensal of the human skin, in particular of lower extremities. Human infections caused by H. kunzii remain rare with only a few cases published in the pubmed database. Nevertheless recent reports indicate that this microorganism has to be considered as an opportunistic pathogen that can be involved in severe infections in human. To the best of our knowledge, we describe here the first known case of infectious endocarditis caused by H. kunzii. CASE PRESENTATION: A 79 year-old man reporting severe polyvascular medical history attended the emergency ward for rapid deterioration of his general state of health. After physical examination and paraclinical investigations, the diagnosis of infectious endocarditis on native mitral valve caused by Helcococcus kunzii was established based on Dukes criteria. MALDI-TOF mass spectrometry and 16S rDNA sequencing allowed an accurate identification to the species level of Helcococcus kunzii. The patient was successfully treated by a medico-surgical approach. The treatment consisted in intravenous amoxicillin during four weeks and mitral valve replacement with a bioprosthestic valve. After an in depth review of patient's medical file, the origin of infection remained unknown. However, a cutaneous portal of entry cannot be excluded as the patient and his General Practitioner reported chronic ulcerations of both feet. CONCLUSIONS: We describe here the first case of endocarditis caused by H. kunzii in an elderly patient with polyvascular disease. This report along with previous data found in the literature emphasizes the invasive potential of this bacterial species as an opportunistic pathogen, in particular for patient with polyvascular diseases. MALDI-TOF mass spectrometry and 16S rDNA sequencing are reliable tools for H. kunzii identification. We also sequenced in this work H.kunzii type strain 103932T CIP and deposited in the Genbank under accession number KM403387. We noticed a 14 base difference between our sequence and the original sequence deposited by Collins et al. under Genbank accession number X69837. Hopefully, the spread of next generation sequencing tools would lead to a more accurate classification of clinical strains.

New insights into typical atrial flutter ablation: extra-isthmus activation time on the flutter wave is predictive of extra-isthmus conduction time after isthmus block.

PURPOSE: Catheter ablation of typical atrial flutter (AFl) is succesful if double electrograms on the ablation line are widely separated. Nevertheless, a small interval may also be compatible with complete isthmus block. Predicting such a situation may avoid useless additionnal radiofrequency (RF) applications. We postulated that measuring the extra-isthmus activation time (EIAT) on the counterclockwise (CCW) flutter wave is correlated with the extra-isthmus conduction time after a proven block. METHODS: Files of 76 patients (71 males, 71 ± 12 years) ablated for typical CCW AFl were reviewed. Ten had 2/1 conduction prohibiting reliable measurement. Three patients with proven crista terminalis shunt were also excluded. In the remaining 63 patients, EIAT was measured on the surface ECG before the first RF pulse from the beginning of the negative deflection of the F wave in lead III to the end of the positive deflection (or beginning of the plateau). After successful ablation and completion of block, right atrial (RA) CCW (during low septal pacing), and clockwise (CW) (during low lateral pacing) activation times were measured. RESULTS: Flutter cycle length was 247 ± 34 ms and EIAT was 142 ± 25 ms. A bidirectionnal isthmus block was obtained in all patients after an RF delivery time of 623 ± 546 s. At a pacing cycle length of 681 ± 71 ms, RA CCW and CW activation times were 147 ± 23 and 139 ± 26 ms, respectively. There was a good correlation between EIA, RA CCW (r = 0.75, p < 0.0001), and CW (r = 0.69, p = 0.0002) activation times. CONCLUSION: EIAT on the flutter wave is an easy and feasible measure. It is correlated with extra-isthmus RA conduction time after block completion. EIAT can be used as a measure to predict the post cavo-tricuspid isthmus block RA activation time.

Robotic magnetic navigation for ablation of human arrhythmias: initial experience.

BACKGROUND: Magnetic navigation system (MNS) (Niobe, Stereotaxis, Saint-Louis, Missouri, USA) allows remote control of a radiofrequency ablation catheter using a steerable magnetic field and a catheter advancement system. AIMS: We report our initial experience of ablation of human arrhythmias using the MNS. METHODS: Eighty-four patients (mean age 54+/-17years; 39 women) had an electrophysiologic study followed by ablation with the MNS using non-irrigated 4, 8 and 3.5mm-tip catheters with three distal magnets. All patients were symptomatic, with commonly-accepted indications for ablation: atrioventricular nodal re-entrant tachycardia (AVNRT; n=37); typical atrial flutter (n=15); accessory pathway (n=12); atypical atrial flutter (n=7); ventricular tachycardia (n=7); atrial tachycardia (n=3); paroxysmal atrial fibrillation (n=3). Electroanatomical mapping was used for atrial flutter, atrial fibrillation, atrial tachycardia and ventricular tachycardia procedures (29 patients, 34%). RESULTS: Ablation was performed successfully in 69 (82%) patients. In 15 patients (18%), MNS technique was unsuccessful: seven typical atrial flutters, four accessory pathways, two left atrial flutters after atrial fibrillation ablation, one ventricular tachycardia and one AVNRT; in all these cases except one typical atrial flutter and two left atrial flutters, success was obtained by switching to the manual technique by means of an irrigated catheter. Total fluoroscopy time was 14+/-11minutes; operator exposure fluoroscopy time was 1.5+/-0.6minutes; procedure time was 169+/-72minutes. CONCLUSION: MNS ablation is a feasible treatment for various human arrhythmias, with a high success rate. Mapping with a magnetic catheter is safe. However, magnetic ablation of typical atrial flutter remains challenging, probably because of insufficient pressure for cavotricuspid isthmus ablation.

Real-time three-dimensional transoesophageal echocardiography for diagnosis of left atrial appendage thrombus.

We report a case where real-time 3D TEE proved the non-thrombotic nature of a particular pectinated muscle arrangement within the LAA.

[Typical atrial flutter: history, mechanisms and radiofrequency "ablation"]. / Le flutter auriculaire typique: histoire, mécanismes et "ablation" par la technique de radiofréquence.

yipical atrial flutter can now be permanently cured by a single session of radiofrequency ablation, a non pharmacological technique. The term "atrial flutter" is in fact somewhat confusing. A review of the history of this form of tachycardia shows that atrial flutter is indeed a multiple entity. While the reentrant nature of atrial flutter has long been known, most cardiologists refer to the typical ECG aspect and right atrial macro reentry circuit with counterclockwise rotation, as described by Puech. It is now possible to classify these flutters according to their electrocardiographic aspect and electrophysiological mechanisms. This article describes the diagnostic signs of typical flutter, and provides a detailed description of the most frequently used radical therapy, namely catheter ablation of the cavotricuspidian isthmus. This technique delivers radiofrequency pulses, under continuous local temperature monitoring, in order to permanently interrupt conduction in this structure. Outcome is assessed with the pacing technique and local electrocardiography. In experienced hands the immediate success rate is very high, late recurrence is rare, and complications are virtually absent.