Florian Hintringer

Transvenous Pacemaker Lead Removal Is Safe and Effective Even in Large Vegetations: An Analysis of 53 Cases of Pacemaker Lead Endocarditis

Background: The aim of this study was to investigate whether transvenous lead removal is safe and effective in patients with lead vegetations greater than 1 cm in size.

Atrioesophageal Fistula After Percutaneous Transcatheter Ablation of Atrial Fibrillation

A 45-year-old white man presented to the emergency department because of fever and fluctuating neurological symptoms including weakness and sensory loss of the right limbs. Six weeks before admittance, the patient had undergone percutaneous transcatheter ablation of drug-refractory atrial fibrillation. Laboratory examination showed markedly elevated white cell count and inflammatory markers, as well as moderately increased cardiac troponin T; however, no chest pain or gastrointestinal symptoms were reported, and the ECG was normal. Computed tomography (CT) scan of the chest revealed a fistula between the …

Regional prevalence and clinical benefit of implantable cardioverter defibrillators in Brugada syndrome

BACKGROUNDnBrugada syndrome (BS) is associated with an increased risk of sudden cardiac death (SCD) caused by ventricular tachyarrhythmia. Thus, implantable cardioverter defibrillators (ICD) became the main therapeutic option in these patients. We aimed to investigate the prevalence of BS in the Eastern Alps as well as the benefit of ICD therapy in this collective.nnnMETHODSnDuring physical examination before military service, 47,606 Austrian men were screened for Brugada ECG pattern. Furthermore, we followed 4491 patients with arrhythmia during the last two decades, of which 26 patients (20 male; age at diagnosis: 43.2 ± 11.6 years) revealed BS. Diagnosis was based on characteristic ECG either at rest (11 patients) or after provocation with Ajmaline (15 patients).nnnRESULTSnThe nationwide screening revealed one individual with Brugada ECG (prevalence of 2.10/100,000 inhabitants). Prior to diagnosis of BS, syncope and SCD survival were observed in 7 and 4 patients, respectively; the remaining 15 patients were asymptomatic. ICD were implanted in 17 patients (15 male). Three asymptomatic patients received no ICD because no tachyarrhythmia was inducible on programmed stimulation. Six asymptomatic patients without family history of sudden death refused further evaluation. Mean ICD follow-up period was 57.0 ± 32.2 months. Two patients (11.7%) needed defibrillation therapy. Four patients (23.5%) received exclusively inappropriate shocks (three due to T-wave oversensing, one due to atrial fibrillation).nnnCONCLUSIONSnBrugada syndrome has a low prevalence in the Eastern alpine region. Patients with BS benefit from ICD implantation, but less frequently than anticipated. The problem of inappropriate ICD discharges is still of major concern.

Sex and age effects on cardiovascular autonomic function in healthy adults

PurposeTo determine the effects of sex and age on cardiovascular autonomic parameters in healthy adults as assessed by Finapres (finger arterial pressure) method and prolonged head-up tilt (HUT).MethodsWe enrolled 81 healthy volunteers (41 females, 40 males, 18–74xa0years) for extensive cardiovascular autonomic function testing including blood pressure (BP) recordings, electrocardiography, and impedance cardiography at rest, under 60° HUT for 45xa0min, active standing for 5xa0min, Valsalva maneuver, and deep breathing (DB). Mean values and orthostatic changes, i.e., differences to baseline, of heart rate (HR), systolic and diastolic BP, stroke volume (SV), and total peripheral resistance (TPR), as well as DB ratio and Valsalva ratio were calculated. A generalized linear model (extended by generalized estimating equations) was used to assess sex- and age-related differences.ResultsMean HR at rest was higher in women than in men (pxa0=xa00.035). In men, we observed significantly higher mean BP at rest (pxa0<xa00.001 systolic and pxa0=xa00.004 diastolic) and during HUT (pxa0=xa00.001 systolic and pxa0<xa00.001 diastolic), mean TPR at rest (pxa0=xa00.034), and mean SV during HUT (pxa0<xa00.001). We found no significant impact of sex on orthostatic changes of HR and BP. Mean TPR during HUT increased with age (pxa0=xa00.001), particularly in older women. Orthostatic changes of HR and diastolic BP, DB ratio, and Valsalva ratio became attenuated with age (pxa0=xa00.018, pxa0=xa00.006, pxa0<xa00.001, and pxa0<xa00.001, respectively).ConclusionsOur study suggests that aging rather than sex needs to be taken into account when interpreting HR and BP changes during prolonged HUT performance.

Duration of the A(H)-A(Md) interval predicts occurrence of AV-block after radiofrequency ablation of the slow pathway.

PurposeModification of the slow pathway (SP) of the atrio-ventricular node by radiofrequency ablation is the most effective treatment to cure AV nodal reentry tachycardia (AVNRT). However, this therapy may be complicated by AV-block (AVB). We sought to evaluate the predictive value of the A(H)–A(Md) interval—the electrical delay between atrial signals on the His- and the ablation-catheter—upon development of AVB during SP ablation.Methods The associations between A(H)–A(Md) interval, occurrence of ventriculo-atrial block (VAB) during junctional activity (JA) and transient or permanent AVB were analyzed retrospectively for 1585 RF applications at the SP in 393 patients diagnosed with AVNRT. The value of A(H)–A(Md) was further tested prospectively in 118 AVNRT patients, who were only ablated at targets with intervals >20xa0ms.ResultsForty-six RF deliveries resulted in transient or permanent AV-conduction disturbances. Shorter A(H)–A(Md) intervals were associated with the occurrence of VAB during JA (pu2009<u20090.001) and AVB (pu2009<u20090.001). A(H)–A(Md) was the strongest predictor for VAB or AVB in multivariate regression analyses, followed by the radiological distance between the catheters. In the prospective study, permanent high-degree AVB was not observed when the A(H)–A(Md) at the ablation site was >20xa0ms.ConclusionThe A(H)–A(Md) interval is a better predictor for occurrence of conduction block during ablation for AVNRT than the radiological distance between the His- and the ablation-catheter. The risk of permanent AVB can be minimized, if only sites with an A(H)–A(Md) longer than 20xa0ms are targeted for ablation.

Achieving elongated lesions employing cardiac cryoablation: a preclinical evaluation study

Cardiac cryoablation applied for treating cardiac arrhythmias has shown promising results after intervention, particularly for the creation of elongated lesions. A model for simulating and assessing cryoablation interventions was developed, evaluated and validated with animal experiments. We employed two simulations of different freezing outlet settings for a loop shaped cryocatheter, applying Pennes heat equation for cardiac tissue. Our experiments demonstrated that an equidistantly spaced freezing outlet distribution of 5mm led to an improved formation of lesions, i.e., elongated lesions were observed throughout the transmural cardiac volume and on the epicardial structure. A complete transmural frozen lesion was not achieved with a freezing outlet distance of 10mm. These simulation results could be experimentally verified by morphological and histological examinations. Using our simulation model we were able to optimize the intervention procedure by predicting and assessing the freezing process. This should further increase the success rate of cardiac cryoablation in clinical interventions.

Letter Regarding Article by Sanders et al, “Spectral Analysis Identifies Sites of High-Frequency Activity Maintaining Atrial Fibrillation in Humans”

To the Editor:nnWe read with great interest a report by Sanders et al1 demonstrating that domains of high-frequency activity maintain atrial fibrillation in humans. Sanders et al computed a parameter called dominant frequency (DF) from bipolar interatrial electrograms. The DF ranges from 4 to 14 Hz. High values correspond to the driving tissue.nnOur comment on the signal processing applied by Sanders et al is motivated by the following question: Is it feasible to compute DFs of a few Hertz from a bipolar electrogram that is filtered from 30 to 500 Hz and thus does not contain any significant frequencies <30 Hz? The answer surprisingly is yes, because of a remarkable signal manipulation left undiscussed by the authors. The signal is rectified before analysis. Fourier analysis of a rectified periodic signal with narrow deflections shows a prominent peak for the inverse of the cycle length, ie, the DF. Without rectifying, the spectrum is shifted to higher frequencies. Thus, the original bipolar signal passes the filter.nnA minor disadvantage is that pronounced harmonics occur. These harmonics have higher relative amplitudes compared with the …

Computer simulation of cardiac cryoablation: Comparison with in vivo data ☆

Simulation of cardiac cryoablation by the finite element method can contribute to optimizing ablation results and understanding the effects of modifications prior to time-consuming and expensive experiments. In this work an intervention scenario using a 9 Fr 8 mm tip applicator applied to ventricular tissue was simulated using the effective heat capacity model based on Pennes bioheat equation. Using experimentally obtained refrigerant flow rates and temperature profiles recorded by a thermocouple located at the tip of the applicator the cooling performance of the refrigerant was estimated and integrated by time and temperature dependent boundary conditions based on distinct phases of a freeze-thaw cycle. Our simulations exhibited a mean difference of approximately 6°C at the applicator tip compared to temperature profiles obtained during in vivo experiments. The presented model is a useful tool for simulation and validation of new developments in clinical cardiac cryoablation.

Influence of vitamin K antagonists and direct oral anticoagulation on coronary artery disease: A CTA analysis

OBJECTIVEnVitamin K antagonists (VKA) are associated with increased vascular calcification which may lead to an elevated cardiovascular risk. If the direct anticoagulants (DOACs) have similar negative vascular effects is unknown. We evaluated the influence of different anticoagulation strategies on coronary artery disease (CAD) using coronary computed tomography angiography (CTA).nnnMETHODSnOverall 702 consecutive patients with non-valvular atrial fibrillation (AF) who underwent CTA for AF ablation planning were enrolled and stratified according to their anticoagulation into VKA, DOAC (all agents) and a control group without oral anticoagulation. Patients were propensity score matched 1:1:1, significant structural heart disease and comorbidities were excluded. CT images were evaluated for plaque burden (calcium score, segment involvement score (SIS) and non-calcified SIS, stenosis grading) and plaque morphology (high risk plaque features: low attenuation, positive remodeling, napkin-ring sign, spotty calcification).nnnRESULTSnFinal analysis included 303 patients (101 patients each group) and showed increased overall plaque burden in patients using VKA compared to DOAC users and the control group (mean affected segments 2.58 vs 1.58 vs 2.100, pu202f=u202f0.008), and a higher prevalence of high-risk plaque (HRP) features (42.6% vs 13.9% vs 26.7%, pu202f<u202f0.0001). Patients treated with DOACs did not differ in conventional CT findings from the control group and showed an even lower prevalence of selected HRP features compared to the control group: low-attenuation plaques (4.0% vs. 14.4%, pu202f=u202f0.014) and napkin-ring sign (0 vs. 5.0%, pu202f=u202f0.029).nnnCONCLUSIONnVitamin K antagonists are associated with a higher plaque burden and increased high-risk plaque features, whereas DOACs may yield a benefit in cardiovascular atherosclerosis.

Catheter‐based edge‐to‐edge mitral valve repair for pulmonary pressure reduction and to postpone heart transplantation in a teenaged patient

We report a case of catheter‐based edge‐to‐edge mitral valve repair in a teenage male patient with non‐ischaemic cardiomyopathy to improve pulmonary hypertension secondary to severe functional mitral regurgitation (FMR) to defer anticipated heart transplantation. A 19‐year‐old patient with previous history of fulminant myocarditis followed by markedly left ventricular dysfunction presented with severe mitral regurgitation 3 years after initial recovery. Slightly over time, deterioration of FMR was associated with gradual increase in pulmonary artery pressures despite optimal medical therapy. MitraClip implantation in this young patient was successfully performed with sustainable improvement of pulmonary hypertension.