Christian Knackstedt

Impact of left ventricular lead position on the efficacy of cardiac resynchronisation therapy: a two-dimensional strain echocardiography study.

Background: Definition of the optimal left ventricular (LV) lead position in cardiac resynchronisation therapy (CRT) is desirable. Objective: To define the optimal LV lead position in CRT and assess the effectiveness of CRT depending on the LV lead position using new myocardial deformation imaging. Methods: Myocardial deformation imaging based on tracking of acoustic tissue pixels in two-dimensional echocardiographic images (EchoPAC, GE ultrasound) was performed in 47 patients with heart failure at baseline and during CRT. In a 36-segment LV model the segment with the latest peak systolic circumferential strain before CRT was determined. The segment with maximal temporal difference in peak systolic circumferential strain on CRT compared with before CRT was assumed to be the LV lead position. The optimal LV lead position was defined as concurrence or immediate neighbouring of the segment with the latest contraction before CRT and those with assumed LV lead location. Results: 25 patients had optimal and 22 non-optimal LV lead positions. Before CRT, the LV ejection fraction (EF) and peak oxygen consumption (Vo2max) were similar in patients with optimal and non-optimal LV lead positions (mean (SD) EFu200a=u200a31.4 (6.1)% vs 30.3 (6.5)% and Vo2maxu200a=u200a14.2 (1.8) vs 14.0 (2.1) ml/min/kg, respectively). At 3 months on CRT, EF increased by 9 (2)% vs 5 (3)% and Vo2max by 2.0 (0.8) vs 1.1 (0.5) ml/min/kg in the optimal vs non-optimal LV lead position groups, respectively (both p<0.001). Conclusions: Concordance of the LV lead site and location of the latest systolic contraction before CRT results in greater improvement in EF and cardiopulmonary workload than the non-optimal LV lead position.

Higher endogenous nitrite levels are associated with superior exercise capacity in highly trained athletes

Factors improving exercise capacity in highly trained individuals are of major interest. Recent studies suggest that the dietary intake of inorganic nitrate may enhance athletic performance. This has been related to the stepwise in vivo bioactivation of nitrate to nitrite and nitric oxide (NO) with the modulation of mitochondrial function. Here we show that higher baseline levels of nitrite are associated with a superior exercise capacity in highly trained athletes independent of endothelial function. Eleven male athletes were enrolled in this investigation and each participant reported twice to the testing facility (total of n=22 observations). Venous blood was obtained to determine the levels of circulating plasma nitrite and nitrate. Endothelial function was assessed by measuring flow-mediated vasodilation (FMD). Hereafter, participants completed a stepwise bicycle exercise test until exhaustion. Blood was drawn from the ear lope to determine the levels of lactate. Lactate anaerobic thresholds (LAT) in relation to heart rate were calculated using non-linear regression models. Baseline plasma nitrite levels correlated with LATs (r=0.65; p=0.001, n=22) and with endothelial function as assessed by FMD (r=0.71; p=0.0002). Correlation coefficients from both testing days did not differ. Multiple linear regressions showed that baseline plasma nitrite level but not endothelial function was an independent predictor of exercise capacity. No such correlations were determined for plasma nitrate levels.

Electrical remodelling in cardiac resynchronization therapy: decrease in intrinsic QRS duration

Introduction Cardiac resynchronization therapy (CRT) provides a therapeutic option for patients with congestive heart failure (CHF) and left bundle-branch block. Structural myocardial remodelling due to CRT has been described extensively. We hypothesized that CRT might also induce electrical remodelling, thus decreasing the intrinsic QRS duration. Methods In 38 patients with CHF (ejection fraction (EF): 26 ± 7%) a CRT device was implanted. 18 patients suff ered from ischaemic cardiomyopathy (ICM) and 20 from dilated cardiomyopathy (DCM). Echocardiography and 12-lead ECGs without pacing were obtained prior to implantation and after 6 and 12 months. Patients were classifi ed as responders in case of an increase in EF ≥ 25% in combination with an increase in NYHA class ≥ 1. Variance analysis was performed to determine the impact of response or underlying heart disease (ICM/DCM) on the extent of change in QRS duration (delta QRS duration). Results The EF increased to 36 ± 10% (P < 0.0001) after 6 months and 40 ± 12% (P < 0.0001) after 12 months of CRT. Intrinsic QRS duration decreased from 171 ± 18 ms before CRT to 164 ± 23 ms (P= 0.027) after 6 months and 161 ± 25 ms (P= 0.002) after 12 months of CRT. 22 patients (58%) were classifi ed as responders. Whereas a signifi cant decrease in intrinsic QRS duration was observed in responders, only a slight decrease was seen in non-responders. However, two-factorial variance analyses did not show a signifi cant infl uence of response or underlying heart disease (ICM/DCM) on delta QRS duration (P= 0.7). Conclusion CRT results in an electrical remodelling with a reduction of the intrinsic QRS duration.

Cardiac Troponin T and I Release After a 30-km Run

Prolonged endurance-type exercise is associated with elevated cardiac troponin (cTn) levels in asymptomatic recreational athletes. It is unclear whether exercise-induced cTn release mirrors a physiological or pathological underlying process. The aim of this study was to provide a direct comparison of the release kinetics of high-sensitivity cTnI (hs-cTnI) and T (hs-cTnT) after endurance-type exercise. In addition, the effect of remote ischemic preconditioning (RIPC), a cardioprotective strategy that limits ischemia-reperfusion injury, was investigated in a randomized controlled crossover manner. Twenty-five healthy volunteers completed an outdoor 30-km running trial preceded by RIPC (4xa0× 5 min 220xa0mm Hg unilateral occlusion) or control intervention. hs-cTnT, hs-cTnI, and sensitive cTnI (s-cTnI) concentrations were examined before, immediately after, 2 and 5 hours after the trial. The completion of a 30-km run resulted in a significant increase in circulating cTn (time: all p <0.001), with maximum hs-cTnT, hs-cTnI, and s-cTnI levels of 47 ± 27, 69 ± 62, and 82 ± 64xa0ng/L (mean ± SD), respectively. Maximum hs-cTnT concentrations were measured in 60% of the participants at 2 hours after exercise, compared with maximum hs-cTnI and s-cTnI concentrations at 5 hours in 84% and 80% of the participants. Application of an RIPC stimulus did not reduce exercise-induced cTn release (timexa0× trial: all p >0.5). In conclusion, in contrast to acute myocardial infarction, maximum hs-cTnT levels after exercise precede maximum hs-cTnI levels. Distinct release kinetics of hs-cTnT and hs-cTnI and the absence of an effect of RIPC favors the concept that exercise-induced cTn release may be mechanistically distinct from cTn release in acute myocardial infarction.

Long-term follow-up of former world-class swimmers: evaluation of cardiovascular function

There is some evidence that long-term high-intensity endurance training might be associated with deterioration in cardiac function and might impose a potential risk for cardiovascular events. Thus, the intention was to retrospectively evaluate the cardiac status in former endurance athletes, particularly right ventricular (RV) dimension and function, to reveal potential cardiac damage. A group of 12 former world-class swimmers (45xa0±xa01.5xa0years) was examined 24.9xa0±xa04.3xa0years after cessation of high-intensity endurance training. They underwent history taking, physical examination, ECG, exercise testing and echocardiography. Furthermore, functional and echocardiography data that were also available from former evaluations were included in the analysis. There was a significant decline in exercise capacity. LV function was normal with a decrease in septal thickness to 9.1xa0±xa01.3 (pxa0<xa00.05) and LV diastolic diameter to 48.9xa0±xa05.6 (pxa0<xa00.05). Still, there was a remaining septal hypertrophy. RV function was 55.3xa0±xa04.2xa0% and there were normal RV dimensions adjusted for body surface area. 25xa0years after the cessation of endurance training there was a normal RV and LV function with a normalization of almost all diameters, still there was a mild LV hypertrophy in some athletes. Consequently, no relevant long-term cardiac remodeling after intensive endurance training was depicted in this group of athletes.

Initial experience with remote magnetic navigation for left ventricular lead placement.

Background — A novel magnetic navigation system allows remote steering of guidewires and catheters.This system may be used for left ventricular lead placement for cardiac resynchronization therapy (CRT).We sought to evaluate the feasibility and safety of magnetic guidewire navigation for CRT procedures. Methods — 123 consecutive patients underwent CRT implantation/revision procedures (including pacemaker upgrades in n = 22 and left ventricular lead placement after dislocation in n = 4 patients). Left ventricular lead placement in a coronary sinus side branch was performed either conventionally or using magnetic navigation. The magnetic navigation system (Niobe) consists of two permanent magnets creating a steerable magnetic field. Guidewires with integrated magnets align to the magnetic field and were used for over-the-wire implantation of pacemaker leads in the coronary sinus. Patients were assigned to conventional (n = 93) or magnetic (n = 30) navigation according to room availability.Venography of the coronary venous system was performed to select a target vessel for lead implantation. Results — Guidewire access to the target vessel was achieved in 100% using magnetic navigation compared to 87% with the conventional approach (P < 0.05). Implantation success rates, total procedure and fluoroscopy times did not differ significantly between groups. No periprocedural death and no intraoperative device dysfunction occurred in either group.The magnetic guidewire ruptured in one patient. Conclusion — Left ventricular lead placement using magnetic guidewire navigation to engage the desired coronary sinus side branch can be successfully performed for CRT.

Biomarkers in outpatient heart failure management; Are they correlated to and do they influence clinical judgment?

AimsHeart failure (HF) management is complicated by difficulties in clinical assessment. Biomarkers may help guide HF management, but the correspondence between clinical evaluation and biomarker serum levels has hardly been studied. We investigated the correlation between biomarkers and clinical signs and symptoms, the influence of patient characteristics and comorbidities on New York Heart Association (NYHA) classification and the effect of using biomarkers on clinical evaluation.Methods and resultsThis post-hoc analysis comprised 622 patients (77u2009±u20098xa0years, 76xa0% NYHA class ≥3, 80xa0% LVEF ≤45xa0%) participating in TIME-CHF, randomising patients to either NT-proBNP-guided or symptom-guided therapy. Biomarker measurements and clinical evaluation were performed at baseline and after 1, 3, 6, 12 and 18xa0months. NT-proBNP, GDF-15, hs-TnT and to a lesser extent hs-CRP and cystatin-C were weakly correlated to NYHA, oedema, jugular vein distension and orthopnoea (ρ-range: 0.12–0.33; pu2009<u20090.01). NT-proBNP correlated more strongly to NYHA class in the NT-proBNP-guided group compared with the symptom-guided group. NYHA class was significantly influenced by age, body mass index, anaemia, and the presence of two or more comorbidities.ConclusionIn HF, biomarkers correlate only weakly with clinical signs and symptoms. NYHA classification is influenced by several comorbidities and patient characteristics. Clinical judgement seems to be influenced by a clinician’s awareness of NT-proBNP concentrations.

Anticoagulant and Antiplatelet Therapy in Patients with Atrial Fibrillation and Coronary Artery Disease

Anticoagulation represents the mainstay of therapy for most patients with atrial fibrillation. Patients on oral anticoagulation often require concomitant antiplatelet therapy, mostly because of coronary artery disease. After coronary stent implantation, dual antiplatelet therapy is necessary. However, the combination of oral anticoagulation and antiplatelet therapy increases the bleeding risk. Risk scores such as the CHA2DS2-Vasc score and the HAS-BLED score help to identify both bleeding and stroke risk in individual patients. The guidelines of the European Society of Cardiology provide a rather detailed recommendation for patients on oral anticoagulation after coronary stent implantation. However, robust evidence is lacking for some of the recommendations, and especially for new oral anticoagulants and new antiplatelets few or no data are available. This review addresses some of the critical points of the guidelines and discusses potential advantages of new anticoagulants in patients with atrial fibrillation after stent implantation.

Hypokaliämische Lähmung bei Hyperthyreose

ZusammenfassungHypokaliämische periodische Lähmungen in Verbindung mit einer Hyperthyreose (thyreotoxische periodische Lähmungen) sind eine in Europa seltene, in Ostasien häufigere klinische Entität. Sie sind durch die Trias einer in Schüben auftretenden, transienten schlaffen Lähmung der Skelettmuskulatur, einer im Anfall manifesten Hypokaliämie und einer Hyperthyreose gekennzeichnet. Die blande Familienanamnese und die Hyperthyreose unterscheidet diese Form von der sporadischen bzw. familiären hypokaliämischen periodischen Lähmung. Ein normaler Säure-Basen-Status und das Fehlen eines Kaliumverlustsyndroms erlaubt die Differenzierung von wichtigen „internistischen“ Erkrankungen. Wir berichten über einen typischen Fall eines jungen chinesischen Mannes mit einer thyreotoxischen periodischen Lähmung bei bisher unbekanntem Morbus Basedow. Die Akuttherapie bestand in der Gabe von Propranolol und einer intravenösen Kaliumsubstitution. Das neurologische Bild war nach 10xa0h vollständig regredient. Die eingeleitete thyreostatische Therapie mit konsekutiver Euthyreose führte zur Anfallsfreiheit.AbstractHypokalemic periodic paralysis as a complication of thyrotoxicosis (thyrotoxic periodic paralysis) most often occurs in east Asian men. It is characterised by recurrent episodes of flaccid paralysis, hypokalemia, and underlying hyperthyroidism. It needs to be distinguished from sporadic and familial forms of periodic hypokalemic paralysis. No disturbances in the acid-base state and no extracorporal potassium loss are present. We report on the typical case of a young Chinese man presenting with hypokalemic periodic paralysis associated with yet unknown Graves’ disease. Intravenous substitution of potassium and oral propranolol were administered. Complete remission was achieved after 10 hours. After medical therapy had normalised thyroid hormone levels, no further hypokalemic paralytic attacks occurred.

Impact of airflow limitation in chronic heart failure

BackgroundComorbidities are common in chronic heart failure (HF) patients, but diagnoses are often not based on objective testing. Chronic obstructive pulmonary disease (COPD) is an important comorbidity and often neglected because of shared symptoms and risk factors. Precise prevalence and consequences are not well known. Therefore, we investigated prevalence, pulmonary treatment, symptoms andxa0quality of life (QOL)xa0of COPD in patients with chronic HF.Methods205 patients with stable HF for at least 1xa0month, aged above 50xa0years, were included from our outpatient cardiology clinic, irrespective of left ventricular ejection fraction. Patients performed post-bronchodilator spirometry, axa0six-minute walk test (6-MWT) and completed the Kansas City Cardiomyopathy Questionnaire (KCCQ). COPD was diagnosed according to GOLD criteria. Restrictive lung function was defined as FEV1/FVC ≥0.70 and FVC <80% of predicted value. The BODE and ADO index, risk scores in COPD patients, were calculated.ResultsAlmost 40% fulfilled the criteria of COPD and 7% had restrictive lung disease, the latter being excluded from further analysis. Noteworthy, 63% of the COPD patients were undiagnosed and 8% of those without COPD used inhalation therapy. Patients with COPD had more shortness of breath despite little difference in HF severity and similar other comorbidities. KCCQ was significantly worse in COPD patients. The ADO and BODE indices were significantly different.ConclusionCOPD is very common in unselected HF patients. It was often not diagnosed and many patients received treatment without being diagnosed with COPD. Presence of COPD worsens symptoms and negatively effects cardiac specific QOL.