Clinical analysis on diagnostic accuracy of Bosch Vivalytic SARS-CoV-2 point-of-care test and evaluation of cycle threshold at admission for COVID-19 risk assessment.

BACKGROUND: Point-of-care (POC) polymerase chain reaction (PCR) tests have the ability to improve testing efficiency in the Coronavirus disease 2019 (COVID-19) pandemic. However, real-world data on POC tests is scarce. OBJECTIVE: To evaluate the efficiency of a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) POC test in a clinical setting and examine the prognostic value of cycle threshold (CT) on admission on the length of hospital stay (LOS) in COVID-19 patients. METHODS: Patients hospitalised between January and May 2021 were included in this prospective cohort study. Patients' nasopharyngeal swabs were tested for SARS-CoV-2 with Allplex™2019-nCoV (Seegene Inc.) real-time (RT) PCR assay as gold standard as well as a novel POC test (Bosch Vivalytic SARS-CoV-2 [Bosch]) and the SARS-CoV-2 Rapid Antigen Test (Roche) accordingly. Clinical sensitivity and specificity as well as inter- and intra-assay variability were analyzed. RESULTS: 120 patients met the inclusion criteria with 46 (38%) having a definite COVID-19 diagnosis by RT-PCR. Bosch Vivalytic SARS-CoV-2 POC had a sensitivity of 88% and specificity of 96%. The inter- and intra- assay variability was below 15%. The CT value at baseline was lower in patients with LOS ≥ 10 days when compared to patients with LOS < 10 days (27.82 (± 4.648) vs. 36.2 (25.9-39.18); p = 0.0191). There was a negative correlation of CT at admission and LOS (r[44]s = - 0.31; p = 0.038) but only age was associated with the probability of an increased LOS in a multiple logistic regression analysis (OR 1.105 [95% CI, 1.03-1.19]; p = 0.006). CONCLUSION: Our data indicate that POC testing with Bosch Vivalytic SARS-CoV-2 is a valid strategy to identify COVID-19 patients and decrease turnaround time to definite COVID-19 diagnosis. Also, our data suggest that age at admission possibly with CT value as a combined parameter could be a promising tool for risk assessment of increased length of hospital stay and severity of disease in COVID-19 patients.

Advantages of score-based delirium detection compared to a clinical delirium assessment-a retrospective, monocentric cohort study.

PURPOSE: Delirium is an underdiagnosed complication on intensive care units (ICU). We hypothesized that a score-based delirium detection using the Nudesc score identifies more patients compared to a traditional diagnosis of delirium by ICU physicians. METHODS: In this retrospective study, all patients treated on a general medical ICU with 30 beds in a university hospital in 2019 were analyzed. Primary outcome was a documented physician diagnosis of delirium, or a delirium score ≥2 using the Nudesc. RESULTS: In 205/943 included patients (21.7%), delirium was diagnosed by ICU physicians compared to 438/943 (46.4%; ratio 2.1) by Nudesc≥2. Both assessments were independent predictors of ICU stay (p<0.01). The physician diagnosis however was no independent predictor of mortality (OR 0.98 (0.57-1.72); p = 0.989), in contrast to the score-based diagnosis (OR 2.31 (1.30-4.10); p = 0.004). Subgroup analysis showed that physicians underdiagnosed delirium in case of hypoactive delirium and delirium in patients with female gender and in patients with an age below 60 years. CONCLUSION: Delirium in patients with hypoactive delirium, female patients and those below 60 years was underdiagnosed by physicians. The score-based delirium diagnosis detected delirium more frequently and correlated with ICU mortality and stay.

Eight years of sales surveillance of antimicrobials for veterinary use in Germany-What are the perceptions?

A surveillance system for sales volumes of antimicrobial agents for veterinary use was established in Germany in 2011. Since then, pharmaceutical companies and wholesalers have been legally obliged to report annual volumes of veterinary antimicrobial products sold to veterinary practices or clinics located in Germany. The evaluation of sales volumes for eight consecutive years resulted in a considerable total decrease by 58% from 1706 tons to 722 tons. During the investigation period, two legally binding measures to control the risk of antimicrobial resistance resulting from the veterinary use of antimicrobials were introduced, a) the German treatment frequencies benchmarking in 2014 and b) the obligation to conduct susceptibility testing for the use of cephalosporins of the 3rd and 4th generation and of fluoroquinolones in 2018. Both had a marked impact on sales volumes. Nonetheless, the category of Critically Important Antimicrobials as defined by the World Health Organization kept accounting for the highest share on sales volumes in Germany in 2018 with 403 tons, despite an overall reduction by 53%. Sales surveillance is considered essential for data retrieval on a global scale and inter-country comparison. However, the usability of a surveillance system based on sales data for risk management of antimicrobial resistance has limitations. The German system does not include off-label use of antimicrobial products authorized for human medicine and does not allow for identification of areas of high risk according to animal species, farm and production types and indications for treatment. For further reduction and enhanced promotion of a prudent use of antimicrobials, targeted measures would be required that could only be deducted from use data collected at farm or veterinary practice level. A surveillance system based on use data is currently lacking in Germany but will be established according to Regulation (EU) 2019/6 on veterinary medicinal products.

Magnetic resonance imaging for pathobiological assessment and interventional treatment of the coronary arteries.

X-ray-based fluoroscopy is the standard tool for diagnostics and intervention in coronary artery disease. In recent years, computed tomography has emerged as a non-invasive alternative to coronary angiography offering detection of coronary calcification and imaging of the vessel lumen by the use of iodinated contrast agents. Even though currently available invasive or non-invasive techniques can show the degree of vessel stenosis, they are unable to provide information about biofunctional plaque properties, e.g. plaque inflammation. Furthermore, the use of radiation and the necessity of iodinated contrast agents remain unfavourable prerequisites. Magnetic resonance imaging (MRI) is a radiation-free alternative to X-ray which offers anatomical and functional imaging contrasts fostering the idea of non-invasive biofunctional assessment of the coronary vessel wall. In combination with molecular contrast agents that target-specific epitopes of the vessel wall, MRI might reveal unique plaque properties rendering it, for example, 'vulnerable and prone to rupture'. Early detection of these lesions may allow for early or prophylactic treatment even before an adverse coronary event occurs. Besides diagnostic imaging, advances in real-time image acquisition and motion compensation now provide grounds for MRI-guided coronary interventions. In this article, we summarize our research on MRI-based molecular imaging in cardiovascular disease and feature our advances towards real-time MRI-based coronary interventions in a porcine model.

La fluoroscopia con rayos X es la herramienta estándar para el diagnóstico y la intervención de coronariopatías. En los últimos años, la tomografía computarizada se ha convertido en una alternativa atraumática a la coronariografía, ya que se puede detectar la calcificación coronaria y ver a través de imágenes las luces de los vasos sanguíneos mediante el uso de medios de contraste yodados. Si bien las técnicas traumáticas o atraumáticas disponibles actualmente pueden mostrar el grado de la estenosis vascular, no pueden proporcionar información sobre las propiedades biofuncionales de la placa de ateroma, por ejemplo, inflamación de la placa de ateroma. Por otra parte, el uso de radiación y la necesidad de agentes de contraste yodados siguen siendo requisitos desfavorables. La resonancia magnética (RM) es una alternativa sin radiación a los rayos X que proporciona contrates de imagen con información anatómica y funcional, lo cual refuerza la idea del diagnóstico biofuncional atraumático de las paredes de los vasos coronarios. En combinación con medios de contraste molecular que actúan sobre epítopos específicos de las paredes de los vasos, la RM puede poner de manifiesto propiedades particulares de la placa de ateroma mediante su representación, por ejemplo, «vulnerabilidad y predisposición a rotura¼. La detección precoz de este tipo de lesiones puede facilitar un tratamiento a tiempo o preventivo antes de que tenga lugar una complicación coronaria grave.Además del diagnóstico por imagen, los avances en la adquisición de imágenes en tiempo real y la compensación del movimiento sirven de base para las intervenciones coronarias guiadas por RM. En este artículo, ofrecemos un resumen de nuestra investigación sobre imagen molecular con resonancia magnética en enfermedades cardiovasculares y presentamos nuestros avances hacia las intervenciones coronarias con RM en tiempo real en un modelo porcino.

Predictors of survival in patients with acute coronary syndrome undergoing percutaneous coronary intervention of unprotected left main coronary artery stenosis.

OBJECTIVE: Aim of this study was to investigate predictors of survival in unstable patients with high SYNTAX-1-score. BACKGROUND: In significant unprotected left main coronary artery (ULMCA) stenosis, treatment options include percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG). While CABG is recommended for stable patients with ULMCA stenosis and a SYNTAX-1-score > 32, PCI may be preferable in unstable or high operative risk patients. METHODS: Retrospective single-center all-comers registry study. RESULTS: A total of 142 patients underwent ULMCA-PCI (~72.9 years, 23.2% females, 54.2% survival in 2-year follow-up), 84 of whom had a SYNTAX-1 > 32 (37.4 ± 12.8). Patients in the high-SYNTAX-1-group (score > 32) were more often in an acute condition compared to low-SYNTAX-2-group (score ≤ 32) including acute myocardial infarction (76.2% vs. 57.4%, p = .024), cardiogenic shock (48.2% vs. 14.8%, p = .001), or need for mechanical support (36.1% vs. 11.1%, p = .001). Survival was predicted by the acute condition including cardiogenic shock (OR 0.06 and 0.05) and myocardial infarction (OR 0.03 and 0.34) in both groups. Performance of the SYNTAX-1-score was limited in our patient collective in both groups (c-index 0.65 vs. 0.63) while SYNTAX-2-PCI-score performed better (c-index 0.67 vs. 0.67). EuroScore II had the best discriminative ability (c-index 0.87 vs. 0.78). CONCLUSIONS: The majority of patients undergoing ULMCA-PCI presented in acute conditions with high SYNTAX-1-score, and is therefore underrepresented in clinical trials. Prognosis was best predicted by the acute condition and the EuroScore II. These data suggest that therapy in unstable patients should be guided by clinical condition over the anatomical SYNTAX-1-score.

Estimating the additional costs per life saved due to transcatheter aortic valve replacement: a secondary data analysis of electronic health records in Germany.

Aortic stenosis (AS) is the most common valvular heart disease, with a dismal prognosis when untreated. Recommended therapy is surgical (SAVR) or transcatheter (TAVR) aortic valve replacement. Based on a retrospective cohort of isolated SAVR and TAVR procedures performed in Germany in 2015 (N = 17,826), we examine the impact of treatment selection on in-hospital mortality and total in-hospital costs for a variety of at-risk populations. Since patients were not randomized to the two treatment options, the two endpoints in-hospital mortality and reimbursement are analyzed using logistic and linear regression models with 20 predefined patient characteristics as potential confounders. Incremental cost-effectiveness ratios were calculated as a ratio of the risk-adjusted reimbursement and mortality differences with 95% confidence intervals obtained by Fieller's theorem. Our study shows that TF-TAVR is more costly that SAVR and that cost differences between the procedures vary little between patient groups. Results regarding in-hospital mortality are mixed. SAVR is the predominant procedure among younger patients. For patients older than 85 years or at intermediate and higher pre-operative risk TF-TAVR seems to be the treatment of choice. Incremental cost-effectiveness ratios (ICER) are most favorable for patients older than 85 years (ICER €154,839, 95% CI €89,163-€302,862), followed by patients at higher pre-operative risk (ICER €413,745, 95% CI €258,027-€952,273). A hypothetical shift from SAVR towards TF-TAVR among patients at intermediate pre-operative risk is associated with a less favorable ICER (€1,486,118, 95% CI €764,732-€23,692,323), as the risk-adjusted mortality benefit is relatively small (- 0.97% point), while the additional reimbursement is still eminent (+€14,464). From a German healthcare system payer's perspective, the additional costs per life saved due to TAVR are most favorable for patients older than 85 and/or at higher pre-operative risk.

Cost Implications of Anticoagulation Strategies After Percutaneous Coronary Intervention Among Patients With Atrial Fibrillation (A PIONEER-AF PCI Analysis).

The PIONEER AF-PCI trial demonstrated that in atrial fibrillation patients who underwent intracoronary stenting, either rivaroxaban 15 mg daily plus P2Y12 inhibitor monotherapy (Group 1) or 2.5 mg rivaroxaban twice daily plus dual antiplatelet therapy (DAPT) (Group 2) was associated with fewer recurrent hospitalizations, primarily for bleeding and cardiovascular events, compared with standard-of-care vitamin K antagonist and DAPT (Group 3). Associated costs are unknown. This study estimates costs associated with rivaroxaban strategies compared with vitamin K antagonist and DAPT. Medication costs were estimated using wholesale acquisition costs, medication discontinuation rates, and costs of monitoring. Using a large US healthcare claims database, the mean adjusted increase in 1-year cost of care for individuals with atrial fibrillation and percutaneous coronary intervention (PCI) rehospitalized for bleeding, cardiovascular, and other events was compared with those not rehospitalized. Using adjudicated rehospitalization rates from PIONEER AF-PCI, cost differences were estimated. Rates of rehospitalization for bleeding were 6.5%, 5.4%, 10.5%, and 20.3%, 20.3%, 28.4% for cardiovascular events in Groups 1, 2, and 3. Medication and monitoring costs were $3,942, $4,115, and $1,703. One-year costs for all recurrent hospitalization costs and/or patient for the groups were $24,535, $20,205, and $29,756. One-year cost increase associated with bleeding rehospitalizations and/or patient was $4,160, $3,212, and $6,876 and was $13,264, $11,545, and $17,220 for cardiovascular rehospitalizations and/or patient. Overall estimated cost per patient was $28,476, $24,320, and $31,458. Compared with warfarin, both rivaroxaban treatment strategies had higher medication costs, but these were more than accounted for by fewer hospitalizations.

Two-year post-discharge costs of care among patients treated with transcatheter or surgical aortic valve replacement in Germany.

BACKGROUND: This study presents data on post-discharge costs of care among patients treated with transcatheter or surgical aortic valve replacement over a two year period. METHODS: Based on a prospective clinical trial, post-discharge utilization of health services and status of assistance were collected for 151 elderly patients via 2250 monthly telephone interviews, valued using standardized unit costs and analysed using two-part regression models. RESULTS: At month 1 post-discharge, total costs of care are substantially elevated (monthly mean: €3506.7) and then remain relatively stable over the following 23 months (monthly mean: €622.3). As expected, the majority of these costs are related to in-hospital care (~98% in month 1 post-discharge and ~72% in months 2-24). Patients that died during follow-up were associated with substantially higher cost estimates of in-hospital care than those surviving the two-year study period, while patients' age and other patient characteristics were of minor relevance. Estimated costs of outpatient care are lower at month 1 than during the rest of the study period, and not affected by the event of death during follow-up. The estimated costs of nursing care are, in contrast, much higher in year 2 than in year 1 and differ substantially by gender and type of procedure as well as by patients' age. Overall, these monthly cost estimates add up to €10,352 for the first and €7467.6 for the second year post-discharge. CONCLUSIONS: Substantial cost increases at month 1 post-discharge and in case of death during follow-up are the main findings of the study, which should be taken into account in future economic evaluations on the topic. Application of standardized unit costs in combination with monthly patient interviews allows for a far more precise estimate of the variability in post-discharge health service utilization in this group of patients than the ones given in previous studies. TRIAL REGISTRATION: German Clinical Trial Register Nr. DRKS00000797 .

In-hospital resource utilization in surgical and transcatheter aortic valve replacement.

BACKGROUND: Little is known about preoperative predictors of resource utilization in the treatment of high-risk patients with severe symptomatic aortic valve stenosis. We report results from the prospective, medical-economic "TAVI Calculation of Costs Trial". METHODS: In-hospital resource utilization was evaluated in 110 elderly patients (age ≥ 75 years) treated either with transfemoral (TF) or transapical (TA) transcatheter aortic valve implantation (TAVI, N = 83), or surgical aortic valve replacement (AVR, N = 27). Overall, 22 patient-specific baseline parameters were tested for within-group prediction of resource use. RESULTS: Baseline characteristics differed between groups and reflected the non-randomized, real-world allocation of treatment options. Overall procedural times were shortest for TAVI, intensive care unit (ICU) length of stay (LoS) was lowest for AVR. Length of total hospitalization since procedure (THsP) was lowest for TF-TAVI; 13.4 ± 11.4 days as compared to 15.7 ± 10.5 and 21.2 ± 15.4 days for AVR and TA-TAVI, respectively. For TAVI and AVR, EuroScore I remained the main predictor for prolonged THsP (p <0.01). Within the TAVI group, multivariate regression analyses showed that TA-TAVI was associated with a substantial increase in THsP (55 to 61 %, p <0.01). Additionally, preoperative aortic valve area (AVA) was identified as an independent predictor of prolonged THsP in TAVI patients, irrespective of risk scores (p <0.05). CONCLUSIONS: Our results demonstrate significant heterogeneity in patients baseline characteristics dependent on treatment and corresponding differences in resource utilization. Prolonged ThsP is not only predicted by risk scores but also by baseline AVA, which might be useful in stratifying TAVI patients. TRIAL REGISTRATION: German Clinical Trial Register Nr. DRKS00000797.

Analysis of the additional costs of clinical complications in patients undergoing transcatheter aortic valve replacement in the German Health Care System.

BACKGROUND: This study aims at analyzing complication-induced additional costs of patients undergoing transcatheter aortic valve replacement (TAVR). METHODS: In a prospective observational study, a total of 163 consecutive patients received either transfemoral (TF-, n=97) or transapical (TA-) TAVR (n=66) between February 2009 and December 2012. Clinical endpoints were categorized according to VARC-2 definitions and in-hospital costs were determined from the hospital perspective. Finally, the additional costs of complications were estimated using multiple linear regression models. RESULTS: TF-TAVR patients experienced significantly more minor access site bleeding, major non-access site bleeding, minor vascular complications, stage 2 acute kidney injury (AKI) and permanent pacemaker implantation. Total in-hospital costs did not differ between groups and were on average €40,348 (SD 15,851) per patient. The average incremental cost component of a single complication was €3438 (p<0.01) and the estimated cost of a TF-TAVR without complications was €34,351. The complications associated with the highest additional costs were life-threatening non-access site bleeding (€47,494; p<0.05), stage 3 AKI (€20,468; p<0.01), implantation of a second valve (€16,767; p<0.01) and other severe cardiac dysrhythmia (€10,611 p<0.05). Overall, the presence of complication-related in-hospital mortality increased costs. CONCLUSIONS: Bleeding complications, severe kidney failure, and implantation of a second valve were the most important cost drivers in our TAVR patients. Strategies and advances in device design aimed at reducing these complications have the potential to generate significant in-hospital cost reductions for the German Health Care System.

"Heart Team" decision making in elderly patients with symptomatic aortic valve stenosis who underwent AVR or TAVI - a look behind the curtain. Results of the prospective TAVI Calculation of Costs Trial (TCCT).

AIMS: Little is known about how "Heart Team" treatment decisions among patients suitable for either surgical aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI) are made under routine conditions. METHODS AND RESULTS: The "Heart Team" decision-making process was analysed with respect to124 patients of a non-randomised prospective clinical trial that included patients aged ≥75 years: 41 patients underwent AVR and 83 underwent TAVI. By use of the non-parametric classification and regression tree (CART) methodology, 21 baseline parameters were tested to reconstruct the decision process retrospectively. Next, multivariate logistic and Cox regression models were fitted to evaluate the decision and outcome relevance (two-year survival) of the parameters as identified in the CART procedure. For patients with a baseline EuroSCORE I ≥13.48%, no further cut-off points were identified and the majority of these patients underwent TAVI. Among patients with a baseline EuroSCORE I <13.48%, age and left ventricular ejection fraction (LVEF) were identified as further relevant decision parameters. The decision relevance of EuroSCORE I (p=0.003), age (p=0.024) and LVEF (p=0.047) were confirmed by multivariate analysis; however, outcome relevance can be confirmed for EuroSCORE I (p=0.015) only, while treatment decision (TAVI or AVR) was not a significant predictor of mortality (p=0.655). CONCLUSIONS: Despite or even because of the systematic risk selection according to EuroSCORE I values, we observed two-year survival rates of about 75% regardless of whether the patient received TAVI or AVR, suggesting that the decisions made by the "Heart Team" were appropriate.

Practice patterns and clinical outcomes among non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients presenting to primary and tertiary hospitals: insights from the EARLY glycoprotein IIb/IIIa inhibition in NSTE-ACS (EARLY-ACS) trial.

OBJECTIVES: We evaluated patients at tertiary [both percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) capable] and primary hospitals in the EARLY-ACS trial. BACKGROUND: Early invasive management is recommended for high-risk non-ST-segment elevation acute coronary syndromes. METHODS: We evaluated outcomes in 9,204 patients presenting to: tertiary sites, primary sites with transfer to tertiary sites ("transferred") and those who remained at primary sites ("non-transfer"). RESULTS: There were 348 tertiary (n = 7,455 patients) and 89 primary hospitals [n = 1,749 patients (729 transferred; 1,020 non-transfer)]. Significant delays occurred in time from symptom onset to angiography (49 hr), PCI (53h), and CABG (178 hr) for transferred patients (P < 0.001). Non-transfer patients had less 30-day death/myocardial infarction [9.4% vs. 11.7% (tertiary); adjusted odds ratio (OR): 0.78 (0.62-0.97), P = 0.026]; transferred (14.0%) and tertiary patients were similar [adjusted OR: 1.23 (0.98-1.53), P = 0.074]. Non-transfer patients had lower 1-year mortality [4.3% vs. 6.3% (tertiary); adjusted hazard ratio (HR): 0.64 (0.47-0.87), P = 0.005]: there was no difference between transferred and tertiary patients [5.2% vs. 6.3%; adjusted HR: 0.80 (0.58-1.12), P = 0.202]. Despite similar rates of catheterization, GUSTO severe/moderate bleeding within 120 hr was less in non-transfer [3.1% vs. 6.7% (tertiary); adjusted OR: 0.47 (0.32-0.68), P < 0.001], whereas transferred (6.1%) and tertiary patients were similar [adjusted OR: 0.94 (0.68-1.30), P = 0.693]. There was no difference in non-CABG bleeding. CONCLUSIONS: Timely angiography and revascularization were often not achieved in transferred patients. Non-transferred patients presenting to primary sites had the lowest event rates and the best long-term survival.

Transfemoral aortic valve implantation: bleeding events, related costs and outcomes.

Although less invasive then SAVR, TAVI is associated with a significant rate of access site and non-access site bleeding. These complications are major determinants of therapy outcome, however, the economic consequences are not well defined. The purpose of this study was to determine the relationship between bleeding, in-hospital resource utilization and costs among patients undergoing transfemoral aortic valve implantation (TF-AVI) at a representative university hospital in Germany. Between February 2010 and December 2011, we prospectively enrolled 60 consecutive patients undergoing TAVI using a 18F transfemoral approach at our institution. The relationship between overt bleeding (OVB), defined according to the definitions provided by the Valve Academic Research Consortium, in-hospital resource utilization and in-hospital costs was investigated. The mean age was 82 (±6) years, 53% were female and the mean EuroScore was 17.2% (±8, 7). Thirty-eight percent (23/60) of the patients had an OVB following TF-AVI procedure. In-hospital mortality was 8.7% in the OVB patients (2/23) and 2.7% among patients without any OVB (1/37; NOVB), which was not statistically significant (p = 0.3). The total length of stay (LOS) of patients with and without bleeding complication were 15.0 ± 6.4 and 10.4 ± 5.1 days, respectively (p < 0.01). Time spent on ICU in the OVB group was twice as long as compared to the NOVB group (120.5 ± 98.5 min vs. 63.6 ± 26.5 min, p < 0.01). Consequently, in-hospital costs were statistically significant higher in OVB patients (40.051 ± 9.293 vs. 33.625 ± 4.368, p < 0.01). Bleeding is associated with increased resource use and in-hospital costs among TF-AVI patients. Our data indicates that strategies reducing bleeding risk may have the potential to generate important in-hospital costs reductions in TF-AVI patients.

Real-time assessment of acute myocardial ischaemia by an intra-thoracic 6-lead ECG: evaluation of a new diagnostic option in the implantable defibrillator.

AIM: In the presence of coronary artery disease, implantable cardioverter-defibrillators (ICD) are used effectively for treating life-threatening tachyarrhythmias. Continuous monitoring of myocardial ischaemia would provide a new diagnostic option in future ICD generations. METHODS AND RESULTS: In 22 selected patients undergoing coronary angioplasty, percutaneous transluminal coronary angioplasty (PTCA), three electrodes, similar to those used in the ICD, were inserted aiming to create six intra-thoracic ECG (IT-ECG) leads according to Einthoven and Goldberger. In total, 27 PTCA were conducted. The diagnostic efficacy for ischaemia assessment was compared with the surface ECG. The IT-ECG proved to be more sensitive than conventional ECG in early and overall ischaemia assessment. At 30 s of coronary artery occlusion, ischaemic ST-segment alterations (> or =0.25 mV) were present in the IT-ECG 2.3 times more often (23 vs. 10/27 PTCA attempts, P<0.01) and at 90 s 1.4 times more often compared with conventional ECG leads (18 vs. 26/27, P<0.05). Intra-thoracic Einthoven 2 (SVC+RVA vs. ICD-housing) and Goldberger 3 (SVC+ICD-housing vs. RVA) had the highest sensitivity (88/85%). Using > or =4 IT-ECG, ischaemia monitoring was independent of severity and site of origin. IT-ECG signals showed double ST-T signal amplitude (4.19+/-0.6 vs. 2.15+/-0.3 mV, ratio: 1.95, P<0.01) at a QRS/ST amplitude ratio similar in the two ECG techniques. CONCLUSION: This study provides strong evidence that the ICD-based IT 6-lead ECG would provide a new and efficient means of assessing a patient's daily ischaemic burden.

Beat-to-beat assessment of QT/RR interval ratio in severe heart failure and overt myocardial ischemia: a measure of electrical integrity in diseased hearts.

The study was designed to assess the beat-to-beat variation of ventricular repolarization in patients with myocardial ischemia, hear failure, and in normal subjects. Autonomic tone may alter the dynamic QT/RR interval relation and thus may be involved in ventricular arrhythmia development, especially in the diseased heart. The study included 145 patients (age 16-86 years) with CHF (LVEF < or = 0.30) or unstable angina pectoris (LVEF > 0.60). The control group consisted of healthy volunteers giving physiological baseline measures for the evaluated parameters: cycle length, QT interval, and QT/RR interval ratio during three time periods. In patients with myocardial ischemia (LVEF > 0.60) and healthy subjects the QT/RR interval ratio did not reveal significant differences between both groups (QT/RR(CAD) = 0.36 +/- 0.77 vs QT/RR(controls) = 0.28 +/- 0.83; NS). In sharp contrast, in patients with severe heart failure, RR dependent instantaneous variation of the QT interval was almost missing and regression line analysis disclosed a QT/RR interval slope substantially enhanced by 196% (compared to normal subjects) and 131% (compared to CAD patients; P < 0.05) with a complete loss of circadian modulation (QT/RR(CHF) = 0.83 +/- 0.71 vs QT/RR(CAD) = 0.36 +/- 0.77 vs QT/RR(controls) = 0.28 +/- 0.83; P < 0.05). Beat-to-beat QT interval assessment provides a dynamic parameter of physiological and altered repolarization in defined study groups. Compared to other groups (preserved LVEF), patients with left ventricular impairment exhibited a significantly increased sensitivity of repolarization to cycle length (enhanced QT/RR interval ratio) and a blunted circadian modulation of the QT interval. This is consistent with concept that increased repolarization disparity may be deleterious being a potential pathophysiological basis for enhanced arrhythmic risk.