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Since myocardium at risk (MAR) is the major prognosticator of final infarct size and outcome in patients with acute myocardial infarction, it is highly desirable to estimate the size of the acutely ischemic myocardium, that is the MAR, in these patients. We assessed MAR size by Tc-99m-sestamibi-SPECT and computerized vectorcardiography using autoradiography as reference method. Transient myocardial ischemia was achieved in 12 pigs by coronary artery occlusion with PTCA catheters. During the procedure, computerized vectorcardiography was continuously recorded. After injection of Tc-99m-sestamibi and gadolinium-153-labelled microspheres, MAR size was estimated by SPECT and post-mortem autoradiography. Different cut-off levels (50-70%) were compared with respect to MAR-SPECT. Tc-99m-sestamibi-SPECT showed a good correlation with autoradiography (r = 0.94). Computerized vectorcardiography showed a good correlation with autoradiography as well as with Tc-99m-sestamibi-SPECT (STC-VM: r = 0.75 and 0.80, respectively, ST-VM: 0.75 and 0.87, respectively). It was found that 1) MAR assessed by Tc-99m-sestamibi-SPECT correlates closely with the autoradiographic reference; 2) a lower cut-off point of 60% of maximum uptake for MAR by Tc-99m-sestamibi-SPECT gives the closest correlation with the autoradiographic reference; and 3) ST-VM and STC-VM correlate well with MAR assessed by Tc-99m-sestamibi-SPECT and autoradiography. [ABSTRACT FROM AUTHOR]

Background and Aim: Cardiac resynchronization therapy (CRT), based on broad QRS duration has proved successful for patients in late stage heart failure (HF), however almost 30% do not respond. Standard segmental Doppler echocardiographic measures of ventricular dyssynchrony are controversial in predicting response, particularly in atrial fibrillation (AF) patients. The aim of this study was to assess echo and clinical predictors of CRT response in AF patients. Methods: We studied the response of 27 HF patients in AF (mean age 74 ±7 years, 78% male) who fulfilled the guidelines for CRT treatment; NYHA class III-IV, despite full medical therapy, QRS duration >120 ms and left ventricular (LV) ejection fraction (EF) <35%, using clinical assessment, NT- proBNP and Doppler echocardiographic examination. Global LV dyssynchrony was assessed by total isovolumic time - t-IVT in s/min [calculated as: 60 - (total ejection time + total filling time)], and Tei index (t-IVT/ejection time). Based on a reduction in the NYHA class and NT-proBNP after CRT, patients were divided into responders (R) and non-responders (NR). Results: Thirteen (48%) of 27 patients were responders, who proved to have lower LVEF (p=0.02), longer t-IVT (p=0.000) and higher Tei index (p=0.03), before CRT compared with NR. All other clinical and echo parameters were not different between groups. Only prolonged t-IVT [0.690 (0.509-0.937), p = 0.02] independently predicted response to CRT. A t-IVT 11 s/min was 69% sensitive and 79% specific (AUC 0.78, p=0.015) in predicting CRT response. Conclusion: Prolonged total isovolumic time, a marker of global LV dyssynchrony, is an independent predictor of CRT response in heart failure patients with atrial fibrillation who fulfill the guidelines criteria for CRT. [ABSTRACT FROM AUTHOR]

Background and Aim: Cardiac resynchronization therapy (CRT), based on broad QRS duration has proved successful for patients in late stage heart failure (HF), however almost 30% do not respond. Standard segmental Doppler echocardiographic measures of ventricular dyssynchrony are controversial in predicting response. The aim of this study was to assess potential additional value of markers of global LV dyssynchrony in predicting CRT response in such patients. Methods: We included 103 HF patients (mean age 67 ±12 years, 82.5% male) who fulfilled the guidelines for CRT treatment; NYHA class III-IV, despite full medical therapy, QRS duration >120 ms and LV ejection fraction (EF) <35%. All patients had full clinical assessment, NT-proBNP and Doppler echocardiographic examination. Global LV dyssynchrony was assessed by total isovolumic time - t-IVT in s/min [calculated as: 60 - (total ejection time + total filling time)], and Tei index (t-IVT/ejection time). Based on a reduction in the NYHA class and NT-proBNP after CRT, patients were divided into responders (R) and non-responders (NR). Results: Sixty-one (50.2%) of 103 patients were responders, who proved to have longer QRS duration (p=0.01), faster heart rate (p=0.001), longer t-IVT (p=0.001), higher Tei index (p<0.01) and lower peak tricuspid regurgitation pressure drop - TRPD (p=0.03) before CRT compared with NR. All other clinical and echo parameters were not different between groups. In multivariate analysis, prolonged t-IVT [0.878 (0.802-0.962), p=0.005], long QRS duration [0.978 (0.960-0.996), p=0.02] and high TRPD [1.047 (1.001-1.096), p=0.047] independently predicted response to CRT. A t-IVT 11.6 s/min was 67% sensitive and 62% specific (AUC 0.69, p=0.001) in predicting CRT response. Respective values for a QRS 151ms were 66% and 62% (AUC 0.65, p=0.01). Combining the two variables had a sensitivity of 67% but higher specificity of 88% in predicting CRT response. Conclusion: Combining prolonged total isovolumic time, a marker of global LV dyssynchrony, and the conventionally used broad QRS duration has a significantly higher specificity in identifying patients likely to respond to CRT. [ABSTRACT FROM AUTHOR]

Aims: To assess the relation between atrial fibrillation (AF) characteristics and health-related quality of life (QoL), and which AF characteristic had the greatest impact., Method: The AF characteristics burden (percentage of time in AF), duration and number of AF episodes/month were obtained from implantable cardiac monitors during the 2-month run-in period in 150 patients included in the randomized CAPTAF trial comparing early ablation and antiarrhythmic drug therapy. The QoL was measured by the General Health and Vitality dimensions of the 36-Item Short-Form Health Survey. AF characteristics were analysed continuously and in quartiles (Q1-Q4)., Results: Greater AF burden (p = 0.003) and longer AF episodes (p = 0.013) were associated with impaired QoL (Vitality score only) in simple linear regression analyses. Greater AF burden was, however, the only AF characteristic associated with lower QoL, when adjusted for sex, type of AF, hypertension, heart rate above 110 beats per minute during AF, and beta-blocker use in multiple linear regression analyses. For every 10% increase in AF burden there was a 1.34-point decrease of Vitality score (95% confidence interval (CI) -2.67 to -0.02, p = 0.047). The Vitality score was 12 points lower (95% CI -22.73 to -1.27, p = 0.03) in patients with an AF burden > 33% (Q4) versus those with < 0.45% (Q1), but only in unadjusted analysis., Conclusion: AF burden had a greater impact on QoL (Vitality), than the duration and number of AF episodes, corroborating that AF burden may be the preferred outcome measure of rhythm control in trials including relatively healthy AF populations., Competing Interests: Dr Blomström-Lundqvist reports receiving grants from Medtronic during the conduct of the study; and personal fees from Bayer, Sanofi, Boston Scientific, and Merck Sharp & Dohme outside the submitted work. Dr Bergfeldt reports receiving personal fees from Sanofi, Bristol-Myers Squibb, Bayer, and Pfizer outside the submitted work. Dr Raatikainen reports receiving grants from Biosense Webster outside the submitted work. All remaining authors have declared no conflicts of interest., (© 2021 The Authors.)

Aims: Concomitant surgical ablation of atrial fibrillation (AF) in patients undergoing mitral valve surgery (MVS) has almost become routine despite lack of convincing information about improved quality-of-life (QOL) and clinical benefit. Quality-of-life was therefore assessed after MVS with or without epicardial left atrial cryoablation., Methods and Results: Sixty-five patients with permanent AF randomized to MVS with or without left atrial cryoablation, in the double-blinded multicentre SWEDMAF trial, replied to the Short Form 36 QOL survey at 6 and 12 months follow-up. The QOL scores at 12 month follow-up did not differ significantly between patients undergoing MVS combined with cryoablation vs. those undergoing MVS alone regarding Physical Component Summary mean 42.8 (95% confidence interval 38.3-47.3) vs. mean 44.0 (40.1-47.7), P = 0.700 or Mental Component Summary mean 53.1 (49.7-56.4) vs. mean 48.4 (44.6-52.2), P = 0.075. All patients, irrespective of allocated procedure, reached the same QOL after surgery as an age-matched Swedish general population. The Physical Component Summary in patients with sinus rhythm did also not differ from those in AF at 12 months; mean 45.4 (42.0-48.7) vs. mean 40.5 (35.5-45.6), P = 0.096) nor was there a difference in Mental Component Summary; mean 51.0 (48.0-54.1) vs. mean 49.6 (44.6-54.5), P = 0.581)., Conclusion: Left atrial cryoablation added to MVS does not improve health-related QOL in patients with permanent AF, a finding that raises concerns regarding recommendations made for this combined procedure.

Objectives: Implantable cardioverter defibrillator (ICD) treatment is effective among long QT syndrome (LQTS) patients at a high risk of sudden cardiac death. Previous studies show that the international guidelines are not always followed, and that risk stratification may be based on genotype rather than individual risk profile. We analysed data from the Swedish ICD & Pacemaker Registry and medical records to examine how international guidelines were followed with regards to phenotype and genotype., Methods and Results: ICD treatment was used in 150 Swedish LQTS patients from 1989-2013. The annual number of implantations increased over the study period. A total of 109 patients were included in the analysis. Most patients (91%) were symptomatic before the implantation. Seventy percent of patients who received ICD treatment met the 2006 Class I or Class IIa recommendations for LQTS treatment. Thirty-one percent of the LQT3 patients received ICD treatment despite being asymptomatic. Among LQT1 patients, 45% received ICD treatment after syncope despite beta-blockers., Conclusions: Thirty percent of Swedish LQTS patients with ICD received the treatment without a strong indication based on international guidelines. LQT3 patients were over-represented among asymptomatic patients. Many LQT1 patients received ICD despite the known effect of beta-blockers in this group.

Introduction: The main indication for ablation of supraventricular tachycardia is symptomatic relief. Generic measures of quality of life are not suitable for direct evaluation of arrhythmia-related symptoms, and a specific tool is needed. The questionnaire U22 quantifies symptoms associated with arrhythmic events. It uses discrete 0-10 scales for quantification of influence of arrhythmia on well-being, intensity of discomfort, type of dominant symptom, and a time aspect that summarizes duration and frequency of spells. We evaluated U22 in a well defined group of patients with paroxysmal supraventricular tachycardia, undergoing an intervention with a distinct end-point and a high success rate., Methods: Symptoms in patients with accessory pathway and atrioventricular nodal re-entrant tachycardia scheduled for ablation were measured with U22 and SF-36 on admission. The evaluation was repeated after 6 months., Results: Altogether 58 patients successfully ablated in 2006-2008 completed the four forms (U22 and SF-36 at base-line and follow-up, 210 ± 35 days after ablation). The score for well-being (0-10; 10 being best) increased from 5.9 ± 2.6 to 7.9 ± 1.9 (P < 0.0005). The score for arrhythmia as cause for impairment in well-being (0-10; 10 being highest) decreased from 7.5 ± 2.8 to 2.0 ± 3.1 (P < 0.0005). The time aspect score (0-10) decreased from 4.7 ± 1.5 to 1.4 ± 1.8 (P < 0.0005). The two SF-36 summary measures PCS and MCS increased from 46.9 ± 9.4 to 48.4 ± 10.7 and from 44.9 ± 12.5 to 49.1 ± 9.9 (P = 0.04 and 0.002)., Conclusion: After successful ablation of accessory pathway and atrioventricular nodal re-entrant tachycardia, the U22 protocol detected a relevant increase in arrhythmia-related well-being. Modest improvement in general well-being was detected by the SF-36 protocol.

Sixteen randomised controlled studies examining the use of pacemakers for the therapeutic prevention of atrial fibrillation were investigated. Four studies dealt with patients without conventional pacemaker indication. A minor positive effect was observed in one study. The validity of the observation is however limited due to a small number of patients and a short follow-up period. Five studies assessed the effect of overdrive pacing and different preventive pacing algorithms. A small, statistically significant positive effect was found in one of these studies. Six studies investigated dual site pacing or septal pacing. Five of these indicated a possible positive effect. Before this approach is implemented clinically, further studies are nevertheless required.