QRS-T angle: is it a specific parameter associated with sudden cardiac death in type 2 diabetes? Results from the SURDIAGENE and the Mini-Finland prospective cohorts.

AIMS/HYPOTHESIS: Type 2 diabetes is associated with a high risk of sudden cardiac death (SCD), but the risk of dying from another cause (non-SCD) is proportionally even higher. The aim of the study was to identify easily available ECG-derived features associated with SCD, while considering the competing risk of dying from non-SCD causes. METHODS: In the SURDIAGENE (Survie, Diabete de type 2 et Genetique) French prospective cohort of individuals with type 2 diabetes, 15 baseline ECG parameters were interpreted among 1362 participants (mean age 65 years; HbA1c 62±17 mmol/mol [7.8±1.5%]; 58% male). Competing risk models assessed the prognostic value of clinical and ECG parameters for SCD after adjusting for age, sex, history of myocardial infarction, N-terminal pro b-type natriuretic peptide (NT-proBNP), HbA1c and eGFR. The prospective Mini-Finland cohort study was used to externally validate our findings. RESULTS: During median follow-up of 7.4 years, 494 deaths occurred including 94 SCDs. After adjustment, frontal QRS-T angle ≥90° (sub-distribution HR [sHR] 1.68 [95% CI 1.04, 2.69], p=0.032) and NT-proBNP level (sHR 1.26 [95% CI 1.06, 1.50] per 1 log, p=0.009) were significantly associated with a higher risk of SCD. Nevertheless, frontal QRS-T angle was the only marker not to be associated with causes of death other than SCD (sHR 1.08 [95% CI 0.84, 1.39], p=0.553 ). These findings were replicated in the Mini-Finland study subset of participants with diabetes (sHR 2.22 [95% CI 1.05, 4.71], p=0.04 for SCD and no association for other causes of death). CONCLUSIONS/INTERPRETATION: QRS-T angle was specifically associated with SCD risk and not with other causes of death, opening an avenue for refining SCD risk stratification in individuals with type 2 diabetes.

Impact of the atrial lead pacing site regarding atrial fibrillation onset in patients with sinus node dysfunction.

Symptomatic sinus node disease (SND) most frequently requires the implantation of a dual chamber pacemaker of which the right atrial lead is generally implanted in the right atrial appendage (RAA) or the lateral wall (LW).The aim of this retrospective study was to evaluate the impact of the right atrial lead pacing site regarding the onset of AF in patients with SND. RESULTS: 126 patients were included (53% males; 76 yo). 64 (51%) patients were implanted in the RAA and 62 (49%) in the LW. The two groups were not different in terms of CHA2DS2-VASc score and indexed left atrial volume. Forty-eight months after implantation, AF occurred in 17 (26.6%) of the RAA group and 6 (9.7%) in the lateral group. In the multivariate models, RAA site was the only factor associated with AF onset, with an Hazard Ratio of 2.5 (95%CI 1.1; 5.7; P=0.03). CONCLUSION: In our study, RAA pacing was associated with 2.5 higher risk of AF onset in patients with SND. Further larger randomized studies are needed to confirm these findings.

Non-invasive hemodynamic determination of patient-specific optimal pacing mode in cardiac resynchronization therapy.

PURPOSE: Cardiac resynchronization therapy (CRT) devices have multiple programmable pacing parameters. The purpose of this study was to determine the best pacing mode, i.e., associated with the greatest acute hemodynamic response, in each patient. METHODS: Patients in sinus rhythm and intact atrioventricular conduction were included within 3 months of implantation of devices featuring SyncAV and multipoint pacing (MPP) algorithms. The effect of nominal biventricular pacing using the latest activated electrode (BiV-Late), optimized atrioventricular delay (AVD), nominal and optimized SyncAV, and anatomical MPP was determined by non-invasive measurement of systolic blood pressure (SBP). CRT response was defined as SBP increase > 10% relative to baseline. RESULTS: Thirty patients with left bundle branch block (LBBB) were included. BiV-Late increased SBP compared to intrinsic rhythm (128 ± 21 mmHg vs. 121 ± 22 mmHg, p = 0.0002). The best pacing mode further increased SBP to 140 ± 19 mmHg (p < 0.0001 vs. BiV-Late). The proportion of CRT responders increased from 40% with BiV-Late to 80% with the best pacing mode (p = 0.0005). Compared to BiV-Late, optimized AVD and optimized SyncAV increased SBP (to 134 ± 21 mmHg, p = 0.004, and 133 ± 20 mmHg, p = 0.0003, respectively), but nominal SyncAV and MPP did not. The best pacing mode was variable between patients and was different from nominal BiV-Late in 28 (93%) patients. Optimized AVD was the most frequent best mode, in 14 (47%) patients. CONCLUSION: In patients with LBBB, the best pacing mode was patient-specific and doubled the magnitude of acute hemodynamic response and the proportion of acute CRT responders compared to nominal BiV-Late pacing. TRIAL REGISTRATION: ClinicalTrials.gov : NCT03779802.

Baroreflex sensitivity assessed with the sequence method is associated with ventricular arrhythmias in patients implanted with a defibrillator for the primary prevention of sudden cardiac death.

BACKGROUND: Left ventricular ejection fraction lacks accuracy in predicting sudden cardiac death, resulting in unnecessary implantation of cardioverter defibrillators for the primary prevention of sudden cardiac death. Baroreflex sensitivity could help to stratify patients at risk of ventricular arrhythmia. AIM: To assess the association between cardiac baroreflex sensitivity and ventricular arrhythmias in patients implanted with an implantable cardioverter defibrillator for the primary prevention of sudden cardiac death after myocardial infarction. METHODS: This case-control single-centre study took place between 2015 and 2016. Cases (n=10) had experienced ventricular arrhythmias treated by the implantable cardioverter defibrillator in the previous 3 years; controls (n=22) had no arrhythmia during the same period. Baroreflex sensitivity was assessed using the temporal sequence method (mean slope) and cross-spectral analysis (low-frequency gain and high-frequency gain). RESULTS: The mean age was 65 years; 94% of the patients were men. 24-hour Holter electrocardiogram autonomous nervous system variables, left ventricular ejection fraction and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) concentration did not differ between cases and controls. The mean slope was lower in cases than in controls (8 vs. 15ms/mmHg [P=0.009] in the supine position; 7 vs. 12ms/mmHg [P=0.038] in the standing position). The mean slope in the supine position was still significantly different between groups after adjustment for age, left ventricular ejection fraction and NT-proBNP (P=0.03). By comparison, low-frequency gain and high-frequency gain did not differ between groups in either the supine or the standing position. CONCLUSION: Patients with ventricular arrhythmias had a lower mean slope compared with those who were free of arrhythmia. A prospective study is needed to confirm this association.

Twenty-four-hour ambulatory ECG monitoring relevancy in myotonic dystrophy type 1 follow-up: Prognostic value and heart rate variability evolution.

BACKGROUND: Patient prognosis in type 1 myotonic dystrophy (DM1) is very poor. Annual 24-hour holter ECG monitoring is recommended but its relevance is debated. Main objective was to determine whether holter ECG parameters could predict global death in DM1 patients and secondarily to assess whether they could predict cardiovascular events and sudden cardiac death, to compare DM1 patients and healthy controls, and to assess their evolution in DM1 over a 5-year period. METHODS: This retrospective study included genetically confirmed DM1. Primary endpoint was global death. Secondary endpoints were labeled "sudden cardiac death" which was a composite of sudden cardiac death, aborted sudden cardiac death, implantable cardioverter defibrillator therapy, sustained ventricular tachycardia, atrioventricular block grade 3, pause >3 s; and "cardiovascular events" which was a composite of all-cause mortality, pacemaker or cardioverter defibrillator implantation, sustained ventricular tachycardia, supraventricular tachycardia, hospitalization for acute cardiac cause and heart failure. RESULTS: Forty-seven patients (22 women, 40 ± 13 years old) were included. Three (7%) DM1 patients died, 9 (19%) experienced "sudden cardiac death" endpoint and 21 (45%) experienced "cardiovascular event" endpoint during mean follow-up of 95 ± 22 months. None of holter ECG parameters were discriminant to predict death or secondary endpoints. Compared to healthy controls, DM1 patients had higher SDNN and LF/HF ratio. Finally, heart rate variability parameters remained stable over a mean interval of 61 ± 15 months excepting pNN50 which decreased significantly. CONCLUSION: Results suggest that annually-repeated holter ECG in DM1 is not useful for stratifying risk of sudden death and cardiovascular outcomes.