24-h Holter ECG Research Articles

Multiple clinical profiles of families with the short QT syndrome

Short QT syndrome (SQTS) is a rare cardiac channelopathy characterized by a shortened corrected QT (QTc)-interval that can lead to ventricular arrhythmias and sudden cardiac death. The aim of this study was to investigate the clinical phenotypes and long-term outcomes of three families harbouring genetic mutations associated with the SQTS. Clinical data included medical history, physical examination, 12-lead ECG, 24-h Holter-ECG, and transthoracic echocardiography from three index patients and their first-degree relatives. Next generation clinical exome sequencing and genetic cascade screening were performed in index patients and their relatives, respectively. Two index patients experienced malignant ventricular arrhythmias and one patient suffered from arrhythmogenic syncope during a median follow-up period of 8 years. They all had genetic mutations associated with the SQTS. Two mutations were found in the KCNH2 gene, and one in the CACNA2D gene. One patient had an additional SCN10A variant. Alive and mutation-positive family members had short QTc-intervals, but no further phenotypic manifestations. None of the mutation-negative family members had an abnormal ECG or any symptoms. In all patients with shortened QTc-intervals, the QTc-interval had a low long-term variability and QTc shortening always remained detectable by 12-lead ECG. This study shows the variety of phenotypic manifestations in different families with SQTS. It further emphasizes the importance of a 12-lead ECG for early diagnosis, and the utility of next generation sequencing for the identification of mutations associated with the SQTS.

Cardiac tumors in children: A 20-year review of clinical presentation, diagnostics and treatment.

The use of new imaging techniques has contributed significantly to earlier diagnosis and treatment of cardiac tumors. The aim of the study was to analyze data from children with cardiac tumors in terms of clinical presentation, the role of noninvasive diagnostic procedures and the long-term outcome. The data analyzed retrospectively concerned 30 children in whom cardiac tumors were diagnosed from January 1995 to July 2015. The cardiac evaluation included a review of the subjects' medical records and medical history, a physical examination, standard 12-lead electrocardiography, echocardiography and 24-h Holter ECG monitoring at the time of diagnosis and at 6-12 month intervals during the follow-up at the authors' outpatient clinic. Most of the children did not need cardiac surgery; surgical tumor excision was necessary in 3 cases only. There was 1 death in the follow-up period. Rhabdomyoma was diagnosed in 22 cases, and in 16 of them tuberous sclerosis was confirmed during the follow-up period. In the remaining 8 cases, fibroma was the most likely diagnosis. The symptomatology of cardiac tumors in children can vary greatly, from the absence of any symptoms up to heart failure and respiratory distress indicating the need for surgical intervention. The diagnosis of cardiac tumors relies almost exclusively on noninvasive imaging techniques. The observations in this study confirm the fact that the most common cardiac tumor in children is rhabdomyoma, which may disappear spontaneously. Most patients with cardiac tumors do not require treatment.

What is the best ST-segment recovery parameter to predict clinical outcome and myocardial infarct size? Amplitude, speed, and completeness of ST-segment recovery after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

AimsST-segment recovery (STR) is a strong mechanistic correlate of infarct size (IS) and outcome in ST-segment elevation myocardial infarction (STEMI). Characterizing measures of speed, amplitude, and completeness of STR may extend the use of this noninvasive biomarker. Methods and resultsCore laboratory continuous 24-h 12-lead Holter ECG monitoring, IS by single-photon emission computed tomography (SPECT), and 30-day mortality of 2 clinical trials of primary percutaneous coronary intervention in STEMI were combined.Multiple ST measures (STR at last contrast injection (LC) measured from peak value; 30, 60, 90, 120, and 240min, residual deviation; time to steady ST recovery; and the 3-h area under the time trend curve [ST-AUC] from LC) were univariably correlated with IS and predictive of mortality. After multivariable adjustment for ST-parameters and GRACE risk factors, STR at 240min remained an additive predictor of mortality. Early STR, residual deviation, and ST-AUC remained associated with IS. ConclusionsMultiple parameters that quantify the speed, amplitude, and completeness of STR predict mortality and correlate with IS.

AN INTERESTING ETIOLOGY OF VENTRICULAR TACHYCARDIA.

Intermittent hypoxia and ventilatory intermittence due to sleep disorders such as obstructive sleep apnea can lead to cardiac arrhythmia, coronary artery disease, conductance disturbances and cardiac failure. Sub-clinical and overt hypothyroidism is an important physiopathological complex that is linked with cardiovascular risk, alteration of lipidic profile promoting atherogenic mechanisms. The two pathologies combined can exponentially increase the cardiovascular event risk. This case report demonstrates a young patient with obesity and arterial hypertension accusing irregular heart beats. Despite a normal resting ECG and echocardiography the patient presented malignant ventricular arrhythmias revealed on the 24h Holter ECG. The Epworth scale was 20 and the patient presented numerous episodes of hypopnea with an increased apnea-hypopnea index associated with ventricular arrhytmias on the polisomnography. The endocrine profile of the patient revealed a sublinical hypothyroidism that untreated can lead to accelerated atherosclerosis and arrhytmic risk. CPAP treatment alongside the levothyroxine treatment at TSH levels above 10mUI/L have controlled the malignant arrhythmic events without complex antiarrhythmic drugs sustaining the pathogenic contributions of this two pathologies in arrhythmogenesis process.

Time domain heart rate variability in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

ABSTRACT: The aim of the present study was to assess heart rate variability (HRV) in Boxer dogs affected by arrhythmogenic right ventricular cardiomyopathy (ARVC). Fourteen Boxer dogs classified as affected and 28 classified as unaffected were included in a prospective case-control study. Dogs underwent 24-hour ambulatory ECG and were classified as affected (>1,000 VPCs/24 hours) or unaffected (<20 VPCs/24 hours) by ARVC based on the number of ventricular arrhythmias. HRV was assessed using 24-h Holter ECG monitoring; the studied parameters were SDNN, SDANN, SDNNIDX, rMSSD and pNN50. Data were submitted to logarithmic transformation and HRV parameters were compared between groups and correlated according to the disease status, number and severity of ventricular arrhythmias using Student’s t test, linear regression and Spearman’s test. There was no interaction between the HRV parameters and the number and severity of ventricular arrhythmias. SDNNlog (2.35±0.14 vs. 2.46±0.12, P=0.01), SDNNIDXlog (2.18±0.14 vs. 2.24±0.10, P=0.002) and pNN50log (1.47±0.19 vs. 1.64±0.13, P=0.002) were significantly lower in the affected group compared with the unaffected. According to this study, HRV are different in a population of Boxers dogs affected by ARVC compared to a population of unaffected dogs, and these differences are not consequences of low cardiac output caused by ventricular arrhythmias since animals that had higher number and complexity of arrhythmias were not those who had lower values of HRV.

Catheter ablation of atrial fibrillation in very young adults: a 5-year follow-up study.

Catheter ablation is an established therapy for symptomatic atrial fibrillation (AF). However, outcome data on catheter ablation for AF in young adults is scarce. From 2005-2014, 85 consecutive young adults (mean age 31 ± 4 years; 69% men) with symptomatic paroxysmal AF (PAF, n = 52) and persistent (Pers) AF (n = 33) underwent pulmonary vein isolation (PVI) [±ablation of complex fractionated atrial electrograms/linear lesions in PVI non-responders] at our centre. Follow-up was based on outpatient visits including 24-h Holter-ECG at 3, 6 and, 12 months post ablation, and every 12 months thereafter. Recurrence was defined as any AF/atrial tachycardia episode >30s following a 3-month blanking period. Follow-up was available for 74/85 (87%) patients. After a median follow-up of 4.6 years (Q1: 2.6; Q3: 6.6) and a mean of 1.5 ± 0.6 (median 1, range 1-3) ablation procedures 84% [including 13% on previously ineffective antiarrhythmic drugs (AAD)] of patients were in stable SR. Single-procedural 1-year/5-year arrhythmia-free survival was 66% [95% confidence interval (CI): 56-78%]/44% (95% CI: 33-59%), respectively. Structural heart disease [SHD; hazard ratio (HR) 2.79 (95% CI 1.52-5.12), P = 0.001] and obesity [HR 1.10 (95% CI 1.00-1.21) per unit increase in body mass index >27 kg/m2, P = 0.05] independently predicted AF recurrence. Major complications occurred in 6/122 (4.9%) procedures (PV stenosis in 3, cardiac tamponade in 1, stroke in 1, and arterial-venous fistula in 1). In the majority of very young adults catheter ablation for AF is effective, and associated with an acceptable complication rate. SHD and obesity are predictors for AF recurrence in this population.

PS 02-67 DOES SYMPATHETIC OVERACTIVATION FEATURE ALL HYPERTENSIVES? DIFFERENCES OF SYMPATHOVAGAL BALANCE ACCORDING TO NIGHT/DAY BLOOD PRESSURE RATIO IN PATIENTS WITH ESSENTIAL HYPERTENSION

Objective: When evaluating the ‘night/day BP ratio’, both hypertensives and normotensives can be arbitrarily classified into four groups: extreme dippers (ratio ≤ 0.8), dippers (0.8 oratio ≤ 0.9), mild dippers (0.9 oratio ≥ 1.0) and reverse dippers (ratio ? 1.0). Reverse and mild dipper hypertensives have poorer prognoses compared with the physiological dipper profile, but the prognostic relevance of the extreme dipper profile remains uncertain. The evaluation of heart rate variability (HRV), obtained by 24-h Holter ECG monitoring, is the most frequently used noninvasive form of assessment of the activity of the autonomic nervous system. Reverse and mild dipper hypertensives have reduced HRV, indicating an overactivation of the sympathetic nervous system (SNS); however, the HRV behavior in extreme dippers is still controversial. Design and Method: The goal of this study was to compare HRV indexes of extreme vs. reverse dipper essential hypertensives measured on the basis of time domains. We enrolled 125 hypertensive subjects, divided in 4 quartiles according to day/night blood pressure (BP) ratios. The upper and lower quartiles (31 subjects per quartile) were compared; 30 normotensive subjects were enrolled as a control group. Results: Time domain HRV parameters of the three groups revealed a higher degree of sympathetic activation in the lower quartile (reverse dipper) vs. the upper quartile (extreme) and normotensive controls. It should be noted that SDNN (the standard deviation of all normal RR intervals) and SDANN (average normal RR intervals for all 5-min) of extreme dipper hypertensives were also greater than those of normotensive controls, although the difference was not statistically significant. When corrected for age, diurnal BP values, nocturnal BP values, waist circumference, anamnestic vascular events, differences in renal function, COPD, liver steatosis and left ventricular hypertrophy maintained statistical significance. HRV parameters related to parasympathetic tone did not show any significant variations among the three groups. Conclusions: Contrary to common belief, not all hypertensives have SNS overactivation.

Evaluation of heart rate measurements in clinical studies: a prospective cohort study in patients with heart disease.

PurposeThe purpose of this study was to evaluate the measurement of heart rate undertaken in clinical studies by (1) assessing the repeatability and reproducibility of heart rate measurements by various methods and under various conditions and (2) determining whether a single heart rate measurement at rest is representative of the circadian and inter-day variation of heart rate.MethodsProspective cohort study in 102 patients with various types of heart disease at Duisburg Heart Center, Germany between 2011 and 2012. The heart rate measurements were based on self-assessment, ECG tracings at rest, and bicycle stress ECG in the office as well as 24-h Holter ECG.ResultsOffice measurements and self-assessment at rest as well as 24-h Holter ECG and self-assessment at rest are highly correlated, but no correlation between self-assessment and office recordings/24 h recordings under exercise conditions was seen. Coefficient of variability was below 10 % for the self-assessment and for office measurements at rest. There were no differences in coefficient of variability during the day and within the 6 days for self-assessment of heart rate at rest and circadian variation was normal.ConclusionsAt rest heart rate measurements by various methods agree sufficiently and inter-day/circadian variation is adequately represented. Under exercise conditions self-assessment of heart rate is not valuable and use of 24 h Holter as well as stress ECG recordings is necessary. Thus, self-reported heart rate measurements by the patient at rest seem to be reliable, but should be used in clinical studies only for heart rate assessment at rest.

Does sympathetic overactivation feature all hypertensives? Differences of sympathovagal balance according to night/day blood pressure ratio in patients with essential hypertension.

When evaluating the 'night/day BP ratio', both hypertensives and normotensives can be arbitrarily classified into four groups: extreme dippers (ratio ⩽0.8), dippers (0.8<ratio ⩽0.9), mild dippers (0.9<ratio⩽1.0) and reverse dippers (ratio ⩾1.0). Reverse and mild dipper hypertensives have poorer prognoses compared with the physiological dipper profile, but the prognostic relevance of the extreme dipper profile remains uncertain. The evaluation of heart rate variability (HRV), obtained by 24-h Holter ECG monitoring, is the most frequently used noninvasive form of assessment of the activity of the autonomic nervous system. Reverse and mild dipper hypertensives have reduced HRV, indicating an overactivation of the sympathetic nervous system (SNS); however, the HRV behavior in extreme dippers is still controversial. The goal of this study was to compare HRV indexes of extreme vs. reverse dipper essential hypertensives measured on the basis of time domains. We enrolled 125 hypertensive subjects, divided in 4 quartiles according to day/night blood pressure (BP) ratios. The upper and lower quartiles (31 subjects per quartile) were compared; 30 normotensive subjects were enrolled as a control group. Time domain HRV parameters of the three groups revealed a higher degree of sympathetic activation in the lower quartile (reverse dipper) vs. the upper quartile (extreme) and normotensive controls. HRV parameters related to parasympathetic tone did not show any significant variations among the three groups. Contrary to common belief, not all hypertensives have SNS overactivation.

Abstract TP216: Atrial Fibrillation Detection in Patients With an Implantable Loop Recorder After Acute Embolic Stroke of Unknown Source (ESUS)

Introduction: The embolic stroke of unknown source concept was introduced as a more rigid analysis of patients with cryptogenic stroke representing a superselection of patients with cardioembolic stroke. These patients are particularly candidates for intermittent AF. As long as AF has not been documented, current concepts do not recommend oral anticoagulation.Implantable loop recorders (ILR) in patients with ESUS may detect AF and establish the indication for oral anticoagulation. The aim of this study was to prospectively assess and predict AF occurrence in patients with ILR after ESUS. Methods: In patients with ESUS (MR imaging based cardioembolic stroke, exclusion of structural cardiac stroke source by TEE, no AF detectable by 72h Stroke Unit monitoring and 24h holter ECG, exclusion of other stroke causes such as symptomatic carotid stenosis) an ILR was implanted and AF detection assessed by daily remote monitoring. The ILR was implanted on average 20 days after stroke. We analyzed the predictive value of different clinical and imaging characteristics for AF detection. Results: By daily remote monitoring of 124 Patients over a period of 12.7±5.5 months, AF was documented and manually confirmed in 29 of 124 patients (23.4%). First AF detection occurred on average after 3.6±3.4 months of monitoring. Characteristics of patients with and without AF detection are shown in the table. Conclusions: Patients with ESUS and asymptomatic AF detected only by long-term continuous monitoring with an ILR were on average older, had a higher CHA2DS2-VASc score and had more often microangiopathy. Other clinical parameters and features of cerebral imaging in ESUS did not increase the probability of AF detection in these preselected patients with ESUS. Importantly, ESUS selection almost doubled AF detection rate compared to recent studies such as the ILR group of the Crystal-AF trial (23.4% in 12.7±5.5 months compared to 12.4% in 12 months).

Impact of left ventricular remodeling and renal function on 24 h-ECG recordings and cardiovascular outcome in elderly hypertensive patients

BackgroundThe prognostic role of left ventricular remodeling and renal function in elderly hypertensive patients has been so far scarcely investigated. AimsWe assessed the impact of left ventricular geometry and renal function on 24h-Holter electrocardiogram (ECG) recordings and outcome in elderly hypertensive patients. MethodsWe enrolled 251 asymptomatic hypertensive elderly patients (>65year-old). Left ventricular remodeling was evaluated by 2-D echocardiogram. Lown's class, mean QTc and standard deviation of all normal R–R intervals (SDNN) were assessed by 24-h Holter-ECG recordings. Data on all-cause and cardiovascular mortality were collected for 2years. ResultsMean age was 76.2±11.4years. High Lown's classes were more frequently observed in the presence of left ventricular hypertrophy (LVH) (57.3% vs. 23.7%; p<0.001). Mean QTc was 444.8±34.8ms and resulted directly correlated with indexed left ventricular mass (r=0.228; p=0.001). Patients with Chronic Kidney Disease (CKD) showed lower SDNN as compared with those with preserved renal function (92.02±36.11ms vs. 103.84±33.96ms, respectively; p=0.017). At 2years, all-cause and cardiovascular mortality rates were 38.0% and 21.1%, respectively. Diabetes mellitus (HR: 2.40; 95% C.I.1.16 to 4.99; p=0.019), CKD (HR: 2.22; 95% C.I.1.10 to 4.52; p=0.028), prolonged QTc (HR: 2.18; 95% C.I.1.07 to 4.41; p=0.030) and SDNN<96ms (HR: 1.98; 95% C.I.1.03 to 4.13; p=0.048) were independent predictors of cardiovascular death at 2year follow-up. ConclusionsCKD and left ventricular remodeling predicted altered ventricular batmotropism. Diabetes, CKD, heart rate variability and QTc are important predictors of cardiovascular death in elderly hypertensive patients.

Concomitant surgical ablation for atrial fibrillation (AF) in patients with significant atrial dilation >55 mm. Worth the effort?

BackgroundConcomitant Surgical AF ablation is an established procedure, recommended in guidelines. However many surgeons are reluctant to perform AF ablation in patients with significantly enlarged left atrium. We therefore analyzed outcomes of patients with left-atrial diameter >55 mm undergoing concomitant AF ablation.MethodsBetween 05/2003 and 12/2012 124 patients with significantly enlarged left-atrium >55 mm underwent concomitant surgical AF ablation. Rhythm monitoring was accomplished by implantable loop recorder (ILR) interrogation (n = 54), or 24-h Holter-ECG (n = 70). Successful ablation was defined as AF Burden <0.5 % in ILR interrogation or absence of AF episode >30 s in 24-h Holter-ECG. Primary endpoint of the study was freedom from AF at 12 months follow-up.ResultsMean patient’s age was 65.7+/−9.6 years, 69.4 % were male. No major ablation or ILR related complications occurred. Mean LA diameter was 60.7+/−4.4 mm. Survival rate at one-year follow up was 94.4 %. 11 (8.8 %) patients received additional catheter-based ablation, while 23 (18.5 %) had an electrical cardioversion during follow-up period. Overall freedom from AF rate after one-year follow-up was 64.4 % and 59.4 % off antiarrhythmic drugs respectively. Logistic regression analysis identified preoperative paroxysmal AF, duration of AF and LA diameter > 70 mm as predictors for rhythm outcome at 12 months follow-up.ConclusionIn this patient cohort with significantly enlarged LA diameter, concomitant surgical AF ablation provided freedom from AF of 64.4 % after one-year follow-up. However in this patient population, an accurate postoperative care with interventions like medical or- electrical cardioversion and additional catheter based ablation is necessary to achieve satisfactory results.

Abstract 15592: Role of Electroanatomic Voltage Mapping for Risk Stratification in Patients With Repaired Congenital Heart Disease Involving the Right Ventricle

Introduction: Among adult patients with previous surgical correction for Tetralogy of Fallot or other repaired Congenital Heart Disease (rCHD) involving the RV, ventricular arrhythmias (VA) and sudden cardiac death (SCD) represent a late complication. The imparied haemodynamics that lead to RV dilatation and overload could also alterate its electroanatomic structure. Hypothesis: 3D electroanatomic mapping (EAM) of the RV could confirm the presence of myocardial electrical abnormalities, allowing to better identify patients at risk for life-threatening arrhythmias. Methods: 146 patients (age 19.2 ±7.0) with rCHD involving the RV were selected from a population undergoing routine post-surgical follow-up, according to the presence of VA or severe RV dilatation. These patients underwent 3D EAM of the RV. We tested the correlation between size of scar tissue (areas with voltage &lt; 0.5 mV) and several parameters universally accepted by the literature as risk factors for VA in this particular patient population. Results: In 125 (85.6%) patients, EAM demonstrated areas of low voltage in the antero-lateral RVOT. In 20 of these (16%, 13.7% of the total) the scar extended to the septum. 72 (49.3%) had a peritricuspid scar, and in 20 (13.7%) other areas of the RV were interested. Total low-voltage area, expressed as % of total endocardial area, was significantly higher in patients with history of PVCs [3.2% (±2.6) vs 2.2% (±1.8), p&lt;0.05], complex PVCs at 24h-Holter ECG (Lown class ≥2) [3.4 (±2.5) vs 2.6 (±2.3), p&lt;0.05], exercise-inducible PVCs [3.8 (±2.4) vs 2.6 (±2.2), p=0.01] and history of previous shunt [4.0 (±2.7) vs 2.6 (±2.2), p=0.01]. Scar size was also positively correlated with age (p=0.01), age at correction (p=0.01) and QRS duration on surface ECG (p&lt;0.05). Conclusions: In patients with rCHD involving the RV it is common to observe endocardial low-voltage areas with variable distribution, not always corresponding to the sites of surgical lesion. Morover, the size of the scar tissue area correlates with some of the parameters which have been already identified as risk factors for life-threatening arrhythmias and SCD in adult patients with CHD. We suggest that EAM should become part of the routine tests for the stratification of arrhythmic risk in this population.

Abstract 15674: Can Heart Rate Turbulence and T-Wave Alternans on Holter Electrocardiograms Predict Serious Cardiac Events in Patients After Myocardial Infarction?

Backgrounds: Patients who survive a myocardial infarction (MI) are at risk of serious events such as sudden cardiac death (SCD). Although the implantable cardioverter-defibrillator (ICD) reduces mortality after MI, there is no reliable method to predict SCD. Because of the relatively low accuracy of Left ventricular ejection fraction (LVEF), noninvasive measures of autonomic tone and cardiac electrical substrate have been developed to identify patients at risk of SCD. Recent studies have reported that heart rate turbulence (HRT) and T-wave alternans (TWA), which can be assessed simply using 24-hr Holter electrocardiogram is a significant index for cardiac events. Material and Methods: A total of 464 patients who was first diagnosed with myocardial infarction and treated with percutaneous coronary intervention (age 63 ± 12, 70.9% male) were analyzed. All patients performed 24-h Holter ECG monitoring during hospitalization (mean duration after MI 2.7 ± 1.8 days) to measure HRT, modified moving average method (MMA)-TWA and other conventional parameters. HRT was determined positive when both turbulence onset and turbulence slope were abnormal and MMA-TWA was determined positive when the maximal voltage was &gt; 64 μV. The cardiac mortality and sudden cardiac death were analyzed for 2 years. Results: HRT was positive in 48 patients (10.3%) and MMA-TWA was positive in 250 patients (53.9%). During 2 years follow-up, 23 patients (4.9%) were died from cardiac disease, including 19 patients (4.1%) with SCD. On univariative analysis, HRT was a significant predictor for cardiac death (Hazard ratio, 4.29; 95% C.I. 1.66-10.98; P = 0.003) and SCD (Hazard ratio, 5.75; 95% C.I. 2.14-15.41; P = 0.001). On multivariative analysis, HRT had the significant value, with a hazard ratio of 3.25 (95% C.I. 1.09-9.74, P = 0.035) for SCD. Older age, lower LVEF, non-use of beta-blocker, presence of non-sustained ventricular tachycardia were another predictor of cardiac events. However, MMA-TWA can not predict cardiac events in this study. Conclusion: The present study revealed that HRT was a significant predictor of SCD. However, MMA-TWA can not predict cardiac events in acute phase of myocardial infarction.

Diagnostic value of electrocardiographic (resting and 24-h Holter) monitoring in comparison with NT-proBNP in the differential diagnosis of patients with cardiogenic and neurogenic syncope

BackgroundSyncope is a cause of 1–6% of hospitalizations. Both European and American syncope guidelines recommend a 12-lead ECG as part of the evaluation of all patients with unexplained loss of consciousness. ObjectivesThe aim of this study was the assessment of the significance of ECG, Holter ECG and the concentration of NT-proBNP that would be useful in the differentiation of patients with cardiac and reflex syncope. MethodsWe investigated 100 patients (56 men), aged 18–77 years with reflex or cardiac syncope over the last 3 years. The following factors were investigated: age, sex, systolic and diastolic blood pressure, the presence of cardiovascular disease. Moreover, we assessed basic resting ECG parameters and 24-h Holter ECG parameters, and NT-proBNP concentration in the differential diagnosis of syncope. ResultsPatients with reflex syncope were younger compared to patients with cardiac syncope (44.4±16.5 vs. 60.8±12.6; p<0.001). A pathologic resting 12-lead ECG was present more frequently in the group with a cardiogenic type of syncope – 12 (24%) vs. 8 (16%). 24-h Holter ECG monitoring showed no statistically significant difference between minimal, mean and maximal heart rates in the analyzed groups. However, statistically significant differences were observed in the occurrence of ventricular and supraventricular arrhythmias between the investigated groups. Patients with cardiac syncope had significantly higher concentrations of NT-proBNP compared to patients with reflex syncope (448.7±212.2 vs. 68.2±64.1; p<0.0001). ConclusionsElevated NT-proBNP concentration is present in patients with a cardiogenic mechanism of syncope, despite the fact that a resting ECG is inconclusive.

Which is responsible for cardiac autonomic dysfunction in non-diabetic patients with metabolic syndrome: Prediabetes or the syndrome itself?

AimsCardiac autonomic dysfunction (CAD) is associated with both prediabetes and metabolic syndrome (MS). Heart rate variability (HRV) and heart rate turbulence (HRT) are reliable 24-h Holter-ECG findings of cardiac autonomic function. This study aimed to investigate the relation between MS and its components and CAD using HRV and HRT. Materials and methodsThe study included 80 non-diabetic patients with MS and 70 control subjects. All study population and the patients with MS were further analyzed for each diagnostic component of MS to investigate which criteria impaired HRV and HRT. ResultsHRV and HRT parameters were disturbed in patients in the MS group. While impairment in HRV and HRT was significantly related to the presence of the fasting plasma glucose (FPG) criterion, there were no differences between groups in terms of the other 4 MS criteria. Moreover, FPG level was significantly correlated with SDNN (r=−0.352, p<0.001), SDNN index (r=−0.423, p<0.001), SDANN (r=−0.301, p<0.001), RMSSD (r=−0.237, p<0.001), pNN50 (r=−0.237, p<0.001), turbulence onset (TO) (r=0.365, p<0.001) and turbulence slope (TS) (r=−0.365, p<0.001). Among the MS diagnostic criteria, only FPG level was an independent determinant of all HRV and HRT parameters. ConclusionsThis study confirms the relation between MS and CAD. Increased FPG alone appears to be responsible for the mentioned findings among the 5 diagnostic criteria. Accordingly, CAD may be the result of prediabetes, not MS in patients with MS.

EFFECTS OF HIGH INTENSITY INTERVAL TRAINING ON HEART RATE RECOVERY, HEART RATE VARIABILITY AND ARRHYTHMIAS IN PATIENTS POST-ACUTE CORONARY SYNDROME

Heart rate recovery (HRR) and heart rate variability (HRV) are important predictors of mortality in patients post-acute coronary syndrome (PACS). High intensity interval exercise (HIIE) decreases the prevalence of arrhythmias and increases HRV in heart failure patients. However, the effects of high intensity interval training (HIIT) on HRR, HRV and arrhythmias in PACS patients are not documented. Our aims were to compare the effects of 12-weeks of HIIT vs. moderate intensity continuous exercise training (MICET) on HRR, HRV and arrhythmias in PACS patients. Thirty-one PACS patients from the Montréal Heart Institute (MHI) were randomly assigned to either HIIT (n=13) or isocaloric MICET (n=18) program on cycle ergometer. Cardiometabolic risk factors, maximal cardiopulmonary exercise test (CPET) and 24h-holter ECG monitoring were performed before and after the intervention. The MICET protocol consisted of 5 min warm-up at 30% maximal aerobic power (MAP) followed by 37 min at 60% of MAP, followed by 5 min cool down at 30% of MAP. The HIIT protocol included 2 to 3 blocks of 10 minutes of repeated phases of 15 sec at 100% of MAP alternating with 15 sec of passive recovery. A four-minute passive recovery was allowed between HIIT blocks. Warm up and cool down consisted of 5-minute cycling periods at 30% MAP. Maximal aerobic power was determined during CPET on cycle ergometer. During training sessions, continuous ECG monitoring was performed while BP was measured every 2 minutes. Heart rate recovery (HRR: Δ bpm) was measured during 5 min of recovery and was averaged every 5 sec. Heart rate variability was measured using 24h-holter monitoring. For HRV, time domain and spectral parameters were assessed. Heart rate recovery was not improved in the MICET group after the training. In the HIIT group, HRR was significantly improved (p<0.05) for the following recovery times: 5, 10, 80s, between 165 and 180s, between 205 and 255s, and between 265 and 275s for the HIIT group. Heart rate variability was unchanged in both groups. No significant atrial or ventricular arrhythmias occurred in either group during or after training sessions. Our results suggest that HIIT improves HRR in PACS patients and may result in higher parasympathetic reactivation during the 5-min recovery period although no long-term effects of HIIT on autonomic regulation of cardiovascular function were observed. In PACS patients, HIIT appears safe and does not increase ventricular arrhythmias.

Impact of type of intervention for aortic valve replacement on heart rate variability

BackgroundIt is known that coronary heart surgery leads to varying degrees of cardiac autonomic derangement, clinically detectable as depression of heart rate variability (HRV) parameters. Few studies report that also surgical replacement of the aortic valve (SAVR) may lead to HRV abnormalities, while very little is known about the autonomic effects obtained after less invasive aortic valve replacement techniques. The study aimed to evaluate HRV after SAVR and to compare it with two less invasive techniques, transapical (TaAVI) and tranfemoral (TfAVI) aortic valve implant. MethodsTime-domain heart rate variability (HRV) parameters have been studied by 24-h Holter ECG in 129 patients after SAVR, in 63 patients after TfAVI and in 19 patients after TaAVI. ResultsAll HRV parameters were significantly depressed in SAVR, while they were almost completely preserved in TfAVI patients; TaAVI cases showed a somehow intermediate behaviour [(SDNN respectively: 71.0±34.9 vs 95.9±29.5 (p<0.001) vs 84.4±32.6ms (p=ns)]. Mean heart rate during the 24-h Holter was 8% higher in SAVR patients than in both TfAVI and TaAVI patients. The reported results were not correlated with echocardiographic ejection fraction, or presence of abnormal glucose metabolism, or degree of anaemia or treatment with beta-blockers. ConclusionsSAVR leads to profound depression of some cardiac autonomic parameters, while less invasive procedures allow better preservation of HRV. In particular TfAVI does not induce any significant deterioration of HRV parameters and seems to be the strategy of valve implant with less impact on the cardiovascular autonomic system.

Heart rate turbulence and deceleration capacity for risk prediction of serious arrhythmic events in Marfan syndrome.

Marfan syndrome (MFS) is associated with a substantial risk for ventricular arrhythmia and sudden cardiac death (SCD). We used heart rate turbulence (HRT) and deceleration capacity (DC), to evaluate the risk stratification for these patients. We enrolled 102 patients [45 male (44.1%), age 40.5±14.6years] with MFS. Blood samples were obtained to determine N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. Transthoracic echocardiography studies were conducted to evaluate heart function parameters and a 24-h holter ECG was performed. An analysis of two HRT parameters, turbulence onset (TO) and turbulence slope (TS), and DC was performed. Therefore, optimal cut-off values were calculated. Primary endpoint was the combination of SCD, ventricular arrhythmia and arrhythmogenic syncope. Secondary endpoint was total mortality. During a follow-up of 1145±491days, 12 (11.7%) patients reached the primary and 8 (7.8%) patients the secondary endpoint. Patients reaching the primary were significantly older, had a higher burden of premature ventricular complexes and NT-proBNP levels and lower values of LVEF, DC and HRT TS. Multivariate analysis identified NT-proBNP (HR 1.25, 95% CI 1.01-1.56, p=.04) and the abnormal HRT (abnormal TS and/or TO (HR 7.04, 95% CI 1.07-46.27, p=.04) as independent risk predictor of arrhythmogenic events. Patients with Marfan syndrome are at risk for severe ventricular arrhythmias and SCD. Abnormal HRT parameters and NT-proBNP values are independent risk factors for arrhythmogenic events and SCD. The assessment of these tools may help predicting SCD patients with MFS.

PP.36.04

Objective: Slow breathing has favorable acute effects in chronic heart failure (CHF) patients. Aim of this study is to test the feasibility and efficacy of a new nonpharmacological CHF treatment method based on slow breathing training (SBT). Design and method: The study is an ongoing cross-over open trial where patients, in random order, undergo a 10–12 week period of SBT with RESPeRATE device (InterCure Ltd., Lod, Israel) and a 10–12 week follow-up under usual care. Patients randomized to SBT are asked to perform each day two separate 15-min sessions of device-guided SBT at a breathing frequency of 6 breaths per minute. In all patients, clinical data collection, polysomnography, 6 minute walking test (6MWT), 24-h Holter ECG monitoring, Minnesota quality of life questionnaire and laboratory tests are performed at baseline and after each study phase. Results: Until now 97 pts have entered the study with the following baseline characteristics: age 66.3 ± 10.9 years, 76 M/21F, 43 with ischemic CHF, NYHA Class I: 4, Class II:52, Class III:3, left ventricular ejection fraction 30.1 ± 6.9%, hypertension:23, history of stroke:5, diabetes:16, apnea-hypopnea index (AHI) 10.3 ± 10.5. So far 60 of them have completed the study. No patients had relevant intervention-related adverse events in the course of the study (2 of them underwent CRT pacemaker implantation, 1 had myocardial infarction without time relation to SBT). Compared with baseline values in subjects who completed SBT phase, 6MWT distance (438 ± 126 vs 448 ± 141, p = 0.015) and LV ejection fraction (31.1 ± 6.8 vs 32.8 ± 6.5, p < 0.005) increased; AHI (9.81 ± 9.52 vs 8.1 ± 9.5, p = 0.027) and NYHA scale decreased (1.98 ± 0.35 vs 1.46 ± 0.50, p < 0.001); no significant changes occurred in NT-proBNP (1293 ± 1555 vs 1214 ± 1555, p = 0.92) or BNP (240 ± 173 vs 227 ± 195, p = 0.49). Conclusions: Preliminary data indicate that SBT is feasible and safe in CHF subjects and suggest an improvement in functional capacity and in sleep disordered breathing severity. If these results are confirmed in a larger sample, they may support SBT as a novel and useful component of cardiorespiratory rehabilitation programmes in CHF.