Accuracy of mobile 6-lead electrocardiogram device for assessment of QT interval: a prospective validation study.

INTRODUCTION: Ambulatory assessment of the heart rate-corrected QT interval (QTc) can be of diagnostic value, for example in patients on QTc-prolonging medication. Repeating sequential 12-lead electrocardiograms (ECGs) to monitor the QTc is cumbersome, but mobile ECG (mECG) devices can potentially solve this problem. As the accuracy of single-lead mECG devices is reportedly variable, a multilead mECG device may be more accurate. METHODS: This prospective dual-centre study included outpatients visiting our cardiology clinics for any indication. Participants underwent an mECG recording using a smartphone-enabled 6­lead mECG device immediately before or immediately after a conventional 12-lead ECG recording. Multiple QTc values in both recordings were manually measured in leads I and II using the tangent method and subsequently compared. RESULTS: In total, 234 subjects were included (mean ± standard deviation (SD) age: 57 ± 17 years; 58% males), of whom 133 (57%) had cardiac disease. QTc measurement in any lead was impossible due to artefacts in 16 mECGs (7%) and no 12-lead ECGs. Mean (± SD) QTc in lead II on the mECG and 12-lead ECG was 401 ± 30 and 406 ± 31 ms, respectively. Mean (± SD) absolute difference in QTc values between both modalities was 12 ± 9 ms (r = 0.856; p < 0.001). In 55% of the subjects, the absolute difference between QTc values was < 10 ms. CONCLUSION: A 6-lead mECG allows for QTc assessment with good accuracy and can be used safely in ambulatory QTc monitoring. This may improve patient satisfaction and reduce healthcare costs.

The accuracy of heartbeat detection using photoplethysmography technology in cardiac patients.

INTRODUCTION: Photoplethysmography (PPG) in wearable sensors potentially plays an important role in accessible heart rhythm monitoring. We investigated the accuracy of a state-of-the-art bracelet (Corsano 287) for heartbeat detection in cardiac patients and evaluated the efficacy of a signal qualifier in identifying medically useful signals. METHODS: Patients from an outpatient cardiology clinic underwent a simultaneous resting ECG and PPG recording, which we compared to determine accuracy of the PPG sensor for detecting heartbeats within 100 and 50 ms of the ECG-detected heart beats and correlation and Limits of Agreement for heartrate (HR) and RR-intervals. We defined subgroups for skin type, hair density, age, BMI and gender and applied a previously described signal qualifier. RESULTS: In 180 patients 7914 ECG-, and 7880 (99%) PPG-heartbeats were recorded. The PPG-accuracy within 100 ms was 94.6% (95% CI 94.1-95.1) and 89.2% (95% CI 88.5-89.9) within 50 ms. Correlation was high for HR (R = 0.991 (95% CI 0.988-0.993), n = 180) and RR-intervals (R = 0.891 (95% CI 0.886-0.895), n = 7880). The 95% Limits of Agreement (LoA) were -3.89 to 3.77 (mean bias 0.06) beats per minute for HR and -173 to 171 (mean bias -1) for RR-intervals. Results were comparable across all subgroups. The signal qualifier led to a higher accuracy in a 100 ms range (98.2% (95% CI 97.9-98.5)) (n = 143). CONCLUSION: We showed that the Corsano 287 Bracelet with PPG-technology can determine HR and RR-intervals with high accuracy in cardiovascular at-risk patient population among different subgroups, especially with a signal quality indicator.

Effectiveness of web-based personalised e­Coaching lifestyle interventions.

INTRODUCTION: Interventions to reduce the impact of modifiable risk factors, such as hypercholesterolaemia, smoking, and overweight, have the potential to significantly decrease the cardiovascular disease burden. The majority of the global population is unaware of their own risk of developing cardiovascular disease. Parallel to the lack of awareness, a rise in obesity and diabetes is observed. e­Health tools for lifestyle improvement have shown to be effective in changing unhealthy behaviour. In this study we report on the results of three different trials assessing the effectiveness of MyCLIC, an e­Coaching lifestyle intervention tool. METHODS: From 2008 to 2016 we conducted three trials: 1) HAPPY NL: a prospective cohort study in the Netherlands, 2) HAPPY AZM: a prospective cohort study with employees of Maastricht UMC+ and 3) HAPPY LONDON: a single-centre, randomised controlled trial with asymptomatic individuals who have a high 10-year CVD risk. RESULTS: HAPPY NL and HAPPY AZM showed that e­Coaching reduced cardiovascular risk. Both prospective trials showed a 20-25% relative reduction in 10-year cardiovascular disease risk. A lesser effect was seen in the HAPPY LONDON trial. A low frequency of logins suggests a low degree of content engagement in the e­Coaching group, which could be age related as the mean age of the participants in the HAPPY LONDON study was high. CONCLUSION: e-Coaching using MyCLIC is a low cost and effective method to perform lifestyle interventions and has the potential to reduce the 10-year cardiovascular disease risk.

Correction to: A mobile one-lead ECG device incorporated in a symptom-driven remote arrhythmia monitoring program. The first 5,982 Hartwacht ECGs.

Correction to: Neth Heart J 2018 https://doi.org/10.1007/s12471-018-1203-4 Unfortunately the original version of this article did not reflect that J.L. Selder and L. Breukel contributed equally to the ….

A mobile one-lead ECG device incorporated in a symptom-driven remote arrhythmia monitoring program. The first 5,982 Hartwacht ECGs.

BACKGROUND: In recent years many mobile devices able to record health-related data in ambulatory patients have emerged. However, well-organised programs to incorporate these devices are sparse. Hartwacht Arrhythmia (HA) is such a program, focusing on remote arrhythmia detection using the AliveCor Kardia Mobile (KM) and its algorithm. OBJECTIVES: The aim of this study was to assess the benefit of the KM device and its algorithm in detecting cardiac arrhythmias in a real-world cohort of ambulatory patients. METHODS: All KM ECGs recorded in the HA program between January 2017 and March 2018 were included. Classification by the KM algorithm was compared with that of the Hartwacht team led by a cardiologist. Statistical analyses were performed with respect to detection of sinus rhythm (SR), atrial fibrillation (AF) and other arrhythmias. RESULTS: 5,982 KM ECGs were received from 233 patients (mean age 58 years, 52% male). The KM algorithm categorised 59% as SR, 22% as possible AF, 17% as unclassified and 2% as unreadable. According to the Hartwacht team, 498 (8%) ECGs were uninterpretable. Negative predictive value for detection of AF was 98%. However, positive predictive value as well as detection of other arrhythmias was poor. In 81% of the unclassified ECGs, the Hartwacht team was able to provide a diagnosis. CONCLUSIONS: This study reports on the first symptom-driven remote arrhythmia monitoring program in the Netherlands. Less than 10% of the ECGs were uninterpretable. However, the current performance of the KM algorithm makes the device inadequate as a stand-alone application, supporting the need for manual ECG analysis in HA and similar programs.

First real-world experience with mobile health telemonitoring in adult patients with congenital heart disease.

BACKGROUND: Arrhythmias and heart failure are common and invalidating sequelae in adult patients with congenital heart disease (CHD). Mobile health (m-Health) enables daily monitoring and a timely response that might prevent deterioration. We present an observational prospective registry to evaluate feasibility of an m­Health telemonitoring program for managing arrhythmia, heart failure and blood pressure in symptomatic adults with CHD. METHODS: Symptomatic adult patients with CHD are enrolled in an m­Health telemonitoring program, which evaluates single-lead ECG, blood pressure and weight measurements. In case of symptoms extra measurements could be performed. Data are collected by mobile apps, matched with individualised thresholds. Patients are contacted if thresholds were exceeded or if arrhythmias were found, for treatment adjustments or reassurance. Data on emergency care utilisation, hospitalisation and patient-reported outcome measures are used to assess quality of life and self-management. RESULTS: 129 symptomatic CHD patients were invited to participate, 55 participated. Reasons for refusing consent included too time consuming to participate in research (30) and to monitor vital signs (14). At baseline 22 patients were in New York Heart Association class ≥ II heart failure, 43 patients had palpitations or documented arrhythmias, and 8 had hypertension. Mean follow-up was 3.0 months, one patient dropped out, and adherence was 97%. CONCLUSION: The first results indicate that this program is feasible with high adherence.

The impact of obesity on the relationship between epicardial adipose tissue, left ventricular mass and coronary microvascular function.

PURPOSE: Epicardial adipose tissue (EAT) has been linked to coronary artery disease (CAD) and coronary microvascular dysfunction. However, its injurious effect may also impact the underlying myocardium. This study aimed to determine the impact of obesity on the quantitative relationship between left ventricular mass (LVM), EAT and coronary microvascular function. METHODS: A total of 208 (94 men, 45 %) patients evaluated for CAD but free of coronary obstructions underwent quantitative [(15)O]H2O hybrid positron emission tomography (PET)/CT imaging. Coronary microvascular resistance (CMVR) was calculated as the ratio of mean arterial pressure to hyperaemic myocardial blood flow. RESULTS: Obese patients [body mass index (BMI) > 25, n = 133, 64 % of total] had more EAT (125.3 ± 47.6 vs 93.5 ± 42.1 cc, p < 0.001), a higher LVM (130.1 ± 30.4 vs 114.2 ± 29.3 g, p < 0.001) and an increased CMVR (26.6 ± 9.1 vs 22.3 ± 8.6 mmHg×ml(-1)×min(-1)×g(-1), p < 0.01) as compared to nonobese patients. Male gender (ß = 40.7, p < 0.001), BMI (ß = 1.61, p < 0.001), smoking (ß = 6.29, p = 0.03) and EAT volume (ß = 0.10, p < 0.01) were identified as independent predictors of LVM. When grouped according to BMI status, EAT was only independently associated with LVM in nonobese patients. LVM, hypercholesterolaemia and coronary artery calcium score were independent predictors of CMVR. CONCLUSION: EAT volume is associated with LVM independently of BMI and might therefore be a better predictor of cardiovascular risk than BMI. However, EAT volume was not related to coronary microvascular function after adjustments for LVM and traditional risk factors.

Brain natriuretic peptide as a predictor of adverse outcome in patients with pulmonary embolism.

BACKGROUND: Despite effective treatment with anticoagulants, 2% to 7% of patients with pulmonary embolism will die as a result of their disease. METHODS AND RESULTS: We examined in 110 consecutive patients with pulmonary embolism whether plasma brain natriuretic peptide (BNP), a novel marker of (right) ventricular dysfunction, is a predictor of fatal pulmonary embolism. The relationship between BNP concentration measured at presentation and clinical outcome was assessed by comparing the proportion of outcome events among tertiles. Positive and negative predictive values of BNP levels in the highest and lowest tertiles were calculated. The risk of death related to pulmonary embolism if the BNP level is >21.7 pmol/L is 17% (95% CI, 6% to 33%). The negative predictive value for uneventful outcome of a BNP value <21.7 pmol/L is 99% (95% CI, 93% to 100%). CONCLUSIONS: This is the first study to show that plasma BNP levels seem to predict adverse outcome in patients with acute pulmonary embolism.

Incremental diagnostic value of epicardial adipose tissue for the detection of functionally relevant coronary artery disease.

BACKGROUND AND AIM: To determine the incremental diagnostic value of epicardial adipose tissue (EAT) volume in addition to the coronary artery calcium (CAC) score for detecting hemodynamic significant coronary artery disease (CAD). METHODS AND RESULTS: 122 patients (mean age 61 ± 10 years, 61% male) without a previous cardiac history underwent a non-contrast CT scan for calcium scoring and EAT volume measurements. Subsequently all patients underwent invasive coronary angiography (ICA) in conjunction with fractional flow reserve (FFR) measurements. A stenosis >90% and/or a FFR ≤0.80 were considered significant. Mean EAT volume and CACscore were 128 ± 51 cm(3) and 418 ± 704, respectively. The correlation between EAT volume and the CACscore was poor (r = 0.11, p = 0.24). Male gender (odds ratio [OR] 2.86, p = 0.01), CACscore ([cut-off value 100] OR 3.31, p = 0.003, and EAT volume ([cut-off value 92 cm(3)] OR 4.28, p = 0.01) were associated with flow-limiting disease. The multivariate model revealed that only male gender (OR 2.50, p = 0.045), CAC score (OR 3.60, p = 0.005), and EAT volume (OR 4.95, p = 0.02) were independent predictors of myocardial ischemia. Using the cut-off values of 100 (CAC score) and 92 cm(3) (EAT volume), sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for detecting functionally relevant CAD as indicated by FFR were 71, 57, 77, 50 and 63% and 91, 29, 85, 44 and 52% for the CACscore and EAT volume, respectively. Adding EAT volume to the CAC score and cardiovascular risk factors did not enhance diagnostic performance for the detection of significant CAD (p = 0.57). CONCLUSION: EAT volume measurements have no diagnostic value beyond calcium scoring and cardiovascular risk factors in the detection of hemodynamic significant CAD.

Increased brain natriuretic peptide as a marker for right ventricular dysfunction in acute pulmonary embolism.

Right ventricular (RV) function is of major prognostic significance in patients with acute pulmonary embolism (PE). The aim of the present study was to evaluate the role of neurohormone plasma brain natriuretic peptide (BNP) in assessing RV function in patients with acute PE. BNP levels were measured in 16 consecutive patients with acute PE as diagnosed by high probability lung scintigraphy or pulmonary angiography. Twelve healthy age-matched volunteers served as controls. All 16 patients underwent standard echocardiography and blood tests during the first hour of presentation. In the patient group, survival was studied for a period of 30 days. Plasma BNP levels in patients with acute PE were higher than in controls (7.2 [95% CI 0.4 to 144.6] versus 1.4[95% CI 0.4 to 4.6] pmol/L, p = 0.0008). Plasma BNP was significantly higher in 5 patients with RV dysfunction compared to II patients with normal RV function (40.2 [95% CI 7.5 to 214.9] versus 3.3 [95% CI 0.4 to 24.9] pmol/L, p = 0.0003). RV systolic pressure was not significantly correlated with BNP (r = 0.42, p = ns). In conclusion, plasma BNP neurohormone levels might be of clinical importance as a supplementary tool for assessment of RV function in patients with acute PE.

Diabetes mellitus is not a contra-indication for peripheral vascular intervention in patients with leg ischemia.

BACKGROUND: The effect of diabetes mellitus on the patency of peripheral vascular interventions was investigated in patients with arterial insufficiency of the leg in a retrospective follow-up study performed between 1993 and 1995. METHODS: In 65 patients without and 36 with diabetes 124 vascular reconstructions were performed because of rest pain and/or ulceration. RESULTS: In diabetic patients ulcers were found more frequently and more distal bypasses were performed. No significant differences were observed between diabetics and non-diabetics as to bypass patency, number of re-interventions and amputations. Smoking and age were significant factors influencing bypass patency. CONCLUSION: Diabetes mellitus in patients with critical leg ischaemia appears to be no reason to refrain from vascular surgery.

Can the green laser doppler measure skin-nutritive perfusion in patients with peripheral vascular disease?

The recently developed green laser (GL; wavelength 543 nm) is thought to measure perfusion derived from a more superficial skin layer than does the standard near-infrared laser (RL; wavelength 780 nm). These lasers were used to investigate the disturbances in the different layers of skin perfusion in ischaemic legs before and after treatment and compared with capillary microscopy. Eighteen patients (20 legs) with different stages of leg ischaemia scheduled for a vascular intervention (11 males, 7 females; median age 73, range: 52-81 years; Fontaine stages II-IV) were investigated by means of capillary microscopy, visualising the nail fold capillary perfusion, and a laser Doppler, equipped with a special dual probe conducting both GL and RL. The probe was attached to the pulp and the dorsum of the big toe to assess skin perfusion at rest and during reactive hyperaemia, while sitting and while supine. Resting and hyperaemic perfusion using GL was low and significantly lower (p < 0.01) than with RL in both areas and positions. Laser Doppler perfusion was higher in the pulp than on the dorsum with both wavelengths (p < 0.05). The hyperaemia response was highest using GL and differed among the three techniques. Postural reduction of capillary and RL flow was reduced, but not with GL. After treatment, skin capillary perfusion improved more clearly than did the laser Doppler perfusion with either wavelength, while postural vasoconstriction improved only when measured with the capillary microscope. The differences found between RL and GL Doppler perfusion, but also between GL and capillary microscopy measurements suggest that the GL does measure the more superficial, but not exclusively the nutritive skin perfusion. Clinically, the use of the green laser in its present form in patients with leg ischaemia offers no advantage over the red laser.

Red and green laser Doppler compared with capillary microscopy to assess skin microcirculation in the feet of healthy subjects.

Skin microvasculature consists of nutritive capillaries and subpapillary arteriolar and venular plexus connected by arteriolovenular anastomoses. Capillary perfusion is of paramount importance for skin viability. Recently a new combined laser Doppler instrument has become available, featuring a combination of near-infrared (RL; 780 nm) and green (GL; 543 nm) laser light sources. Theoretically, the red laser will penetrate deeper, whereas the green laser will read fairly superficially. This may enable differentiation between the more superficial, i.e., capillary, and the deeper skin layers. To test this hypothesis, the combined laser Doppler technique was compared with nail fold capillary microscopy in the feet of 10 healthy subjects. Seven males and 3 females with a median age of 26 (range 20-42) years and without arterial pathology were investigated. The laser Doppler (Periflux 4001, Perimed) was equipped with a special dual probe conducting both GL and RL. The probe was attached to the pulp of the big toe (with many AV-shunts) and to the nail fold, at the site where capillary microscopy was performed too. Laser Doppler and capillary perfusion was assessed at rest and during postocclusive reactive hyperemia. These measurements were performed both in the sitting and the supine positions to test the postural vasoconstriction response. Median resting and hyperemic skin perfusion with GL were lower (P < 0.01) than with the RL in both areas and positions, except for the resting value in the sitting position on the dorsum of the toe. Plantar perfusion was found significantly higher than dorsal perfusion only with the RL in the supine position (P < 0.01). GL and RL on the plantar, but not the dorsal, side showed a significantly decreased perfusion upon dependency (P < 0.05), both at rest and during hyperemia. In contrast, resting and peak capillary velocity did show a decrease on dependency (P < 0.05). Although the green laser measures a lower perfusion than does the red laser, which is likely to be derived from more superficial skin layers, it does not show a reactivity similar to that measured with capillary microscopy. Thus, it is questionable whether the green laser exclusively measures capillary perfusion.

Optimisation of the non-invasive assessment of critical limb ischaemia requiring invasive treatment.

OBJECTIVE: to assess the optimal cut-off values of toe blood pressure (TBP) and transcutaneous oxygen pressure (TcpO(2)) in the supine and sitting positions, in order to accurately detect the presence of severe leg ischaemia requiring invasive treatment. METHODS: in 49 consecutive patients (65 legs) with severe ischaemia according to clinical symptoms of Fontaine III or IV and a lowered ankle blood pressure, TBP and TcpO(2)were measured in the supine and sitting positions. Treatment within 6 weeks after the diagnosis was classified as either conservative or invasive (revascularisation or amputation). RESULTS: of the 65 legs, 38 (58%) required invasive treatment. The mean ankle pressure for this group was 70 mmHg. The optimal cut-off value for TBP was 38 mmHg and for TcpO(2)35 mmHg. A TBP of

The value of non-invasive techniques for the assessment of critical limb ischaemia.

OBJECTIVE: The European Consensus Document (ECD) defines critical ischaemia (CI) according to clinical (Fontaine) and blood pressure parameters. However, clinical symptoms may be non-specific and CI may exist without severely reduced blood pressures. This study prospectively investigated the additive value of transcutaneous oxygen tension (pO2) and toe blood pressure measurements to assess the presence of CI. METHODS: Forty-nine patients with 65 legs clinically classified as Fontaine stages III (n = 23) and IV (n = 26) were studied. Ankle and toe systolic blood pressure and pO2 were measured to assess the presence of CI (cut-off values were 50, 30 and 30 mmHg, respectively). The surgeon was blinded for the toe pressure and pO2 results. The treatment received within 1 month after presentation was recorded as being either conservative or invasive (vascular surgery or PTA). RESULTS: An ankle pressure of < or = 50 mmHg classified only 17% of the legs as having CI. By adding toe pressure and pO2, significantly more legs (63%; p < 0.0001) were classified as CI, of which 68% received invasive therapy. Forty-nine percent of the legs with an ankle pressure > 50 mmHg were treated invasively, whereas only 32% of the legs classified as not having CI by means of toe pressure and pO2 underwent invasive therapy. If the need for invasive treatment is used as the "gold standard" for the presence of CI, 54% of the legs would accurately be classified on the basis of the ankle blood pressure. The combination of toe pressure and pO2 would have yielded 71% and the ECD criteria 72% and accurately classified legs. The odds ratio for invasive therapy given a pO2 or toe pressure above the cut-off value was 14. CONCLUSION: Ankle blood pressure measurements have limited diagnostic value. Adding toe and/or oxygen pressures enhances the detection of CI requiring invasive therapy.

Dobutamine-induced increase of right ventricular contractility without increased stroke volume in adolescent patients with transposition of the great arteries: evaluation with magnetic resonance imaging.

OBJECTIVE: Prognosis in patients with surgically corrected (Senning or Mustard) transposition of the great arteries (TGA) depends mainly on right ventricular (RV) function and RV functional reserve. We examined the role of dobutamine stress in the early detection of RV dysfunction in asymptomatic or slightly symptomatic patients with TGA using magnetic resonance imaging (MRI). DESIGN AND PATIENTS: Twelve asymptomatic or slightly symptomatic patients with chronic RV pressure overload, surgically corrected (Mustard or Senning) TGA (age 22.8 (+/- 3.4) years; New York Heart Association (NYHA) class I/II) and nine age matched healthy volunteers (age 27.3 (+/- 4.4) years) were included. MRI was applied both at baseline and during dobutamine stress (start dose 5 microg/kg/min to maximum dose 15 microg/kg/min) to determine RV and left ventricular (LV) stroke volumes (SV) and ejection fraction (EF). RESULTS: At baseline only RVEF was significantly higher in controls than in patients (71 (+/- 9) vs. 57 (+/- 10)%, p < 0.001), other RV parameters were not significantly different between the two examined groups: RVSV (86 (+/- 21) vs. 72 (+/- 27) ml, p = ns), RV end-diastolic volume (EDV) (123 (+/- 37) vs. 123 (+/- 33) ml, p = ns), and heart rate (61 (+/- 10) vs. 69 (+/- 14) bpm, p = ns), respectively. During dobutamine stress RVEF increased significantly both in controls and patients (20 (+/- 16) vs. 17 (+/- 18)%, p < 0.01 and p < 0.02 vs. rest, respectively), but stress RVEF was significantly higher in controls than in patients (85 (+/- 3) vs. 66 (+/- 7)%, p < 0.0001). RVSV increased significantly in controls (22 (+/- 19)%, p < 0.02), and there was no significant increase in RVSV in patients (-10 (+/- 28)%, p = ns). The controls showed no change in RVEDV (2 (+/- 17)%, p = ns), but in patients a significant decrease in RVEDV (-24 (+/- 15)%, p < 0.001) was observed. Maximal heart rate was significantly higher in patients than in controls (122 (+/- 20) vs. 101 (+/- 14) bpm, p < 0.02). CONCLUSION: In asymptomatic or slightly symptomatic patients with surgically corrected TGA dobutamine had a positive inotropic effect on RV, but the increased contractility was not accompanied by an appropriate increase in SV. Our data suggest inadequate RV filling in this category of patients, possibly due to rigid atrial baffles and compromised atrial function or decreased compliance due to RV hypertrophy.

ECG determinants in adult patients with chronic right ventricular pressure overload caused by congenital heart disease: relation with plasma neurohormones and MRI parameters.

OBJECTIVE: To examine retrospectively the changes in ECG parameters over time and their correlation with other quantitative right ventricular (RV) function parameters in patients with chronic RV pressure overload caused by congenital heart disease. METHODS: 48 patients with chronic RV pressure overload caused by the following congenital heart diseases were studied: nine with congenitally corrected transposition of the great arteries (TGA), 12 with surgically corrected TGA, and 27 with a subpulmonary pressure overloaded RV. QRS duration and dispersion were measured manually from standard ECG recorded twice within five years. RV end diastolic volume (EDV) and RV mass were determined by magnetic resonance imaging. Brain natriuretic peptide (BNP) plasma concentrations were measured. RESULTS: QRS duration and QRS dispersion increased in all patient groups during the follow up period. QRS duration increased significantly in the congenitally corrected TGA (p = 0.04) and the subpulmonary pressure overloaded RV groups (p = 0.01). QRS dispersion increased significantly in patients with surgically corrected TGA (p = 0.03) and in the subpulmonary pressure overloaded RV group (p = 0.02). A significant correlation was found between QRS duration and RVEDV (r = 0.71, p < 0.0001). RV mass was significantly correlated with QRS duration in patients with tetralogy of Fallot (r = 0.67, p = 0.01). Mean (SD) plasma brain natriuretic peptide concentrations (6.6 (5.4) pmol/l) were increased compared with normal reference values but no correlation was found with ECG parameters or RV systolic pressure. No malignant arrhythmia or sudden death occurred. CONCLUSIONS: ECG parameters worsened gradually in asymptomatic or minimally symptomatic patients with chronic RV pressure overload, regardless of the nature of their congenital heart disease. In all patients, a significant positive correlation was found between QRS duration and RVEDV. In patients with tetralogy of Fallot there was also a correlation between QRS duration and RV mass.