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Heart rate (HR) at rest is an important marker of prognosis in heart failure, but has not been addressed in pulmonary arterial hypertension (PAH). To determine the prognostic value of HR at rest in patients with PAH, we retrospectively analyzed 140 consecutive patients with idiopathic PAH. Electrocardiogram (ECG)-derived HR at rest was evaluated as a potential predictor of adverse prognosis (death or lung transplantation), in addition to World Health Organization functional class, 6-minute walk distance, and hemodynamics before and approximately 1 year and 2 years after initiation of PAH treatment. During follow-up, 49 patients (35%) died, and 5 patients (4%) underwent lung transplantation. Before treatment initiation and after 1 year and 2 years of treatment, respectively, a higher HR at rest was an independent predictor of adverse prognosis (hazard ratios per 10-beats/min increase 1.76, 95% confidence interval 1.42 to 2.18, 2.31, 95% confidence interval 1.58 to 3.38, 2.1, 95% confidence interval 1.39 to 3.19, respectively, p <0.001 for all). Change in HR between the first and last ECG also independently predicted prognosis (hazard ratio per 1-beat/min increase 1.03, 95% confidence interval 1.01 to 1.06). In conclusion, a higher HR at rest and an important increase in HR at rest during follow-up signify a considerable risk of death in patients with PAH. ECG-derived HR at rest is an important marker of prognosis and should be assessed before and at frequent intervals after initiation of treatment for PAH. [Copyright &y& Elsevier]

The article assesses whether the electrocardiogram (ECG) is useful for monitoring treatment response based on changes in pulmonary vascular resistance (PVR) in patients with pulmomary arterial hypertension (PAH). An ECG was recorded in 81 PAH patients at the time of diagnostic right heart catheterization and a year after treatment. Results conclude that routine ECG evaluation can be a vital contribution to assess the treatment response in PAH patients.

The study aimed to assess whether the 12-lead ECG-derived ventricular gradient, a vectorial representation of ventricular action potential duration heterogeneity directed toward the area of shortest action potential duration, can improve ECG diagnosis of chronic right ventricular (RV) pressure load. ECGs from 72 pulmonary arterial hypertension patients recorded <30 days before onset of therapy were compared with ECGs from matched healthy control subjects (n = 144). Conventional ECG criteria for increased RV pressure load were compared with the ventricular gradient. In 38 patients a cardiac magnetic resonance (CMR) study had been performed within 24 h of the ECG. By multivariable analysis, combined use of conventional ECG parameters (rsr' or rsR' in VI, RJS > 1 with R > 0.5 mV in VI, and QRS axis >90°) had a sensitivity of 89% and a specificity of 93% for presence of chronic RV pressure load. However, the ventricular gradient not only had a higher diagnostic accuracy for chronic RV pressure load by receiver operating characteristic analysis [areas under the curve (AUC) = 0.993, SE 0.004 as. AUC = 0.945, SE 0.021, P < 0.05], but also discriminated between mild-to-moderate and severe RV pressure load. CMR identified an inverse relation between the ventricular gradient and RV mass, and a trend toward a similar relation with RV volume. In conclusion, chronically increased RV pressure load is electrocardiographically reflected by an altered ventricular gradient associated with RV remodeling-related changes in ventricular action potential duration heterogeneity. The use of the ventricular gradient allows ECO detection of even mildly increased RV pressure load. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To assess the effect of pulmonary valve replacement (PVR) on the repolarization of patients with tetralogy of Fallot. Background: Pulmonary valve regurgitation may cause right ventricular failure in adult patients with Fallot''s tetralogy. In these patients, prolonged depolarization and disturbed repolarization are associated with ventricular arrhythmias and sudden cardiac death. Methods: Thirty Fallot patients (age 32±9 years, 19 male) eligible for PVR were studied with cardiac magnetic resonance imaging (CMR) before and 6 months after PVR. Electrocardiograms obtained during initial and follow-up CMR were analyzed and occurrence of ventricular arrhythmias was studied. Results: Right ventricular end-diastolic volume (RV EDV) decreased from 322±87 to 215±57 ml after PVR (P <0.0001). The spatial QRS-T angle normalized from 117±34 to 100±35°, P =0.0004 (normal angle <105°). QT dispersion and T-wave complexity did not change significantly. T-wave amplitude decreased from 376±121 to 329±100 μV (P =0.01). T-wave area decreased from 43±15 to 38±13 μV s (P =0.02). Decreases in T-wave amplitude and area were most prominent in the right precordial leads overlying the RV. Three patients had sustained ventricular arrhythmias and one patient died suddenly. These patients had a QRS duration >160 ms. No severe ventricular arrhythmias were found in patients with a RV EDV <220 ml, QRS-T angle <100°, QT dispersion <60 ms or T-wave complexity <0.30. Conclusion: Normal repolarization indices may be associated with the absence of severe ventricular arrhythmias. PVR in Fallot patients with dilated right ventricles has a beneficial effect on electrocardiographic indices of repolarization heterogeneity. [Copyright &y& Elsevier]

The study aim was to assess three-dimensional electrocardiogram (ECG) changes during development of pulmonary arterial hypertension (PAH). PAH was induced in male Wistar rats (n = 23) using monocrotaline (MCT; 40 mg/kg sc). Untreated healthy rats served as controls (n = 5). ECGs were recorded with an orthogonal three-lead system on days 0, 14, and 25 and analyzed with dedicated computer software. In addition, left ventricular (LV)-to-right ventricular (RV) fractional shortening ratio was determined using echocardiography. Invasively measured RV systolic pressure was 49 (SD 10) mmHg on day 14 and 64 (SD 10) mmHg on day 25 vs. 25 (SD 2) mmHg in controls (both P < 0.001). Baseline ECGs of controls and MCT rats were similar, and ECGs of controls did not change over time. In MCT rats, ECG changes were already present on day 14 but more explicit on day 25: increased RV electromotive forces decreased mean QRS-vector magnitude and changed QRS-axis orientation. Important changes in action potential duration distribution and repolarization sequence were reflected by a decreased spatial ventricular gradient magnitude and increased QRS-T spatial angle. On day 25, LV-to-RV fractional shortening ratio was increased, and RV hypertrophy was found, but not on day 14. In conclusion, developing PAH is characterized by early ECG changes preceding RV hypertrophy, whereas severe PAH is marked by profound ECG changes associated with anatomical and functional changes in the RV. Three-dimensional ECG analysis appears to be very sensitive to early changes in RV afterload. [ABSTRACT FROM AUTHOR]