Electrocardiography at diagnosis and close to the time of death in pulmonary arterial hypertension

Electrocardiographic Prognostic Marker in Pulmonary Arterial Hypertension: RS Time

BACKGROUND

Pulmonary hypertension is a condition that involves the remodeling of the right ventricle. Ongoing remodeling is also associated with disease prognosis. During the restructuring process, complex changes such as hypertrophy and dilatation may also be reflected in electrocardiographic parameters.

OBJECTIVES

Our study aimed to investigate the relationship between prognosis and electrocardiographic parameters in patients with pulmonary arterial hypertension.

METHODS

The study was designed retrospectively and included patients diagnosed with pulmonary arterial hypertension between 2010 and 2022. The patients were divided into two groups based on their survival outcome. Various parameters, including electrocardiographic, demographic, echocardiographic, catheter, and blood parameters, were compared between the two groups. A p-value of <0.05 was considered statistically significant.

RESULTS

In the multivariate Cox analyses, the parameters that were found to be independently associated with survival were the 6-minute walk test, mean pulmonary artery pressure, presence of pericardial effusion, and time between the beginning of the QRS and the peak of the S wave (RS time) (p<0.05 for each). Of all the parameters, RS time demonstrated the best diagnostic performance (AUC:0.832). In the survival analysis, a significant correlation was found between RS time and survival when using a cut-off value of 59.5 ms (HR: 0.06 [0.02-0.17], p < 0.001).

CONCLUSIONS

According to the results of our study, a longer RS time is associated with poor prognosis in patients with pulmonary arterial hypertension. We can obtain information about the course of the disease with a simple, non-invasive parameter.

Cardiac Arrhythmias in Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension: Mechanistic Insights, Pathophysiology, and Outcomes

Arrhythmias are increasingly recognized as severe complications of precapillary pulmonary hypertension, encompassing pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Despite their significant contribution to symptoms, morbidity, in-hospital mortality, and potentially sudden death in PAH/CTEPH, there remains a lack of comprehensive data on epidemiology, pathophysiology, and outcomes to inform the management of these patients. This review provides an overview of the latest evidence on this subject, spanning from the molecular mechanisms underlying arrhythmias in the hypertrophied or failing right heart to the clinical aspects of epidemiology, diagnosis, and treatment.

The Early Detection of Pulmonary Hypertension

BACKGROUND

Up to 1% of the world population and 10% of all persons over age 65 suffer from pulmonary hypertension (PH). The latency from the first symptom to the diagnosis is more than one year on average, and more than three years in 20% of patients. 40% seek help from more than four different physicians until their condition is finally diagnosed.

METHODS

This review is based on publications retrieved by a selective literature search on pulmonary hypertension.

RESULTS

The most common causes of pulmonary hypertension are left heart diseases and lung diseases. Its cardinal symptom is exertional dyspnea that worsens as the disease progresses. Additional symptoms of right heart failure are seen in advanced stages. Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are rare, difficult to diagnose, and of particular clinical relevance because specific treatments are available. For this reason, strategies for the early detection of PAH and CTEPH have been developed. The clinical suspicion of PH arises in a patient who has nonspecific symptoms, electrocardiographic changes, and an abnormal (NT-pro-)BNP concentration. Once the suspicion of PH has been confirmed by echocardiography and, if necessary, differential-diagnostic evaluation with a cardiopulmonary stress test, and after the exclusion of a primary left heart disease or lung disease, the patient should be referred to a PH center for further diagnostic assessment, classification, and treatment.

CONCLUSION

If both the (NT-pro-)BNP and the ECG are normal, PH is unlikely. Knowledge of the characteristic clinical manifestations and test results of PH is needed so that patients can be properly selected for referral to specialists and experts in PH.

Remembering the Occam's Razor: Could Simple Electrocardiographic Findings Provide Relevant Predictions for Current Hemodynamic Criteria of Pulmonary Hypertension?

BACKGROUND

We evaluated the predictive value of electrocardiographic (ECG) findings for pulmonary hemodynamics assessed by right heart catheterization (RHC).

METHODS

Our study population comprised 562 retrospectively evaluated patients who underwent RHC between 2006 and 2022. Correlations between ECG measures and pulmonary arterial systolic and mean pressures (PASP and PAMP) and pulmonary vascular resistance (PVR) were investigated. Moreover, receiver operating characteristic (ROC) curve analysis assessed the predictive value of ECG for pulmonary hypertension (PH) and precapillary PH.

RESULTS

The P-wave amplitude (Pwa) and R/S ratio (r) in V1 and V2, Ra in augmented voltage right (aVR), right or indeterminate axis, but not P wave duration (Pwd) or right bundle branch block (RBBB) significantly correlated with PASP, PAMP, and PVR (P <.001 for all). The partial R2 analysis revealed that amplitude of R wave (Ra) in aVR, R/Sr in V1 and V2, QRS axis, and Pwa added to the base model provided significant contributions to variance for PASP, PAMP, and PVR, respectively. The Pwa > 0.16 mV, Ra in aVR > 0.05 mV, QRS axis > 100° and R/Sr in V1 > 0.9 showed the highest area under curve (AUC) values for PAMP > 20 mm Hg. Using the same cutoff value, Ra in aVR, Pwa, QRS axis, and R/Sr in V1 showed highest predictions for PVR > 2 Wood Units (WU).

CONCLUSION

In this study, Pwa, Ra in aVR, right or indeterminate axis deviations, and R/Sr in V1 and V2 showed statistically significant correlations with pulmonary hemodynamics, and Ra in aVR, R/Sr in V2 and V1, QRS axis, and Pwa contributed to variance for PASP, PAMP, and PVR, respectively. Moreover, Pwa, Ra in aVR, QRS axis, and R/Sr in V1 seem to provide relevant predictions for PH and precapillary PH.

Electrocardiographic changes after balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension: Data from the Hellenic Registry

BACKGROUND

Balloon pulmonary angioplasty (BPA) has provided an effective invasive treatment for inoperable patients with chronic thromboembolic pulmonary hypertension (CTEPH). The hemodynamic improvement achieved by BPA has significantly increased the long-term prognosis of these patients, mostly by reversing the negative remodeling of the right ventricle (RV).

MATERIALS AND METHODS

In a cohort of 17 patients with symptomatic CTEPH hemodynamic data were collected before and after the completion of BPA sessions. After the confirmation of statistically significant hemodynamic improvement, we examined the changes in certain prespecified electrocardiographic (ECG) parameters (PR interval duration, QRS duration, QTc interval duration, R wave and S wave amplitude in lead I, R wave and S wave amplitude in precordial leads V1, V5 and V6) before the initiation and one month after the completion of BPA sessions. In addition, ECGs were qualitatively assessed before and after treatment for the presence of ECG abnormalities related to PH, proposed by the guidelines of the European Society of Cardiology (ESC). The term ESC criteria 1-6 was used for their description.

RESULTS

Statistically significant correlation (p < 0.05) was found between the reduction in mean pulmonary artery pressure (mPAP) and the decrease of the depth of the S wave in leads I (p 0.0069), V5 (p 0.0003), V6 (p 0.0011) and in the R wave amplitude in leads V5 (p 0.0122) and V6 (p 0.0185). From the ESC criteria, RV strain pattern was the commonest in the initial cohort, with significant improvement after therapies.

CONCLUSION

Hemodynamic improvement after BPA therapies is correlated with improved ECG amplitude parameters in leads I, V5 and V6. RV strain pattern is common among untreated patients with significant improvement after therapies.

Analysis of Electrocardiographic Criteria of Right Ventricular Hypertrophy in Patients with Chronic Thromboembolic Pulmonary Hypertension before and after Balloon Pulmonary Angioplasty

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) may lead to typical electrocardiographic changes that can be reversed by balloon pulmonary angioplasty (BPA). The aim of this study was to investigate the significance of rarely used electrocardiogram (ECG) parameters, possible electrocardiographic differences between residual and significantly improved CTEPH and the role of electrocardiographic parameters in low mPAP (mean pulmonary arterial pressure) ranges since the mPAP threshold for the definition of pulmonary hypertension has recently been adjusted (≥25 mmHg to >20 mmHg).

MATERIAL AND METHODS

Between March 2014 and October 2020, 140 patients with CTEPH and 10 with CTEPD (chronic thromboembolic pulmonary disease) without pulmonary hypertension (PH) were retrospectively enrolled (12-lead ECG and right heart catheterization before and 6 months after BPA). The ECG parameters of right heart strain validated by studies and clinical experience were evaluated. Special attention was paid to six specific ECG parameters. After BPA, the cohort was divided into subgroups to investigate possible electrocardiographic differences with regard to the haemodynamic result.

RESULTS

The present study confirmed that the typical electrocardiographic signs of CTEPH can be found on an ECG, can regress after BPA and partially correlate well with haemodynamic parameters. "R V1, V2 + S I, aVL - S V1" was a parameter of particular note. BPA reduced its frequency (47% vs. 29%) statistically significantly after Bonferroni correction (p < 0.001). Moreover, it showed a good correlation with mPAP and PVR (r-values: 0.372-0.519, p-values: < 0.001). Exceeding its cut-off value before therapy was associated with more severe CTEPH before therapy (higher mPAP, PVR, NT-pro-BNP and troponin and lower TAPSE) and an increased risk of death. Exceeding its cut-off value before and after therapy was associated with more severe CTEPH after therapy (higher RAP, mPAP, PVR, NT-pro-BNP and NYHA class) and an increased risk of death. Men tend to be affected more frequently. After subgrouping, it was observed that a higher median mPAP was associated with a higher right atrial pressure (RAP), a higher pulmonary vascular resistance (PVR) and a lower cardiac output (CO) before and after BPA. In addition, under these conditions, more and more severe electrocardiographic pathologies were detected before and after BPA. Some patients with low mPAP also continued to show mild ECG changes after BPA. In some cases, very few to no pathological ECG changes were detected, and the ECG could present as mostly normal in some patients (5% before BPA and 13% after BPA).

CONCLUSION

"R V1, V2 + S I, aVL - S V1" seems to be able to support the diagnosis of CTEPH, indicate therapeutic improvement and estimate haemodynamics. It also seems capable of predicting a (persistent) severe disease with probably increased need for therapy and increased mortality. Mild PH has been observed to have either no or few mild ECG changes. This might complicate the (early) detection of PH.

Electrocardiogram in patients with pulmonary hypertension

INTRODUCTION

Pulmonary hypertension (PH) is a potentially life-threatening cardiovascular disease defined by a mean pulmonary arterial pressure (mPAP) > 20 mmHg. Due to non-specific symptoms, PH is often diagnosed late and at advanced stage. In addition to other diagnostic modalities, the electrocardiogram (ECG) can help in establishing the diagnosis. Knowledge of typical ECG signs could help to detect PH earlier.

METHODS

A non-systematic literature review on the typical electrocardiographic patterns of PH was performed.

RESULTS

Characteristic signs of PH include right axis deviation, SIQIIITIII and SISIISIII patterns, P pulmonale, right bundle branch block, deep R waves in V1 and V2, deep S waves in V5 and V6, and right ventricular hypertrophy (R in V1 + S in V5, V6 > 1,05 mV). Repolarisation abnormalities such as ST segment depressions or T wave inversions in leads II, III, aVF, and V1 to V3 are common as well. Furthermore, a prolonged QT/QTc interval, an increased heart rate, or supraventricular tachyarrhythmias can be observed. Some parameters may even provide information about the patient's prognosis.

CONCLUSION

Not every PH patient shows electrocardiographic PH signs, especially in mild PH. Thus, the ECG is not useful to completely rule out PH, but provides important clues to PH when symptoms are present. The combination of typical ECG signs and the co-occurrence of electrocardiographic signs with clinical symptoms and elevated BNP levels are particularly suspicious. Diagnosing PH earlier could prevent further right heart strain and improve patient prognosis.

Association of Electrocardiographic Signs of Right Ventricular Hypertrophy and Clot Localization in Chronic Thromboembolic Pulmonary Hypertension

The role of electrocardiography (ECG) in chronic thromboembolic pulmonary hypertension (CTEPH) diagnosis and prognosticating has not been yet established. We aimed to assess the relationships of the recommended ECG criteria of right ventricular hypertrophy (RVH) with clot localization in CTEPH patients. ECG patterns of RVH according to the American College of Cardiology Foundation were assessed in patients with newly diagnosed CTEPH. We enrolled 58 (45.3%) patients with proximal and 70 (54.7%) with distal CTEPH. Receiver-operating characteristics curves analysis indicated that the following ECG abnormalities predicted proximal CTEPH localization: R_V1 > 6 mm—AUC 0.75 (CI: 0.66–0.84, p < 0.00001); S_V6 > 3 mm—AUC 0.70 (CI: 0.60–0.79, p < 0.00001); S_I > R_I wave—AUC 0.67 (CI: 0.58–0.77, p = 0.0004); R_V1:S_V1 > 1.0—AUC 0.66 (CI: 0.56–0.76, p = 0.0009); R_V1 peak > 0.035 s (QRS < 120 ms)—AUC 0.66 (CI: 0.56–0.75, p = 0.0016); R_V1:S_V1 > R_V3(V4):S_V3(V4)—AUC-0.65 (CI: 0.54–0.75, p = 0.0081); R_aVR > 4 mm—AUC 0.62 (CI: 0.52–0.71, p = 0.002) and P_II > 2.5 mm—AUC 0.62 (CI: 0.52–0.72, p = 0.00162). Pulmonary vascular resistance significantly correlated with amplitudes of R_V1 (r = 0.34, p = 0.008), S_V6 (r = 0.53, p = 0.000027) and P_II (r = 0.44, p = 0.00007). In patients with CTEPH, only 8 out of 23 ECG RVH criteria were useful for differentiating between proximal and distal CTEPH localization and we found that R_V1 and S_V6 may contribute as potential discriminators.

ECG in the clinical and prognostic evaluation of patients with pulmonary arterial hypertension: an underestimated value

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare disease leading to right ventricular (RV) failure and manifests in decreasing exercise tolerance. Our study aimed to assess the usefulness of electrocardiographic parameters reflecting right heart hypertrophy as predictors of clinical status in PAH.

METHODS

The retrospective analysis included 26 patients, mean 49 ± 17 years of age, diagnosed with PAH, and eligible to undergo cardiopulmonary exercise test (CPET). The relations between ECG values and parameters obtained in procedures such as six-minute walk test (6-MWT), echocardiography, right heart catheterization (RHC), and CPET were analyzed.

RESULTS

P-wave amplitude in lead II correlated positively with CPET parameter of respiratory response: minute ventilation to carbon dioxide production slope (VE/VCO₂ slope; r = 0.436, p = 0.029) and echocardiographic estimated RA pressure (RAP; r = 0.504, p = 0.02). RV Sokolow-Lyon index (RVSLI) positively correlated with echocardiographic parameters reflecting RV function, overload, and afterload-tricuspid regurgitation pressure gradient (TRPG; r = 0.788, p < 0.001), RV free wall thickness (r = 0.738, p < 0.001), and mean pulmonary arterial pressure (mPAP_ECHO; r = 0.62, p = 0.0016), respectively, as well as VE/VCO₂ slope (r = 0.593, p = 0.001) and mPAP assessed directly in RHC (mPAP_RHC; r = 0.469, p = 0.0497). R-wave in lead aVR correlated positively with TRPG (r = 0.719, p < 0.001), mPAP_ECHO (r = 0.446, p = 0.033), and several hemodynamic criteria of PAH diagnosis: positively with mPAP_RHC (r = 0.505, p = 0.033) and pulmonary vascular resistance (r = 0.554, p = 0.026) and negatively with pulmonary capillary wedge pressure (r = -0.646, p = 0.004). QRS duration correlated positively with estimated RAP (r = 0.589, p = 0.004), vena cava inferior diameter (r = 0.506, p = 0.016), and RA area (r = 0.679, p = 0.002) and negatively with parameters of exercise capacity: peak VO₂ (r = -0.486, p = 0.012), CPET maximum load (r = - 0.439, p = 0.025), and 6-MWT distance (r = -0.430, p = 0.046). ROC curves to detect intermediate/high 1-year mortality risk (based on ESC criteria) indicate RVSLI (cut-off point: 1.57 mV, AUC: 0.771) and QRS duration (cut-off points: 0.09 s, AUC: 703 and 0.1 s, AUC: 0.759) as relevant predictors.

CONCLUSION

Electrocardiography appears to be an important and underappreciated tool in PAH assessment. ECG corresponds with clinical parameters reflecting PAH severity.

Is derived vectorcardiography a potential screening tool for pulmonary hypertension?

BACKGROUND

Patients with atrial septal defects and pulmonary hypertension would benefit from early identification and treatment of pulmonary hypertension prior to closure. Noninvasive screening tools for pulmonary hypertension are inadequate. Electrocardiography, though readily available, has so far been of limited screening utility in patients with pulmonary hypertension. We hypothesize that derived vectorcardiographic parameters will aid in identifying increased right ventricular afterload and thus provide an additional screening tool for pulmonary hypertension in patients with secundum atrial septal defects.

OBJECTIVE

Establish whether vectorcardiography can be used to screen for pulmonary hypertension.

METHODS

A retrospective review of patients with secundum atrial septal defects (ASD) who underwent cardiac catheterization at the University of Minnesota from 2012 to 2020 was performed. We excluded patients with other congenital heart diagnoses, insufficient hemodynamic data, or lacking sinus rhythm electrocardiogram at time of cardiac catheterization. Parameters analyzed included: Sokolow-Lion right ventricular hypertrophy criteria, PR duration, QRS duration, corrected QT intervals, QRS and T wave frontal plane axes, rSR', R' amplitude, as well as vectorcardiographic parameters (Kors regression-related method), the QRS vector magnitude, T wave vector magnitude, and the spatial QRS-T angle. These were compared to measures of pulmonary hypertension obtained at cardiac catheterization.

RESULTS

The spatial QRS-T angle significantly differentiated ASD patients with pulmonary hypertension (median 104 degrees, interquartile range 55-137 degrees) from ASD patients without pulmonary hypertension (median 37 degrees, interquartile range 21-63 degrees, p-value of 0.002). At a cut-off of 124 degrees, the positive and negative predictive values for identification of pulmonary hypertension were 36.4% and 96.4%, respectively, with an odds ratio of 13.4 (95% confidence interval of 2.9 to 63.7). The positive predictive value was significantly improved when combined with echocardiographic data to screen for pulmonary hypertension.

CONCLUSION

The spatial QRS-T angle is associated with pulmonary hypertension in patients with secundum atrial septal defects.

Electrocardiographic changes in Emphysema

Chronic obstructive lung disease (COPD), predominantly emphysema, causes several thoracic anatomical and hemodynamic changes which may cause changes in various electrocardiographic parameters. A 12-lead electrocardiogram (ECG), which is often a part of routine evaluation in most clinical settings, may serve as a useful screening modality for diagnosis of COPD or emphysema. Our current article aims to provide a comprehensive review of the electrocardiographic changes encountered in COPD/emphysema utilizing published PubMed and Medline literature database. Several important ECG changes are present in COPD/emphysema and may serve as a good diagnostic tool. Verticalization of P-vector, changes in QRS duration, pattern recognition of precordial R-wave progression and axial shifts can be considered some of the most valuable markers among other changes. In conclusion, 12-lead surface electrocardiogram can serve as a valuable tool for the diagnosis of COPD and/or emphysema. An appropriate knowledge of these ECG changes can not only help in the diagnosis but can also immensely help in an appropriate clinical management of these patients.

Assessment of Clinical Usefulness of Resting Electrocardiogram (PH-ECG Score) in Monitoring the Efficacy of Balloon Pulmonary Angioplasty (BPA) in Patients with Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

BACKGROUND

Balloon pulmonary angioplasty (BPA) is a form of therapy for chronic thromboembolic pulmonary hypertension (CTEPH). The study objective is to assess the clinical usefulness of resting ECG (PH-ECG score) in monitoring the efficacy of BPA in CTEPH patients.

METHODS AND RESULTS

Ninety-four (n = 94) CTEPH patients were included in the analysis. A standard 12-lead-ECG was performed before the first BPA session and after completion of treatment. The whole analysed population (n = 94) was divided into the following two groups: derivation cohort (n = 41) and validation cohort (n = 53). The derivation cohort was divided into the following two subgroups: patients with mean pulmonary artery pressure (mPAP) after the completion of therapy < 25 mmHg (n = 21) and patients with mPAP after the completion of therapy ≥ 25 mmHg (n = 20). In the first subgroup, four (R-wave V1 + S-wave V5/V6 > 10.5 mm, QRS-wave axis > 110 degrees, R-wave V1 > S-wave V1, SIQIII pattern) of the six ECG parameters of overload of the right cardiac chambers showed statistically significant differences (p < 0.005). That was followed by a determination of the sensitivity and specificity, positive (PPV) and negative predictive value (NPV), and ROC curve (AUC 0.9; 95% CI: 0.792-1.000) for the variable that was a sum of the above four ECG parameters (PH-ECG score). The absence of all of the four ECG parameters at rest (PH-ECG score = 0) well reflected patients with mPAP < 25 mmHg (sensitivity, 100%; specificity, 80%; PPV, 84%; NPV, 100%). In the validation cohort with mPAP < 25 mmHg and PH-ECG score = 0, sensitivity, specificity, PPV, and NPV were 86%, 77%, 73%, and 89%, respectively.

CONCLUSIONS

Resting ECG trace is clinically useful in the monitoring of therapeutical effects of BPA in CTEPH patients.

The prediction of right atrial pressure using electrocardiogram: a novel approach

Aims

Pulmonary hypertension (PH) is a serious disorder that can complicate pulmonary and cardiovascular diseases. Right atrial (RA) pressure is a robust predictor of the pulmonary hypertension severity, which is measured via right heart catheterization. Limited studies have been carried out to assess the association between electrocardiogram data and the RA pressure as a prognostic factor of PH. In this study, the relation between P wave and PR segment changes with RA pressure was evaluated.

Methods and results

In this study, 94 patients in PH groups of 1, 3, and 4, based on the World Health Organization classification, were entered. RA pressure was measured using the right heart catheterization. PR segment and P wave morphology in leads II and V₁ were evaluated in patient's electrocardiogram. The median age of the patients was 35.5 years old in which 64.9% of them were female. The distribution of patients in groups 1, 3, and 4 PH were 77.7%, 5.3%, and 17%, respectively. Among the studied P wave and PR segment changes, PR segment depression in lead II and pulmonary P wave in lead V₁ had significant relation with the RA pressure (P‐value <0.001). The sensitivity, specificity, and negative predictive values of PR segment depression for detection of patients with high RA pressure (RA pressure > 14 mmHg) were 80%, 84%, and 94%. The specificity and negative predictive values of pulmonary P wave in lead V₁ were determined 89% and 88%.

Conclusions

It was found that the PR segment depression in lead II and pulmonary P wave in lead V₁ associate with the RA pressure in patients with precapillary PH. PR segment depression had useful sensitivity, specificity, and negative predictive values, and the pulmonary P wave in lead V₁ had acceptable specificity and negative predictive values for detection of patients with high RA pressure. Therefore, the electrocardiogram can be used as a screening tool for determination of pulmonary hypertension severity.

Extended Precordial T Wave Inversions Are Associated with Right Ventricular Enlargement and Poor Prognosis in Pulmonary Hypertension

In pulmonary hypertension (PH), T wave inversions (TWI) are typically observed in precordial leads V1–V3 but can also extend further to the left-sided leads. To date, the cause and prognostic significance of this extension have not yet been assessed. Therefore, we aimed to assess the relationship between heart morphology and precordial TWI range, and the role of TWI in monitoring treatment efficacy and predicting survival. We retrospectively analyzed patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) treated in a reference pulmonary hypertension center. Patients were enrolled if they had a cardiac magnetic resonance (cMR) and 12-lead surface ECG performed at the time of assessment. They were followed from October 2008 until March 2021. We enrolled 77 patients with PAH and 56 patients with inoperable CTEPH. They were followed for a mean of 51 ± 33.5 months, and during this time 47 patients died (35.3%). Precordial TWI in V1–V6 were present in 42 (31.6%) patients, while no precordial TWI were observed only in 9 (6.8%) patients. The precordial TWI range correlated with markers of PH severity, including right ventricle to left ventricle volume RVEDVLVEDV (R = 0.76, p < 0.0001). The presence of TWI in consecutive leads from V1 to at least V5 predicted severe RV dilatation (RVEDVLVEDV ≥ 2.3) with a sensitivity of 88.9% and specificity of 84.1% (AUC of 0.90, 95% CI = 0.83–0.94, p < 0.0001). Presence of TWI from V1 to at least V5 was also a predictor of mortality in Kaplan–Meier estimation (p = 0.02). Presence of TWI from V1 to at least V5 had a specificity of 64.3%, sensitivity of 58.1%, negative predictive value of 75%, and positive predictive value of 45.5% as a mortality predictor. In patients showing a reduction in TWI range of at least one lead after treatment compared with patients without this reduction, we observed a significant improvement in RV-EDV and RV−EDVLV−EDV. We concluded that the extension of TWI to left-sided precordial leads reflects significant pathological alterations in heart geometry represented by an increase in RV/LV volume and predicts poor survival in patients with PAH and CTEPH. Additionally, we found that analysis of precordial TWI range can be used to monitor the effectiveness of hemodynamic response to treatment of pulmonary hypertension.

Chronic Thromboembolic Pulmonary Hypertension - What Have We Learned From Large Animal Models

Chronic thrombo-embolic pulmonary hypertension (CTEPH) develops in a subset of patients after acute pulmonary embolism. In CTEPH, pulmonary vascular resistance, which is initially elevated due to the obstructions in the larger pulmonary arteries, is further increased by pulmonary microvascular remodeling. The increased afterload of the right ventricle (RV) leads to RV dilation and hypertrophy. This RV remodeling predisposes to arrhythmogenesis and RV failure. Yet, mechanisms involved in pulmonary microvascular remodeling, processes underlying the RV structural and functional adaptability in CTEPH as well as determinants of the susceptibility to arrhythmias such as atrial fibrillation in the context of CTEPH remain incompletely understood. Several large animal models with critical clinical features of human CTEPH and subsequent RV remodeling have relatively recently been developed in swine, sheep, and dogs. In this review we will discuss the current knowledge on the processes underlying development and progression of CTEPH, and on how animal models can help enlarge understanding of these processes.

A new electrocardiographic concept: V1-V2-V3 are not only horizontal, but also frontal plane leads

According to conventional teaching, the limb leads in the electrocardiogram (ECG) represent the frontal plane electrical vectors of the heart, whereas the chest leads signify the horizontal plane. The anterior chest leads V1-V2-V3, however, also have strong frontal plane representation which can result in morphological similarities in these leads to the augmented unipolar leads of the Einthoven triangle. This review highlights the significance of recognizing V1-V2-V3 as not only horizontal, but also as frontal plane leads. Appreciation of this phenomenon helps elucidate a colorful variety of clinically important but seemingly bizarre ECG manifestations that could not be explained otherwise.

Comparison of Mobile Application-Based ECG Consultation by Collective Intelligence and ECG Interpretation by Conventional System in a Tertiary-Level Hospital

BACKGROUND AND OBJECTIVES

A mobile application (app)-based electrocardiogram (ECG) consultation system (InterMD Co., Ltd., Seoul, Korea) using the collective intelligence (CI) and the availability of large-scale digitized ECG data would extend the utility of ECGs beyond their current limitations, while at the same time preserving interpretability that remains critical to medical decision-making.

METHODS

We developed a new mobile app-based ECG consultation system by CI for general practitioners. We compared the responses of ECG reading between the mobile app-based CI system and the conventional system in a tertiary referring hospital.

RESULTS

We analyzed 376 consecutive ECGs between December 2017 and May 2019. Of these, 159 ECGs (42.3%) were interpreted by CI through the mobile app-based ECG consultation system and 217 ECGs (57.7%) were analyzed by cardiologists in the conventional systems based on electronic medical record data in a tertiary hospital. All ECG readings were confirmed by an electrophysiologist (EP). The time to an initial response by the CI system was faster than that of the conventional system (6.6 hours vs. 35.8 hours, p<0.0001). The number of responses of each ECG in CI system outnumbered those of the conventional system in the tertiary hospital (3.1 vs. 1.2, p<0.0001). The consensus of the ECG readings with EP was similar in both systems (98.6% vs. 100%, p=0.158).

CONCLUSIONS

The mobile app-based ECG consultation system by CI is as reliable method as the conventional referral system. It would expand the app of the 12-lead ECG with the collaboration of physicians in clinics and hospitals without time and space constraints.

Assessment of electrocardiographic markers of acute and long-term hemodynamic improvement in patients with pulmonary hypertension

Background

The remodeling of the right heart in patients with chronic pulmonary hypertension (cPH) is associated with the appearance of electrocardiographic (ECG) abnormalities. We investigated the resolution of ECG markers of right ventricular hypertrophy (RVH) caused by acute and long‐term hemodynamic improvement.

Methods

Twenty‐nine (29) patients with chronic thromboembolic pulmonary hypertension (CTEPH) and seven patients with pulmonary arterial hypertension (PAH) were included in the analysis. Patients with CTEPH achieved a significant long‐term hemodynamic improvement following the treatment with balloon pulmonary angioplasty (BPA); all the patients with PAH reported significant acute hemodynamic relief after a single inhalation of iloprost, fulfilling the criteria of responder. Standard 12‐lead ECG was performed before and after intervention.

Results

The interval between baseline and control ECG in CTEPH and PAH groups was 28 (IQR: 17–36) months and 15 min (IQR: 11–17), respectively. Despite similar hemodynamic improvement in both groups, only the CTEPH group presented significant changes in most analyzed ECG parameters: T‐wave axis (p = .002), QRS‐wave axis (p = .012), P‐wave amplitude (p < .001) and duration in II (p = .049), R‐wave amplitude in V₁ (p = .017), R:S ratio in V₁ (p = .046), S‐wave amplitude in V₅ (p = .004), R‐wave amplitude in V₅ (p = .044), R:S ratio in V₅ (p = .004), S‐wave amplitude in V₆ (p = .026), R‐wave amplitude in V₆ (p = .01), and R‐wave amplitude in aVR (p = .031). In patients with PAH, significant differences were found only for P wave in II (duration: p = .035; amplitude: p = .043) and QRS axis (p = .018).

Conclusions

The effective treatment of cPH ensures improvement in ECG parameters of RVH, but it requires extended time.

Automated and Interpretable Patient ECG Profiles for Disease Detection, Tracking, and Discovery

BACKGROUND

The ECG remains the most widely used diagnostic test for characterization of cardiac structure and electrical activity. We hypothesized that parallel advances in computing power, machine learning algorithms, and availability of large-scale data could substantially expand the clinical inferences derived from the ECG while at the same time preserving interpretability for medical decision-making.

METHODS AND RESULTS

We identified 36 186 ECGs from the University of California, San Francisco database that would enable training of models for estimation of cardiac structure or function or detection of disease. We segmented the ECG into standard component waveforms and intervals using a novel combination of convolutional neural networks and hidden Markov models and evaluated this segmentation by comparing resulting electrical intervals against 141 864 measurements produced during the clinical workflow. We then built a patient-level ECG profile, a 725-element feature vector and used this profile to train and interpret machine learning models for examples of cardiac structure (left ventricular mass, left atrial volume, and mitral annulus e-prime) and disease (pulmonary arterial hypertension, hypertrophic cardiomyopathy, cardiac amyloid, and mitral valve prolapse). ECG measurements derived from the convolutional neural network-hidden Markov model segmentation agreed with clinical estimates, with median absolute deviations as a fraction of observed value of 0.6% for heart rate and 4% for QT interval. Models trained using patient-level ECG profiles enabled surprising quantitative estimates of left ventricular mass and mitral annulus e' velocity (median absolute deviation of 16% and 19%, respectively) with good discrimination for left ventricular hypertrophy and diastolic dysfunction as binary traits. Model performance using our approach for disease detection demonstrated areas under the receiver operating characteristic curve of 0.94 for pulmonary arterial hypertension, 0.91 for hypertrophic cardiomyopathy, 0.86 for cardiac amyloid, and 0.77 for mitral valve prolapse.

CONCLUSIONS

Modern machine learning methods can extend the 12-lead ECG to quantitative applications well beyond its current uses while preserving the transparency that is so fundamental to clinical care.

Pathophysiology, incidence, management, and consequences of cardiac arrhythmia in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

Arrhythmias are increasingly recognized as serious, end-stage complications of pre-capillary pulmonary hypertension, including pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Although arrhythmias contribute to symptoms, morbidity, in-hospital mortality, and possibly sudden death in PAH/CTEPH, there remains a paucity of epidemiologic, pathophysiologic, and outcome data to guide management of these patients. This review summarizes the most current evidence on the topic: from the molecular mechanisms driving arrhythmia in the hypertrophied or failing right heart, to the clinical aspects of epidemiology, diagnosis, and management.

Acute biventricular hemodynamic effects of cardiac resynchronization therapy in right bundle branch block

BACKGROUND

Controversy remains regarding the use of cardiac resynchronization therapy (CRT) in patients with heart failure with right bundle branch block (RBBB) and reduced left ventricular (LV) ejection fraction. Moreover, little is known about acute hemodynamic changes with CRT in this subgroup as compared with patients with left bundle branch block (LBBB).

OBJECTIVE

The purpose of this study was to evaluate the acute biventricular hemodynamic response of CRT and other pacing configurations, including the effects of atrioventricular (AV) delay and atrial pacing, to understand the effects of CRT in RBBB.

METHODS

Forty patients (9 with RBBB and 31 with LBBB) undergoing CRT implantation underwent temporary pacing with varying configurations and AV delay. The acute hemodynamic response was assessed via invasive measurements of dP/dt_max (maximal rate of change in pressure) in the left ventricle (LV) as well as the right ventricle (RV) in patients with RBBB.

RESULTS

Patients with LBBB had a greater LV dP/dt_max response to CRT than did patients with RBBB. In patients with RBBB, single- or dual-site RV pacing configurations resulted in greater increases in RV dP/dt_max than did biventricular pacing. Optimal AV delays that maximized RV dP/dt_max were shorter than optimal AV delays for LV dP/dt_max. Furthermore, AV delays chosen to maximize improvement in RV dP/dt_max frequently resulted in negative effects on LV dP/dt_max.

CONCLUSION

These findings demonstrate a complex relationship between pacing configuration, AV delay, and hemodynamic responses. The biventricular hemodynamic response in patients with heart failure with RBBB might be improved by optimizing pacing modalities and AV delays. This may be particularly important in patients with diseases in whom RV failure predominates, such as patients with pulmonary hypertension and LV assist device.

Change in R wave in lead V1 predicts survival of patients with pulmonary arterial hypertension

Clinical guidelines for pulmonary hypertension recommend evaluating treatment response through various methods; however, electrocardiography (ECG) is not included as one of the methods of choice. We aimed to identify ECG parameters that correlated with prognosis in patients with pulmonary arterial hypertension (PAH). A total of 112 consecutive patients with PAH were enrolled in this study. Among them, 83 with treatment escalation were studied for further analysis. Survival analyses were conducted using the Kaplan-Meier method with the log-rank test. Cox proportional hazards regression modeling was used to identify predictors of survival. Receiver operating characteristic analysis was used to determine cut-off values for selected variables. ECG parameters were changed from baseline to three months after treatment. Patients in whom the R wave amplitude in lead V1 decreased by ≥1 mm (0.1 mV) within three months demonstrated significantly better survival ( P = 0.017). Our results suggest that evaluation of ECG parameters can contribute to assessments of survival in patients with PAH.

ECG Markers of Hemodynamic Improvement in Patients with Pulmonary Hypertension

Introduction

Several diagnostic tests have been recommended for risk assessment in pulmonary hypertension (PH), but the role of electrocardiography (ECG) in monitoring of PH patients has not been yet established. Therefore the aim of the study was to evaluate which ECG patterns characteristic for pulmonary hypertension can predict hemodynamic improvement in patients treated with targeted therapies.

Methods

Consecutive patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) were eligible to be included if they had had performed two consecutive right heart catheterization (RHC) procedures before and after starting of targeted therapies. Patients were followed up from June 2009 to July 2017. ECG patterns of right ventricular hypertrophy according to American College of Cardiology Foundation were assessed.

Results

We enrolled 80 patients with PAH and 11 patients with inoperable CTEPH. The follow-up RHC was performed within 12.6 ± 10.0 months after starting therapy. Based on median change of pulmonary vascular resistance, we divided our patients into two subgroups: with and without significant hemodynamic improvement. R_V1, max⁡R_V1,2 + max⁡S_I,aVL − S_V1, and P_II improved along with the improvement of hemodynamic parameters including PVR. They predicted hemodynamic improvement with similarly good accuracy as shown in ROC analysis: R_V1 (AUC: 0.75; 95% CI: 0.63–0.84), P_II (AUC: 0.67, 95% CI: 0.56–0.77), and max⁡R_V1,2 + max⁡S_I,aVL − S_V1 (0.73; 95% CI: 0.63–0.82). In Cox regression only change in R_V1 remained significant mortality predictor (HR: 1.12, 95% CI: 1.01–1.24).

Conclusion

Electrocardiogram may be useful in predicting hemodynamic effects of targeted therapy in precapillary pulmonary hypertension. Decrease of R_V1, max⁡R_V1,2 + max⁡S_I,aVL − S_V1, and P_II corresponds with hemodynamic improvement after treatment. Of these changes a decrease of R wave amplitude in V₁ is associated with better survival.

Use of ECG and Other Simple Non-Invasive Tools to Assess Pulmonary Hypertension

Background

There is a broad consensus that pulmonary hypertension (PH) is to be diagnosed by right heart catheterization (RHC) and that the most important non-invasive tool is echocardiography. However, the role of simple non-invasive tools in the work-up of PH is not clearly defined. We hypothesized that the use of simple non-invasive techniques may help to guide important decisions in the diagnostics of pulmonary hypertension.

Objectives

We aimed to develop an algorithm with the use of simple, non-invasive tools in order to identify patients with very high or very low likelihood of PH.

Methods

We retrospectively analyzed all consecutive patients undergoing RHC between 2005 and 2010 in our center and performed logistic regression of simple non-invasive parameters regarding detection and exclusion of PH and derived a two-step algorithm. In a prospective study we evaluated this algorithm between 2011 and 2013.

Results

The retrospective cohort consisted of n = 394 patients of which 49% presented with PH. Right axis deviation in the ECG was present in 90/394 patients and had a positive predictive value (PPV) of 93% for PH. The combination of non-right axis deviation, N-terminal pro brain natriuretic peptide (NT-proBNP)<333pg/ml, arterial oxygen saturation (SO₂)≥95.5% and WHO functional class I-II was present in 69/394 patients and excluded PH with a negative predictive value (NPV) of 96%. The prospective study confirmed these results in a cohort of n = 168 patients (PPV:92%, NPV:97%). Taken together, simple non-invasive tools allowed a prediction regarding the presence or absence of PH in 42% of patients with suspected PH.

Conclusion

ECG, NT-proBNP, SO₂ and WHO functional class may predict the presence or absence of PH in almost half of the patients with suspected PH, suggesting an important role for these variables in the work-up of patients at risk for PH.

Clinical Trial Registration

NCT01607502

Non-invasive screening for pulmonary hypertension in idiopathic pulmonary fibrosis

BACKGROUND

Pulmonary hypertension (PH) is a common complication of idiopathic pulmonary fibrosis (IPF) that is associated with poor prognosis. Noninvasive screening for PH in IPF patients is challenging and a combination of several noninvasive determinations can improve discrimination.

METHODS

We included 235 IPF patients who underwent right heart catheterization (RHC) as part of the lung transplant evaluation. We measured electrocardiographic (ECG) and echocardiographic variables as well as the pulmonary artery (PA) and ascending aorta (AA) diameters on chest CT. We recorded results of arterial blood gases (ABG), pulmonary function (PFT) and 6-min walk tests (6MWT).

RESULTS

Several variables were predictors of PH in IPF patients in univariable models including a lower arterial oxygenation and 6MWT distance; worse right ventricular (RV) function, rightward deviation of the QRS axis and a higher FVC/DLCOc ratio, PA/AA diameter ratio, and estimated RV systolic pressure. In multivariable analysis, a worse RV function and higher PA/AA ratio remained predictors of PH (c-index 0.75 (0.65-0.84)). Similarly, a worse RV function, a higher PA/AA ratio and a rightward QRS axis deviation were independent predictors of precapillary PH (c-index 0.86 (0.76-0.92)). A combination of PA/AA diameter ratio <1.1, a QRS axis <90° and normal RV function showed a negative predictive value of 85% for precapillary PH.

CONCLUSIONS

There are significant differences in ECG, echocardiographic, chest CT, PFT and ABG parameters between IPF patients with and without PH. However, these noninvasive tests alone or combination have limited discrimination ability for PH screening in IPF.

Changes in surface electrocardiogram in patients with chronic thromboembolic pulmonary hypertension undergoing pulmonary endarterectomy. Correlations with hemodynamic and echocardiographic improvements after surgery

BACKGROUND

The aim of the present study was to evaluate the changes of electrocardiographic (ECG) markers of right ventricular (RV) hypertrophy/overload in patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing pulmonary endarterectomy (PEA).

METHODS AND RESULTS

We evaluated 99 CTEPH patients who underwent PEA. P wave amplitude in DII, R wave amplitude in V1 and the number of patients with negative T wave in V1-V3 decreased significantly at 1month after surgery with no further change at 1year, in parallel with the rapid improvement in right heart hemodynamics. S wave amplitude in V1, R:S wave ratio in lead V6 and prevalence of SIQIII pattern improved significantly at 1year, in parallel with the progressive reverse remodeling of the right ventricle at echocardiography.

CONCLUSIONS

The study shows that some of the ECG markers of RV hypertrophy/overload better reflect RV hemodynamic overload while others better reflect the pathologic remodeling of the right ventricle.

Severity of arterial and chronic thromboembolic pulmonary hypertension is associated with impairment of heart rate turbulence

BACKGROUND

Heart rate turbulence (HRT) impairment is a validated and an independent indicator of cardiovascular death. There are limited data on HRT in pulmonary hypertension (PH), so we assessed potential HRT alterations in PH, especially in relation to its severity.

METHODS

Thirty-three out of 41 patients were enrolled in the study aged 49.7 ± 15.9 years (22 with arterial, 11 with chronic thromboembolic PH). Routine evaluations, right heart catheterization, and 24-hour Holter monitoring with heart rate variability and HRT assessment were performed.

RESULTS

HRT was significantly impaired in PH patients, as compared to 25 healthy controls: mean turbulence onset (TO) was -0.27% versus -2.60% (P < 0.0001), and median turbulence slope (TS) was 3.13 versus 13.5 msRR (P < 0.0001). Abnormal HRT (TO ≥ 0.0% and/or TS ≤ 2.5 ms/RR) was found in 63.3% of PH patients. Patients with PH and abnormal HRT presented more compromised functional, biochemical, and hemodynamic status than PH patients with normal TO and TS values. Multivariate stepwise regression analysis showed that TO value was related to oxygen desaturation <90% in 6-minute walking test (6-MWT; OR 0.41, P < 0.001) and was related to N-Terminal pro-B type Natriuretic Peptide concentration (OR 0.40, P < 0.001); TS was related to 6-MWT distance (OR 0.53, P < 0.0001).

CONCLUSIONS

Patients with arterial or chronic thromboembolic PH are characterized by significant impairment of HRT which is related to the disease severity. We hypothesize that patients with abnormal HRT could be considered as subjects with an increased risk of cardiovascular death, however, it needs further investigation.