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

Electrocardiographic Abnormalities and Their Association with Outcomes in Randomized Clinical Trials of Pulmonary Arterial Hypertension

Rationale: Pulmonary arterial hypertension (PAH) is a progressive disease with manifestations including right atrial enlargement, right ventricular dysfunction, dilation, and hypertrophy. Electrocardiography (ECG) is a noninvasive, inexpensive test that is routinely performed in clinical settings. Prior studies have described separate abnormal findings in the electrocardiograms of patients with PAH. However, the role of composite ECG findings reflective of right heart disease (RHD) for risk stratification, clinical trial enrichment, and management of patients with PAH has not been explored. Objectives: To describe a pattern of RHD on ECG in patients with PAH and to investigate the association of this pattern with clinical measures of disease severity and outcomes. Methods: We harmonized individual participant data from 18 phase III randomized clinical trials of therapies for PAH (1998-2013) submitted to the U.S. Food and Drug Administration. RHD was defined as the presence of right ventricular hypertrophy, right axis deviation, right atrial enlargement, or right bundle branch block on ECG. Random effects linear regression, multilevel ordinal regression (cumulative link model), and Cox proportional hazards models were used to assess the association of RHD by ECG with 6-minute walk distance (6MWD), World Health Organization (WHO) functional class, and clinical worsening after a priori adjustment for age, sex, body mass index, and PAH etiology. Effect modification of treatment and ECG abnormalities was assessed by including an interaction term. Results: A total of 4,439 patients had baseline ECG, and 68% of patients had evidence of RHD. RHD on ECG was associated with higher pulmonary vascular resistance (P < 0.001) and higher mean pulmonary artery pressures (P < 0.001). Patients with RHD on ECG had 10 meters shorter 6MWD (P = 0.005) and worse WHO functional class (P < 0.001) at baseline. RHD on baseline ECG was associated with increased risk of clinical worsening (hazard ratio, 1.42; 95% confidence interval; 1.21, 1.67; P < 0.001). Patients with RHD had greater treatment effect in terms of 6MWD, WHO functional class, and time to clinical worsening than those without (P for interaction = 0.03, 0.001, and 0.03, respectively). Conclusions: RHD by ECG may be associated with worse outcomes and potentially greater treatment effect. Electrocardiograms could be an inexpensive, widely available noninvasive method to enrich clinical trial populations in PAH.

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.

Pulmonary Hypertension in Left Ventricular Valvular Diseases: A Comprehensive Review on Pathophysiology and Prognostic Value

Left ventricular (LV) valvular diseases, make up one of the most common etiologies for pulmonary hypertension (PH), and it is not well understood how and at which degree it affects prognosis. The aim of the present study was a comprehensive review of the pathophysiologic mechanism of PH in patients with LV valvular diseases and the prognostic value of baseline and post-intervention PH in patients undergoing interventional treatment. The pathophysiology of PH in patients with LV valvular diseases involves gradual elevation of left ventricular filling pressure and left atrial pressure, which are passively transmitted to the pulmonary circulation and raise pulmonary artery systolic pressure (PASP). A long-lasting exposure to elevated PASP progressively leads to initially functional and thereafter irreversible structural changes in the pulmonary vasculature, leading up to high pulmonary vascular resistance. Surgical treatment of severe LV valvular diseases is highly effective in patients without resting PH or those with exercise-induced PH (EIPH) before intervention. In the case of pre-operative PH, successful interventional therapy decreases PASP, but the post-operative cardiac and all-cause mortality remain higher compared to patients without pre-operative PH. Hence, it is of paramount importance to detect patients with severe LV valvulopathies before the development of PH, since they will get greater benefits from early intervention.

Electrocardiogram to Determine Mitral and Aortic Valve Opening and Closure

PURPOSE

Knowledge of the timing of cardiac valve opening and closing is important in cardiac physiology. The relationship between valve motion and electrocardiogram (ECG) is often assumed, however is not clearly defined. Here we investigate the accuracy of cardiac valve timing estimated using only the ECG, compared to Doppler echocardiography (DE) flow imaging as the gold standard.

METHODS

DE was obtained in 37 patients with simultaneous ECG recording. ECG was digitally processed and identifiable features (QRS, T, P waves) were examined as potential reference points to determine opening and closure of aortic and mitral valves, as compared to DE outflow and inflow measurement. Timing offset of the cardiac valves opening and closure between ECG features and DE was measured from derivation set (n = 19). The obtained mean offset in combination with the ECG features model was then evaluated on a validation set (n = 18). Using the same approach, additional measurement was also done for the right sided valves.

RESULTS

From the derivation set, we found a fixed offset of 22 ± 9 ms, 2 ± 13 ms, 90 ± 26 ms, and - 2 ± - 27 ms when comparing S to aortic valve opening, Tend to aortic valve closure, Tend to mitral valve opening, and R to mitral valve closure respectively. Application of this model to the validation set showed good estimation of aortic and mitral valve opening and closure timing value, with low model absolute error (median of the mean absolute error of the four events = 19 ms compared to the gold standard DE measurement). For the right-sided (tricuspid and pulmonic) valves in our patient set, there was considerably higher median of the mean absolute error of 42 ms for the model.

CONCLUSION

ECG features can be used to estimate aortic and mitral valve timings with good accuracy as compared to DE, allowing useful hemodynamic information to be derived from this easily available test.

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.