The relationship of QRS morphology with cardiac structure and function in patients with heart failure

Influence of Right and Left Bundle Branch Block in Patients With Cardiogenic Shock and Cardiac Arrest

OBJECTIVES

The study investigates the prognostic impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) in patients with cardiogenic shock (CS) compared with no bundle branch block (BBB). In patients with heart failure, existence of RBBB and LBBB has influence on prognosis.

DESIGN

Prospective registry-study.

SETTING

ICU of a tertiary academic hospital in Germany.

PATIENTS

Adult patients with CS.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Consecutive patients with CS were included. The prognostic impact of RBBB and LBBB on 30-day all-cause mortality was tested within the entire cohort and in the subgroup of CS patients with cardiac arrest at admission. The final study cohort comprised 248 patients. Patients with RBBB showed the highest 30-day all-cause mortality followed by LBBB and no BBB (72.5% vs. 52.9% vs. 50.0%; log-rank p = 0.015). These findings were consistent even after solely including CS patients with cardiac arrest (90.0% vs. 73.3% vs. 62.2%; log-rank p = 0.008). After adjustment for lactate, norepinephrine, troponin I, Acute Physiology Score, Society of Cardiovascular Angiography & Interventions shock stage, and heart rate in a multivariable Cox regression analysis, RBBB still revealed a negative impact on 30-day all-cause mortality (hazard ratio [HR], 1.807; 95% CI, 1.107-2.947; p = 0.018), whereas LBBB was not associated with 30-day all-cause mortality. In this multivariable Cox regression model lactate (HR, 1.065; 95% CI, 1.018-1.115; p = 0.006), troponin I (HR, 1.003; 95% CI, 1.001-1.005; p = 0.001), and Acute Physiology Score (HR, 1.033; 95% CI, 1.001-1.066; p = 0.041) were as well associated with 30-day all-cause mortality. Finally, no association of RBBB was found with the incidence of liver or severe renal failure.

CONCLUSIONS

Besides the Acute Physiology Score, lactate, and troponin levels, RBBB was associated with an increased 30-day all-cause mortality in consecutive CS patients with and without cardiac arrest, whereas LBBB showed no prognostic impact.

The prognostic value of right ventricular ejection fraction by cardiovascular magnetic resonance in heart failure: A systematic review and meta-analysis

BACKGROUND

Cardiac magnetic resonance (CMR) is considered the gold standard for the assessment of right ventricular ejection fraction (RVEF). Previous studies have suggested that RVEF may be a predictor of adverse outcomes in heart failure (HF). In this study, we aimed to systematically review the prognostic value of RVEF, evaluated by CMR, across the spectrum of left ventricular systolic function in patients with HF.

METHODS

Electronic databases were searched for studies investigating the prognostic value of RVEF in HF, irrespective of left ventricular ejection fraction (LVEF). A random-effects meta-analysis was conducted for mortality and HF hospitalization. Subgroup analyses were also performed based on the presence of reduced (<50%) or preserved LVEF (≥50%).

RESULTS

In total, 46 studies enrolling 14,344 patients were included. In the pooled analyses, impaired RVEF was a powerful predictor of mortality (HR: 1.26, 95% CI: 1.18-1.33, I²: 13%, per 10% decrease in RVEF) and death or HF hospitalization (HR: 1.31, 95% Cl: 1.2-1.42, I²: 27%, per 10% decrease in RVEF). A decrease in RVEF was strongly associated with increased risk of mortality or hospitalization both in HF with reduced EF (HR: 1.24, 95% CI: 1.13-1.36, I²: 2%, per 10% decrease in RVEF) and in HF with preserved EF (HR: 1.24, 95% CI: 1.09-1.40, I²: 0%, per 10% decrease in RVEF).

CONCLUSION

Impaired RVEF on CMR strongly predicts adverse outcomes in patients with HF regardless of LVEF. RV systolic function should be carefully evaluated in these patients. Prospero Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021256967.

Morphologies and prognostic significance of left ventricular volume/time curves with cardiac magnetic resonance in patients with non-ischaemic heart failure and left bundle branch block

Patients with non-ischaemic systolic heart failure (HF) and left bundle branch block (LBBB) can display a wide or narrow pattern (WP/NP) of the systolic phase of the left ventricular (LV) volume/time (V/t) curve in cardiac magnetic resonance (CMR). The clinical and prognostic significance of these patterns is unknown. Consecutive patients with non-ischaemic HF, LV ejection fraction < 50% and LBBB underwent 1.5 T CMR. Maximal dyssynchrony time (time between the earliest and latest end-systolic peaks), systolic dyssynchrony index (standard deviation of times to peak volume change), and contractility index (maximum rate of change of pressure-normalized stress) were calculated. The endpoint was a composite of cardiovascular death, HF hospitalization, and appropriate defibrillator shock. NP was found in 29 and WP in 72 patients. WP patients had higher volumes and NT-proBNP, and lower LVEF. WP patients had a longer maximal dyssynchrony time (absolute duration: 192 ± 80 vs. 143 ± 65 ms, p < 0.001; % of RR interval: 25 ± 11% vs. 8 ± 4%, p < 0.001), a higher systolic dyssynchrony index (13 ± 4 vs. 7 ± 3%, p < 0.001), and a lower contractility index (2.6 ± 1.2 vs 3.2 ± 1.7, p < 0.05). WP patients had a shorter survival free from the composite endpoint regardless of age, NT-proBNP or LVEF. Nonetheless, WP patients responded more often to cardiac resynchronization therapy (CRT) than those with NP (24/28 [86%] vs. 1/11 [9%] responders, respectively; p < 0.001). In patients with non-ischaemic systolic HF and LBBB, the WP of V/t curves identifies a subgroup of patients with greater LV dyssynchrony and worse outcome, but better response to CRT.

Resting Heart Rate as an Important Predictor of Mortality and Morbidity in Ambulatory Patients With Heart Failure: A Systematic Review and Meta-Analysis

BACKGROUND

Resting heart rate is a risk factor of adverse heart failure outcomes; however, studies have shown controversial results. This meta-analysis evaluates the association of resting heart rate with mortality and hospitalization and identifies factors influencing its effect.

METHODS AND RESULTS

We systematically searched electronic databases in February 2019 for studies published in 2005 or before that evaluated the resting heart rate as a primary predictor or covariate of multivariable models of mortality and/or hospitalization in adult ambulatory patients with heart failure. Random effects inverse variance meta-analyses were performed to calculate pooled hazard ratios. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess evidence quality. Sixty-two studies on 163,445 patients proved eligible. Median population heart rate was 74 bpm (interquartile range 72-76 bpm). A 10-bpm increase was significantly associated with increased risk of all-cause mortality (hazard ratio 1.10, 95% confidence interval 1.08-1.13, high quality). Overall, subgroup analyses related to patient characteristics showed no changes to the effect estimate; however, there was a strongly positive interaction with age showing increasing risk of all-cause mortality per 10 bpm increase in heart rate.

CONCLUSIONS

High-quality evidence demonstrates increasing resting heart rate is a significant predictor of all-cause mortality in ambulatory patients with heart failure on optimal medical therapy, with consistent effect across most patient factors and an increased risk trending with older age.

MRI-Based Computational Torso/Biventricular Multiscale Models to Investigate the Impact of Anatomical Variability on the ECG QRS Complex

AIMS

Patient-to-patient anatomical differences are an important source of variability in the electrocardiogram, and they may compromise the identification of pathological electrophysiological abnormalities. This study aims at quantifying the contribution of variability in ventricular and torso anatomies to differences in QRS complexes of the 12-lead ECG using computer simulations.

METHODS

A computational pipeline is presented that enables computer simulations using human torso/biventricular anatomically based electrophysiological models from clinically standard magnetic resonance imaging (MRI). The ventricular model includes membrane kinetics represented by the biophysically detailed O'Hara Rudy model modified for tissue heterogeneity and includes fiber orientation based on the Streeter rule. A population of 265 torso/biventricular models was generated by combining ventricular and torso anatomies obtained from clinically standard MRIs, augmented with a statistical shape model of the body. 12-lead ECGs were simulated on the 265 human torso/biventricular electrophysiology models, and QRS morphology, duration and amplitude were quantified in each ECG lead for each of the human torso-biventricular models.

RESULTS

QRS morphologies in limb leads are mainly determined by ventricular anatomy, while in the precordial leads, and especially V1 to V4, they are determined by heart position within the torso. Differences in ventricular orientation within the torso can explain morphological variability from monophasic to biphasic QRS complexes. QRS duration is mainly influenced by myocardial volume, while it is hardly affected by the torso anatomy or position. An average increase of 0.12 ± 0.05 ms in QRS duration is obtained for each cm3 of myocardial volume across all the leads while it hardly changed due to changes in torso volume.

CONCLUSION

Computer simulations using populations of human torso/biventricular models based on clinical MRI enable quantification of anatomical causes of variability in the QRS complex of the 12-lead ECG. The human models presented also pave the way toward their use as testbeds in silico clinical trials.

Clinical and prognostic relationships of pulmonary artery to aorta diameter ratio in patients with heart failure: a cardiac magnetic resonance imaging study

BACKGROUND

The pulmonary artery (PA) distends as pressure increases.

HYPOTHESIS

The ratio of PA to aortic (Ao) diameter may be an indicator of pulmonary hypertension and consequently carry prognostic information in patients with chronic heart failure (HF).

METHODS

Patients with chronic HF and control subjects undergoing cardiac magnetic resonance imaging were evaluated. The main PA diameter and the transverse axial Ao diameter at the level of bifurcation of the main PA were measured. The maximum diameter of both vessels was measured throughout the cardiac cycle and the PA/Ao ratio was calculated.

RESULTS

A total of 384 patients (mean age, 69 years; mean left ventricular ejection fraction, 40%; median NT-proBNP, 1010 ng/L [interquartile range, 448-2262 ng/L]) and 38 controls were included. Controls and patients with chronic HF had similar maximum Ao and PA diameters and PA/Ao ratio. During a median follow-up of 1759 days (interquartile range, 998-2269 days), 181 patients with HF were hospitalized for HF or died. Neither PA diameter nor PA/Ao ratio predicted outcome in univariable analysis. In a multivariable model, only age and NT-proBNP were independent predictors of adverse events.

CONCLUSIONS

The PA/Ao ratio is not a useful method to stratify prognosis in patients with HF.

Cardiac Dysfunction, Congestion and Loop Diuretics: their Relationship to Prognosis in Heart Failure

BACKGROUND

Diuretics are the mainstay of treatment for congestion but concerns exist that they adversely affect prognosis. We explored whether the relationship between loop diuretic use and outcome is explained by the underlying severity of congestion amongst patients referred with suspected heart failure.

METHOD AND RESULTS

Of 1190 patients, 712 had a left ventricular ejection fraction (LVEF) ≤50 %, 267 had LVEF >50 % with raised plasma NTproBNP (>400 ng/L) and 211 had LVEF >50 % with NTproBNP ≤400 ng/L; respectively, 72 %, 68 % and 37 % of these groups were treated with loop diuretics including 28 %, 29 % and 10 % in doses ≥80 mg furosemide equivalent/day. Compared to patients with cardiac dysfunction (either LVEF ≤50 % or NT-proBNP >400 ng/L) but not taking a loop diuretic, those taking a loop diuretic were older and had more clinical evidence of congestion, renal dysfunction, anaemia and hyponatraemia. During a median follow-up of 934 (IQR: 513-1425) days, 450 patients were hospitalized for HF or died. Patients prescribed loop diuretics had a worse outcome. However, in multi-variable models, clinical, echocardiographic (inferior vena cava diameter), and biochemical (NTproBNP) measures of congestion were strongly associated with an adverse outcome but not the use, or dose, of loop diuretics.

CONCLUSIONS

Prescription of loop diuretics identifies patients with more advanced features of heart failure and congestion, which may account for their worse prognosis. Further research is needed to clarify the relationship between loop diuretic agents and outcome; imaging and biochemical measures of congestion might be better guides to diuretic dose than symptoms or clinical signs.

Sutureless aortic valve replacement with Perceval bioprosthesis: are there predicting factors for postoperative pacemaker implantation?

OBJECTIVES

Aortic valve replacement (AVR) with sutureless bioprostheses has become an alternative to conventional AVR for patients with intermediate to high operative risk. However, this technique is associated with an increased risk of postoperative conduction disorders.

METHODS

We analysed 258 patients who underwent AVR with the Perceval prosthesis from July 2010 to September 2014 at our centre. Electrocardiography were obtained at baseline to record preoperatively the presence of conduction disorders. Preoperative risk factors, intraoperative procedures and complications (61 variables) were compared between patients with permanent pacemaker (PPM group) and without (no-PPM group) need for postoperative PPM implantation.

RESULTS

One hundred and sixty-nine patients underwent isolated AVR with the Perceval bioprosthesis, 89 patients had associated surgery and 23 patients underwent redo operations. The mean age was 77.7 ± 5 years, 139 patients were female (46%) and the mean logistic EuroSCORE was 13.2 ± 11%. At baseline, 8 patients had already an implanted pacemaker. Postoperatively, 27 patients (10.5%) required new PPM implantation due to complete atrioventricular block. On univariate analysis, age (PPM vs no-PPM group: 80 ± 5 vs 77 ± 5 years, P = 0.009) and preoperative presence of right bundle branch block (RBBB) [overall n = 20 (7.8%); PPM vs no-PPM group: 9 vs 11 (33 vs 4.8%); P < 0.001] were identified as independent predictors of postoperative conduction disorders, but only pre-existing RBBB persisted on multivariate analysis (odds ratio 11.3-C-statistic 0.74, error estimate 0.064, confidence interval 0.672-0.801; P = 0.0002). Among patients undergoing sutureless AVR, the rate of PPM implantation was high.

CONCLUSIONS

The analysis of the data collected made it possible to identify preoperatively a subset of patients undergoing sutureless AVR at higher risk of postoperative atrioventricular block. Additional surgical precautions should be implemented to prevent the occurrence of conduction disorders after sutureless AVR.

Ventricular conduction abnormalities as predictors of long-term survival in acute de novo and decompensated chronic heart failure

Aims

Data on the prognostic role of left and right bundle branch blocks (LBBB and RBBB), and nonspecific intraventricular conduction delay (IVCD; QRS ≥ 110 ms, no BBB) in acute heart failure (AHF) are controversial. Our aim was to investigate electrocardiographic predictors of long‐term survival in patients with de novo AHF and acutely decompensated chronic heart failure (ADCHF).

Methods and Results

We analysed the admission electrocardiogram of 982 patients from a multicenter European cohort of AHF with 3.9 years' mean follow‐up. Half (51.5%, n = 506) of the patients had de novo AHF. LBBB, and IVCD were more common in ADCHF than in de novo AHF: 17.2% vs. 8.7% (P < 0.001) and 20.6% vs. 13.2% (P = 0.001), respectively, and RBBB was almost equally common (6.9% and 8.1%; P = 0.5), respectively. Mortality during the follow‐up was higher in patients with RBBB (85.4%) and IVCD (73.7%) compared with patients with normal ventricular conduction (57.0%); P < 0.001 for both. The impact of RBBB on prognosis was prominent in de novo AHF (adjusted HR 1.93, 1.03–3.60; P = 0.04), and IVCD independently predicted death in ADCHF (adjusted HR 1.79, 1.28–2.52; P = 0.001). Both findings were pronounced in patients with reduced ejection fraction. LBBB showed no association with increased mortality in either of the subgroups. The main results were confirmed in a validation cohort of 1511 AHF patients with 5.9 years' mean follow‐up.

Conclusions

Conduction abnormalities predict long‐term survival differently in de novo AHF and ADCHF. RBBB predicts mortality in de novo AHF, and IVCD in ADCHF. LBBB has no additive predictive value in AHF requiring hospitalization.