Changes In QRS Duration Research Articles

0436: Prevalence and clinical impact of QRS duration in patients with low-flow/low-gradient aortic stenosis due to left ventricular systolic dysfunction

To evaluate the prognostic impact of QRS width in patients with low-flow/low-gradient aortic stenosis (LF/LGAS). Among 88 consecutive patients referred to our institution for LF/LGAS from September 1994 to March 2007, baseline demographic, clinical, echocardiographic and electrocardiographic data were collected. This population was divided in two groups according to baseline QRS duration (cutoff: QRS≥ 130ms). Follow-up data, including electrocardiographic evolution and overall mortality were analyzed. The mean follow-up duration was 3.1 (2.2-6.2) years. In the whole group, 67 patients underwent surgical aortic valve replacement. Forty-nine patients (56%) had a QRS duration≥ 130ms. Among operated patients, there was no significant change in QRS duration between baseline and latest follow-up (126±26 vs. 131±25ms; p=0.82). In addition, wider QRS was a strong independent predictor of overall mortality [HR=2.20; CI, 1.15–4.24; p=0.027]. Significant intra-ventricular conduction disturbances are common in patients with LF/LGAS and do not recover after aortic valve replacement. QRS duration is strongly associated with mortality in this selected population.

MitraClip in CRT non-responders with severe mitral regurgitation

BackgroundSevere mitral regurgitation (MR) ≥3+ and left ventricular dyssynchrony in heart failure patients are markers of CRT non response. The MitraClip (MC) implantation is a therapy for MR ≥3+ in patients with high surgical risk of mitral valve reconstruction. Methods and resultsWe investigated 42 patients with CRT and MR ≥3+ who received an MC device at our center. One and two year mortality rates were compared with the predicted mortality by Seattle Heart Failure Model (SHFM) and meta-analysis global group in chronic heart failure (MAGGIC), using the baseline characteristics of patients at the time of MC implantation.The median time interval between CRT and MC implantation was 20.1 (4.5–43.3) months. In 19 patients we observed a functional regurgitation with normal leaflets and in 23 patients a degenerative mechanism for mitral regurgitation. There was no change in mean QRS duration by biventricular pacing or MC implantation. The use of MC led to significant reductions in: median N-terminal pro-brain natriuretic peptide (NT-proBNP) level (pg/ml) from 3923 to 2636 (p=0.02), tricuspid regurgitation pressure gradient (TRPG) from 43 to 35mmHg (p=0.019) and in left ventricular end-diastolic volume (LVEDV) by MC (p=0.008). At the 2year follow-up interval the all-cause mortality was 25%. ConclusionMC implantation leads to an improvement of NT-proBNP level, TRPG and LVEDV in both functional and degenerative MR but does not influence QRS duration. Two year all-cause mortality was 25% and did not differ significantly from that predicted by SHFM and MAGGIC.

Electrocardiogram characteristics prior to in-hospital cardiac arrest.

Survival after in-hospital cardiac arrest (I-HCA) remains < 30 %. There is very limited literature exploring the electrocardiogram changes prior to I-HCA. The purpose of the study was to determine demographics and electrocardiographic predictors prior to I-HCA. A retrospective study was conducted among 39 cardiovascular subjects who had cardiopulmonary resuscitation from I-HCA with initial rhythms of pulseless electrical activity (PEA) and asystole. Demographics including medical history, ejection fraction, laboratory values, and medications were examined. Electrocardiogram (ECG) parameters from telemetry were studied to identify changes in heart rate, QRS duration and morphology, and time of occurrence and location of ST segment changes prior to I-HCA. Increased age was significantly associated with failure to survive to discharge (p < 0.05). Significant change was observed in heart rate including a downtrend of heart rate within 15 min prior to I-HCA (p < 0.05). There was a significant difference in heart rate and QRS duration during the last hour prior to I-HCA compared to the previous hours (p < 0.05). Inferior ECG leads showed the most significant changes in QRS morphology and ST segments prior to I-HCA (p < 0.05). Subjects with an initial rhythm of asystole demonstrated significantly greater ECG changes including QRS morphology and ST segment changes compared to the subjects with initial rhythms of PEA (p < 0.05). Diagnostic ECG trends can be identified prior to I-HCA due to PEA and asystole and can be further utilized for training a predictive machine learning model for I-HCA.

Immediate effects of upper thoracic spine manipulation on hypertensive individuals

Purpose:The aims of this study were to determine if there were any statistically significant immediate effects of upper thoracic spinal manipulative therapy (SMT) on cardiovascular physiology in hypertensive individuals.Introduction:Preliminary research suggests that SMT to various regions of the spine may be capable of lowering systolic and diastolic blood pressure in hypertensive individuals. Further studies are warranted to corroborate or refute these findings as well as measure how other attributes of cardiovascular physiology are impacted by SMT.Methods:Fifty hypertensive participants (age = 45·5±13·9 years, height = 1·69±0·10 m, body mass = 93·9±21·5 kg: mean±standard deviation (SD)) were equally randomized into a single-blind, controlled trial involving two study groups: supine diversified anterior upper thoracic SMT of T1–4, or a ‘no T-spine contact’ control. Outcome measures were electrocardiogram, bilateral pulse oximetry, and bilateral blood pressure measurement performed at baseline, post 1-minute intervention, and post 10-minute intervention. An independent samples t-test was used to compare between-group differences at baseline. A repeated measures ANOVA was used to compare within-group changes over time.Results:Within-group changes in PR interval and QRS duration demonstrated that the atria were transiently less active post-SMT and the ventricles were more active post-SMT, however the changes were clinically minimal.Conclusion:The results of this study, and the limited existing normotensive, thoracic-specific SMT research in this field, suggest that cardiovascular physiology, short-term, is not affected by upper thoracic spine SMT in hypertensive individuals to a clinically relevant level.

QRS DURATION CHANGES IN PATIENTS WITH SINGLE VENTRICLE PHYSIOLOGY: BIRTH TO 10 YEARS

Background QRS prolongation may be a predictor of mortality in certain forms of congenital heart disease. Minimal data exist describing changes in QRS duration in patients with single ventricles (SVs). The goal was to describe changes in QRS duration in patients with SV and to determine if differences existed between single right ventricle (sRV) versus single left ventricle (sLV) patients. Methods Chart review was performed on patients with SV physiology. Patients were divided into sRV and sLV groups. QRS durations were measured monthly for the first 6 months, at 1 year, and then yearly until 10 years. t-tests were used for analysis. Results One hundred sixty patients were evaluated (95 sRV, 65 sLV). The greatest change in QRS duration for the entire cohort occurred in the first 6 months of life versus 6 months to 10 years of age (1.81 ms/month vs 0.20 ms/month). sRV QRS durations were significantly longer than sLV QRS durations at 1 year (78.9 ± 12.6 ms vs 73.2 ± 11.9 ms), 2 year (81.7 ± 14.7 ms vs 73.4 ± 12.5 ms), 4 year (84.2 ± 12.1 ms vs 77.9 ± 16.4 ms), 6 year (90.8 ± 12.7 ms vs 83.4 ± 13.4 ms), 7 year (90.8 ± 16.5 ms vs 81.2 ± 16.6 ms), and 8 year (96.7 ± 13.6 ms vs 84.8 ± 13.9 ms) time points. Conclusion The greatest change in QRS duration in SV patients occurred in the first 6 months of life when these patients’ ventricles were volume loaded. Differences in QRS duration between sRV and sLV patients occurred early in life. Further studies are needed to determine if minimizing volume load early in life decreases the rate of change in QRS duration.

ELECTRICAL RESYNCHRONIZATION IS NOT RELATED TO HEMODYNAMIC RESPONSE IN CARDIAC RESYNCHRONIZATION THERAPY

Cardiac resynchronization therapy (CRT) is based on restoring left ventricular dyssynchrony. It is known that CRT induced changes in QRS duration poorly predict hemodynamic effect. This study assessed invasively obtained endocardial and epicardial left ventricular activation with and without CRT and

Prevalence and clinical impact of QRS duration in patients with low‐flow/low‐gradient aortic stenosis due to left ventricular systolic dysfunction

To evaluate the prognostic impact of QRS width in patients with low-flow/low-gradient aortic stenosis (LF/LGAS). Among 88 consecutive patients referred to our institution for LF/LGAS from September 1994 to March 2007, baseline demographic, clinical, echocardiographic, and electrocardiographic data were collected. This population was divided into two groups according to baseline QRS duration (cut-off QRS ≥130 ms). Follow-up data, including electrocardiographic evolution and overall mortality, were analysed. The mean follow-up duration was 3.1 (2.2-6.2) years. In the whole group, 67 patients underwent surgical aortic valve replacement. Forty-nine patients (56%) had a QRS duration ≥130 ms. Among operated patients, there was no significant change in QRS duration between baseline and latest follow-up (126 ± 26 ms vs. 131 ± 25 ms; P = 0.82). In addition, wider QRS was a strong independent predictor of overall mortality (hazard ratio 2.20, 95% confidence interval 1.15-4.24; P = 0.027). Significant intraventricular conduction disturbances are common in patients with LF/LGAS and do not recover after aortic valve replacement. QRS duration is strongly associated with mortality in this selected population.

The Relationship between the Reverse Left Ventricular Remodelling Developing After Cardiac Resynchronisation Therapy and the Postimplantation Changes in QRS Duration and Presence of Fragmented QRS

OP-023 In this study we aimed to investigate clinical and echocardiographic parameters that affects development of left ventricular reverse remodelling after cardiac resynchronisation therapy (CRT) and association between reverse remodelling with electrical remodelling and fragmented QRS. Totally

Dynamic Changes of QRS Duration in Patients With Heart Failure

Heart failure (HF) is a progressive disease in spite of optimal medical management. Cardiac resynchronization therapy is an effective therapy to reduce mortality, morbidity, and HF hospitalization in HF patients with systolic dysfunction and wide QRS duration. Clinical practice guidelines suggested that a defined QRS duration is used to determine if CRT should be used. This has an implicit assumption that a specific QRS duration defines whether the patient benefits from CRT and that QRS duration is static with minimal changes over time.

Delayed intrinsicoid deflection onset in surface ECG lateral leads predicts left ventricular reverse remodeling after cardiac resynchronization therapy

Up to one-third of the patients who undergo cardiac resynchronization therapy (CRT) are not responders. To demonstrate that delayed lateral left ventricular activation time determined through time to intrinsicoid deflection onset (ID) predicts response after CRT. The ID in leads I, aVL, V₁ and V₂, and V₅ and V₆ were measured in 135 patients who underwent CRT. A CRT response was defined as a decrease in left ventricular end-systolic volume (LVESV) exceeding 15% at 6 months. In patients with left bundle branch block or nonspecific intraventricular conduction delay, response was predicted by longer ID in lead I (odds ratio [OR] 3.23; 95% confidence interval (CI) 1.4-7.4; per 20-ms increase), in lead aVL (OR 3.0; 95% CI 1.2-7.3; per 20-ms increase), and in lead I minus lead V₁ (OR 2.4; 95% CI 1.2-4.7) adjusting for baseline QRS duration and LVESV. Results were similar after adjusting for postimplant or change in QRS duration. The ID parameters were better predictors of response than QRS duration parameters. ID in lead I/QRS duration ratio (OR 3.1; 95% CI 1.6-5.9) also increased the odds of response after adjusting for baseline LVESV. Cutoff values for ID in leads--I, 110 ms; aVL, 130 ms; I minus V₁, 90 ms--and ID in lead I/QRS duration ratio of 0.69 yielded a sensitivity and a specificity as high as 83% and 81%. Measurement of ID on surface electrocardiography permits a preimplant, noninvasive means of determining left ventricle activation delay; is a good predictor of CRT response; and represents a promising alternative to QRS duration parameters.

Low-dose dobutamine induces left ventricular mechanical dyssynchrony in patients with dilated cardiomyopathy and a narrow QRS: A study using real-time three-dimensional echocardiography

AimsThe effects of inotropic agents on left ventricular (LV) synchrony in heart failure patients are still unknown. The purpose of this study was to investigate the effects of dobutamine on LV mechanical dyssynchrony and LV systolic performance in patients with dilated cardiomyopathy (DCM) and a narrow QRS using real-time three-dimensional echocardiography (RT3DE). Methods and resultsThirty-three patients with idiopathic DCM and a narrow QRS underwent low-dose dobutamine stress echocardiography (LDSE) with RT3DE. A time-global LV volume curve and time-regional LV volume curves were derived from RT3DE. Regional LV stroke volumes were summed in each stage, and the dobutamine-induced increase in the sum of regional LV stroke volumes was considered as the sum of regional contractile reserve. Systolic dyssynchrony index (SDI) was calculated as follows: (standard deviation of time to minimal volume for regional LV segments)×100/RR duration. Among the 33 patients, low-dose dobutamine increased global LV stroke volume (SV) in 28 (85%), but decreased global LVSV in the remainder (15%). The sum of regional contractile reserve was modestly correlated with the dobutamine-induced increase in global LVSV (R=0.57, p<0.001). In contrast, low-dose dobutamine increased SDI in 14 (42%) patients without a significant change in QRS duration, and there was an inverse correlation between the increase in SDI and the increase in global LVSV induced by dobutamine (R=−0.67, p<0.001). ConclusionsDobutamine may induce LV mechanical dyssynchrony in a substantial proportion of patients with DCM and a narrow QRS. In such cases, regional LV contractile reserve does not fully contribute to an increase in global LVSV.

QRS Duration Changes in Patients with Hypoplastic Left Heart Syndrome Undergoing Hybrid Palliation: Prehybrid to Post‐Fontan

QRS prolongation has been shown to be a predictor of mortality in patients with certain forms of congenital heart disease. QRS changes have not been well described in patients with single ventricle physiology, particularly in those undergoing the hybrid procedure. To describe QRS changes in a cohort of patients with hypoplastic left heart syndrome (HLHS) who underwent hybrid palliation and to evaluate if QRS duration is associated with mortality. Chart review of 54 patients with HLHS who underwent hybrid procedure between 2002 and 2009 was performed. Patients awaiting surgical palliation were excluded. Patients who survived Fontan completion (HLHS-S, n = 30) were compared to non-survivor (HLHS-NS, n = 24). Electrocardiograms were reviewed for maximal QRS duration (ms) at three pre- and postsurgical stages: (1) hybrid procedure, (2) comprehensive stage 2 procedure, and (3) Fontan procedure. In HLHS-S, there was a significant increase in QRS from birth to Fontan completion (15.6 ± 9.3 ms). QRS duration increased 8.5 ± 8.9 ms between posthybrid to precomprehensive stage 2, and 5.4 ± 9.7 ms between postcomprehensive stage 2 to Fontan. Following Fontan procedure, mean QRS decreased 4.3 ± 8.5 ms. There was no significant mean difference in QRS change between HLHS-S and HLHS-NS following hybrid procedure. Pre- and posthybrid and pre- and postcomprehensive stage 2 QRS durations were not different between HLHS-S and HLHS-NS who underwent a comprehensive stage 2 procedure. There was a significant difference in QRS difference following comprehensive stage 2 in HLHS-S (0.9 ± 7.1 ms) compared to HLHS-NS (-7.1 ± 10.0 ms). QRS duration significantly increased from hybrid to Fontan completion in HLHS-S. There was a significant decrease in QRS duration in patients who died following comprehensive stage 2 procedure. Larger studies are needed to assess the significance of these QRS changes.

Evaluation of clinical and electrocardiographic changes during the euthanasia of horses

The objective of this prospective field study was to investigate whether commonly used criteria for clinical death occurred at the same time as cardiac death, as determined by electrocardiography. Specific ECG changes during euthanasia were also studied. Twenty-nine horses were euthanized with pentobarbital at two different dose rates and 15 of the 29 horses also received detomidine hydrochloride for sedation. ECG was recorded prior to and during euthanasia. Time to collapse, cessation of reflexes, heart sounds and asystole were recorded. ECG recordings were used to calculate RR intervals, PQ duration, QRS duration, distance from QRS complex to end of T wave corrected for HR (QTc interval), duration of T-wave from peak to end (TpeakTend) and amplitudes of T wave (Tpeak) before and during euthanasia. Differences between groups and ECG changes were evaluated using analysis of variance.Clinical determination of death occurred before cardiac death (P<0.05). Sedated horses took longer to collapse than unsedated horses (P<0.0001), but asystole occurred faster in sedated horses (P<0.0001). No significant changes in QRS duration were observed, but RR, PQ, QTc, TpeakTend and Tpeak were influenced by both pentobarbital dose and sedation (P<0.05–<0.0001). In conclusion, sedation prior to euthanasia resulted in a shorter time to asystole and is therefore recommended for the euthanasia of horses. Importantly, the results show that the clinical definition of death occurred significantly earlier than cardiac death (defined as asystole), which indicates that the clinical declaration of death in horses could be premature compared to that used in humans.

Long-term follow up after transcatheter closure of atrial septal defect and patent foramen ovale in adults

Background : The aim of our study was to define long-term electrocardiographic and echocardiographic changes and complications after transcatheter closure of atrial septal defect and patent foramen ovale in adults. Methods : The clinical, electrocardiographic and echocardiographic follow-up of 137 consecutive patients that underwent transcatheter closure of atrial septal defect (51 patients) or patent foramen ovale (86 patients) in a 10-year period was analyzed retrospectively. Results : In the patent foramen ovale group, we observed no significant postprocedural changes. There were no changes in heart rate, heart rhythm and PR or QRS duration in both groups. In the atrial septal defect group, we observed a leftward shift in the heart axis (p = 0.017), a decrease in the estimated systolic pulmonary artery pressure (p = 0.024), decreased tricuspid early diastolic flow velocity (p = 0.002), a decrease in the right chamber dimensions (p = 0.0004) and interventricular septal movement normalization (p < 0.0001). Most of the complications were mild and occurred early after the procedure. Three early serious complications were documented. Conclusions : No electrocardiographic or echocardiographic changes occurred after patent foramen ovale closure. Atrial septal defect closure is related to significant early morphological and hemodynamic improvement. Postprocedural complications are usually early and mild but serious late complications can occur. For that reason, long-term follow up is recommended in these patients.

THE EFFECT OF ATROVASTATIN ON THE QRS DURATION IN THE PATIENTS WITH ACUTE ANTERIOR ST ELEVATION MYOCARDIAL INFARCTION UNDERGOING PRIMARY ANGIOPLASTY

ObjectivesTo evaluate the value of intensive atorvastatin treatment on changes of QRS duration and ventricular arrhythmia in the patients with acute anterior ST elevation myocardial infarction undergoing primary Angioplasty.MethodsFrom December...

THE EFFECT OF ATROVASTATIN ON THE QRS DURATION IN THE PATIENTS WITH ACUTE ANTERIOR ST ELEVATION MYOCARDIAL INFARCTION UNDERGOING PRIMARY ANGIOPLASTY

ObjectivesTo evaluate the value of early and intensive atrovastatin treatment on changes of QRS duration and ventricular arrhythmia in the patients with acute anterior ST elevation myocardial infarction undergoing primary...

062 ECG Predictors of Adverse Outcomes in Patients With Atrial Fibrillation: A Combined Affirm and AF-CHF Sub-Study

BackgroundWhile resting ECG parameters have been shown to independently predict adverse cardiovascular outcomes in various populations with and without cardiovascular disease, the prognostic value of these findings have not been specifically addressed in patients with atrial fibrillation.MethodsWe conducted a combined post hoc analysis on all 5436 patients with a history of non-permanent atrial fibrillation randomized to rhythm- versus rate-control therapy in AFFIRM and AF-CHF trials. A total of 7159 baseline ECGs (4848 in atrial fibrillation and 2311 in sinus rhythm) were analyzed to assess the predictive value of the PR interval, QRS duration, and QT intervals on hospitalizations and mortality. Univariate and stepwise multivariate Cox regression models were created for the following outcomes: cardiovascular mortality, all-cause mortality, arrhythmic death, time to first hospitalization, and time to first cardiovascular hospitalization. Separate analyses were performed in atrial fibrillation and in sinus rhythm.ResultsIncreased QRS duration (≥120 msec) was significantly and independently associated with all-cause mortality (HR 1.38; p<0.0001), cardiovascular death (HR 1.50; p<0.0001), arrhythmic death (HR 1.86; p=0.0001), any hospitalisation (HR 1.12; p=0.02), and cardiovascular hospitalisation (HR 1.24; p=0.0002). Increased PR interval (>200 msec) was significantly and independently associated with cardiovascular (HR 1.55; p=0.01), and arrhythmic mortality (HR 2.05; p=0.005). Prolonged QTc (440 msec) predicted cardiovascular hospitalisation (HR 1.23; p=0.04) and arrhythmic mortality (men; HR 1.42; p=0.03). Uncorrected QT interval and rate of change in QRS duration were not predictive of adverse outcomes.ConclusionSimple parameters on baseline ECG significantly and independently predict adverse cardiovascular outcomes in patients with a history of atrial fibrillation. BackgroundWhile resting ECG parameters have been shown to independently predict adverse cardiovascular outcomes in various populations with and without cardiovascular disease, the prognostic value of these findings have not been specifically addressed in patients with atrial fibrillation. While resting ECG parameters have been shown to independently predict adverse cardiovascular outcomes in various populations with and without cardiovascular disease, the prognostic value of these findings have not been specifically addressed in patients with atrial fibrillation. MethodsWe conducted a combined post hoc analysis on all 5436 patients with a history of non-permanent atrial fibrillation randomized to rhythm- versus rate-control therapy in AFFIRM and AF-CHF trials. A total of 7159 baseline ECGs (4848 in atrial fibrillation and 2311 in sinus rhythm) were analyzed to assess the predictive value of the PR interval, QRS duration, and QT intervals on hospitalizations and mortality. Univariate and stepwise multivariate Cox regression models were created for the following outcomes: cardiovascular mortality, all-cause mortality, arrhythmic death, time to first hospitalization, and time to first cardiovascular hospitalization. Separate analyses were performed in atrial fibrillation and in sinus rhythm. We conducted a combined post hoc analysis on all 5436 patients with a history of non-permanent atrial fibrillation randomized to rhythm- versus rate-control therapy in AFFIRM and AF-CHF trials. A total of 7159 baseline ECGs (4848 in atrial fibrillation and 2311 in sinus rhythm) were analyzed to assess the predictive value of the PR interval, QRS duration, and QT intervals on hospitalizations and mortality. Univariate and stepwise multivariate Cox regression models were created for the following outcomes: cardiovascular mortality, all-cause mortality, arrhythmic death, time to first hospitalization, and time to first cardiovascular hospitalization. Separate analyses were performed in atrial fibrillation and in sinus rhythm. ResultsIncreased QRS duration (≥120 msec) was significantly and independently associated with all-cause mortality (HR 1.38; p<0.0001), cardiovascular death (HR 1.50; p<0.0001), arrhythmic death (HR 1.86; p=0.0001), any hospitalisation (HR 1.12; p=0.02), and cardiovascular hospitalisation (HR 1.24; p=0.0002). Increased PR interval (>200 msec) was significantly and independently associated with cardiovascular (HR 1.55; p=0.01), and arrhythmic mortality (HR 2.05; p=0.005). Prolonged QTc (440 msec) predicted cardiovascular hospitalisation (HR 1.23; p=0.04) and arrhythmic mortality (men; HR 1.42; p=0.03). Uncorrected QT interval and rate of change in QRS duration were not predictive of adverse outcomes. Increased QRS duration (≥120 msec) was significantly and independently associated with all-cause mortality (HR 1.38; p<0.0001), cardiovascular death (HR 1.50; p<0.0001), arrhythmic death (HR 1.86; p=0.0001), any hospitalisation (HR 1.12; p=0.02), and cardiovascular hospitalisation (HR 1.24; p=0.0002). Increased PR interval (>200 msec) was significantly and independently associated with cardiovascular (HR 1.55; p=0.01), and arrhythmic mortality (HR 2.05; p=0.005). Prolonged QTc (440 msec) predicted cardiovascular hospitalisation (HR 1.23; p=0.04) and arrhythmic mortality (men; HR 1.42; p=0.03). Uncorrected QT interval and rate of change in QRS duration were not predictive of adverse outcomes. ConclusionSimple parameters on baseline ECG significantly and independently predict adverse cardiovascular outcomes in patients with a history of atrial fibrillation. Simple parameters on baseline ECG significantly and independently predict adverse cardiovascular outcomes in patients with a history of atrial fibrillation.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Effect of QRS Duration and Morphology on Cardiac Resynchronization Therapy Outcomes in Mild Heart Failure

Background— Cardiac resynchronization therapy (CRT) decreases mortality, improves functional status, and induces reverse left ventricular remodeling in selected populations with heart failure. We aimed to assess the impact of baseline QRS duration and morphology and the change in QRS duration with pacing on CRT outcomes in mild heart failure. Methods and Results— Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) was a multicenter randomized trial of CRT among 610 patients with mild heart failure. Baseline and CRT-paced QRS durations and baseline QRS morphology were evaluated by blinded core laboratories. The mean baseline QRS duration was 151±23 milliseconds, and 60.5% of subjects had left bundle-branch block (LBBB). Patients with LBBB experienced a 25.3-mL/m 2 mean reduction in left ventricular end-systolic volume index ( P &lt;0.0001), whereas non-LBBB patients had smaller decreases (6.7 mL/m 2 ; P =0.18). Baseline QRS duration was also a strong predictor of change in left ventricular end-systolic volume index with monotonic increases as QRS duration prolonged. Similarly, the clinical composite score improved with CRT for LBBB subjects (odds ratio, 0.530; P =0.0034) but not for non-LBBB subjects (odds ratio, 0.724; P =0.21). The association between clinical composite score and QRS duration was highly significant (odds ratio, 0.831 for each 10-millisecond increase in QRS duration; P &lt;0.0001), with improved response at longer QRS durations. The change in QRS duration with CRT pacing was not an independent predictor of any outcomes after correction for baseline variables. Conclusion— REVERSE demonstrated that LBBB and QRS prolongation are markers of reverse remodeling and clinical benefit with CRT in mild heart failure. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00271154.

Electrocardiographic QRS Duration Reflects Right Ventricular Remodeling in Patients Undergoing Corrective Surgery for Isolated Tricuspid Regurgitation: A Comparative Study with Cardiac Magnetic Resonance Imaging

The role of electrocardiogram (ECG) is unclear for the longitudinal follow-up of patients who undergo corrective surgery for isolated severe tricuspid regurgitation (TR). This study sought to investigate the usefulness of changes in QRS duration of ECG after TR surgery in predicting right ventricular (RV) reverse remodeling as determined by cardiac magnetic resonance imaging (CMR). We enrolled 30 consecutive TR patients (27 women, aged 57.8 ± 9.6 years) who had undergone prior left-sided valve surgery. A computer-assisted analysis was performed for objective calculation of QRS duration before and after surgery. At a median CMR follow-up of 27.5 months postsurgery, QRS duration was cut by 14.6%, from 110.4 ± 14.6 msec to 96.9 ± 11.9 msec (P < 0.001), while CMR showed a decrease in RV end-diastolic volume index (RV-EDVI) from 179.5 ± 59.7 to 119.1 ± 30.4 mL/m(2) (P < 0.001). QRS duration correlated significantly with RV-EDVI and RV end-systolic volume index (r = 0.65, P < 0.001 and r = 0.53, P < 0.001, respectively), and a percent change in QRS duration was significantly correlated with a percent change in RV-EDVI (r = 0.40, P = 0.03). When significant RV reverse remodeling was defined as a reduction in RV-EDVI ≥20% following TR surgery, the sensitivity and specificity for significant RV reverse remodeling were 75% and 78%, respectively, with a 9% reduction in QRS duration (P = 0.01, area underneath the receiver operator curve [AUC] = 0.81). The extent of changes in postoperative QRS duration can be used as a useful, inexpensive, and simple index reflecting the occurrence of significant RV reverse remodeling in patients undergoing corrective TR surgery.