Surface fragmented QRS in a patient with hypertrophic cardiomyopathy and malignant arrhythmias: Is there an association?

Sudden cardiac arrest in hypertrophic cardiomyopathy with dynamic cavity obstruction: The case for a decatecholaminisation strategy

Catecholamines are entrenched in the management of shock states. A paradigm shift has pervaded the critical care arena in recent years acknowledging their propensity to cause harm and fuel a 'death-spiral'. We present the case of a 21-year-old male following a witnessed out-of-hospital cardiac arrest who received high-quality cardiopulmonary resuscitation and standard advanced life support for refractory ventricular fibrillation until return of spontaneous circulation after 70 min. Early post-admission echocardiography revealed severe diffuse sub-basal left ventricular hypertrophy with dynamic mid-cavity obstruction and akinetic apical pouching. Within this context, a decatecholaminised strategy comprising a beta-blocker was used to augment the left ventricular end-diastolic volume and attain cardiovascular stability.

Mid-ventricular Hypertrophic Obstructive Cardiomyopathy with Apical Aneurysm Complicated with Syncope by Sustained Monomorphic Ventricular Tachycardia

Mid-ventricular hypertrophic obstructive cardiomyopathy with secondary formation of apical aneurysm is a rare variant of hypertrophic cardiomyopathy. They have a unique behavior because unlike other variants it causes sustained monomorphic ventricular tachycardia, which makes it particularly severe.

QRS fragmentation: its role in sherlocking the arrhythmogenic heart

The electrocardiogram (ECG) is a commonly available basic diagnostic modality in in-patient, out-patient, and emergency departments. In patients with coronary artery disease (CAD), the presence of a fragmented QRS (f-QRS), which is an extra R wave (R′), notching of the single R wave, notching of the S wave in at least two contiguous leads on the 12-lead ECG, is associated with a myocardial scar from previous myocardial injury. Furthermore, the presence of f-QRS has been shown to be associated with adverse outcomes in CAD and non-CAD patients. In the present paper, we will solely focus on the usefulness and utilization of f-QRS in predicting ventricular tachyarrhythmia in many heart diseases, that is, ischemic cardiomyopathy, non-ischemic cardiomyopathy, hypertrophic obstructive cardiomyopathy, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy. In the majority of such cases, ventricular tachyarrhythmia results in sudden cardiac death. Diagnosing them beforehand can lead to prevention and/or early treatment of these arrhythmias to prevent potential morbidity and mortality.

QRS Fragmentation and QTc Duration Relate to Malignant Ventricular Tachyarrhythmias and Sudden Cardiac Death in Patients with Hypertrophic Cardiomyopathy

BACKGROUND

QRS fragmentation (fQRS) and prolonged QTc interval on surface ECG are prognostic in various cardiomyopathies other than hypertrophic cardiomyopathy (HCM). The association between fQRS and prolonged QTc duration with occurrence of ventricular tachyarrhythmias or sudden cardiac death (VTA/SCD) in patients with HCM was explored.

METHODS AND RESULTS

One hundred and ninety-five clinical HCM patients were studied. QTc duration was derived applying Bazett's formula; fQRS was defined as presence of various RSR' patterns, R or S notching and/or >1 additional R wave in any non-aVR lead in patients without pacing or (in)complete bundle branch block. The endpoints comprised SCD, ECG documented sustained VTA (tachycardia or fibrillation) or appropriate implantable cardioverter defibrillator (ICD) therapies (antitachycardia pacing [ATP] or shock) for VTA in ICD recipients (n = 58 [30%]). QT prolonging drugs recipients were excluded. After a median follow-up of 5.7 years (IQR 2.7-9.1), 26 (13%) patients experienced VTA or SCD. Patients with fQRS in ≥3 territories (inferior, lateral, septal, and/or anterior) (p = 0.004) or QTc ≥460 ms (p = 0.009) had worse cumulative survival free of VTA/SCD than patients with fQRS in <3 territories or QTc <460 ms. fQRS in ≥3 territories (ß 4.5, p = 0.020, 95%CI 1.41-14.1) and QTc ≥460 ms (ß 2.7, p = 0.037, 95%CI 1.12-6.33) were independently associated with VTA/SCD. Likelihood ratio test indicated assessment of fQRS and QTc on top of conventional SCD risk factors provides incremental predictive value for VTA/SCD (p = 0.035).

CONCLUSIONS

Both fQRS in ≥3 territories and QTc duration are associated with VTA/SCD in HCM patients, independently of and incremental to conventional SCD risk factors.

The Presence of Fragmented QRS on 12-Lead Electrocardiography in Patients with Coronary Artery Ectasia

Background and Objectives

Coronary artery ectasia (CAE) is an angiographic finding characterized by dilation of an arterial segment with a diameter at least 1.5 times that of its adjacent normal coronary artery. Fragmented QRS (fQRS) complexes are electrocardiographic signals which reflect altered ventricular conduction around regions of a myocardial scar and/or ischaemia. In the present study, we aimed to evaluate the presence of fQRS in patients with CAE.

Subjects and Methods

The study population included 100 patients with isolated CAE without coronary artery disease (CAD) and 80 angiographically normal controls. fQRS was defined as the presence of an additional R wave or notching of R or S wave or the presence of fragmentation in two contiguous leads corresponding to a major coronary artery territory.

Results

The two groups were similar in terms of age, sex, hypertension, dyslipidemia, and family history of CAD. The presence of fQRS was significantly (p<0.05) higher in the CAE group than that in the normal coronary artery group (29% vs. 6.2%, p=0.008). Isolated CAE were detected most commonly in the right coronary artery (61%), followed by left anterior descending artery (52%), left circumflex artery (36%), and left main artery (9%). Multivariate stepwise logistic regression analysis showed that CAE {odds ratio (OR) 1.412; 95% confidence interval (CI) 1.085-1.541; p=0.003} and diabetes (OR 1.310; 95% CI 1.025-1.482; p=0.041) were independently associated with fQRS.

Conclusion

The presence of fragmented QRS associated with increased risk for arrhythmias and cardiovascular mortality was significantly higher in patients with CAE than in patient with normal coronary artery. Further studies are needed to determine whether the presence of fragmented QRS is a possible new risk factor for patients with CAE.

Hypertrophic cardiomyopathy: Can the noninvasive diagnostic testing identify high risk patients?

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death (SCD) in the young, particularly among athletes. Identifying high risk individuals is very important for SCD prevention. The purpose of this review is to stress that noninvasive diagnostic testing is important for risk assessment. Extreme left ventricular hypertrophy and documented ventricular tachycardia and fibrillation increase the risk of SCD. Fragmented QRS and T wave inversion in multiple leads are more common in high risk patients. Cardiac magnetic resonance imaging provides complete visualization of the left ventricular chamber, allowing precise localization of the distribution of hypertrophy and measurement of wall thickness and cardiac mass. Moreover, with late gadolinium enhancement, patchy myocardial fibrosis within the area of hypertrophy can be detected, which is also helpful in risk stratification. Genetic testing is encouraged in all cases, especially in those with a family history of HCM and SCD.

Variations of QRS Morphology in Patients with Dilated Cardiomyopathy; Clinical and Prognostic Implications

The QRS represents the simultaneous activation of the right and left ventricles, although most of the QRS waveform is derived from the larger left ventricular musculature. Although normal QRS duration is <100 millisecond (ms), its duration and shape are quite variable from patient to patient in idiopathic dilated cardiomyopathy (IDCM). Prolongation of QRS occurs in 14% to 47% of heart failure (HF) patients. Left bundle branch block (LBBB) is far more common than right bundle branch block (RBBB). Dyssynchronous left ventricular activation due to LBBB and other intraventricular conduction blocks provides the rationale for the use of cardiac resynchronization therapy with biventricular pacing in patients with IDCM. Fragmented QRS (fQRS) is a marker of depolarization abnormality and present in significant number of the patients with IDCM and narrow QRS complexes. It is associated with arrhythmic events and intraventricular dyssynchrony. The purpose of this manuscript is to present an overview on some clinical, echocardiographic and prognostic implications of various QRS morphologies in patients with IDCM.

Fragmented surface ECG was a poor predictor of appropriate therapies in patients with Chagas' cardiomyopathy and ICD implantation (Fragmented ECG in CHAgas' Cardiomyopathy Study)

BACKGROUND

Main causes of death in chronic Chagas' cardiomyopathy (CChC) are progressive congestive heart failure and sudden cardiac death. Implantable cardioverter defibrillators (ICD) have been proved an effective therapy to prevent sudden death in patients with CChC. Identification of predictors of sudden death remains a challenge.

OBJECTIVE

To determine whether surface fragmented ECG (fQRS) helps identifying patients with CChC and ICDs at higher risk of presenting appropriate ICD therapies.

METHODS

Multicenter retrospective study. All patients with CChC and ICDs were analyzed. Clinical demographics, surface ECG, and ICD therapies were collected.

RESULTS

A total of 98 patients were analyzed. Another four cases were excluded due to pacing dependency. Mean age was 55.5 ± 10.4 years, male gender 65%, heart failure New York Heart Association class I 47% and II 38%. Mean left ventricular ejection fraction (LVEF) 39.6 ± 11.8%. The indication for ICD was secondary prevention in 70% of patients. fQRS was found in 56 patients (59.6%). Location of fragmentation was inferior (57.1%), lateral (35.7%), and anterior (44.6%). Rsr pattern was the more prevalent (57.1%). Predictors of appropriate therapy in the multivariate model were: increased age (P = 0.01), secondary prevention indication (P = 0.01), ventricular pacing >50% of the time (P = 0.004), and LVEF <30% (P = 0.01). The presence of fQRS did not identify patients at higher risk of presenting appropriate therapies delivered by the ICD (P = 0.87); regardless of QRS interval duration.

CONCLUSIONS

fQRS is highly prevalent among patients with CChC. It has been found a poor predictor of appropriate therapies delivered by the ICD in this population.

Fragmented QRS as a predictor of arrhythmic events in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES

This study aims to determine whether fragmented QRS (fQRS) in the surface electrocardiogram (ECG) at implantable cardioverter defibrillator (ICD) implant can predict arrhythmic events using appropriate therapy delivered by the ICD as a surrogate.

BACKGROUND

Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder associated with life-threatening arrhythmias frequently requiring an ICD. Seeking a noninvasive method of risk stratification remains a challenge.

METHODS

This paper is a retrospective, multicenter study of patients with HOCM and ICD. Surface 12-lead ECGs were analyzed. Appropriate therapy was validated by a blinded Core Lab. Univariate and multivariate analyses were performed. A p value of <0.05 was considered significant.

RESULTS

We included 102 patients from 13 centers. Mean age at implant was 41.16 ± 18.25 years, 52% were male. Mean left ventricular ejection fraction was 61.56 ± 9.46% and two thirds had heart failure according to the New York Heart Association class I. Secondary prophylaxis ICD implantation was the indication for implant in 40.2% of cases. About half received a single-chamber ICD. fQRS was present at the time of diagnosis in 21 and in 54% at ICD implant. At a mean follow-up of 47.8 ± 39.3 months, 41 patients (40.2%) presented with appropriate therapy. In a multivariate logistic regression, predictors of appropriate therapy included fQRS at implant (odds ratio [OR], 16.4; 95% confidence interval [CI], 3.6-74.0; p = 0.0003), history of combined ventricular tachycardia/fibrillation/sudden death (OR, 14.3; 95% CI, 3.2-69.3; p = 0.001) and history of syncope (OR, 5.5; 95% CI, 1.5-20.4; p = 0.009). Ten deaths (9.8%) occurred during the follow-up. fQRS in the lateral location increased the risk of appropriate therapy (p < 0.0001).

CONCLUSIONS

fQRS predicts arrhythmic events in patients with HOCM and should be considered in a model of risk stratification.