Rare association of hypertrophic cardiomyopathy and complete atrioventricular block with prompt disappearance of outflow gradient after DDD pacing

Characteristics of Primary Bradyarrhythmia in Hypertrophic Cardiomyopathy: A 10-Year, Single-Center Analysis

Background: Secondary bradyarrhythmias in hypertrophic cardiomyopathy (HCM) have been extensively reported. The prevalence and characteristics of primary bradyarrhythmias in HCM have yet to be investigated. Methods: We retrospectively enrolled 101 consecutive patients with HCM who were referred to the arrhythmia center from May 2010 to October 2020. The clinical features of patients with bradyarrhythmias were analyzed. Results: Twenty-nine (28.7%) patients had primary bradyarrhythmias, and six (5.9%) patients had secondary third-degree atrioventricular block (AVB). Of the 29 patients, 17 (58.6%) had sinus node dysfunction (SND), 14 (48.3%) had AVB, and two (6.9%) had both SND and AVB. The median age was 62 years old, and 69% were male. Six (20.7%) patients had left ventricular obstructive outflow tract obstruction, 15 (51.7%) had a history of syncope, and one (3.4%) had a family history of HCM. Most patients (86.2%) had New York Heart Association functional class I or II, and the median left ventricular ejection fraction was 63%. A total of 22 patients received pacemaker implantation, including 17 (77.3%) dual-chamber pacing, four (18.2%) single-chamber ventricular pacing, and one (4.5%) cardiac resynchronization therapy. Conclusions: Primary bradyarrhythmias need to be evaluated in HCM patients with arrhythmia-related symptoms. Patients with HCM might need pacemaker implantation for primary bradyarrhythmias.

Syncope in hypertrophic cardiomyopathy (part I): An updated systematic review and meta-analysis

AIMS

To describe the proportion of patients with syncope among those affected by hypertrophic cardiomyopathy (HCM) and the relevance of syncope as risk factor for sudden cardiac death and life-threatening arrhythmic events.

METHOD AND RESULTS

Systematic review of original articles that assessed syncope in HCM patients. Literature search of PubMed including all English publications from 1973 to 2021.We found 57 articles for a total of 21.791 patients; of these, 14 studies reported on arrhythmic events in the follow-up. Syncope was reported in 15.8% (3.452 of 21.791) patients. It was considered unexplained in 91% of cases. Life-threatening arrhythmic events occurred in 3.6% of non-syncopal patients and in 7.7% of syncopal patients during a mean follow-up of 5.6 years. A relative risk of 1.99 (95%CI 1.39 to 2.86) was estimated for syncope patients by the random effect model using Haldane continuity correction for 0 events.

CONCLUSIONS

In the current practice, the cause of syncope remained unexplained in most patients affected by HCM. The management of patients seems mainly driven by risk stratification rather than identification of the aetiology of syncope. There is a need of precise instructions how to apply the recommendations of current guidelines to this disease, which tests are indicated and how to interpret their findings. The protocol was registered in Prospero (ID: 275963).

Unusual Midventricular LV Obstruction With Flow Aimed to the Apex Due to Apical RV Pacing: Elimination by Sequential Septo-Apical RV Pacing

We report the case of an 88-year-old man who developed a mid-left-ventricular (LV) obstruction caused by apical pacing to manage third-degree atrioventricular block. The flow generated by the obstruction was directed toward the LV apex and appeared from late systole to early diastole. The obstruction appeared to result from earlier contraction at the apex compared with the midventricular portion of the LV, which was followed by an also earlier apical relaxation. The obstruction was eliminated by using a second right-ventricular mid-septally attached electrode combined with a sequential septo-apical pacing (septal stimulation 40 ms before apical pacing).

Cardiac Magnetic Resonance Identified the Fibrotic Lesion Associated with Syncope Attack Due to Complete Atrioventricular Block in a Patient with Hypertrophic Cardiomyopathy and Aortic Stenosis

An 84-year-old man presented with syncope. Prior to admission, ambulatory electrocardiogram had demonstrated non-sustained ventricular tachycardia. Echocardiography showed severe aortic stenosis. He was also diagnosed with hypertrophic cardiomyopathy (HCM) by cardiac magnetic resonance (CMR) showing remarkable inhomogeneous left ventricular hypertrophy and extensive late gadolinium enhancement (LGE) in the lesions at the upper border and right-ventricular side of the basal-mid septal wall. Finally, he showed complete atrioventricular (AV) block followed by a long pause and syncope several times after admission. In this case with several possible causes of syncope, the CMR findings suggested a clue concerning the etiology of his syncope: complete AV block in HCM.

A Rare Case of Complete Heart Block in a Young Patient

Introduction

Complete heart block (CHB) is considered as one of the dangerous rhythms since it can progress to lethal arrhythmias such as ventricular tachycardia. It can be congenital or acquired. Patients may present with frequent palpitations, presyncope, dyspnea, or chest pain but also may remain asymptomatic. Extensive work-up should be conducted to exclude secondary causes such as infections, cardiac ischemia or myopathies, autoimmune diseases, or endocrinological diseases. In our paper, we would like to present a case of CHB in the setting of aortic abdominal thrombus that nearly occluded both renal arteries. The CHB in this case is thought to be caused by hypertensive cardiomyopathy due to ongoing uncontrolled hypertension, which is caused by bilateral renal artery stenosis.

Case Presentation

A 31-year-old male with history of active smoking was incidentally found to have high blood pressure, bradycardia, and CHB on electrocardiogram. The patient was admitted to a cardiology ward and extensive work-up revealed hypokinesia of the left ventricle with low ejection fraction and left ventricle concentric hypertrophy, large abdominal aortic thrombus with bilateral renal artery stenosis, and evidence of arterial collateral connections, which suggest chronicity. The patient then was placed on four antihypertensive medications but eventually, he underwent bilateral renal artery stenting and insertion of permanent pacemaker for his CHB. The patient's blood pressure then was under control with only one medication, and subsequent CT angiogram showed no evidence of stenosis of both renal arteries.

Conclusion

Uncontrolled hypertension can lead to hypertensive cardiomyopathy, which in turn can cause conduction abnormalities such as CHB. Although hypertension can be secondary to a treatable underlying cause, permanent pacemaker is essential to treat CHB.

Unmasking the truth

In the emergency setting, shortness of breath is a frequent presenting complaint to physicians worldwide. The differential diagnosis is often broad and requires careful analysis of investigations to reach the correct diagnosis. The authors present a case of acute heart failure with a number of unusual presenting features that suggested an uncommon aetiology.

Severe cardiac conduction disturbances and pacemaker implantation in patients with hypertrophic cardiomyopathy

The aims of this study were to determine the prevalence of severe cardiac conduction disturbances in a cohort of 451 patients with hypertrophic cardiomyopathy and to describe the characteristics of, and outcomes in, those who required a permanent pacemaker. A pacemaker was implanted in 48 patients (11%): 20 had sinus node dysfunction and 28 had an atrioventricular conduction disturbance. Primary bradyarrhythmia (which was not related to iatrogenic atrioventricular block or therapeutic ablation of the atrioventricular node) was the reason for permanent pacemaker implantation in 36 patients (8%). In 18% of cases, at least one other family member had a permanent pacemaker. In this patient series, a high prevalence of severe cardiac conduction disturbance leading to permanent pacemaker implantation was observed. Severe cardiac conduction disturbance in hypertrophic cardiomyopathy may also have a familial component.

Familial conduction system disease associated with hypertrophic cardiomyopathy

A large family with a new phenotype of conduction system disease including heart blocks and preexcitation associated with hypertrophic cardiomyopathy and transmitted in an autosomal dominant pattern is described.

Abnormal His-Purkinje system conduction leading to complete atrioventricular block in patients with hypertrophic cardiomyopathy: a report of 3 cases

This case report describes three hypertrophic cardiomyopathy patients with abnormal His-Purkinje conduction and complete atrioventricular block with attacks of syncope and cardiopulmonary arrest. Although arrhythmias are common in hypertrophic cardiomyopathy, complete atrioventricular block is very rare. Prolonged QRS duration and abnormal His-Purkinje system conduction may result in complete atrioventricular block.