Accelerated idioventricular rhythm as a manifestation of chronic renocardiac syndrome: A case report.

In this case report, we describe a patient who presented with chronic symptoms and signs of uremia and persistent accelerated idioventricular rhythm (AIVR) on electrocardiogram. Findings from blood tests, echocardiography, renal ultrasound, and renal scan were suggestive of heart failure with reduced ejection fraction and chronic kidney disease, and attendance of daily hemodialysis sessions led to the restoration of sinus rhythm. Typically, AIVR has a favorable prognosis and, if necessary, medical intervention focuses on addressing the underlying responsible causes. Accumulation of uremic toxins has the potential to trigger the formation of AIVR and clearance of small solutes through conventional hemodialysis may contribute to sinus rhythm restoration.

Association of clinical, laboratory and imaging biomarkers with the occurrence of acute myocardial infarction in patients without standard modifiable risk factors - rationale and design of the "Beyond-SMuRFs Study".

BACKGROUND: Acute myocardial infarction (AMI) remains the leading cause of mortality worldwide. The majority of patients who suffer an AMI have a history of at least one of the standard modifiable risk factors (SMuRFs): smoking, hypertension, dyslipidemia, and diabetes mellitus. However, emerging scientific evidence recognizes a clinically significant and increasing proportion of patients presenting with AMI without any SMuRF (SMuRF-less patients). To date, there are no adequate data to define specific risk factors or biomarkers associated with the development of AMIs in these patients. METHODS: The ''Beyond-SMuRFs Study'' is a prospective, non-interventional cohort trial designed to enroll patients with AMI and no previous coronary intervention history, who undergo coronary angiography in two academic hospitals in Thessaloniki, Greece. The rationale of the study is to investigate potential relations between SMuRF-less AMIs and the clinical, laboratory and imaging profile of patients, by comparing parameters between patients with and without SMuRFs. Complete demographic and comprehensive clinical data will be recorded, Venous blood samples will be collected before coronary angiography and the following parameters will be measured: total blood count, standard biochemistry parameters, coagulation tests, hormone levels, glycosylated hemoglobin, N- terminal pro-B-type natriuretic peptide and high-sensitivity troponin T levels- as well as serum levels of novel atherosclerosis indicators and pro-inflammatory biomarkers. Furthermore, all participants will undergo a complete and comprehensive transthoracic echocardiographic assessment according to a pre-specified protocol within 24 h from admission. Among others, 2D-speckle-tracking echocardiographic analysis of cardiac chambers and non-invasive calculation of myocardial work indices for the left ventricle will be performed. Moreover, all patients will be assessed for angiographic parameters and the complexity of coronary artery disease using the SYNTAX score. Multivariable linear and logistic regression models will be used to phenotypically characterize SMuRF-less patients and investigate independent clinical, laboratory, echocardiographic and angiographic biomarkers-predictors of SMuRF-less status in AMI.The first patient was enrolled in March 2022 and completion of enrollment is expected until December 2023. DISCUSSION: The ''Beyond-SmuRFs'' study is an ongoing prospective trial aiming to investigate potential clinical, laboratory and imaging biomarkers associated with the occurrence of AMIs in SMuRF-less patients. The configuration of these patients' profiles could lead to the development of personalized risk-stratification models predicting the occurrence of cardiovascular events in SΜuRF-less individuals. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05535582 / September 10, 2022.

Risk assessment of post-myocardial infarction patients with preserved ejection fraction using 45-min short resting Holter electrocardiographic recordings.

BACKGROUND: Risk stratification for sudden cardiac death in post-myocardial infarction (post-MI) patients remains a challenging task. Several electrocardiographic noninvasive risk factors (NIRFs) have been associated with adverse outcomes and were used to refine risk assessment. This study aimed to evaluate the performance of NIRFs extracted from 45-min short resting Holter ECG recordings (SHR), in predicting ventricular tachycardia inducibility with programmed ventricular stimulation (PVS) in post-MI patients with preserved left ventricular ejection fraction (LVEF). METHODS: We studied 99 post-MI ischemia-free patients (mean age: 60.5 ± 9.5 years, 86.9% men) with LVEF ≥40%, at least 40 days after revascularization. All the patients underwent PVS and a high-resolution SHR. The following parameters were evaluated: mean heart rate, ventricular arrhythmias (premature ventricular complexes, couplets, tachycardias), QTc duration, heart rate variability (HRV), deceleration capacity, heart rate turbulence, late potentials, and T-wave alternans. RESULTS: PVS was positive in 24 patients (24.2%). HRV, assessed by the standard deviation of normal-to-normal R-R intervals (SDNN), was significantly decreased in the positive PVS group (42 ms vs. 51 ms, p = .039). SDNN values <50 ms were also associated with PVS inducibility (OR 3.081, p = .032 in univariate analysis, and 4.588, p = .013 in multivariate analysis). No significant differences were identified for the other NIRFs. The presence of diabetes, history of ST-elevation MI (STEMI) and LVEF <50% were also important predictors of positive PVS. CONCLUSIONS: HRV assessed from SHR, combined with other noninvasive clinical and echocardiographic variables (diabetes, STEMI history, LVEF), can provide an initial, practical, and rapid screening tool for arrhythmic risk assessment in post-MI patients with preserved LVEF.

Neuromuscular diseases and their cardiac manifestations under the spectrum of cardiovascular imaging.

Neuromuscular diseases (NMDs) include a broad spectrum of disorders that affect motor unit in every possible site, extending from the cell body of peripheral nerves to the muscle. The different lesion sites make this group of inherited disorders difficult to diagnose. Many NMDs, especially those involving skeletal muscles, can present significant cardiovascular complications, ranging from rhythm disturbances to the development of dilated or hypertrophic cardiomyopathy. Heart disease represents a major cause of morbidity and mortality among NMD patients, underlining the vital need for further familiarization with the pathogenesis and assessment of cardiac involvement. Cardiovascular imaging is the cornerstone for the evaluation of heart disorders in NMDs, with conventional echocardiography still offering a portable, affordable, and easily accessible solution. Meanwhile, newer echocardiographic techniques such as speckle tracking imaging in combination with cardiac magnetic resonance add new insights into further substrate characterization. The purpose of this review is to offer a brief presentation of the main NMDs and their cardiovascular complications, as well as the presentation of data that highlight the importance of cardiovascular imaging in early diagnosis, monitoring, and prognosis of these patients. Lastly, the authors provide a simple guide about which clinical features, imaging findings, and follow-up plan to adopt in each myopathic disorder.

Meta-analysis addressing the impact of cardiovascular-acting medication on peak oxygen uptake of patients with HFpEF.

As our therapeutic armamentarium for HFpEF is insufficient, research has been focusing on the potential beneficial effect of existing pharmaceutical regimens on this specific patient population. A series of RCTs have recently examined the impact of various pharmaceutical treatments with proven benefit in HFrEF, on the improvement of symptoms of HFpEF patients. This systematic review and meta-analysis comprised studies of adult patients with HFpEF and evaluated the impact of different cardiovascular acting medication on cardiorespiratory fitness, reflected by peak VO2 values measured during CPET. The primary outcome was difference between groups in the change of peak VO2 (ΔpeakVO2). Literature search involved PubMed/MEDLINE, Scopus and Web of Science databases. Our search identified 3634 records and 19 studies were included in qualitative analysis; 12 studies with 1341 patients were finally included in primary outcome analysis. ΔpeakVO2 between baseline and study-end did not significantly change after treatment with spironolactone, ivabradine, sildenafil, or oral inorganic nitrate and neither did difference in 6MWT distance after treatment with spironolactone. Spironolactone led to statistically significant reduction in E/E' ratio study-end values (WMD - 1.64, 95%CI - 2.42 to - 0.86, I2 = 87%, p < 0.0001), as well as to a significant increase in MLHFQ values (WMD 0.75, 95%CI 0.02 to 1.48, I2 = 0%, p = 0.65), indicating deterioration in HRQoL among HFpEF patients. A series of established cardiovascular acting medication in HFrEF seems not to confer significant benefit in peak VO2 and 6MWT distance in HFpEF. Spironolactone is associated with improvements in diastolic function and with a significant deterioration in HRQoL of this population.

Effect of sodium-glucose co-transporter-2 inhibitors on arterial stiffness: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Arterial stiffness represents an established cardiovascular risk marker. Sodium-glucose co-transporter-2 (SGLT-2) inhibitors have significant cardio-protective effects. Herein we sought to determine the effect of SGLT-2 inhibitors on pulse wave velocity (PWV). METHODS: We searched PubMed, Cochrane Library, and grey literature from inception to 7th February 2022 for randomized controlled trials (RCTs) enrolling adult subjects with or without type 2 diabetes mellitus (T2DM), assigned to a SGLT-2 inhibitor versus control and addressing their effect on PWV. We set as primary efficacy outcome the change in PWV with SGLT-2 inhibitors versus placebo or control. RESULTS: We pooled data from six trials in a total of 452 enrolled participants assigned either to SGLT-2 inhibitor or control. Overall, SGLT-2 inhibitor treatment compared to control resulted in a nonsignificant decrease in PWV. Exclusion of a trial utilizing cardiac magnetic resonance imaging for the assessment of PWV demonstrated that SGLT-2 inhibitors induce a significant reduction in PWV by 0.21 m/s. When we restricted our analysis to RCTs enrolling subjects with T2DM, we observed that SGLT-2 inhibitor compared to control resulted in a significant decrease in PWV by 0.17 m/s. CONCLUSION: SGLT-2 inhibitors do not decrease PWV in patients with established cardiovascular disease or cardiovascular risk factors. However, we have shown that SGLT-2 inhibitors lead to a slight, but significant decrease in PWV in patients with T2DM. The latter finding is of great value, based on the significant correlation between PWV and micro- and macro-vascular complications of T2DM.

Noninvasive risk factors for the prediction of inducibility on programmed ventricular stimulation in post-myocardial infarction patients with an ejection fraction ≥40% at risk for sudden cardiac arrest: Insights from the PRESERVE-EF study.

BACKGROUND: In the PRESERVE-EF study, a two-step sudden cardiac death (SCD) risk stratification approach to detect post-myocardial infarction (MI) patients with left ventricle ejection fraction (LVEF) ≥40% at risk for major arrhythmic events (MAEs) was used. Seven noninvasive risk factors (NIRFs) were extracted from a 24-h ambulatory electrocardiography (AECG) and a 45-min resting recording. Patients with at least one NIRF present were referred for invasive programmed ventricular stimulation (PVS) and inducible patients received an Implantable Cardioverter - Defibrillator (ICD). METHODS: In the present study, we evaluated the performance of the NIRFs, as they were described in the PRESERVE-EF study protocol, in predicting a positive PVS. In the PRESERVE-EF study, 152 out of 575 patients underwent PVS and 41 of them were inducible. For the present analysis, data from these 152 patients were analyzed. RESULTS: Among the NIRFs examined, the presence of signal averaged ECG-late potentials (SAECG-LPs) ≥ 2/3 and non-sustained ventricular tachycardia (NSVT) ≥1 eposode/24 h cutoff points were important predictors of a positive PVS study, demonstrating in the logistic regression analysis odds ratios 2.285 (p = .027) and 2.867 (p = .006), respectively. A simple risk score based on the above cutoff points in combination with LVEF < 50% presented high sensitivity but low specificity for a positive PVS. CONCLUSION: Cutoff points of NSVT ≥ 1 episode/24 h and SAECG-LPs ≥ 2/3 in combination with a LVEF < 50% were important predictors of inducibility. However, the final decision for an ICD implantation should be based on a positive PVS, which is irreplaceable in risk stratification.

Ultrasound-guided versus anatomic landmark-guided vascular access in cardiac electrophysiology procedures: A systematic review and meta-analysis.

INTRODUCTION: Electrophysiology (EP) procedures are nowadays the gold-standard method for tachyarrhythmia treatment with impressive success rates, but also with a considerable risk of complications, mainly vascular. A systematic review and meta-analysis was performed to evaluate the safety of ultrasound (US)-guided femoral vein access in EP procedures compared to the traditional anatomic landmark-guided method. METHODS: We searched Pubmed (MEDLINE), Embase, Web of Science, and Cochrane electronic databases for relevant entries, dated from January 1st, 2000 to June 30th, 2021. Only observational studies and randomized controlled trials were included in this analysis. Data extraction included study details, patient characteristics, procedure details, and all types of vascular complications. Complications were classified as major if any intervention, prolongation of hospitalization, or readmission was required. RESULTS: 9 studies (1 randomized controlled trial and 8 observational), with 7858 participants (3743 in the US-guided group, 4115 in the control group), were included in the meta-analysis. Overall vascular complication rates were significantly decreased in the US-guided group compared to the control group (1.2 versus 3.2%, RR = 0.38, 95% CI, 0.27-0.53), in all EP procedures. Sub-group analysis of AF ablation procedures yielded similar results (RR 0.41, 95% CI, 0.29-0.58, p < 0.00001). The event reduction effect was significant for both major and minor vascular complications. CONCLUSION: US-guided vascular access in EP procedures is associated with significantly reduced vascular complications, compared to the standard anatomic landmark-guided approach, regardless of procedure complexity.

Fibrosis in hypertrophic cardiomyopathy: role of novel echo techniques and multi-modality imaging assessment.

Hypertrophic cardiomyopathy (HCM) represents one of the primary cardiomyopathies and may lead to heart failure and sudden cardiac death. Among various histologic features of the disease examined, assessment of myocardial fibrosis may offer valuable information, since it may be considered the common nominator for all HCM connected complications. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) has emerged as the reference noninvasive method for visualizing and quantifying myocardial fibrosis in patients with HCM. T1 mapping, a promising new CMR technique, may provide an advantage over conventional LGE-CMR, by permitting a more valid quantification of diffuse fibrosis. On the other hand, echocardiography offers a significantly more portable, affordable, and easily accessible solution for the study of fibrosis. Various echocardiographic techniques ranging from integrated backscatter and contrast-enhanced ultrasound to two- (2D) or three-dimensional (3D) deformation and shear wave imaging may offer new insights into substrate characterization in HCM. The aim of this review is to describe thoroughly all different modalities that may be used in everyday clinical practice for HCM fibrosis evaluation (with special focus on echocardiographic techniques), to concisely present available evidence and to argue in favor of multi-modality imaging application. It is essential to understand that the role of various imaging modalities is not competitive but complementary, since the information provided by each one is necessary to illuminate the complex pathophysiologic pathways of HCM, offering a personalized approach and treatment in every patient.

Impact of centre volume on atrial fibrillation ablation outcomes in Europe: a report from the ESC EHRA EORP Atrial Fibrillation Ablation Long-Term (AFA LT) Registry.

AIMS: The aim of the study was to investigate differences in clinical outcomes and complication rates among European atrial fibrillation (AF) ablation centres related to the volume of AF ablations performed. METHODS AND RESULTS: Data for this analysis were extracted from the ESC EHRA EORP European AF Ablation Long-Term Study Registry. Based on 33rd and 67th percentiles of number of AF ablations performed, the participating centres were classified into high volume (HV) (≥ 180 procedures/year), medium volume (MV) (<180 and ≥74/year), and low volume (LV) (<74/year). A total of 91 centres in 26 European countries enrolled in 3368 patients. There was a significantly higher reporting of cardiovascular complications and stroke incidence in LV centres compared with HV and MV (P = 0.039 and 0.008, respectively) and a lower success rate after AF ablation (55.3% in HV vs. 57.2% in LV vs. 67.4% in MV centres, P < 0.001), despite lower CHA2DS2-VASc score of patients, enrolled in LVs and less complex ablation techniques used. Adjustments of confounding factors (including type of AF ablation) led to elimination of these differences. CONCLUSION: Low-volume centres tended to present slightly higher cardiovascular complications' and stroke incidence and a lower unadjusted success rate after AF ablation, despite the fact that ablation procedures and patients were of lower risk compared with MV and HV centres. On the other hand, adjusted overall complication and recurrence rates were non-significantly different among different volume centres, a fact reflecting the heterogeneity of patient and procedural profiles, and a counterbalance between expertise and risk level among participating centres.

EHRA expert consensus statement and practical guide on optimal implantation technique for conventional pacemakers and implantable cardioverter-defibrillators: endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), and the Latin-American Heart Rhythm Society (LAHRS).

With the global increase in device implantations, there is a growing need to train physicians to implant pacemakers and implantable cardioverter-defibrillators. Although there are international recommendations for device indications and programming, there is no consensus to date regarding implantation technique. This document is founded on a systematic literature search and review, and on consensus from an international task force. It aims to fill the gap by setting standards for device implantation.

Iron deficiency as therapeutic target in heart failure: a translational approach.

Heart failure (HF) is a potentially debilitating condition, with a prognosis comparable to many forms of cancer. It is often complicated by anemia and iron deficiency (ID), which have been shown to even further harm patients' functional status and hospitalization risk. Iron is a cellular micronutrient that is essential for oxygen uptake and transportation, as well as mitochondrial energy production. Iron is crucially involved in electrochemical stability, maintenance of structure, and contractility of cardiomyocytes. There is mounting evidence that ID indeed hampers the homeostasis of these properties. Animal model and stem cell research has verified these findings on the cellular level, while clinical trials that treat ID in HF patients have shown promising results in improving real patient outcomes, as electromechanically compromised cardiomyocytes translate to HF exacerbations and arrhythmias in patients. In this article, we review our current knowledge on the role of iron in cardiac muscle cells, the contribution of ID to anemia and HF pathophysiology and the capacity of IV iron therapy to ameliorate the patients' arrhythmogenic profile, quality of life, and prognosis.

Arrhythmic risk stratification in post-myocardial infarction patients with preserved ejection fraction: the PRESERVE EF study.

AIMS: Sudden cardiac death (SCD) annual incidence is 0.6-1% in post-myocardial infarction (MI) patients with left ventricular ejection fraction (LVEF)≥40%. No recommendations for implantable cardioverter-defibrillator (ICD) use exist in this population. METHODS AND RESULTS: We introduced a combined non-invasive/invasive risk stratification approach in post-MI ischaemia-free patients, with LVEF ≥ 40%, in a multicentre, prospective, observational cohort study. Patients with at least one positive electrocardiographic non-invasive risk factor (NIRF): premature ventricular complexes, non-sustained ventricular tachycardia, late potentials, prolonged QTc, increased T-wave alternans, reduced heart rate variability, abnormal deceleration capacity with abnormal turbulence, were referred for programmed ventricular stimulation (PVS), with ICDs offered to those inducible. The primary endpoint was the occurrence of a major arrhythmic event (MAE), namely sustained ventricular tachycardia/fibrillation, appropriate ICD activation or SCD. We screened and included 575 consecutive patients (mean age 57 years, LVEF 50.8%). Of them, 204 (35.5%) had at least one positive NIRF. Forty-one of 152 patients undergoing PVS (27-7.1% of total sample) were inducible. Thirty-seven (90.2%) of them received an ICD. Mean follow-up was 32 months and no SCDs were observed, while 9 ICDs (1.57% of total screened population) were appropriately activated. None patient without NIRFs or with NIRFs but negative PVS met the primary endpoint. The algorithm yielded the following: sensitivity 100%, specificity 93.8%, positive predictive value 22%, and negative predictive value 100%. CONCLUSION: The two-step approach of the PRESERVE EF study detects a subpopulation of post-MI patients with preserved LVEF at risk for MAEs that can be effectively addressed with an ICD. CLINICALTRIALS.GOV IDENTIFIER: NCT02124018.

Electrophysiological markers predicting impeding AV-block during ablation of atrioventricular nodal reentry tachycardia.

BACKGROUND: Radiofrequency (RF) ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is occasionally complicated with atrioventricular block (AVB) often predicted by junctional beats (JB) with loss of ventriculo-atrial (VA) conduction. METHODS: We analyzed retrospectively 153 patients undergoing ablation of SP for typical AVNRT. Patients were divided into two age groups: 127 ≤ 70 years and 26 > 70 years. We analyzed the interval between the atrial electrogram in the His-bundle position and the distal ablation catheter [A(H)-A(RFd)] and between the distal ablation catheter and the proximal coronary sinus catheter [A(RFd)-A(CS)] before RF applications with and without JB. We evaluated if these intervals can be used as predictors of JB incidence and also of JB with loss of VA conduction. We also assessed if age influences the risk of loss of VA conduction. RESULTS: The A(H)-A(RFd) and A(RFd)-A(CS) intervals were significantly shorter in RF applications causing JB than those without JB (33 ± 11 ms vs 39 ± 9 ms, P < 0.001, 14 ± 9 ms vs 20 ± 7 ms, P < 0.001, respectively). The A(H)-A(RFd) and A(RFd)-A(CS) intervals were also significantly shorter in RFs causing JB with VA block than those with VA conduction (29 ± 11 ms vs 35 ± 11 ms, P < 0.001, 8 ± 8 ms vs 17 ± 8 ms, P < 0.001, respectively). Patients > 70 years had shorter intervals (36 ± 11 ms vs 29 ± 8 ms, P  =  0.012, 17 ± 8 ms vs 13 ± 7 ms, P  =  0.027, respectively), while VA block was more common in this age group. CONCLUSIONS: The A(H)-A(RFd) and A(RFd)-A(CS) intervals can be used as markers for predicting JB occurrence as well as impending AVB. JB with loss of VA conduction occur more often in older patients possibly due to a higher position of SP.

Left atrial voltage mapping using a new impedance-based algorithm in patients with paroxysmal atrial fibrillation.

AIMS: Atrial fibrosis is associated with the pathogenesis and progression of atrial fibrillation (AF). We sought to evaluate the extent of left atrial (LA) scarring in patients with paroxysmal AF (PAF) undergoing catheter ablation using a new impedance-based algorithm. METHODS: We prospectively enrolled 73 consecutive patients (43 males, 58 years) with PAF who underwent pulmonary vein antral isolation. We first performed high-density bipolar voltage mapping during sinus rhythm using Tissue Proximity Indicator (TPI), one of the features of the ConfiDense mapping module integrated in the electroanatomic mapping system. A dense LA shell was created initially without TPI (mean points 2,411) and subsequently activating TPI (mean points 1,167). Each point was classified according to the peak-to-peak bipolar voltage electrogram based on two criteria (criterion A: healthy >0.8 mV, border zone: 0.4-0.8 mV, scarred: <0.4 mV; criterion B: healthy: >0.5 mV, border zone: 0.25-0.5 mV, scarred: <0.25 mV). RESULTS: LA voltage analysis represented significantly smaller scarred areas when mapping was performed with TPI-ON compared with TPI-OFF in both voltage criteria (average LA voltage area: 3.02 ± 5.28 cm2 vs 9.15 ± 13.11 cm2 vs in criterion A and 1.19 ± 2.54 cm2 vs 5.61 ± 9.56 cm2 in criterion B). A statistically significant voltage difference was observed in all segments of the left atrium between the two mapping protocols, particularly on the inferior wall. CONCLUSION: A more specific delineation of LA fibrosis may be produced using the TPI feature of the ConfiDense mapping module, through elimination of false-positive annotated mapping points due to low contact.

Coincidental ganglionated plexus modification during radiofrequency pulmonary vein isolation and post-ablation arrhythmia recurrence.

AIMS: Vagal responses (VR) during left atrial ablation for atrial fibrillation (AF) treatment have been reported to be associated with less recurrences, presumably because they are a sign of ganglionated plexi modification. Our objective was to evaluate whether coincidentally elicited VR during left atrial ablation are associated with lower AF recurrence rates. METHODS AND RESULTS: This is a post hoc analysis of a prospective study of 291 patients with paroxysmal AF undergoing radiofrequency pulmonary vein isolation (PVI). Vagal responses were defined as episodes of heart rate <40 bpm or asystole lasting >5 s elicited during energy application. Sixty-eight patients (23.4%) had a VR during ablation. In Kaplan-Meier analysis, mean recurrence-free survival was 449 days (95% confidence interval 411-488) in patients with VR when compared with 435 days (95% confidence interval 415-455) in those without (P = 0.310). The 12-month recurrence rate estimates were 25 and 27%, respectively. In an unadjusted Cox model, VR was associated with an odds ratio for recurrence of 0.77 (95% confidence interval 0.46-1.28). CONCLUSION: Coincidentally elicited VR during radiofrequency PVI in patients with paroxysmal AF do not appear to be related to lower risk of arrhythmia recurrence. This may mean that, even if a VR is truly a sign of coincidental ablation of a ganglionated plexus, this does not necessarily mean that a therapeutic modification has been effected, at least to a degree associated with clinical benefit.

Electrical storm in a patient with Duchenne muscular dystrophy cardiomyopathy triggered by abrupt ß-blocker interruption.

We present a case of a young man with Duchenne muscular dystrophy cardiomyopathy (DMDC) having an implantable cardioverter defibrillator for secondary prevention, who presented with electrical storm shortly after ß-blocker interruption. The patient was stabilized and remained free of ventricular arrhythmias soon after reinitiating b-adrenoreceptor antagonists. The present case highlights the importance of sympathetic blockage in patients with DMDC due to existing pathophysiology of excess diastolic Ca2+ leak from sarcoplasmic reticulum as a result of ryanodine receptor dysfunction.