Frequent Premature Ventricular Contractions Research Articles

Successful ablation of premature ventricular contractions originating from the posterior-superior process of the left ventricle approaching from the right atrium in a 13-year-old male.

This is a case of a 13-year-old male with frequent premature ventricular contractions with QRS configurations of the left superior axis and left bundle branch block, which originated from the posterior-superior process of the left ventricle. Premature ventricular contractions were successfully eliminated by delivering radiofrequency energy to the inferior wall of the right atrium without causing either junctional rhythm or atrioventricular block. Ventricular arrhythmias originating from this site have been sporadically reported in adults; however, this is the first report in a child.

Impact of left ventricular hypertrophy on frequency and complexity of ventricular arrhythmia among hypertensive Egyptian patients

BackgroundLeft ventricular hypertrophy (LVH) is associated with an increased risk of ventricular arrhythmias and cardiovascular mortality. The study objective was to investigate the effect of LVH severity on the complexity and severity of ventricular arrhythmias among a subset of Egyptian hypertensive patients.ResultsThe study cohort consisted of 60 hypertensive patients with LVH as diagnosed by echocardiography. Their mean age was (53.7 ± 12.3) years. 36 males (40%) and 24 females (60%). Diabetes mellitus was found in 26 patients (43%), 41% of these cases were smokers. 48-h Holter monitoring was performed in all cases to assess the frequency of ventricular premature contractions (VPC) and their complexity using the Lown grading. Increasing posterior wall thickness end diastole (PWTd) was an independent predictor of increasing VPC frequency, each 1 mm increase in the PWTd is associated with a 1.26% increase in the VPC% among total heart beats (b = 12.6, p < 0.001). Higher-grade VPCs—defined as grade 4a, 4b, and 5—were seen in 29 patients (48.3%). Interventricular septum thickness end diastole, PWTd, left ventricular mass, and left ventricular mass index (LVMI), were significantly higher among patients with higher Lown grading (p < 0.001). Using logistic regression analysis, female sex and LVMI were independent predictors of more complex VPC (OR = 8.766, p = .014), (OR = 1.096, p < 0.001), respectively. Among females, LVMI of more than 120 g/m2 can differentiate between high- and low-grade VPCs with 71% sensitivity and 80% specificity, while among males, LVMI of more than 129.5 g/m2 can differentiate between high and low-grade VPCs with 86% sensitivity and 66% specificity.ConclusionsThe frequency and complexity of ventricular arrhythmias among hypertensive heart disease are correlated with the severity of ventricular hypertrophy. Female sex and increasing left ventricular mass index are independent predictors of more complex forms of ventricular arrhythmias.

Diagnosis and treatment of arrhythmogenic cardiomyopathy in children

Objective: To summarize the clinical manifestations, experiences in diagnosis and treatment of arrhythmogenic cardiomyopathy (ACM) in children. Methods: A retrospective analysis of the clinical manifestations, laboratory tests, radiological features, treatment and follow-up results was conducted in 11 children diagnosed with ACM at the center of congenital heart disease, Beijing anzhen hospital from May 2010 to March 2022. Results: A total of 11 patients aged 2 to 16 years, including 5 males and 6 females were diagnosed with ACM. The clinical manifestations included decreased activity tolerance (7 patients), heart failure (4 patients), syncope or sudden death (3 patients), palpitation (3 patients), and chest tightness and pain (3 patients). Electrocardiogram showed right bundle branch block in 9 cases, paroxysmal ventricular tachycardia in 4 cases, frequent premature ventricular contraction in 4 cases, ventricular pre-excitation in 1 case, left bundle branch block in 1 case, and first degree atrioventricular block in 2 cases. Echocardiography showed enlargement of the right heart, widening of the right ventricular outflow tract, and thinning and bulging of the local wall of the right ventricle with reduced pulsation. Ventricular thrombosis was found in 2 cases. Six children underwent cardiac magnetic resonance imaging, which mainly showed severe enlargement of the right heart, thin free wall of the right ventricle, decreased right heart function, enhanced right ventricular myocardium, and formation of right ventricular aneurysm. Two children underwent myocardial biopsy examination and presented with typical pathological changes of ACM. Genetic tests in five patients revealed DSG2 gene mutation in 2 cases, PKP2 gene mutation in 2 cases, and MYH6 gene mutation in 1 case. All patients received anti heart failure treatment and antiarrhythmic drugs. Two children received anticoagulant treatment due to ventricular thrombosis. Radiofrequency ablation was performed in 2 patients. Glenn procedure was performed in 4 patients, and heart transplantation was performed in 1 patient due to progressive heart failure. The follow-up period ranged from 6 months to 12 years. Two cases died of right heart failure, 6 cases had different degrees of heart failure, 1 case had intermittent chest tightness and pain, and 2 cases were stable. Conclusions: ACM is a progressive genetic cardiomyopathy characterized by decreased activity tolerance, cardiac failure and arrhythmia in pediatric patients. The diagnosis is mainly based on clinical manifestations, electrocardiogram, cardiac imaging changes, and genetic testing. Early detection, diagnosis, and personalized treatment can improve the prognosis.

Variable clinical expression of a novel FLNC truncating variant in a large family

BackgroundVariants in Filamin-C (FLNC) have been associated with various hereditary cardiomyopathies. Recent literature reports a prevalence of sudden cardiac death (SCD) of 13–25% among carriers of truncating-variants, with mean age of 42±15 years for first SCD event. This study reports two familial cases of SCD and the results of cascade screening of their large family. MethodsMolecular-autopsy of the SCD victims revealed a novel truncating-variant in the FLNC gene (chr 7:128496880 [hg19]; NM_001458.5; c.7467_7474del; p.(Ser2490fs)). We screened thirty-two family members following genetic counseling, and variant carriers underwent a comprehensive workup followed by consultation with a cardiologist with expertise in the genetics of cardiac diseases. ResultsSeventeen variant carriers were identified: ages between 9 and 85 (mean 47±26). Fifteen underwent clinical evaluation. To date, none of the identified carriers has had major adverse events. In evaluated patients, ECG showed right-axis deviation in 60% (n = 9). Holter recorded frequent premature ventricular contractions (PVCs) (991±2030 per 24 h) in 33% (n = 5) with 4 patients having polymorphic PVC morphology. Three carriers had echocardiographic evidence of mild left-ventricular (LV) systolic dysfunction and another with mild LV dilatation. Cardiac magnetic-resonance (CMR) exhibited late‑gadolinium-enhancement in 10 out of 11 exams, mainly in the mid-myocardium and sub-epicardium, frequently involving the septum and the inferior-lateral wall. ConclusionThis large FLNC truncating variant carrier family exhibits high cardiomyopathy penetrance, best diagnosed by CMR, with variable clinical expressions. These findings present a challenge in SCD prevention management and underscoring the imperative for better risk stratification measures.

Prevalence of frequent premature ventricular contractions and nonsustained ventricular tachycardia in older women screened for atrial fibrillation in the Women’s Health Initiative

BackgroundFrequent premature ventricular contractions (PVCs) and nonsustained ventricular tachycardia (NSVT) have been associated with cardiovascular disease and mortality. Their prevalence, especially in ambulatory populations, is understudied and limited by few female participants and the use of short-duration (24- to 48-hour) monitoring. ObjectiveThe objective of this study was to report the prevalence of frequent PVCs and NSVT in a community-based population of women likely to undergo electrocardiogram (ECG) screening by sequential patch monitoring. MethodsParticipants from the Women’s Health Initiative Strong and Healthy (WHISH) trial with no history of atrial fibrillation (AF) but 5-year predicted risk of incident AF ≥5% by CHARGE-AF score were randomly selected to undergo screening with 7-day ECG patch monitors at baseline, 6 months, and 12 months. Recordings were reviewed for PVCs and NSVT (>5 beats); data were analyzed with multivariate regression models. ResultsThere were 1067 participants who underwent ECG screening at baseline, 866 at 6 months, and 777 at 12 months. Frequent PVCs were found on at least 1 patch from 4.3% of participants, and 1 or more episodes of NSVT were found in 12 (1.1%) women. PVC frequency directly correlated with CHARGE-AF score and NSVT on any patch. Detection of frequent PVCs increased with sequential monitoring. ConclusionIn postmenopausal women at high risk for AF, frequent PVCs were relatively common (4.3%) and correlated with higher CHARGE-AF score. As strategies for AF screening continue to evolve, particularly in those individuals at high risk of AF, the prevalence of incidental ventricular arrhythmias is an important benchmark to guide clinical decision-making.

Difficulties in selecting antiarrhythmic therapy in a patient with left ventricular noncompaction and atrial septal defect: a case report

Introduction. Left ventricular noncompaction (LVNC) is a rare heterogeneous pathology characterized by a two-layered structure with a predominance of non-compact layer in the form of multiple trabeculations and pockets between them, communicating with the left ventricular cavity. One of the rare LVNC phenotypes is a combination with congenital heart defects, including atrial septal defect (ASD).Brief description. The article presents a case report describing the difficulties of selecting antiarrhythmic therapy in a patient with LVNC and ASD, complicated by arrhythmias due to heart failure. The diagnosis of LVNC was confirmed by the Petersen criterion using magnetic resonance imaging.Discussion. Cardiac arrhythmias in patients with LVNC and congenital heart defects, as a result of both anatomical and hemodynamic causes of electrical heart instability, constitute a danger of thromboembolism and sudden cardiac death, and also contribute to heart failure progression. The case is of interest due to the rare combination of LVNC and ASD, complicated by frequent episodes atrial fibrillation and premature ventricular contractions in the form of parasystoles, as well as difficulties in selecting antiarrhythmic therapy. Pulmonary vein cryoballoon ablation eliminated the source of atrial fibrillation. Ventricular ectopic activity was stopped using the anticonvulsant drug carbamazepine.

Propensity-score matched comparison of renal and neurohormonal effects of catheter ablation for frequent premature ventricular contractions in patients with and without systolic dysfunction.

Catheter ablation (CA) for premature ventricular contractions (PVCs) restores cardiac and renal functions in patients with reduced left ventricular ejection fraction (LVEF); however, its effects on preserved EF remain unelucidated. The study cohort comprised 246 patients with a PVC burden of >10% on Holter electrocardiography. Using propensity matching, we compared the changes in B-type natriuretic peptide (BNP) levels and estimated glomerular filtration rate (eGFR) in patients who underwent CA or did not. Postoperative BNP levels were decreased significantly in the CA group, regardless of the degree of LVEF, whereas there was no change in those of the non-CA group. Among patients who underwent CA, BNP levels decreased from 44.1 to 33.0 pg/mL in those with LVEF ≥50% (p = .002) and from 141.0 to 87.9 pg/mL in those with LVEF <50% (p < .001). Regarding eGFR, postoperative eGFR was significantly improved in the CA group of patients with LVEF ≥50% (from 71.4 to 74.7 mL/min/1.73 m2, p = .006), whereas it decreased in the non-CA group. A similar trend was observed in the group with a reduced LVEF. Adjusted for propensity score matching, there was a significant decrease in the BNP level and recovery of eGFR after CA in patients with LVEF >50%. This study showed that CA for frequent PVCs decreases BNP levels and increases eGFR even in patients with preserved LVEF.

Association between excess catecholamine synthesis and polymorphic premature ventricular contraction

BackgroundThe reasons for the etiology of premature ventricular contractions (PVCs) are not specifically known. Many patients are resistant to medical treatment, and a factor that would predict response to medical treatment cannot be identified. This study aims to investigate if a high catecholamine level results in polymorphic PVC. MethodsThis study was obtained by prospective data registry analysis. A total of 100 patients, 50 from the PVC group, and 50 from the control group have been evaluated. The participants who were included in the patient group had a polymorphic PVC of 5% or more in their 24-h Holter evaluations. Metanephrine showing the level of adrenaline and normetanephrine, showing the level of noradrenaline levels have been measured from these urine samples. ResultThere was no difference between the two groups in terms of biochemical and essential characteristics. Normetanephrine level has been significantly higher in the PVC group compared to the control group (323.9 ± 208.9 μg to 129.25 ± 67.88 μg; p < 0.001). Similarly, metanephrine level has also been higher in the PVC group (124.75 ± 82.43 μg to 52.615 ± 36,54 μg; p < 0.001). A positive and moderate correlation has been identified between the number and ratio of PVC and the metanephrine and normetanephrine levels. ConclusionIn this study, we found that the catecholamine levels were higher in the polymorphic PVC group than in the healthy volunteers. Also, an increase in the number and rate of PVC has been observed as the catecholamine levels increased. Clinical Trial RegistrationUrine Levels of Metanephrine and Normetanephrine in Patients With Frequent PVC; ClinicalTrials.gov number NCT03447002

Detection of cardiac arrhythmias following acute coronary syndrome using a connected continuous rhythm monitoring device

Abstract Background The incidence of cardiac arrhythmias following acute coronary syndrome (ACS) is not well-known. Purpose To describe the incidence of clinically relevant cardiac arrhythmias following low-risk ACS, using a connected continuous rhythm monitoring device. Methods In a prospective, single arm and open label, observational study, patients in sinus rhythm and with a left ventricular ejection fraction &amp;gt; 40% discharged home after an ACS were equipped with a rhythm monitoring tee-shirt, providing a high-quality continuous 15-lead electrocardiogram signals. Patients were prompted to wear the device as much as possible, for a maximum length of 30 days. Recorded data were reviewed by two independent cardiologists. The primary endpoint was the occurrence of clinically relevant arrhythmias – defined as either new atrial fibrillation, ventricular tachycardia, accelerated idioventricular rhythm or frequent premature ventricular contractions (≥ 500/day) – detected by the device over the first 30 days after hospital discharge following the ACS. Results From January 2020 to August 2022, 99 patients were discharged home with a functional rhythm monitoring device, among whom 45 (55%) were ST-segment elevation myocardial infarction. The median recording duration was 13 days (range: 1-30), with a median workable signal of 9 days. Recorded data were interpretable in 82 patients. At least one clinically relevant arrhythmia occurred in 10 patients (12.2%) during follow-up. Median time to first arrhythmia was 16,5 days (IQR: 8,5-23). Paroxysmal atrial fibrillation was detected in 3 patients (3.7%), non-sustained ventricular tachycardia in 4 patients (4.9%), accelerated idioventricular rhythm in 3 patients (3.7%) and frequent premature ventricular contractions in 5 patients (6.1%) (Figure 1). None of these arrhythmias were symptomatic. No sustained ventricular tachycardia was detected. Conclusions Asymptomatic cardiac arrhythmias were frequent after ACS in patients considered at low risk for further events. The long-term clinical risk of these arrhythmias remains to be studied.

The role of heart rate variability in predicting the response to beta blocker in patients with frequent premature ventricular contractions

Abstract Background Frequent premature ventricular contractions (PVCs) in patients with structurally normal heart are not uncommon. Beta blocker is generally used to reduce symptom and burden of PVCs, but the response to beta blockers vary from patient to patient. Purpose This study aimed to investigate whether the heart rate variability (HRV) values could predict the response to beta blockers in patients with frequent PVCs. Methods We analyzed the patients who underwent 24-hour Holter monitoring and had PVC burden &amp;gt;3% in baseline 24-hour Holter monitoring. Bisoprolol and nebivolol was used to reduce symptom and burden of PVCs. The response to beta blocker was defined as the reduction of PVCs burden more than 50% in follow-up Holter monitoring. Baseline HRV was measured by time domain and frequency domain methods using 24-hour Holter monitoring. Results A total of 125 patients (mean age, 52.1 ± 14.7 years; male, 38.3%) underwent repeated 24-hour Holter monitoring were finally analyzed. Mean follow-up duration between the Holter monitoring was 205 ± 200 days. Among 125 patients with frequent PVCs, 45 patients had response to beta blockers. The ratio of low-frequency (LF) and high-frequency (HF) was higher in response group than those with non-response to beta blocker (P=0.016). LF, HF, and other variables measured by time-domain method were not associated with response to beta blocker. Conclusion The HRV value, especially LF/HF ratio, could predict the response to beta blockers in patients with idiopathic frequent PVCs.

Novel PVC detection algorithm in an implantable cardiac monitor for longitudinal risk monitoring

Abstract Background Guideline therapy is recommended in patients with frequent premature ventricular contractions (PVCs). Longitudinal monitoring of the PVC burden can effectively guide treatment options, stratify patient risk, and manage HF progression. Implantable cardiac monitors (ICMs) may provide a suitable long-term diagnostic tool to monitor PVC burden and guide clinical therapy. Objective Quantify the performance of a novel QRS morphology and timing-based PVC detection algorithm as implemented for an ICM. Methods The algorithm utilizes self-adapting timing-based ectopy detection and dynamic measures of QRS morphology to identify unifocal and multifocal PVCs. The training dataset consisted of 200 sECG episodes recorded in implanted BIOMONITOR (BM) devices, collected from 48 patients. The algorithm was then evaluated on 227 sixty-second duration sECG episodes from 79 BM patients in the CERTITUDE registry. Each beat was adjudicated as normal, PVC, or PAC by at least two clinical experts. In a total of 22,433 beats, 756 true PVCs were assessed (3.4% PVC prevalence). Overall, patient averaged, and generalized estimating equation (GEE) estimates for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated, as well as patient-specific PVC burden (PVCs/Total Beats). Results Patient-averaged PVC detection sensitivity was 73.8%, with a PPV of 89.2%, specificity of 99.6%, and NPV of 99.1%. Using a GEE model to adjust for multiple episodes per patient, the algorithm achieved detection sensitivity of 66.6±9.8% (95% CI) and PPV of 86.6±6.5%, with specificity of 99.5±0.4% and NPV of 99.0±0.5%. The main reasons for missed PVC detections were morphological similarities to normal beats, insufficient prematurity, or lack of a compensatory pause. Additionally, the algorithm faithfully represented the PVC burden, with a median difference of -0.24% between the PVC burden calculated by the detection algorithm and the adjudicated burden. Algorithm burden was highly correlated with the true PVC burden for each patient, with a Pearson correlation coefficient of 0.80 (p &amp;lt; 0.0001). Conclusions The PVC detection algorithm was highly specific, achieving a specificity of 99.6% and a sensitivity of 73.8%, and accurately representing the overall PVC burden for each patient. This PVC detection algorithm would provide a valuable clinical diagnostic marker to monitor PVC burden trends to guide therapy as well as assess the longitudinal risk of HF. Measurement of PVC burden combined with the 5.5-year longevity of the BIOMONITOR ICM could provide an innovative approach to optimize clinical management of patients.Example PVCs detected by the algorithm

Cardiac Sarcoidosis treated with non-steroidal immunosuppressive therapy

Abstract Background Non-steroidal immunosuppressive therapy is a potential treatment strategy for cardiac sarcoidosis. However, due to the lack of robust evidence, it is not recommended as an established treatment option in the guideline. Purpose The purpose of the study is to demonstrate the clinical outcome of the patients with cardiac sarcoidosis using non-steroidal immunosuppressive therapy in a retrospective registry entitled ILLUMINATE-CS (ILLUstration of the Management and prognosIs of JapaNese pATiEnts with Cardiac Sarcoidosis). Methods Of an entire cohort of 512 patients, 26 who received immunosuppressive therapy other than steroids were recruited for the analysis. The clinical outcome included all-cause death, fatal ventricular arrhythmic event (FVAE), and worsening heart failure with hospitalization. Results The reasons to use non-steroidal immunosuppressant were increased fluorodeoxyglucose (FDG) accumulation on the heart suggesting worsened inflammation (n = 13), side effects of steroid (n = 7), ventricular tachycardia or frequent ventricular premature contraction (n=4), complete atrioventricular block (n = 2), worsened symptom relating to non-cardiac sarcoidosis including neuro and pulmonary sarcoidosis (n = 2), and the other reason (n = 2), with some overlapping. Used non-steroidal immunosuppressants were comprised of methotrexate (n = 20, 6.9 ± 2.1 mg/week), cyclosporine (n =2, 75 or 100 mg/day), cyclophosphamide (n = 2, 25 or 50 mg/day), and azathioprine (n = 3, 100 mg/day in each). Side effects of non-steroidal immunosuppressant were observed in six cases and included one with methotrexate-related interstitial pneumonia, one with a methotrexate-associated lymphoproliferative disorder, one with septic coxitis with methotrexate, one with methotrexate-induced acute kidney injury, one with methotrexate-induced hepatic dysfunction, and one with azathioprine-induced anemia. After the addition of a non-steroidal immunosuppressant, steroids could be reduced in 14 cases of 26 cases with a median maintenance dose of 5 (interquartile range of 5–17) mg, although no cases stopped steroids. Of 13 cases who started non-steroidal immunosuppressant for the increased FDG uptake, decreased FDG uptake was observed in seven cases at the follow-up scan. Clinical outcome events were observed in 11 cases (42.3%). Detected events included all-cause death in five cases (19.2%), FVAE in four cases (15.4%), and worsening heart failure with hospitalization in five cases (19.2%), with some overlapping. Conclusions Non-steroidal immunosuppressive therapy may be a possible treatment option for patients who are not stabilized using sole steroid therapy or who suffer from the side effects of steroids.

Arrhythmic form of mitral valve prolapse: presentation, risk stratification and management

Abstract Background Mitral valve prolapse (MVP) is a common finding that has been considered as benign condition for a long time. However, some anatomic forms have been recently recognized to be associated with life-threatening ventricular arrhythmia and sudden cardiac death (SCD), recently known as arrhythmic MVP (AMVP). Objectives This study is aiming to clinically characterize and risk stratify patients with malignant phenotype of MVP of high risk for ventricular arrhythmia which may lead to SCD. We aim to explore characteristics and assess potential markers for MVP induced ventricular arrhythmia that might need monitoring and follow up with medical or invasive treatment as implantable cardioverter-defibrillator, catheter ablation or even surgical repair. Methods A prospective cohort study of 45 (age 35±8, 29 females), consecutive patients with MVP and/or mitral annular disjunction (MAD) and comprehensive clinical arrhythmia on resting electrocardiography (ECG) or 48-hours Holter monitoring , Doppler echocardiography and contrast based cardiac magnetic resonance (CMR) characterization were identified. Patients were followed-up for a period of maximum one year to identify any further management needed. Results Frequent ventricular arrhythmia was evidently seen associated to MVP (69% with at least ventricular ectopy ≥5%), as well as complex ventricular arrhythmia (31% with sustained or non-sustained ventricular tachycardia ) P&amp;lt;0.001. AMVP was strongly associated with premature ventricular contractions (PVCs) having Right bundle branch block (RBBB) morphology on ECG and late gadolinium enhancement (LGE) on CMR (all p&amp;lt;0.05). Furthermore, it was shown to be associated with bileaflet prolapse and higher left ventricular volumes, however not statistically significant. On Follow-up, Out of 36 patients with ventricular arrhythmia, 64% were controlled on medical anti-arrhythmic and some others were referred either for ablation after worsening of symptoms despite of medical treatment (27.8%), implantable cardioverter-defibrillator device for secondary VT prophylaxes (5.6%) or surgery (2.8%) due to progression in mitral regurgitation severity and deterioration of symptoms. Conclusion In this small cohort study, characteristic form of MVP was found to be associated with ventricular arrhythmia more common in the form of frequent PVCs and less common in the complex form. Although majority of patients were controlled on medical treatment, few patients required further invasive management despite of medical treatment . Thus, arrhythmia associated with a special form of MVP could be life threatening and needs close monitoring, long follow-up and proper management approach to prevent SCD. Large prospective studies with comprehensive approach and long term follow up is pivotal. CMR T1 mapping and electro anatomical CARTO mapping could help in better detection and proper defining of arrhythmia substrate in future studies.AMVP illustration

Abstract 15242: The Flipside of Flecainide: A Case of Flecainide Induced Loss of Capture

Introduction: Flecainide is a class 1c anti-arrhythmic agent that slows phase 0 of the fast inward sodium (Na) channels in a rate-dependent fashion leading to decreased conduction velocity in the His-Purkinje and ventricular myocardium. Its high affinity and slow unbinding prolong QRS duration on electrocardiogram (EKG). Partial renal excretion and a narrow therapeutic index of 0.2-1mcg/mL can cause drug toxicity. Case: A 72-year-old woman presented with palpitations and weakness. She had a history of non-ischemic cardiomyopathy, biventricular (BiV) implantable cardioverter defibrillator, frequent premature ventricular contractions on flecainide 100 mg twice a day, and chronic kidney disease. She was hypotensive and with acute kidney injury. EKG showed wide complex ventricular rhythm, QRS duration of 305 ms and intermittent ventricular pacing (Fig.1A), changed since EKG 6 months ago (Fig.1B). Device interrogation revealed normal sensing and impedances but failure to capture from all 3 leads. She had stable lead parameters and appropriate BiV pacing 6 months ago. Chest X ray showed stable lead positions. Flecainide toxicity was suspected, and Na bicarbonate infusion was started. Flecainide level was 2.4mcg/mL (normal &lt;1mcg/mL). She went into an idioventricular rhythm which terminated spontaneously (Fig.1C). After 48 hours of Na bicarbonate infusion, lead capture was noted with narrower QRS (198 ms) (Fig.1D) and on day 6, EKG was back to effective BiV pacing with QRS duration 127 ms (Fig.1E). Discussion: This case highlights the EKG manifestations of flecainide toxicity including QRS widening, sine-wave pattern and loss of pacing capture due to prolonged ventricular refractoriness. It also underscores the reversibility of this condition with prompt treatment using Na bicarbonate. Conclusion: Early recognition and rapid treatment of the cardiac effects of flecainide toxicity is critical in managing a life threatening but reversible medical condition.

Abstract 18811: Heart Failure in a Carrier of Danon Disease

Background: Danon Disease is a rare X-linked dominant genetic condition characterized by hypertrophic cardiomyopathy, skeletal muscle myopathy, and intellectual disability, among other serious complications. The disease is a lysosomal storage disorder in which a mutation in the LAMP-2 gene causes a defect in the lysosome membrane and an accumulation of glycogen in vital tissue including cardiac muscle cells. It occurs more commonly in males, who are also more severely affected than females with this condition. There are no specific treatments available, although studies involving gene therapy have been ongoing. Patients with Danon Disease often require heart transplantation as treatment for end-stage heart failure. Description of Case: A 37-year-old female with a known family history of Danon Disease was discovered to be a carrier of the LAMP-2 mutation after presenting to the hospital with dizziness and palpitations. An echocardiogram obtained at the time of diagnosis revealed left ventricular hypertrophy and left ventricular apical thrombus with normal ejection fraction. She was started on anticoagulation and began following closely with a heart failure clinic. Since diagnosis, she has had multiple echocardiograms which have shown a steady decline in her ejection fraction to 25% and biventricular failure. An ICD was placed, with no shocks ever administered. She has had multiple hospital admissions for exacerbations of heart failure since diagnosis. Telemetry monitoring during these admissions revealed frequent premature ventricular contractions attributed to the patient’s severe cardiomyopathy. Despite continuation of guideline-directed medical treatment, this patient’s systolic heart failure is anticipated to continue worsening. She will likely require heart transplant, for which evaluation has already been initiated. Discussion: Danon Disease is a rare lysosomal storage disorder that often involves progressively worsening cardiomyopathy. Individuals with a known family history of this condition should be referred early for genetic testing. If found to have the condition or be a carrier, they should begin following with a heart failure specialist and consideration for advanced therapies, like transplant, should be initiated.

Endothelin Modulates Rhythm Disturbances and Autonomic Responses to Acute Emotional Stress in Rats.

The ubiquitous peptide endothelin is currently under investigation as a modulatory factor of autonomic responses to acute emotional stress. Baseline plasma levels of endothelin alter blood pressure responses, but it remains unclear whether autonomic activity and arrhythmogenesis (i.e., brady- or tachyarrhythmias) are affected. We recorded sympathetic and vagal indices (derived from heart rate variability analysis), rhythm disturbances, voluntary motion, and systolic blood pressure after acute emotional stress in conscious rats with implanted telemetry devices. Two strains were compared, namely wild-type and ETB-deficient rats, the latter displaying elevated plasma endothelin. No differences in heart rate or blood pressure were evident, but sympathetic responses were blunted in ETB-deficient rats, contrasting prompt activation in wild-type rats. Vagal withdrawal was observed in both strains at the onset of stress, but vagal activity was subsequently restored in ETB-deficient rats, accompanied by low voluntary motion during recovery. Reflecting such distinct autonomic patterns, frequent premature ventricular contractions were recorded in wild-type rats, as opposed to sinus pauses in ETB-deficient rats. Thus, chronically elevated plasma endothelin levels blunt autonomic responses to acute emotional stress, resulting in vagal dominance and bradyarrhythmias. Our study provides further insights into the pathophysiology of stress-induced tachyarrhythmias and syncope.

Number of ventricular premature beats and other causes of cardiomyopathy associated with arrhythmia: case reports

We report a case of two patients with frequent idiopathic premature ventricular contractions. One of them had more than 25% of ventricular contractions per day leading to fast development of cardiomyopathy and its complete regression upon ventricular arrhythmia elimination. The second one had from 40% to 73% of ventricular contractions per day including non-sustained and sustained ventricular tachycardia without any structural changes of the heart during 28 years of follow-up.

Enhancing the performance of premature ventricular contraction detection in unseen datasets through deep learning with denoise and contrast attention module

Premature ventricular contraction (PVC) is a common and harmless cardiac arrhythmia that can be asymptomatic or cause palpitations and chest pain in rare instances. However, frequent PVCs can lead to more serious arrhythmias, such as atrial fibrillation. Several PVC detection models have been proposed to enable early diagnosis of arrhythmias; however, they lack reliability and generalizability due to the variability of electrocardiograms across different settings and noise levels. Such weaknesses are known to aggravate with new data. Therefore, we present a deep learning model with a novel attention mechanism that can detect PVC accurately, even on unseen electrocardiograms with various noise levels. Our method, called the Denoise and Contrast Attention Module (DCAM), is a two-step process that denoises signals with a convolutional neural network (CNN) in the frequency domain and attends to differences. It focuses on differences in the morphologies and intervals of the remaining beats, mimicking how trained clinicians identify PVCs. Using three different encoder types, we evaluated 1D U-Net with DCAM on six external test datasets. The results showed that DCAM significantly improved the F1-score of PVC detection performance on all six external datasets and enhanced the performance of balancing both the sensitivity and precision of the models, demonstrating its robustness and generalization ability regardless of the encoder type. This demonstrates the need for a trainable denoising process before applying the attention mechanism. Our DCAM could contribute to the development of a reliable algorithm for cardiac arrhythmia detection under real clinical electrocardiograms.

Electrocardiographic Characteristics, Identification, and Management of Frequent Premature Ventricular Contractions.

Premature ventricular complexes (PVCs) are frequently encountered in clinical practice. The association of PVCs with adverse cardiovascular outcomes is well established in the context of structural heart disease, yet not so much in the absence of structural heart disease. However, cardiac magnetic resonance (CMR) seems to contribute prognostically in the latter subgroup. PVC-induced myocardial dysfunction refers to the impairment of ventricular function due to PVCs and is mostly associated with a PVC burden > 10%. Surface 12-lead ECG has long been used to localize the anatomic site of origin and multiple algorithms have been developed to differentiate between right ventricular and left ventricular outflow tract (RVOT and LVOT, respectively) origin. Novel algorithms include alternative ECG lead configurations and, lately, sophisticated artificial intelligence methods have been utilized to determine the origins of outflow tract arrhythmias. The decision to therapeutically address PVCs should be made upon the presence of symptoms or the development of PVC-induced myocardial dysfunction. Therapeutic modalities include pharmacological therapy (I-C antiarrhythmic drugs and beta blockers), as well as catheter ablation, which has demonstrated superior efficacy and safety.

Focus on malignant ventricular premature contractions

Premature ventricular contractions (PVCs) are common. Although often benign, they can also be associated with increased morbidity and mortality. The aim of this review was to assess the risk evaluation of PVCs in patients with or without structural heart disease and discuss the management of this arrhythmia.Reports published in English were searched in PubMed with the following search terms: premature ventricular contraction, ectopic ventricular beat, ventricular extrasystole, antiarrhythmic drugs, ablation, ventricular arrhythmia, ventricular tachycardia, ventricular fibrillation and torsade de pointe.This analysis suggests that all patients with frequent PVCs should be assessed for PVC burden, symptom status and the presence of structural heart disease. PVCs in patients with structurally normal hearts was once considered a benign phenomenon. Uncommonly, PVCs may provoke life-threatening arrhythmias. Ventricular fibrillation is the initial mode of malignant rapid ventricular arrhythmias (MRVAs). Patients with malignant PVC and PVC burden >10% are at increased risk of MRVA in case of myocardial infarction and heart failure. MRVA is the primary cause of sudden cardiac death in patients with and without structural heart disease. Therapeutic options include medical therapy and catheter ablation, the latter more effective and potentially curable, particularly in patients with left ventricular dysfunction.The timely recognition and effective treatment of malignant PVCs in symptomatic patients with underling cardiomyopathy are mandatory to initiate early therapies before the occurrence of adverse clinical outcomes and to improve the long-term prognosis.