Therapeutic Inefficacy and Proarrhythmic Nature of Metoprolol Succinate and Carvedilol Therapy in Patients With Idiopathic, Frequent, Monomorphic Premature Ventricular Contractions.

BACKGROUND: Antiarrhythmic drugs remain the first-line therapy for treatment of idiopathic ventricular arrhythmias. STUDY QUESTION: The aim of this study was to assess the therapeutic efficacy of extended-release metoprolol succinate (MetS) and carvedilol for idiopathic, frequent, monomorphic premature ventricular contractions (PVCs). STUDY DESIGN: Study population consisted of 114 consecutive patients: 71 received MetS and 43 received carvedilol. MEASURES AND OUTCOMES: All patients underwent 24-hour Holter monitoring at baseline and during drug therapy. PVC-burden response to drug therapy was categorized as "good" (≥80% reduction), "poor" (either <80% reduction or ≤50% increase), and "proarrhythmic" responses (>50% increase) based on change in PVC burden compared with baseline. RESULTS: Most common presenting symptom was palpitations (65.8%), followed by coincidental discovery (29%). The mean MetS and carvedilol dosages were 65.57 ± 30.67 mg/d and 23.66 ± 4.26 mg/d, respectively. "Good," "poor," and "proarrhythmic" responses were observed in 11.3% and 16.3%, 63.4% and 67.4%, and 25.3% and 16.3% of patients treated with MetS and carvedilol, respectively. In patients with relatively high (≥16%) PVC burden, the sum of "poor"/"proarrhythmic" response was observed in 95.5% and 86.4% of patients treated with MetS and carvedilol, respectively. "Proarrhythmic" response was observed in 21.9% of the patients, particularly in the presence of relatively lower (≤10%) baseline PVC burden. Patients with "good" response during beta-blocker therapy had higher baseline daily average intrinsic total heart beats compared with patients with "poor"/"proarrhythmic" response combined (96,437 ± 26,488 vs. 86,635 ± 15,028, P = 0.047, respectively). Side effects and intolerance were observed in 5.6% and 18.6% of patients treated with MetS and carvedilol, respectively. CONCLUSIONS: MetS and carvedilol for idiopathic, frequent, monomorphic PVCs are frequently inefficient. Therapeutic efficacy decreases further in patients with relatively high (≥16%) PVC burden. Relatively higher baseline daily intrinsic total heart beats may be used to predict "good" response before beta-blocker therapy.

Assessment of atrial functional remodeling in patients with atrioventricular nodal reentrant tachycardia with and without drug-induced type 1 Brugada pattern: A case-control study.

PURPOSE: The time interval between the onset of the P-wave on electrocardiogram (ECG) and peak A' velocity of the lateral left atrial wall assessed by tissue Doppler imaging (PA-TDI interval) determine total atrial conduction time (TACT) which reflects atrial remodeling and arrhythmic substrate. In this retrospective study, we aimed to assess TACT in patients with atrioventricular nodal reentrant tachycardia (AVNRT) with and without drug-induced type 1 Brugada electrocardiogram ECG pattern (DI-Type 1 BrP) and control subjects. METHODS: Study population consisted of 62 consecutive patients (46 women; mean age 44 ± 12 years) undergoing electrophysiological study and ablation for symptomatic, drug-resistant AVNRT, and 42 age-matched and sex-matched control subjects. All patients and control subjects underwent ajmaline challenge test and tissue Doppler imaging. RESULTS: A DI-Type 1 BrP was uncovered in 24 of 62 patients with AVNRT (38.7%). PA-TDI interval was similar among AVNRT patients with and without DI-Type 1 BrP (124 ± 12 ms vs 119 ± 14 ms, respectively, P = .32), but significantly longer in patients with AVNRT with as well as without DI-Type 1 BrP than in control subjects (124 ± 12 ms and 119 ± 14 ms vs 105 ± 11 ms, respectively, P < .001). CONCLUSION: The TACT assessed by PA-TDI interval is longer in patients with AVNRT with and without DI-Type 1 BrP than in age-matched and sex-matched healthy control subjects.

Recognition and clinical implications of high prevalence of migraine in patients with Brugada syndrome and drug-induced type 1 Brugada pattern.

INTRODUCTION: We have previously reported high 1-year prevalence of migraine in patients with atrial arrhythmias associated with DI-type 1 BrP. The present study was designed to determine the lifetime prevalence of migraine in patients with Brugada syndrome (BrS) or drug-induced type 1 Brugada pattern (DI-type 1 BrP) and control group, to investigate the demographic and clinical characteristics, and to identify clinical variables to predict underlying BrS/DI-type 1 BrP among migraineurs. METHODS AND RESULTS: Lifetime prevalence of migraine and migraine characteristics were compared between probands with BrS/DI-type 1 BrP (n = 257) and control group (n = 370). Lifetime prevalence of migraine was 60.7% in patients with BrS/DI-type 1 BrP and 30.3% in control group (p = 3.6 × 10-14 ). On stepwise regression analysis, familial migraine (odds ratio [OR] of 4.4; 95% confidence interval [CI]: 2.0-9.8; p = 1.3 × 10-4 ), vestibular migraine (OR of 5.4; 95% CI: 1.4-21.0); p = .013), migraine with visual aura (OR of 1.8; 95% CI: 1.0-3.4); p = .04) and younger age-at-onset of migraine (OR of 0.95; 95% CI: 0.93-0.98); p = .004) were predictors of underlying BrS/DI-type 1 BrP among migraineurs. Use of anti-migraine drugs classified as "to be avoided" or "preferably avoided" in patients with BrS and several other anti-migraine drugs with potential cardiac INa /ICa channel blocking properties was present in 25.6% and 26.9% of migraineurs with BrS/DI-type 1 BrP, respectively. CONCLUSION: Migraine comorbidity is common in patients with BrS/DI-type 1 BrP. We identify several clinical variables that point to an underlying type-1 BrP among migraineurs, necessitating cautious use of certain anti-migraine drugs.

Coexistence of atrioventricular accessory pathways and drug-induced type 1 Brugada pattern.

BACKGROUND: Atrial arrhythmias, particularly atrioventricular nodal reentrant tachycardia, can coexist with drug-induced type 1 Brugada electrocardiogram (ECG) pattern (DI-Type1-BrP). The present study was designed to determine the prevalence of DI-Type1-BrP in patients with atrioventricular accessory pathways (AV-APs) and to investigate the clinical, electrocardiographic, electrophysiologic, and genetic characteristics of these patients. METHODS: One-hundred twenty-four consecutive cases of AV-APs and 84 controls underwent an ajmaline challenge test to unmask DI-Type1-BrP. Genetic screening and analysis was performed in 55 of the cases (19 with and 36 without DI-Type1-BrP). RESULTS: Patients with AV-APs were significantly more likely than controls to have a Type1-BrP unmasked (16.1 vs 4.8%, P = 0.012). At baseline, patients with DI-Type1-BrP had higher prevalence of chest pain, QR/rSr' pattern in V1 and QRS notching/slurring in V2 and aVL during preexcitation, rSr' pattern in V1 -V2 , and QRS notching/slurring in aVL during orthodromic atrioventricular reentrant tachycardia (AVRT) compared to patients without DI-Type1-BrP. Abnormal QRS configuration (QRS notching/slurring and/or fragmentation) in V2 during preexcitation was present in all patients with DI-Type1 BrP. The prevalence of spontaneous preexcited atrial fibrillation (AF) and history of AF were similar (15% vs 18.3%, P = 0.726) in patients with and without DI-Type1-BrP, respectively. The prevalence of mutations in Brugada-susceptibility genes was higher (36.8% vs 8.3%, P = 0.02) in patients with DI-Type1-BrP compared to patients without DI-Type1-BrP. CONCLUSIONS: DI-Type1-BrP is relatively common in patients with AV-APs. We identify 12-lead ECG characteristics during preexcitation and orthodromic AVRT that point to an underlying type1-BrP, portending an increased probability for development of malignant arrhythmias.

Disappearance of Idiopathic Outflow Tract Premature Ventricular Contractions After Catheter Ablation of Overt Accessory Pathways.

BACKGROUND: Multiple mechanisms have been proposed for idiopathic premature ventricular contractions (PVCs) originating from the outflow tracts (OTs). Recent observations such as the coexistence of these arrhythmias with atrioventricular nodal reentrant tachycardias and the association between discrete prepotentials and successful ablation sites of ventricular arrhythmias (VAs) from the OTs suggest a common link. OBJECTIVE: In this case series we draw attention to a unique association between accessory pathways (APs) and idiopathic PVCs from the OTs, disappearing after AP ablation. METHODS: We identified 6 cases in collaboration with several international electrophysiology centers, which presented with pre-excitation in association with OT, and in 1 case inflow tract (IT), PVCs on 12-lead surface ECG. RESULTS: Six cases displayed pre-excitation and PVCs, in 5 cases originating from the right ventricular outflow tract (RVOT) and in 1 case from the right ventricular inflow tract (RVIT). In all patients, PVCs were monomorphic and had fixed coupling intervals, in 3 cases presenting in bigeminy. Catheter ablation of the AP led to the simultaneous disappearance of PVCs in 5 of 6 cases. The sites of ablation were remote from the OTs in all these cases. In most cases, the occurrence of OT PVCs was closely associated with the presence of pre-excitation. CONCLUSION: The coexistence of pre-excitation and PVCs from the OTs and the fact that in 5 of 6 cases PVCs disappeared after AP ablation suggests a common mechanism for arrhythmia genesis.

Brugada syndrome, Brugada phenocopy or none?

Brugada syndrome is a form of inherited arrhythmia syndrome characterized by a distinct ST-segment elevation in the right precordial leads. Brugada phenocopies are clinical entities that present with an electrocardiographic pattern identical to Brugada syndrome and may obey to various clinical conditions. We present a case of a suicidal attempt using a high dose of propafenone causing a Brugada-type electrocardiographic pattern. Is this a Brugada syndrome case, a Brugada phenocopy or something else?

Genome-Wide Association Study of Copy Number Variations in Patients with Familial Neurocardiogenic Syncope.

Neurocardiogenic syncope (NCS) is the most frequent type of syncope characterized by a self-limited episode of systemic hypotension. In this study, we conducted the first genome-wide association study testing copy number variations for association with NCS. Study population consisted of 107 consecutive patients with recurrent syncope and positive head-up tilt table testing. Four families with NCS were selected for CNV analysis. Affymetrix GeneChip(®) SNP 6.0 array was used for CNV analysis. Data and statistical analysis were performed with Affymetrix genotyping console 4.0 and GraphPad Prism v6. Positive family history of NCS was present in 19.6 % (n = 21) in our study population (n = 107). Twenty-six CNV regions were found to be significantly altered in families with NCS (P < 0.05). Several CNVs were identified in families with NCS. Further studies comprising wider study population are required to determine the effect of these variations on NCS development.

Spontaneous atrioventricular nodal reentrant tachycardia in patients with idiopathic ventricular arrhythmias: the incidence, clinical, and electrophysiologic characteristics.

INTRODUCTION: Spontaneous or inducible atrioventricular nodal reentrant tachycardia (AVNRT) may coexist with idiopathic ventricular arrhythmias (IVAs). The aim of this study was to determine the incidence and the clinical and electrophysiologic characteristics of patients with spontaneous AVNRT among patients with IVAs. METHODS: Nine hundred eighty-seven consecutive patients with IVA (n = 398), patients with clinical and spontaneous AVNRT (n = 327), and patients with preexcitation syndrome (n = 262) were prospectively included in the study. RESULTS: Spontaneous AVNRT was present in 36 (9.0%) of 398 patients with IVA. The most common (97%) mode of presentation was palpitation due to spontaneous AVNRT. Absence of symptoms was frequent among patients with IVA and without spontaneous AVNRT compared to patients with IVA and spontaneous AVNRT (28.9% vs 0%, P = 0.0001). Patients with IVA and spontaneous AVNRT had lower median premature ventricular contraction (PVC) burden (1.9% vs 9.45%, P = 0.0001) and higher left ventricular ejection fraction (LVEF; 64.2 ± 4.9% vs 59.2 ± 9.9%, P = 0.0001) compared to patients with IVA and without spontaneous AVNRT. Relatively high PVC burden (≥10%) was present in 19.4% of patients with spontaneous AVNRT and IVA. The prevalence of IVA was significantly higher in patients with AVNRT compared to patients with preexcitation syndrome (11% vs 0.76%, P < 0.0001). CONCLUSIONS: Spontaneous AVNRT among patients with IVAs was relatively common in our study population. Spontaneous AVNRT in patients with IVAs can be a protective factor for left ventricular function. Greater LVEF in patients with spontaneous AVNRT and IVA compared to patients with IVA alone can be explained by earlier recognition of IVAs due to presence of symptomatic AVNRT and/or lower PVC burden.

Stress cardiomyopathy (Tako-Tsubo) associated with sustained polymorphic ventricular tachycardia.

We present a case of 38-year-old woman with stress cardiomyopathy presenting to the emergency department with a 1-week history of recurrent syncope due to sustained polymorphic ventricular tachycardia.

Chronic cough and tachycardia-induced cardiomyopathy in a patient with idiopathic frequent, monomorphic premature ventricular contractions.

A 70-year-old woman presented with a 1-year history of dry cough. Extensive work-up ruled out common causes of chronic cough. She was found to have very frequent, monomorphic premature ventricular contractions (PVCs) and mild-to-moderate left ventricular systolic dysfunction. Propafenone 450 mg/day resulted in complete resolution of her cough and disappearance of PVCs within 24 hours of initiation. One month after the initiation of propafenone therapy, left ventricular ejection fraction normalized and her chronic cough resolved completely.

Time course of recovery of left ventricular systolic dysfunction in patients with premature ventricular contraction-induced cardiomyopathy.

BACKGROUND: Idiopathic ventricular arrhythmias in the form of frequent, monomorphic premature ventricular contractions (PVC) can cause PVC-induced cardiomyopathy (PICMP). The aim of this study was to determine the baseline echocardiographic characteristics and the time course and degree of recovery of left ventricular (LV) systolic dysfunction in patients with PICMP. METHODS: Study population consisted of 348 consecutive patients (205F/143M, 44 ± 19 y/o) with frequent PVCs and/or ventricular tachycardia. PICMP was defined as LV ejection fraction (LVEF) of <55% in the absence of any detectable underlying heart disease and improvement of LVEF ≥ 15% following treatment of ventricular arrhythmia. Patients with PCIMP underwent transthoracic echocardiography for LV size and function at 1 week and at 1-3 to 6-12 months of follow-up. RESULTS: Twenty-four patients (8F/16M, 47 ± 18 y/o) with PICMP with complete echocardiographic data were included in the study. Average baseline LV end-diastolic diameter, LV end-systolic volume, LV mass index, and LVEF were 55.4 ± 6.8 mm, 69.6 ± 23.3 mL, 110.2 ± 28.3 g/m2, and 41 ± 8.4%, respectively. Mild-to-moderate mitral regurgitation (MR) was present in 13 (54%) patients. Early improvement (≥25% increase in LVEF at 1-week follow-up compared to baseline) was observed in 13 (54%) patients. Patients with early improvement had higher LVEF at 12 months of follow-up compared to patients without early improvement (58.8 ± 5.0% vs 52.5 ± 6.7%, P = 0.019). CONCLUSIONS: PCIMP is characterized by mild-to-moderate global LV systolic dysfunction with slightly increased LV mass and mild-to-moderate MR. Greatest improvement in LV systolic dysfunction was observed at 1-week follow-up in our study population. Early improvement in LVEF may potentially predict the complete reversibility of LV systolic dysfunction.

Cardiac resynchronization therapy with or without anatomical reverse remodeling does not affect defibrillation threshold.

BACKGROUND: Recent clinical trials have documented beneficial reverse-remodeling effects with cardiac resynchronization therapy (CRT). The aim of this study was to investigate the effect of CRT with or without reverse anatomical remodeling of the left ventricle on defibrillation threshold (DFT) levels in a prospective and consecutive group of patients with class II-IV systolic heart failure. METHODS: Study population consisted of 29 patients (14 women and 15 men; mean age 61±11 years old). All patients underwent baseline (within 24-hours of cardiac resynchronization therapy-defibrillator [CRT-D] implantation) and 6-month follow-up DFT testing. Reverse anatomical remodeling of the left ventricle was defined as ≥15% reduction in left ventricular end-systolic volume at the end of 6 months of follow-up compared to baseline. RESULTS: Baseline, average DFT was 8.8±5.9 J. Left ventricular end-diastolic volume was the only predictor of baseline DFT level (P=0.02) among the baseline demographics. Safety margin of at least 10 J was achieved in all patients. Average DFT at the end of 6 months of biventricular pacing was 9.2±6.9 J. One patient (3.4%) failed to have a safety margin of 10 J. Reverse anatomical remodeling was observed in 14 (48%) patients and did not have any effect on DFT level. There were no complications related to DFT testings. CONCLUSIONS: Baseline average DFT in patients undergoing CRT-D was ≤10 J in our study. CRT-D with or without anatomical reverse remodeling does not affect DFT at the end of 6 months of follow-up. High DFT level at the end of 6 months of follow-up is rare (3.4%) among patients with current CRT-D devices.

Late gadolinium enhancement CMR in patients with tachycardia-induced cardiomyopathy caused by idiopathic ventricular arrhythmias.

BACKGROUND: Idiopathic ventricular arrhythmias in the form of monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia (VT) can cause tachycardia-induced cardiomyopathy (TICMP). The aim of this study was to determine the prevalence of late gadolinium enhancement (LGE) in patients with TICMP caused by idiopathic ventricular arrhythmias. METHODS: The study population consisted of 298 consecutive patients (174 F/124 M; mean age 45±17 years) with frequent PVCs and/or VT. TICMP was defined as left ventricular ejection fraction (LVEF) of ≤50% in the absence of any detectable underlying heart disease and improvement of LVEF≥15% after effective treatment of index ventricular arrhythmia. RESULTS: Twenty-seven (9.1%) patients found to have LVEF≤50% and diagnosed as presumptive TICMP. Improvement in LVEF after effective treatment of index ventricular arrhythmia was observed in 22 of 27 patients (TICMP group; mean PVC burden of 30.8±9.9%). LVEF did not improve in five of 27 patients (primary cardiomyopathy group; mean PVC burden of 28.8±10.1%). LGE-cardiac magnetic resonance (CMR) imaging was performed in 19 of 22 patients with TICMP and one patient (5%) had LGE. All five patients with primary cardiomyopathy underwent LGE-CMR imaging and four patients (80%) had LGE. CONCLUSIONS: LGE is a rare finding in patients with TICMP caused by idiopathic ventricular arrhythmias. LGE-CMR can be used in the diagnostic work-up of patients with TICMP. Further prospective studies are required to determine the role of LGE-CMR in predicting the recovery of left ventricular systolic dysfunction in patients with presumptive TICMP.

Electrocardiographic variables associated with underlying Brugada syndrome or drug-induced Type 1 Brugada pattern in patients with slow/fast atrioventricular nodal reentrant tachycardia.

Background: The coexistence of clinical atrioventricular nodal reentrant tachycardia (AVNRT) and drug-induced type 1 Brugada pattern (DI-Type 1 BrP) has been previously reported. The present study was designed to determine the 12-lead ECG characteristics at baseline and during AVNRT and to identify a subset of 12-lead ECG variables of benefit associated with underlying Brugada syndrome (BrS)/DI-Type 1 BrP among patients with slow/fast AVNRT. Methods: A total of 40 (11 numerical/29 categorical) 12-lead ECG parameters were analyzed and compared between patients with (n = 69) and without (n = 104) BrS/DI-Type1-BrP matched for age, female gender, body mass index, left ventricular ejection fraction and comorbid conditions. Five distinct types of ECG pattern (Type A/B/C/D/E) in V1-V2 leads during AVNRT were defined. Results: A total of nine electrocardiographic variables, four at baseline, and five during AVNRT were identified. At baseline, patients with BrS/DI-Type 1 BrP had higher prevalence of interatrial block, leftward shift of frontal plane QRS axis, the absence of normal QRS pattern (the presence of rSr' pattern or type 2/3 Brugada pattern) in V1-V2 and QRS fragmentation in inferior leads compared to patients without BrS/DI-Type 1 BrP. During AVNRT, patients with BrS/DI-Type 1 BrP had higher prevalence of Type A ECG pattern ("coved-type" ST-segment elevation) in V1-V2, Type C ECG pattern (pseudo-r' deflection in V1 and "RBBB-like" pattern in V2), pseudo-r' deflection in V1, QRS fragmentation in inferior leads and "isolated" QRS fragmentation/notching/slurring in aVL compared to patients without BrS/DI-Type 1 BrP. Conclusions: We identify several electrocardiographic variables that point to an underlying type 1 BrP among patients with slow/fast AVNRT.

Sodium channel ß1 subunit mutations associated with Brugada syndrome and cardiac conduction disease in humans.

Brugada syndrome is a genetic disease associated with sudden cardiac death that is characterized by ventricular fibrillation and right precordial ST segment elevation on ECG. Loss-of-function mutations in SCN5A, which encodes the predominant cardiac sodium channel alpha subunit NaV1.5, can cause Brugada syndrome and cardiac conduction disease. However, SCN5A mutations are not detected in the majority of patients with these syndromes, suggesting that other genes can cause or modify presentation of these disorders. Here, we investigated SCN1B, which encodes the function-modifying sodium channel beta1 subunit, in 282 probands with Brugada syndrome and in 44 patients with conduction disease, none of whom had SCN5A mutations. We identified 3 mutations segregating with arrhythmia in 3 kindreds. Two of these mutations were located in a newly described alternately processed transcript, beta1B. Both the canonical and alternately processed transcripts were expressed in the human heart and were expressed to a greater degree in Purkinje fibers than in heart muscle, consistent with the clinical presentation of conduction disease. Sodium current was lower when NaV1.5 was coexpressed with mutant beta1 or beta1B subunits than when it was coexpressed with WT subunits. These findings implicate SCN1B as a disease gene for human arrhythmia susceptibility.

Tachycardia-induced cardiomyopathy in patients with idiopathic ventricular arrhythmias: the incidence, clinical and electrophysiologic characteristics, and the predictors.

INTRODUCTION: Idiopathic ventricular arrhythmias in the form of monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia (VT) can cause tachycardia-induced cardiomyopathy (TICMP). The aim of this study was to determine the incidence, clinical and electrophysiologic characteristics, and the predictors of TICMP in patients with idiopathic ventricular arrhythmias. METHODS: Study population consisted of 249 consecutive patients (148 F/101 M, 45 ± 20 y/o) with frequent PVCs and/or VT. All patients underwent transthoracic echocardiography and 24-hour Holter monitoring. TICMP was defined as left ventricular ejection fraction (LVEF) of ≤50% in the absence of any detectable underlying heart disease and improvement of LVEF ≥15% following effective treatment of index ventricular arrhythmia. RESULTS: Seventeen (6.8%) patients had TICMP. Patients with TICMP compared to patients with preserved LVEF were more likely to be male (65% vs 39%, P = 0.043) and asymptomatic (29% vs 9%, P = 0.018), and were more likely to have higher PVC burden (29.4 ± 9.2 vs 8.1 ± 7.4, P < 0.001), persistence of PVCs throughout the day (65% vs 22%, P = 0.001), and repetitive monomorphic VT (24% vs 0.9%, P < 0.001). PVC burden of 16% by ROC curve analysis best separated the patients with TICMP compared to patients with preserved LVEF (sensitivity 100%, specificity 87%, area under curve 0.96). CONCLUSIONS: TICMP was relatively common (∼1 in every 15 patients) in our study population. The predictors of TICMP were male gender, absence of symptoms, PVC burden of ≥16%, persistence of PVCs throughout the day, and the presence of repetitive monomorphic VT.

Frequency of Irritable Bowel Syndrome in Patients with Brugada Syndrome and Drug-Induced Type 1 Brugada Pattern.

Irritable bowel syndrome (IBS) is one of the most widely recognized functional bowel disorders (FBDs) with a genetic component. SCN5A gene and SCN1B loci have been identified in population-based IBS cohorts and proposed to have a mechanistic role in the pathophysiology of IBS. These same genes have been associated with Brugada syndrome (BrS). The present study examines the hypothesis that these two inherited syndromes are linked. Prevalence of FBDs over a 12 months period were compared between probands with BrS/drug-induced type 1 Brugada pattern (DI-Type 1 BrP) (n = 148) and a control group (n = 124) matched for age, female sex, presence of arrhythmia and co-morbid conditions. SCN5A/SCN1B genes were screened in 88 patients. Prevalence of IBS was 25% in patients with BrS/DI-Type 1 BrP and 8.1% in the control group (p = 2.34 × 10-4). On stepwise logistic regression analysis, presence of current and/or history of migraine (OR of 2.75; 95% CI: 1.08 to 6.98; p = 0.033) was a predictor of underlying BrS/DI-Type 1 BrP among patients with FBDs. We identified 8 putative SCN5A/SCN1B variants in 7 (12.3%) patients with BrS/DI-Type 1 BrP and 1 (3.2%) patient in control group. Five out of 8 (62.5%) patients with SCN5A/SCN1B variants had FBDs. In conclusion, IBS is a common co-morbidity in patients with BrS/DI-Type 1 BrP. Presence of current and/or history of migraine are a predictor of underlying BrS/DI-Type 1 BrP among patients with FBDs. Frequent co-existence of IBS and BrS/DI-Type 1 BrP necessitates cautious use of certain drugs among the therapeutic options for IBS that are known to exacerbate the Brugada phenotype.