The incidence of cardiac arrhythmias during exercise stress testing: a focus on patients with severe obesity undergoing sleeve gastrectomy.

INTRODUCTION: Obesity is associated with a higher risk of cardiac arrhythmias. Sleeve gastrectomy (SG) is a common bariatric surgery with beneficial effects on weight loss and comorbidities. The study aimed to investigate the prevalence of arrhythmias during maximal exercise testing in patients with moderate-severe obesity and to evaluate the impact of SG on these arrhythmic events. METHODS: All patients with moderate or severe obesity who were considered suitable candidates for SG between June 2015 and September 2020 were recruited. Each patient underwent three incremental, maximal, ECG-monitored cardiopulmonary exercise test 1 month before and 6 and 12 months after SG; the frequency and complexity of ventricular premature beats (VPBs) and atrial premature beats (APBs) have been evaluated during rest, exercise and recovery phases. RESULTS: Fifty patients with severe obesity (BMI 46.39 ± 7.89 kg/m2) were included in the study. After SG, patients presented a decreased BMI (34.15 ± 6.25 kg/m2 at 6 months post-SG and 31.87 ± 5.99 kg/m2 at 12 months post-SG). At 6 months post-SG, an increase in VPBs, mainly during the recovery phase, was observed. At 12 months post-SG, a reduction in VPBs compared with the 6 months evaluation was showed. CONCLUSION: Although in the early post-surgical phase the risk of exercise-induced arrhythmias may be higher, SG does not seem to increase the occurrence of arrhythmias in the long-term. No life-threating arrhythmias were found during post-SG evaluations.

Elimination of Benign Ventricular Premature Beats or Ventricular Tachycardia with Catheter Ablation versus Two Different Optimal Antiarrhythmic Drug Treatment Regimens (Sotalol or Verapamil/Flecainide).

BACKGROUND: Symptomatic idiopathic ventricular arrhythmias (VA), including premature beats (VPB) and nonsustained ventricular tachycardia (VT) are commonly encountered arrhythmias. Although these VA are usually benign, their treatment can be a challenge to primary and secondary health care providers. Mainstay treatment is comprised of antiarrhythmic drugs (AAD) and, in case of drug intolerance or failure, patients are referred for catheter ablation to tertiary health care centers. These patients require extensive medical attention and drug regimens usually have disappointing results. A direct comparison between the efficacy of the most potent AAD and primary catheter ablation in these patients is lacking. The ECTOPIA trial will evaluate the efficacy of 2 pharmacological strategies and 1 interventional approach to: suppress the VA burden, improve the quality of life (QoL), and safety. HYPOTHESIS: We hypothesize that flecainide/verapamil combination and catheter ablation are both superior to sotalol in suppressing VA in patients with symptomatic idiopathic VA. STUDY DESIGN: The Elimination of Ventricular Premature Beats with Catheter Ablation versus Optimal Antiarrhythmic Drug Treatment (ECTOPIA) trial is a randomized, multicenter, prospective clinical trial to compare the efficacy of catheter ablation versus optimal AAD treatment with sotalol or flecainide/verapamil. One hundred eighty patients with frequent symptomatic VA in the absence of structural heart disease or underlying cardiac ischemia who are eligible for catheter ablation with an identifiable monomorphic VA origin with a burden ≥5% on 24-h ambulatory rhythm monitoring will be included. Patients will be randomized in a 1:1:1 fashion. The primary endpoint is defined as >80% reduction of the VA burden on 24-h ambulatory Holter monitoring. After reaching the primary endpoint, patients randomized to one of the 2 AAD arms will undergo a cross-over to the other AAD treatment arm to explore differences in drug efficacy and QoL in individual patients. Due to the use of different AAD (with and without ß-blocking characteristics) we will be able to explore the influence of alterations in sympathetic tone on VA burden reduction in different subgroups. Finally, this study will assess the safety of treatment with 2 different AAD and ablation of VA.

Effects of atrial electromechanical delay and ventriculoatrial conduction over the atrial functions in patients with frequent extrasystole and preserved ejection fraction.

BACKGROUND: The deterioration of left atrial and ventricular functions was demonstrated in patients with frequent ventricular extrasystole (fVES). The exact pathophysiology of left atrial dysfunction in patients with fVES is unclear. Retrograde ventriculoatrial conduction (VAC) often accompanies fVES, which may contribute to atrial dysfunction. We investigated whether atrial electromechanical delay and VAC are related to these atrial functions in patients with frequent right ventricular outflow tract (RVOT) VES and preserved ejection fraction (pEF). METHODS: This study included 21 patients with pEF (eight males, 48 ± 11 years), who had experienced more than 10 000 RVOT-VES during 24-h Holter monitoring and had undergone electrophysiological study/ablation. The study also included 20 healthy age- and sex-matched control subjects. Transthoracic echocardiography was performed on all of the subjects. Atrial conduction time was obtained by using tissue Doppler imaging. Strain analysis was performed with two-dimensional speckle tracking echocardiography. RESULTS: The peak atrial longitudinal strain was significantly impaired in patients with fVES (P = 0.01). In addition, although the interatrial and left atrial conduction delay times were significantly different between each group (P < 0.001, P < 0.001), the right atrial conduction delay times were similar. When patients with fVES were divided into groups depending on the existence of retrograde VAC, atrial deformation parameters and conduction delay time did not significantly differ between either group. CONCLUSION: Frequent RVOT-VES causes left atrial dysfunction. This information is obtained through strain analyses and recordings of left atrial conduction times in patients with pEF. Regardless, retrograde VAC is not related to atrial dysfunction.

Double ventricular response in dual AV nodal pathways mimicking interpolated premature beat.

Double ventricular response in dual atrioventricular (AV) nodal pathways can result in nonreentrant supraventricular tachycardia. Since this condition was first described in 1979, around 20 cases have been reported. Here, we present the case of a patient with a confirmed diagnosis of double ventricular response in dual AV nodal pathways resembling an interpolated premature beat who underwent successful radiofrequency ablation of the slow pathway.

"Pseudo" Hisian extrasystole arising from the proximal portion of the left bundle branch.

The diagnosis of a Hisian extrasystole is based on simple electrocardiographic features and both an extrasystole arising from the His-Bundle ("true" Hisian extrasystole) and also one from the proximal portion of the bundle branch ("pseudo" Hisian extrasystole) would be diagnosed as Hisian extrasystoles [1]. Here we report a case of "pseudo" Hisian extrasystole arising from the proximal portion of the left bundle branch and the successful catheter ablation was achieved in the right coronary cusp.

Utility of Substrate Mapping Using Extrasystole to Localise Comprehensive Ventricular Tachycardia Circuits: Results From Intra-operative Mapping Studies.

BACKGROUND: Substrate mapping-based identification of all ventricular tachycardia (VT) circuits (diastolic activation), including partial and complete diastolic circuits in clinical and nonclinical VT, could be beneficial in guiding VT ablation to prevent VT recurrence. The utility of extrasystole induced late potentials has not been compared with late potentials in sinus rhythm (SR) and right ventricular pacing (RVp). METHODS: Intraoperative simultaneous panoramic endocardial mapping of 21 VTs in 16 ischemic heart disease patients was performed with the use of a 112-bipole endocardial balloon. The decrement of near-field electrogram later than surface QRS during extrasystole (eLP) was studied. RESULTS: Patients had a mean age of 52 ± 9 years and were predominantly (75%) male. The mean sensitivity of eLP (0.75 [95% confidence interval [CI] 0.72-0.78]) to detect VT circuits was better than SR (0.33 [0.30-0.36]; P < 0.001) and RVp (0.36 [0.33-0.39]; P < 0.001) without significant differences in specificity, eLP (0.77 [0.74-0.81], SR (0.82 [0.80-0.84]; P = 0.23), and RVp (0.81 [0.78-0.83]; P = 0.11). Both negative (NPV) and positivie (PPV) predictive values were significantly better for eLP mapping. The mean NPV was 0.77 (95% CI 0.74-0.81), 0.57 (0.55-0.59), and 0.58 (0.55-0.61) for eLP, SR, and RVp, respectively (P < 0.0001). PPV was 0.75 (95% CI 0.72-0.78), 0.63 (0.59-0.67), and 0.63 (0.59-0.67) for eLP, SR, and RVp, respectively (P < 0.001). Overall diagnostic performance (area under the receiver operating characteristic curve) was significantly better for eLP (0.85 [95% CI 0.80-0.90] compared with SR (0.63 [0.56-0.72]; P < 0.001) or RVp (0.61 [0.52-0.74]; P < 0.001). CONCLUSIONS: Evoked late potential mapping is a better tool to detect comprehensive diastolic circuits activated during VT, compared with eLP mapping in sinus rhythm or RV pacing.

Successful catheter cryoablation of Hisian ectopy using 2 new diagnostic criteria based on unipolar and bipolar recordings of the His electrogram.

We describe the case of a 61-year-old woman who underwent successful catheter cryoablation of a symptomatic Hisian ectopy. Diagnosis was based on features of the HV interval assessed from a bipolar recording during mapping. The location of the arrhythmic focus was identified using simultaneous unipolar and bipolar recordings of the His electrogram. This case report highlights the use of 2 new criteria for the diagnosis and mapping of Hisian ectopy, and the successful use of cryothermia for the ablation of extrasystoles arising from the His bundle.

Inferior Vena Cava as a Trigger for Paroxysmal Atrial Fibrillation: Incidence, Characteristics, and Implications.

BACKGROUND: Identifying nonpulmonary vein triggers during atrial fibrillation (AF) ablation is of great importance. Currently, there are limited data on AF triggered by the inferior vena cava (IVC). OBJECTIVES: This study was performed to investigate the incidence, characteristics, and implications of IVC triggers for AF. METHODS: A total of 661 patients who underwent initial paroxysmal AF ablation were included. After pulmonary vein isolation, ectopic beats that triggered AF were further studied. Activation mapping and angiography were performed to confirm the location of ectopic origin. Electrocardiographic analysis of the ectopic P-wave (P'-wave) was performed. RESULTS: Six patients (0.91%) with AF triggered by the IVC were confirmed. The mean distance from the earliest activation site to the IVC ostium was 6.8 ± 2.5 mm (5.2 to 11.2 mm). Furthermore, the arrhythmogenic foci within the IVC were all located at the apical hemisphere of the IVC (3 at the septal side and 3 at the anterior side). A total of 2.3 ± 0.5 applications of radiofrequency energy were delivered to eliminate IVC triggers. The mean duration of the P' wave was 91.2 ± 11.2 milliseconds (81 to 108 milliseconds), which was narrower than that of the sinus P-wave (115.2 ± 19.3 milliseconds [87 to 139 milliseconds]; P = 0.002). Moreover, the configuration of all P' waves in the inferior leads was negative. During a mean follow-up period of 25.5 ± 7.3 months, all 6 patients remained arrhythmia free without antiarrhythmic drugs. CONCLUSIONS: IVC trigger, a rare but latent source of paroxysmal AF, could be identified and safely eliminated by focal radiofrequency ablation. Ectopic beats originating from the IVC presented with narrow P'-wave duration and negative P' waves in all inferior leads.

Ablation of polymorphic ventricular tachycardias in patients with structural heart disease.

BACKGROUND AND OBJECTIVES: Monomorphic ventricular premature beats (VPB) originating from the Purkinje network can induce polymorphic ventricular tachycardia (PMVT) and ventricular fibrillation (VF) storm. We hereby report the results of targeted ablation to treat PMVT/VF storms initiated by monomorphic VPB in seven patients with structural heart disease and left ventricular (LV)-dysfunction (n=4 withcoronary artery disease (CAD), n=2 with chronic and remote myocarditis, n=1 after aortic valve replacement). METHODS AND RESULTS: Pace-mapping and activation mapping was used to identify optimal ablation targets. Earliest activation during mapping was found midseptal of LV in three patients, midinferoseptal of LV in two patients. One patient with myocarditis showed earliest activation at free wall of right ventricle, the other one basal midseptal of LV. Local ventricular electrograms at the successful ablation sites were preceded by short, high frequency, low amplitude potentials by 22-90 ms (median 35 ms). The same local potentials were seen in sinus rhythm. Cycle lengths of VT ranged between 200 and 360 ms (median 245 ms). A median of nine radiofrequency (RF)-ablations (range 3-19) were necessary to abolish all local Purkinje potentials at the site of earliest activation. Two patients with CAD died due to refractory heart failure. The other five patients had no recurrence of PMVT and VF during follow up (median 10 months, range 1-27 months). CONCLUSION: The distal Purkinje network plays an important role in triggering PMVT/VF in patients with structural heart disease. Ablation of the triggering VPB originating from the Purkinje arborization is feasible; prevents recurrence in a long-term follow up; and is potentially life saving in patients with severe LV-dysfunction after myocardial infarction, in patients after aortic valve replacement, or in patients with myocarditis particularly when medical treatment, including antiarrhythmic drugs, failed to suppress electrical storms.

Identification of valve-related artifact during cardiac mapping.

PURPOSE: During cardiac mapping, it is critical to discriminate signals related to cardiac conduction versus those due to mechanical interaction with other cardiac structures such as valves. We sought to define characteristics that could facilitate discrimination of valve artifact from cardiac conduction signals. METHODS: Patients with structurally normal heart undergoing mapping for ventricular arrhythmias arising from the vicinity of the aortic valve between January 2013 and May 2015 were included. Potentials felt to reflect aortic valve opening (occurring at the end of the QRS after the local ventricular signal) were termed A1, and those felt to reflect valve closure were termed A2. RESULTS: A total of 24 patients had mapping in the sinuses of Valsalva, and 10 (average age 40 + 15, 60% male) were found to have additional signals (A1 and/or A2) notable during mapping. In all patients, intervals between A1 and A2 shortened after ectopic beats and lengthened after compensatory pauses. These variations in the interval matched the change in systolic duration on Doppler echocardiography. Overdrive atrial pacing was performed in four patients, which demonstrated progressive shortening of intervals between A1 and A2. Pacing always revealed local capture without affecting A1 or A2. In the one patient in whom ablation was performed in these areas, there was no effect on A1 or A2, suggesting these signals represented artifact. CONCLUSIONS: Valve-related signals in the aortic sinuses are commonly seen and can be distinguished. The interval between A1 and A2 correlated with mechanical systole and varied in a physiologically predictable manner with heart rate changes.

Pulmonary vein morphology in patients with paroxysmal atrial fibrillation initiated by ectopic beats originating from the pulmonary veins: implications for catheter ablation.

BACKGROUND: Successful ablation of ectopic beats originating from the pulmonary veins (PV) could eliminate paroxysmal atrial fibrillation (PAF). However, information about the structure of the PV in patients with PAF that is initiated by PV ectopic beats has not been reported. METHODS AND RESULTS: We studied the morphology of the PVs and measured their diameters in 3 groups of patients. Group I included 52 patients (aged 66+/-14 years; 44 men) with focal atrial fibrillation (AF) from the PVs. Group II included 8 patients (aged 50+/-10 years; 3 men) with focal AF from the superior vena cava or cristal terminalis. Group III included 23 control patients (aged 55+/-16 years; 17 men). Of the control patients, 11 had AV node and 12 had AV reentrant tachycardia. After an atrial transseptal procedure, selective PV angiography using a biplane system with a right anterior oblique view of 30 degrees, a left anterior oblique view of 60 degrees, and a cranial angle of 20 degrees was performed. The ostial and proximal portions of the right and left superior PVs (RSPV and LSPV) were significantly dilated in group I patients compared with those in groups II and III. Furthermore, the ostia of the RSPV and LSPV were significantly dilated in group II compared with group III patients. However, the mean diameters of the inferior PVs were similar between the 3 groups. Comparisons of the individual PV diameters among the 3 subgroups of group I (which was divided according to where the ectopic focus was located) showed nonselective dilatation of the PV. CONCLUSIONS: Nonspecific dilatation of the ostia and proximal portion of superior PVs were found in patients with PAF initiated by ectopic beats from the superior PVs.

Catheter ablation of paroxysmal atrial fibrillation initiated by non-pulmonary vein ectopy.

BACKGROUND: Most of the ectopic beats initiating paroxysmal atrial fibrillation (PAF) originate from the pulmonary vein (PV). However, only limited data are available on PAF originating from the non-PV areas. METHODS AND RESULTS: Two hundred forty patients with a total of 358 ectopic foci initiating PAF were included. Sixty-eight (28%) patients had AF initiated by ectopic beats (73 foci, 20%) from the non-PV areas, including the left atrial posterior free wall (28, 38.3%), superior vena cava (27, 37.0%), crista terminalis (10, 3.7%), ligament of Marshall (6, 8.2%), coronary sinus ostium (1, 1.4%), and interatrial septum (1, 1.4%). Catheter ablation eliminated AF with acute success rates of 63%, 96%, 100%, 50%, 100%, and 0% in left atrial posterior free wall, superior vena cava, crista terminalis, ligament of Marshall, coronary sinus ostium, and interatrial septum, respectively. During a follow-up period of 22+/-11 months, 43 patients (63.2%) were free of antiarrhythmic drugs without AF recurrence. CONCLUSIONS: Ectopic beats initiating PAF can originate from the non-PV areas, and catheter ablation of the non-PV ectopy has a moderate efficacy in treatment of PAF.

Effect of phenylephrine on focal atrial fibrillation originating in the pulmonary veins and superior vena cava.

OBJECTIVES: This study was aimed at evaluating the effects of phenylephrine infusion on the occurrence of focal atrial fibrillation (AF). BACKGROUND: Paroxysmal AF can be initiated by ectopic atrial beats originating in the pulmonary vein (PV) or superior vena cava (SVC). The effect of change in autonomic tone on this focal AF is unknown. METHODS: This study included 12 patients with frequent bursts of AF documented by 24-h Holter monitoring. The number and coupling interval of spontaneous ectopic activity and bursts of AF were evaluated for 1 min before and after phenylephrine (2 to 3 microg/kg) injection. RESULTS: After detailed mapping, four patients had a focus located in the left superior PV, six in the right superior PV and two in the SVC. In 10 patients with AF foci originating in the PVs, the frequency of ectopic activity (19.5 +/- 27.4 vs. 11.4 +/- 22.9 beats/min, p = 0.059) was reduced as well as AF bursts (14 +/- 3 vs. 1.8 +/- 2.7 bursts/min, p = 0.005) before versus after phenylephrine injection; the minimal coupling interval of ectopic activity and AF bursts became longer compared with baseline. The maximal percent increase in sinus cycle length after phenylephrine injection was significantly greater in patients with complete suppression of AF compared with those with partial suppression (43 +/- 19 vs. 14 +/- 5%, p = 0.01). However, no significant effect of phenylephrine on AF originating in the SVC was found. CONCLUSIONS: Change in autonomic tone induced by phenylephrine injection was effective in suppressing focal AF originating in the PVs but not in the SVC.

Radiofrequency catheter ablation for management of symptomatic ventricular ectopic activity.

OBJECTIVES: This study assessed the useful role of intracardiac mapping and radiofrequency catheter ablation in eliminating drug-refractory monomorphic ventricular ectopic beats in severely symptomatic patients. BACKGROUND: Ventricular ectopic activity is commonly encountered in clinical practice. Usually, it is not associated with life-threatening consequences in the absence of significant structural heart disease. However, frequent ventricular ectopic beats can be extremely symptomatic and even incapacitating in some patients. Currently, reassurance and pharmacologic therapy are the mainstays of treatment. There has been little information on the use of catheter ablation in such patients. METHODS: Ten patients with frequent and severely symptomatic monomorphic ventricular ectopic beats were selected from three tertiary care centers. The mean frequency +/- SD of ventricular ectopic activity was 1,065 +/- 631 beats/h (range 280 to 2,094) as documented by baseline 24-h ambulatory electrocardiographic (ECG) monitoring. No other spontaneous arrhythmias were documented. These patients had previously been unable to tolerate or had been unsuccessfully treated with a mean of 5 +/- 3 antiarrhythmic drugs. The site of origin of ventricular ectopic activity was accurately mapped by using earliest endocardial activation time during ectopic activity or pace mapping, or both. RESULTS: During electrophysiologic study, no patient had inducible ventricular tachycardia. The ectopic focus was located in the right ventricular outflow tract in nine patients and in the left ventricular posteroseptal region in one patient. Frequent ventricular ectopic beats were successfully eliminated by catheter-delivered radiofrequency energy in all 10 patients. The mean number of radiofrequency applications was 2.6 +/- 1.3 (range 1 to 5). No complications were encountered. During a mean follow-up period of 10 +/- 4 months, no patient had a recurrence of symptomatic ectopic activity, and 24-h ambulatory ECG monitoring showed that the frequency of ventricular ectopic activity was 0 beat/h in seven patients, 1 beat/h in two patients and 2 beats/h in one patient. CONCLUSIONS: Radiofrequency catheter ablation can be successfully used to eliminate monomorphic ventricular ectopic activity. It may therefore be a reasonable alternative for the treatment of severely symptomatic, drug-resistant monomorphic ventricular ectopic activity in patients without significant structural heart disease.

Morphological characteristics of P waves during selective pulmonary vein pacing.

OBJECTIVES: We sought to assess the value of 12-lead electrocardiogram (ECG) P-wave morphology to recognize the paced pulmonary vein (PV). BACKGROUND: Prediction of arrhythmogenic PVs producing ectopy or initiating atrial fibrillation (AF) using 12-lead ECG may facilitate curative ablation. METHODS: In 30 patients P-wave configurations were studied during sinus rhythm and during pacing at six sites from the four PVs: top and bottom of each superior PV and both inferior PVs. The P-wave amplitude, duration and morphology were assessed, and predictive accuracies were calculated for the most significant parameters. An algorithm predicting the paced PV was developed and prospectively evaluated in a different population of 20 patients. RESULTS; Three criteria were used to distinguish right from left PV: 1) a positive P-wave in lead aVL and the amplitude of P-wave in lead I > or =50 microV indicated right PV origin (specificity 100% and 97%, respectively); 2) a notched P-wave in lead II was a predictor of left PV origin (specificity 95%); and 3) the amplitude ratio of lead III/II and the duration of positivity in lead V(1) were also helpful in distinguishing left versus right PV origin. In addition, superior PVs could be distinguished from inferior according to the amplitude in lead II (> or =100 microV). In prospective evaluation, an algorithm based on the above four criteria identified 93% of left versus right PV and totally 79% of the specific PVs paced. CONCLUSIONS: Pacing from the different PVs produced a P-wave with distinctive characteristics that could be used as criteria in an algorithm to identify the PV of origin with an accuracy of 79%.