Micra implantation in a patient with transposition of great arteries.

We describe a 56-year-old male with transposition of the great arteries and Mustard repair, superior vena cava obstruction, atrial fibrillation, and progressive deterioration of his epicardial lead performance. We were successful in deploying of Micra (Medtronic, Minneapolis, MN, USA) at the septo-apical area of his nonsystemic ventricle in a stable position with satisfactory pacing and sensing thresholds.

Long-term pacemaker dependency and impact of pacing on mortality following transcatheter aortic valve replacement with the LOTUS valve.

OBJECTIVES: To determine permanent pacemaker (PPM) dependency following transcatheter aortic valve replacement (TAVR) with the Lotus™ valve system (Boston Scientific), and the impact of PPM implantation on long-term morbidity and mortality. BACKGROUND: Conduction abnormalities are among the most common complications following TAVR. Limited studies have assessed pacing dependency following TAVR. METHODS: Consecutive patients (n = 166) with severe aortic stenosis who underwent TAVR with the Lotus valve system were prospectively recruited from a single-center. PPMs were implanted according to standard clinical criteria. Patients were followed in-hospital and at 1, 3, 6, and 12 months to determine pacemaker dependency and clinical outcomes. RESULTS: Fourteen patients with a pre-existing PPM (8%) were excluded with the remaining 152 patients aged 83.6 ± 5.6 years and 46% male. PPMs were implanted 3.8 ± 4 days post-TAVR in 38/152 patients (25%). Indication for PPM was complete heart block in 29 (76%) of patients. At 30-day and one-year follow up, 57% and 38% of patients were pacemaker dependent, respectively. The mean ventricular pacing percentage decreased in the first three months after PPM implantation and remained relatively stable after that. CONCLUSION: Only 38% of Lotus recipients who require a PPM following TAVR with the Lotus valve remain pacing dependent at one year.

Aborted sudden cardiac death in a patient with implantable loop recorder.

We discuss a 46-year-old man with history of hypertension and inferior wall myocardial infarction and mild left ventricular dysfunction who presented with aborted sudden cardiac death due to episodes of ventricular tachyarrhythmia detected by a Reveal-LINQ which had been implanted one year prior to presentation.

Diffuse inverted T waves in a young man with structurally normal heart: a case report.

We discuss a young man with episodes of chest pain and dyspnea accompanied with transient T-wave inversion in precordial and inferior leads that repeated several times. Cardiovascular evaluation did not disclose any structural abnormality. Memory T wave following episodes of idiopathic left septal ventricular tachycardia was the reason of these changes and did not repeat after arrhythmia ablation.

The prevalence and prognostic role of vitamin D deficiency in patients with acute coronary syndrome: a single centre study in South-West of Iran.

BACKGROUND: The objectives of this study were estimating the prevalence of vitamin D deficiency in patients with acute coronary syndrome comparing with normal people and evaluating the relationship between vitamin D deficiency and short-term mortality in these patients. METHODS: We considered 106 patients with non-ST elevation myocardial infarction and high-risk unstable angina and 110 patients with ST elevation myocardial infarction as group A. The control group (group B) consisted of 120 individuals without any known cardiovascular diseases or systemic disease. We measured serum 25-hydroxyvitamin D in all cases and classified them according to their serum 25-hydroxyvitamin D levels. Sufficient vitamin D level was considered ≥30 ng/ml. We followed the patients for 30 days after index admission. RESULTS: The prevalence of hypovitaminosis D in group A was much higher than group B. In group A, 72% of patients had serum 25-hydroxyvitamin D level of 20 ng/ml or less. This percentage was only 27.4% in control group. We did not find any significant relationship between vitamin D deficiency and short-term mortality in patients with acute coronary syndrome. CONCLUSION: Our data suggest that vitamin D deficiency was present in most of patients admitted with acute coronary syndrome in Ahvaz.

Randomized Prospective Comparison of Two Protocols for Head-up Tilt Testing in Patients with Normal Heart and Recurrent Unexplained Syncope.

BACKGROUND: This randomized study was aimed to compare the diagnostic value of two head-up tilt testing protocols using sublingual nitroglycerin for provocation in patients with recurrent unexplained syncope and normal heart. METHODS: The patients with normal findings in physical examination, electrocardiography and echocardiography were randomly submitted to one of upright tilt test protocols. The only difference between two protocols was that nitroglycerin was administered after a five minute resting phase in supine position during protocol B. We also considered eighty normal persons as the control group. RESULTS: Out of 290 patients that underwent tilt testing, 132 patients were in group A versus 158 patients in group B. Both groups had an identical distribution of clinical characteristics. Tilt test was positive in 79 patients in group A (25 in passive phase, 54 in active phase) versus 96 patients in group B (43 in passive phase, 53 in active phase). There was no significant difference between results in two groups (P value= 0.127). Forty cases were tested with protocol A and forty underwent tilt testing with protocol B. Tilt test was positive in 4 cases with protocol A versus 3 cases in protocol B. The positive rates of tilt testing with protocol A was 60% while it was 61% in protocol B. The specificity of testing with protocol A was 90% and it was 92.5% in protocol B. CONCLUSIONS: According to our data, adding a period of rest and returning to supine position before nitroglycerin administration had no additional diagnostic yield.

Worldwide survey on implantation of and outcomes for conduction system pacing with His bundle and left bundle branch area pacing leads.

BACKGROUND: Adoption and outcomes for conduction system pacing (CSP), which includes His bundle pacing (HBP) or left bundle branch area pacing (LBBAP), in real-world settings are incompletely understood. We sought to describe real-world adoption of CSP lead implantation and subsequent outcomes. METHODS: We performed an online cross-sectional survey on the implantation and outcomes associated with CSP, between November 15, 2020, and February 15, 2021. We described survey responses and reported HBP and LBBAP outcomes for bradycardia pacing and cardiac resynchronization CRT indications, separately. RESULTS: The analysis cohort included 140 institutions, located on 5 continents, who contributed data to the worldwide survey on CSP. Of these, 127 institutions (90.7%) reported experience implanting CSP leads. CSP and overall device implantation volumes were reported by 84 institutions. In 2019, the median proportion of device implants with CSP, HBP, and/or LBBAP leads attempted were 4.4% (interquartile range [IQR], 1.9-12.5%; range, 0.4-100%), 3.3% (IQR, 1.3-7.1%; range, 0.2-87.0%), and 2.5% (IQR, 0.5-24.0%; range, 0.1-55.6%), respectively. For bradycardia pacing indications, HBP leads, as compared to LBBAP leads, had higher reported implant threshold (median [IQR]: 1.5 V [1.3-2.0 V] vs 0.8 V [0.6-1.0 V], p = 0.0008) and lower ventricular sensing (median [IQR]: 4.0 mV [3.0-5.0 mV] vs. 10.0 mV [7.0-12.0 mV], p < 0.0001). CONCLUSION: In conclusion, CSP lead implantation has been broadly adopted but has yet to become the default approach at most surveyed institutions. As the indications and data for CSP continue to evolve, strategies to educate and promote CSP lead implantation at institutions without CSP lead implantation experience would be necessary.

Ventricular tachycardia or supraventricular tachycardia?

It shows a pseudo -A-V-V-A response after stopping overdrive atrial pacing of a broad complex tachycardia.

Long-term longevity and clinical outcomes of Linox S/SD implantable cardioverter-defibrillator leads: a single-center experience.

PURPOSE: Since the introduction of the Biotronik Linox S/SD leads in 2006, there have been multiple reports of premature lead failure. The purpose of this study was to investigate the longevity of the Linox S/SD leads and to identify the possible predictors of lead failure in a single tertiary implant center. METHODS: We retrospectively reviewed patients who underwent implantation of Linox S/SD leads or Sorin Vigila 1CR/2CR leads (the same Linox S/SD leads marketed by Sorin) at our center. The cumulative lead survival was estimated using the Kaplan-Meier curve, and variables associated with lead failure were assessed by Cox proportional hazard model. RESULTS: A total of 187 patients (154 (82%) male) underwent Linox S/SD or Vigila 1CR/2CR implantation between 2007 and 2013. During follow-up with a median time of 75 months, nine lead failures were identified (4.8%). The mean and median times from lead implantation to lead failure were 70.7 ± 21 months and 64 (45-111) months, respectively. The cumulative survival probability for the Linox S/SD at 5 years was 97.1% and at 12 years was 90.3%. Non-physiological high-rate sensing was the most common type of lead failure in patients. In two-thirds of these patients, this led to inappropriate shock. We did not find any significant relationships between patients' clinical and procedural characteristics and lead failure. CONCLUSIONS: At our center, the 5-year lead survival of the Linox S/SD has been better than reports from other centers. The majority of lead failures presented as non-physiological high-rate sensing with subsequent inappropriate therapy.

Significance of signal averaged electrocardiography in patients with advanced heart failure and intraventricular conduction delay.

AIMS: Signal averaged electrocardiography is a noninvasive method to evaluate the presence of the potentials that are generated by tissues, activated later than their usual timing in the cardiac cycle. The purpose of this study was to demonstrate the correlation of data obtained via signal averaged electrocardiography and left ventricular dyssynchrony. METHODS: We included the patients with advanced systolic left ventricular dysfunction (ejection fraction

Junctional ectopic tachycardia (JET).

Junctional ectopic tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. Enhanced normal automaticity has been postulated as the mechanism of JET in the majority of patients. It is more common in children and can be seen as congenital or in postoperative settings. It is often a narrow complex tachycardia but can present as a wide complex tachycardia as a result of aberrant conduction. Its differentiation from other arrhythmias especially atrioventricular nodal reentrant tachycardia (AVNRT) can be challenging. Medical treatment of JET is difficult, and catheter ablation remains the mainstay of treatment in refractory cases with a high risk of atrioventricular block and recurrence.

Pacemaker-mediated arrhythmias.

Pacemakers can be directly involved in initiating or sustaining different forms of arrhythmia. These can cause symptoms such as dyspnea, palpitations, and decompensated heart failure. Early detection of these arrhythmias and optimal pacemaker programming is pivotal. The aim of this review article is to summarize the different types of pacemaker-mediated arrhythmias, their predisposing factors, and mechanisms of prevention or termination.

Correlation between results of head-up tilt test and clinical features in patients with syncope or presyncope.

BACKGROUND: Head-up tilt test (HUTT) is a well-established diagnostic tool in patients with suspected vasovagal syncope. Identification of factors that predict a positive HUTT result could simplify diagnostic steps. The aim of this study was to assess the correlation between clinical characteristics of patients with suspected neurocardiogenic syncope or presyncope and results of HUTT. MATERIALS AND METHODS: The study group consisted of 90 patients (55 men, 35 women; mean age, 43.2 +/- 17 years) with a history of syncope or presyncope. Cardiological and neurologic test findings were normal in every patient. The patients were tilted to a 70 degrees position for 45 minutes. If the first phase produced a negative response, the patients received 400 mug of sublingual nitroglycerin for the second phase and continued to be tilted for an additional 15 minutes. RESULTS: Sixty-four patients had a positive HUTT result, characterized by a vasodepressive response in 26 patients, mixed response in 24 patients, and cardioinhibitory response in 14 patients. In logistic regression analysis, the presence of prodromal symptoms was a predictor of a positive HUTT result (P = .002). CONCLUSION: We showed that the prognostic performance of clinical features, including the time interval between the last episode and HUTT, the number of syncope or presyncope episodes, age, and sex, was not ideal. The presence of prodromal symptoms might be more likely to predict a positive response during HUTT.

Loss of cardiac resynchronization therapy in a patient with a biventricular implantable cardioverter-defibrillator.

Here, we discuss the case of a man with a history of ischemic cardiomyopathy and cardiac resynchronization therapy defibrillator implantation, who presented to emergency department with decompensated heart failure due to the loss of resynchronization therapy. The reason for the malfunction was left ventricle upper rate interval lock-in due to inappropriate programming of the device.

Inappropriate ICD discharge due to T-wave oversensing in a patient with the Brugada syndrome.

Accurate sensing is an essential requirement for appropriate functioning of implantable cardioverter-defibrillator (ICD). T-wave oversensing remains as an annoying problem in currently available ICD. The Brugada syndrome with its inherent dynamic variations in electrophysiologic phenomena may complicate ICD therapy. We report a patient with diagnosis of Brugada syndrome who presented with frequent inappropriate therapy due to intermittent T-wave oversensing. This problem could not be eliminated by device reprogramming and necessitated implantation of a new sense/pace lead.

Predictors of appropriate ICD therapy in patients with implantable cardioverter-defibrillator.

BACKGROUND: Understanding the predictors of appropriate implantable cardioverter defibrillator (ICD) therapy could help to better identify candidates for ICD implantation. METHODS: One hundred and sixty two patients with ICD (111 with coronary artery disease [CAD] and 51 with dilated cardiomyopathy [DCM]) were included in the study. Clinical, electrocardiographic, and ICD stored data and electrograms were collected. RESULTS: During mean follow up of 15+/-11 months 54 patients (33%) received > or = 1 appropriate ICD therapy (AICDT). We used binary logistic regression analysis with forward selection method to find the potential predictors of appropriate ICD therapy after device implantation. Male gender (odds ratio [OR] = 2.76, 95% confidence interval [CI] = 1.1-7.1, P=0.021), DCM as underlying heart disease (OR = 4.2, 95% CI = 1.9-9.5, P=0.001), and QRS width > 100 ms (OR = 2.58, 95% CI = 1.2-5.4, P=0.010) were correlated with increased likelihood of AICDT during the follow up period. In subgroup analysis of the patients with CAD and DCM, QRS duration > 100 ms was correlated with the probability of > or = 1 AICDT. In our patients indication of ICD implantation (primary versus secondary prevention) did not influence probability of > or = 1 AICDT (adjusted OR = 1.66, 95% CI = 0.7-4.0, Mantel-Haenszel P value P=0.355). CONCLUSION: QRS width could be used as an additional simple risk stratifier beyond EF to identify potential candidates who would benefit more from ICD implantation. This may have practical implications for patient selection especially in developing countries. Indication of ICD implantation (primary versus secondary prevention) did not affect the probability of > or = 1 AICDT during the follow up period.

Effect of cardiac resynchronization therapy on the incidence of ventricular arrhythmias in patients with an implantable cardioverter-defibrillator.

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces mortality in selected patients with heart failure. However, this result may not be entirely related to the beneficial hemodynamic effects of CRT. OBJECTIVES: The purpose of this study was to assess retrospectively the effect of CRT on the incidence of appropriate therapy in patients with an implantable cardioverter-defibrillator (ICD). METHODS: Sixty-five patients (48 men and 17 women; mean age 58 +/- 13 years) with an ICD (31 biventricular, 34 dual-chamber) were included in the study. Clinical, ECG, and ICD stored data and electrograms were collected. RESULTS: Biventricular and dual-chamber ICDs were implanted in 31 and 34 patients, respectively, who had either ischemic (n = 36) or dilated cardiomyopathy (n = 29). Thirty-two (49%) patients received > or =1 appropriate ICD therapy during follow-up of 11 +/- 8 months. Thirty-five percent and 62% of patients with biventricular (n = 11) and dual-chamber ICDs (n = 21), respectively, received appropriate ICD therapy during the follow-up period (odds ratio = 0.340, P = .048). Stratifying the patients according to underlying heart disease and ejection fraction resulted in an adjusted odds ratio = 0.239 (P = .029). Comparing the rate of > or =1 appropriate ICD therapy between the two groups by Kaplan-Meier analysis and the log rank test resulted in P = .027. CONCLUSION: In this retrospective analysis, biventricular pacing was associated with a decreased incidence of sustained ventricular arrhythmias requiring ICD therapy. The antiarrhythmic effect of biventricular pacing could contribute to the reduction in mortality reported in recent large-scale clinical trials on CRT. However, further prospective studies are warranted to clarify this issue.

Changes in Heart Rate Variability Parameters after Elective Percutaneous Coronary Intervention.

BACKGROUND: Patients with chronic stable angina often have a state of sympathetic hyperactivity. It is considered associated with myocardial ischemia and disappears after ischemia elimination. The aim of this study was to investigate the changes in heart rate variability parameters, a noninvasive technique for the evaluation of the autonomic nervous system activity, after successful revascularization in these patients to evaluate this theory. METHODS: The patients were enrolled among those who underwent successful percutaneous coronary intervention. Short-term heart rate variability analyses of all the patients were obtained, and time-domain indices (standard deviation of normal-to-normal intervals [SDNN], standard deviation of differences of successive R-R intervals [SDSD], root-mean square differences of successive R-R intervals [rMSSD], percentage of R-R intervals differing > 10 ms from the preceding one [PNN10], percentage of R-R intervals differing > 20 ms from the preceding one [PNN20], percentage of R-R intervals differing > 30 ms from the preceding one [PNN30], percentage of R-R intervals differing > 40 ms from the preceding one [PNN40], percentage of R-R intervals differing > 50 ms from the preceding one [PNN50], percentage of R-R intervals differing > 60 ms from the preceding one [PNN60], and percentage of R-R intervals differing > 70 ms from the preceding one [PNN70]) were analyzed. All the measurements were made before and after percutaneous coronary intervention. RESULTS: This study included 64 patients, comprising 27 men and 37 women at a mean age of 56.8 ± 9.1 years. There was a significant difference only between pre- and post-revascularization SDNN (27.5 ± 19.72 vs. 41 ± 41.4; p value = 0.013). The other parameters showed no significant differences after successful coronary intervention. Conclusion : Our data indicate that the increase in SDNN in patients with stable angina pectoris undergoing percutaneous coronary intervention seems to be prominent.

The prognostic role of serum uric acid level in patients with acute ST elevation myocardial infarction.

OBJECTIVES: The role of uric acid as a prognostic factor in patients with acute ST elevation myocardial infarction is controversial. The purpose of this study was to demonstrate the relationship between serum uric acid level and mortality during admission period and 30-day period after admission. METHODS: We assessed the relation between serum uric acid level and in-hospital and short-term mortality rates in 184 patients admitted with acute ST elevation myocardial infarction. We divided the patients according to their gender and uric acid level measured on admission into four groups: group A1: men with uric acid ⩽7 mg/dl versus group B1: men with uric acid >7 mg/dl and group A2: women with uric acid ⩽5.6 mg/dl versus group B2: women with uric acid >5.6 mg/dl. The patients were followed for 30 days after admission. RESULTS: In-hospital mortality rate in group B1 was higher than group A1 [P value: 0.011, Relative risk: 13.33 (95% confidence interval: 1.55-114.7)]. Short-term all-cause mortality was significantly higher in group B1 patients [P value: 0.037, Relative risk: 3.3 (95% confidence interval: 1.02-10.64)]. Multivariate logistic regression analysis of data showed an odds ratio of 15.23 for in-hospital mortality and odds ratio of 3.76 for short-term mortality in male hyperuricemic patients. CONCLUSIONS: Our data suggest that in the acute phase of ST elevation myocardial infarction, uric acid has a prognostic role for in-hospital and short-term (30-day) mortality in men.