Diagnostic yield of head-up tilt table test in hypertrophic cardiomyopathy and unexplained syncope: the knot does not seem to be unraveling.

BACKGROUND: Conflicting results have been published considering the diagnostic performance of head-up tilt test (HUTT) in patients with hypertrophic cardiomyopathy (HCM). We aimed to conduct a meta-analysis to evaluate the diagnostic value of HUTT in the evaluation of unexplained syncope in patients with HCM. METHODS: We performed a structured systematic database search using the following keywords: hypertrophic cardiomyopathy, syncope, unexplained syncope, head-up tilt test, tilt table test, tilt testing, orthostatic stress, autonomic function, autonomic response. Studies in which the HUTT was used to define autonomic dysfunction in patients with syncope at baseline or without syncope were included in the final analysis. RESULTS: A total of 252 HCM patients from 6 studies (159 patients without a history of syncope and 93 with a history of syncope, respectively) were evaluated. HUTT was positive in 50 (19.84%) of 252 patients (in 21 of 93 patients (22.58%) with a history of syncope and in 29 of 159 patients (18.24%) without a history of syncope, respectively). The pooled total sensitivity and specificity of the HUTT for detecting syncope were 22.1% (14.8-35.1%) and 83.6% (73.2-91.6%), respectively. The summary receiver operator curve showed that HUTT had an only modest discriminative ability for syncope with an area under the curve value of 0.565 (0.246-0.794). CONCLUSION: Although HUTT has significant limitations in diagnosis of unexplained syncope in patients with HCM, it may still be used to determine hypotensive susceptibility. Other autonomic tests can be used in diagnostic workflow in this population.

Diagnostic accuracy of Apple Watch Series 6 recorded single-lead ECGs for identifying supraventricular tachyarrhythmias: a comparative analysis with invasive electrophysiological study.

BACKGROUND: The advancements in wearable technology have made the detection of arrhythmias more accessible. While smartwatches are commonly used to detect patients with atrial fibrillation, their effectiveness in the differential diagnosis of supraventricular tachycardias (SVT) lacks consensus. METHODS: A study was conducted on 47 patients with documented SVTs on a 12-lead ECG. All patients in the cohort underwent electrophysiology study with induction of SVT. A 6th generation Apple Watch was used to record ECG tracings during baseline sinus rhythm and during induced SVT. Cardiology residents and attending cardiologists evaluated these recordings to diagnose the differential diagnosis of SVT. RESULTS: The evaluation revealed 27 cases of typical atrioventricular nodal reentrant tachycardia (AVNRT), 11 cases of atrioventricular reentrant tachycardia (AVRT), and 9 cases of atrial tachycardia/atrial flutter (AT/AFL) among the induced tachycardias. Attending physicians achieved an accuracy of 66.0 to 76.6%, and residents demonstrated accuracy rates between 68.1 and 74.5%. Interrater reliability was assessed using Fleiss's Kappa method, resulting in a moderate level of agreement between residents (Kappa = 0.465, p < 0.001, 95% CI 0.30-0.63) and attendings (Kappa = 0.519, p < 0.001, 95% CI 0.35-0.68). The overall Kappa value was 0.417 (p < 0.001, 95% CI 0.34-0.49). CONCLUSIONS: Smartwatch recordings demonstrate moderate feasibility in diagnosing SVT when following a pre-specified algorithm. However, this diagnostic performance was lower than the accuracy obtained from 12-lead ECG tracings when blinded to procedure outcomes.

Left atrial functions in the early period after cryoballoon ablation for paroxysmal atrial fibrillation.

PURPOSE: In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after pulmonary vein isolation (PVI) procedure. Although previous studies have investigated the altered mechanical functions of the LA with radiofrequency (RF) ablation, changes in the LA functions in the early period after cryoablation (CB-2) have not been clearly demonstrated. This study aims to explore the early periodical changes in mechanical functions of the LA in patients with PAF who underwent CB-2 based ablation through the help of echocardiographic methods which contain Doppler and strain parameters. METHODS: Consecutive 77 patients (mean age: 57.5 ±  11.2; 57% men) with PAF underwent CB-2 were prospectively analyzed. All patients were in sinus rhythm before and after the procedure. The LA dimensions, the LA reservoir strain, the LA atrial contractile strain and the LA conduit strain and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure. RESULTS: Acute procedural success was achieved in all cases. No major complications were observed. LA reservoir strain and LA contractile strain showed significant recovery after the procedure. (28.3 ± 12.8 vs. 34.6 ± 13.8, p < .001 and -10.8 ± 7.9 vs. -13.9 ± 9.3, p = .014 respectively). No significant change was demonstrated in other echocardiographic parameters. CONCLUSION: Significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF.

Intracardiac electrogram characteristics of intramural outflow tract ventricular arrhythmias.

BACKGROUND: Annotation of earliest depolarization which depends on maximum dV/dt of unipolar-electrograms and unipolar QS morphology identify site of origin for ventricular premature contractions (VPC). However, identification of unipolar QS morphology has limitations due to low spatial resolution. This study aims to compare electrogram characteristics at successful ablation site in patients with outflow tract (OT) VPC. METHODS: Local activation time (LAT), duration, and voltage data of each bipolar- and unipolar-electrogram at the successful ablation sites from the right ventricle OT (RVOT) and the left ventricle OT (LVOT) cases were analyzed. RESULTS: Forty-four of 60 (73%) of patients were ablated from RVOT and in 16/60 (27%) required ablation from both sides. All patients had acute VPC suppression. Bipolar-electrogram-QRS onset was earlier (36.4 ± 14.5 ms vs 26.3 ± 7.4 ms, p = 0.01), duration of bipolar-electrogram was shorter (56.9 ± 18.9 ms vs 78.9 ± 21.8 ms, p = 0.002), and bi-voltage amplitude was higher (3.2 ± 2.3 mV vs 1.4 ± 1.1 mV, p = 0.07) for patients with RVOT-only ablation. Mean bipolar-unipolar-electrogram difference was 4.4 ± 4.5 ms in the RVOT group vs 12.8 ± 4.9 ms in RVOT + LVOT group (p < 0.001). Unipolar QS morphology was recorded in 3.0 ± 3.9 vs 3.6 ± 1.8 cm2 in RVOT and RVOT + LVOT group, respectively (p = 0.41). Unipolar-electrogram revealed W pattern in 3/44 of RVOT vs 5/16 of RVOT + LVOT group, respectively (p = 0.01). In 18/60 (30%) of patients, unipolar QS was not identified at successful ablation site. CONCLUSION: QS in unipolar-electrogram was not a perfect predictor for successful ablation sites. Analysis of bipolar voltage amplitude and duration with bipolar-unipolar-electrogram time difference may identify presence of a deeper source.

Comparison of choroidal thicknesses in patients with coronary artery disease and patients at risk of coronary artery disease.

PURPOSE: The study aimed to compare choroidal thicknesses (CTh) in patients with coronary artery disease (CAD) and patients at risk of coronary artery disease and investigate whether thinning of the choroid can be used as a biomarker for development of coronary artery disease in patients at risk. MATERIALS AND METHODS: The study group was composed of 103 eyes of 53 patients with coronary artery disease, and the control group was composed of 62 eyes of 32 patients with diabetes mellitus, hypertension and/or hyperlipidemia without coronary artery disease. CAD was diagnosed in patients with one of the following: myocardial infarction with/without ST segment elevation, clinically proven history of cardiac catheterization testifying greater than 50% obstruction in at least one coronary artery, revascularization operations. The control group consisted of clinically proven patients with normal coronary arteries. The choroidal thickness was measured with enhanced depth imaging optical coherence tomography under the fovea and at six other points, located at 500 micron, 1000 micron and 1500 micron nasal to the fovea and 500 micron, 1000 micron, 1500 micron temporal to the fovea. RESULTS: The subfoveal choroidal thickness was significantly thinner in the coronary artery disease group compared to the control group (244 µm vs. 289 µm; p < 0,001). In all other measured regions (nasal 500, nasal 1000, nasal 1500, temporal 500, temporal 1000, and temporal 1500 micron), CTh was statistically significant thinner in the CAD group. A negative significant linear relationship (low level) between CAD duration and choroidal thickness in the subfoveal, nasal 1000, nasal 1500, temporal 500, temporal 1000 micron regions was detected. CONCLUSION: Patients with CAD have a decreased choroidal thickness compared to patients at risk of CAD. Detection of CTh thinning in a patient with diseases, such as diabetes, hypertension and/or hypercholesterolemia, which pose a risk for CAD may be a predictor of development of coronary artery disease. Clinical Trials Registration Kocaeli Derince Training and Research Hospital ethics committee-protocol number: 2020-106.