This diagnostic image displays a schematic diagram of a continuous segment of an electrocardiogram (ECG) signal waveform, utilized in the context of cardiac rhythm analysis and machine learning classification. The graph plots the amplitude value (on the y-axis, ranging from 0.0 to 0.5) against time in seconds (T (s) on the x-axis, spanning 0 to 800 seconds). The waveform demonstrates typical physiological oscillations consisting of repeated peaks and troughs that correspond to cardiac electrical activity. Gridlines are provided at 0.1 intervals for amplitude and 50-second intervals for time to facilitate precise measurement. Such continuous data segments are essential in medical informatics for preprocessing tasks like heartbeat segmentation, denoising, and the identification of arrhythmias, such as right bundle-branch blocks or atrial premature contractions (APC). The visual representation serves as a foundational tool for understanding signal morphology and the temporal distribution of heartbeats in cardiovascular diagnostic studies.

This pathophysiology diagram consists of three stacked electrophysiological simulation traces over a 6-second period, illustrating cellular cardiac arrhythmias. The Y-axes represent membrane potential (Vm in mV), sodium current (INa in pA/pF), and sodium inactivation (INa inact.). The simulation compares two starting states: 'Initial condition 1' (black line) and 'Initial condition 2' (red line), where the latter begins with a membrane potential 1 mV higher than the former. The Vm trace demonstrates the development of early afterdepolarizations (EADs) during the repolarization phase of the action potentials. Initially, the two simulation traces are identical, but they eventually diverge, illustrating sensitivity to initial conditions and chaotic dynamics in cardiac electrical signaling. The corresponding INa traces show that during EADs, there is a reactivation of sodium currents, which correlates with partial recovery in the INa inactivation variable. This visual evidence supports the role of sodium channel window currents in triggering irregular EADs under pathological conditions, such as long QT syndrome or heart failure.

Two grayscale fluoroscopic images illustrate cardiac anatomy and classification criteria for proximal versus non-proximal ventricular arrhythmias. The left panel shows a Right Anterior Oblique (RAO 35°) projection, with labels for the anterior, posterior, and inferior aspects of the heart. A solid white line outlines the cardiac silhouette, while a dashed region defines the proximal half of the heart, where structures like the His bundle and proximal fascicles are located. A bisecting line with tick marks indicates the division between proximal and distal sections. The right panel shows a Left Anterior Oblique (LAO 45°) projection, highlighting the interventricular septum and lateral wall. A similar dashed area delineates the targeted septal and proximal anterior wall regions. These images serve as a fluoroscopic guide for identifying successful ablation sites in patients with focal Purkinje ventricular arrhythmias, emphasizing anatomical landmarks used to differentiate arrhythmia origins based on septal and proximal proximity.

This pathophysiology diagram illustrates the multi-level mechanisms leading to arrhythmia in Fabry Disease (FD), categorized into primary, secondary, environmental, and ventricular effects. The 'Primary' section focuses on cellular dysfunction, showing GLA mutations leading to Gb3 accumulation, which triggers endoplasmic reticulum dysfunction, mitochondrial impairment, Golgi dysfunction, sarcomere dysfunction, and direct ion channel dysfunction. The 'Secondary' section details macro-level pathological changes: cardiac myocyte hypertrophy, myocardial ischemia (represented by a perfusion scan), myocardial fibrosis, and cardiomyocyte death, all associated with troponin release and designated as pro-arrhythmic. 'Environmental' factors include renal impairment, hyperkalemia (K+), and dialysis, which contribute to myocardial inflammation (depicted via histopathology showing myocytes, inflammatory cells, and fibrotic tissue). The final column, 'Ventricular Effects,' displays diagnostic ultrasound images correlating these processes with clinical stages of diastolic and systolic dysfunction. The diagram uses arrows to establish bidirectional relationships between hypertrophy, ischemia, fibrosis, and inflammation, highlighting the complex, interrelated substrate for both atrial and ventricular arrhythmias in FD.

This composite figure presents a comprehensive clinical workup for dilated cardiomyopathy (DCM) and associated arrhythmias. Panels (a-c) display cardiovascular monitoring findings: a standard 12-lead ECG (a) showing atrial fibrillation with complete atrioventricular (AV) block (bradycardia at 40 bpm); a rhythm strip (b) capturing non-sustained ventricular tachycardia (NSVT); and a post-intervention ECG (c) demonstrating a regular paced rhythm following cardiac resynchronization therapy defibrillator (CRTD) implantation. Radiographic and imaging studies include a chest X-ray (d) showing cardiomegaly with a cardiothoracic ratio of 60.4% and pulmonary congestion; an echocardiogram with M-mode (e) indicating left ventricular systolic dysfunction; and a cardiovascular magnetic resonance (CMR) image (f) revealing late gadolinium enhancement (LGE) within the left ventricle, suggestive of myocardial fibrosis. Histopathological examination of endomyocardial biopsy specimens (g, h) at 50x magnification shows interstitial fibrosis via Hematoxylin and Eosin (g) and Elastica-Masson (h) staining. The collection illustrates the diagnostic progression from primary electrical disturbances to structural heart disease and definitive histopathological confirmation in a patient with an LMNA mutation.

A 12-lead baseline electrocardiogram (ECG) recorded at 25 mm/s and 10 mm/mV, demonstrating complex cardiac conduction abnormalities. The tracing shows a rapid, irregular atrial arrhythmia, likely atrial fibrillation or high-frequency atrial tachycardia, with an atrial rate of approximately 180 beats per minute. Distinct P waves are absent, replaced by fibrillatory waves visible in the baseline, particularly in lead V1. Concurrent with this is a complete (third-degree) atrioventricular (AV) block, evidenced by the total dissociation between atrial activity and ventricular response. The ventricles are driven by a junctional escape rhythm, resulting in a slow, regular ventricular rate of approximately 43 beats per minute. The QRS complexes are relatively narrow (approximately 90 ms), consistent with a supra-Hisian escape focus. The tracing includes limb leads (I, II, III, aVR, aVL, aVF) and precordial leads (V1-V6), with a continuous lead II rhythm strip at the bottom. This visual record is characteristic of advanced conduction system disease, often associated with LMNA-related cardiomyopathies or other structural heart diseases.

A standard 12-lead diagnostic electrocardiogram (ECG) demonstrating atrial fibrillation with rapid ventricular response (RVR). The tracing shows a classic irregularly irregular rhythm with narrow QRS complexes (100 ms duration). There is a total absence of discernible P waves, which are replaced by baseline fibrillatory oscillations, most visible in lead V1. The ventricular rate is approximately 119 beats per minute, indicating tachycardia. The ECG includes the limb leads (I, II, III, aVR, aVL, aVF) and precordial leads (V1-V6), with a continuous rhythm strip of lead II at the bottom. Automated measurements provided at the top of the tracing confirm a QTc of 438 ms and a heart rate increase compared to prior records. This diagnostic image serves as a clinical example of supraventricular tachycardia originating from disorganized atrial electrical activity, necessitating evaluation for hemodynamic stability and rate/rhythm control.

A 12-lead electrocardiogram (ECG) demonstrating an irregularly irregular rhythm with a rapid ventricular response, characteristic of atrial fibrillation. Notable features include the absence of distinct P waves and varying R-R intervals. The ventricular rate is tachycardia, estimated at over 150 bpm. A widening of the QRS complex is observed, exceeding 120 ms. In the precordial leads V1-V3, there is a prominent RSR' pattern, where the terminal R wave is taller than the initial R wave, coupled with secondary ST-segment depression and T-wave inversion. Leads V5 and V6 exhibit characteristic slurred S waves. These morphological findings are diagnostic of a right bundle branch block (RBBB). This diagnostic image is clinically significant for identifying acute right ventricular strain or conduction disturbances in the context of emergency presentations such as syncope or suspected pulmonary embolism. It is suitable for medical students and clinicians studying cardiovascular diagnostics and acute care.

TABLE 9 Antiarrhythmic Drug Therapy Options for Patients With HCM and AF <table><thead><tr><th>Antiarrhythmic Drug</th><th>Efficacy for AF</th><th>Adverse Effects</th><th>Toxicities</th><th>Use in HCM</th></tr></thead><tbody><tr><td>Disopyramide</td><td>Modest</td><td>Anticholinergic<br>HF</td><td>Prolonged QTc<br>TdP</td><td>Particularly with early onset AF<br>Generally used in conjunction with atrioventricular nodal blocking agents</td></tr><tr><td>Flecainide and propafenone</td><td>...</td><td>Prolonged QRS</td><td>Proarrhythmia<br>Typical atrial flutter</td><td>Not generally recommended in the absence of an ICD</td></tr><tr><td>Sotalol</td><td>Modest</td><td>Fatigue Bradycardia</td><td>Prolonged QTc<br>TdP</td><td>Reasonable</td></tr><tr><td>Dofetilide</td><td>Modest</td><td>Headache</td><td>Prolonged QTc<br>TdP</td><td>Reasonable</td></tr><tr><td>Dronedarone</td><td>Low</td><td>HF</td><td>Prolonged QTc</td><td>...</td></tr><tr><td>Amiodarone</td><td>Modest-high</td><td>Bradycardia</td><td>Liver, lung, thyroid, skin, neurologic<br>Prolonged QTc</td><td>Reasonable</td></tr></tbody></table> AF indicates atrial fibrillation; HCM, hypertrophic cardiomyopathy; HF, heart failure; ICD, implantable cardioverter-defibrillator; and TdP, torsades de pointes.

Recommendations for delivery and lactation <table><thead><tr><th>COR</th><th>LOE</th><th>Recommendations</th><th>References</th></tr></thead><tbody><tr><td>1</td><td>C-LD</td><td>1. In pregnant patients with cardiac arrhythmias, the route of delivery (vaginal or cesarean) should be determined by the birth plan and obstetrical factors in accordance with best clinical practice, along with continuation of antiarrhythmic drug therapy.</td><td>179</td></tr><tr><td>1</td><td>C-LD</td><td>2. Pregnant patients receiving antiarrhythmic drug therapy or at risk of cardiac arrhythmias should receive adequate pain control during labor, ideally with the use of neuraxial anesthesia (epidural), to avoid pain-induced catecholamine surges that may trigger preexisting arrhythmias.</td><td>180</td></tr><tr><td>1</td><td>C-LD</td><td>3. In breastfeeding patients, antiarrhythmic drug therapy should be used when clinically indicated, with a preference for agents with the best safety profile during lactation.</td><td>181-192</td></tr><tr><td>1</td><td>C-LD</td><td>4. In breastfeeding patients with life-threatening cardiac arrhythmias refractory or with contraindications to other treatment, the decision to treat with amiodarone should balance the severity of the arrhythmia against the potential risk for long-term toxicity with consideration of the risks and benefits of breast milk compared with alternatives such as infant formula or donated breast milk.</td><td>183,191</td></tr></tbody></table>

TABLE 3 (Continued) <table><thead><tr><th>Botto classification</th><th>Lesion</th><th>CNVs and CNV syndromes</th><th>Monogenic Syndromes</th><th>Genes also associated with apparently isolated CHDs</th><th>Chromosomal</th></tr></thead><tbody><tr><td>NA</td><td>Other vascular defects</td><td>• 1p36 deletion syndrome (Ebstein anomaly)<br>• 7q11.23 deletion/Williams Syndrome (SVAS)<br>• 11q terminal deletion syndrome/ Jacobsen syndrome (mitral stenosis)<br>• 1p36 deletion syndrome (LVNC)</td><td>• Coffin-Lowry (MVP)<br>• Fragile X (MVP)<br>• Marfan (MVP)</td><td>• DCHS1 (MVP)<br>• MYBPC3 (mitral valve regurgitation)<br>• MYH7 (Ebstein anomaly)</td><td rowspan="2"></td></tr><tr><td>NA</td><td>Overlap with Cardiomyopathy/ Conduction Disease</td><td></td><td>• Cantu (HCM)<br>• CFC (HCM)<br>• Coffin-Lowry (LVNC)<br>• Costello (HCM)<br>• Holt-Oram (conduction defects)<br>• Noonan (HCM)<br>• Timothy (LQTS)</td><td>• ACTC1 (HCM, DCM, LVNC)<br>• HAND2 (LVNC)<br>• MYH6 (HCM, DCM)<br>• MYH7 (LVNC, HCM)<br>• DCM)<br>• MYBPC3 (HCM)<br>• NFATC1 (LVNC)<br>• NKX2-5 (LVNC, conduction disease)<br>• PRDM16 (cardiomyopathy, conduction defects)<br>• TBX5 (disease)<br>• TBX20 (LVNC, DCM)</td></tr></tbody></table>