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This is the complete lecture note for MED606 Cardiology II. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: MED 606 Course title: Cardiology II Course credit load: 2 Units Series 1: Pathological Functional States of the Heart: Systolic and Diastolic Dysfunction, and Arrhythmias • Part 1.1: Heart Failure: Systolic Dysfunction o Sub Part 1.1.1: Pathophysiology of systolic heart failure o Sub Part 1.1.2: Clinical presentation of systolic heart failure o Sub Part 1.1.3: Classification and grading of heart failure • Part 1.2: Heart Failure: Diastolic Dysfunction o Sub Part 1.2.1: Pathophysiology of diastolic dysfunction o Sub Part 1.2.2: Clinical presentation and diagnosis of diastolic heart failure o Sub Part 1.2.3: Distinguishing systolic from diastolic heart failure • Part 1.3: Principles of Cardiac Arrhythmias o Sub Part 1.3.1: Mechanisms of arrhythmia o Sub Part 1.3.2: Classification of arrhythmias o Sub Part 1.3.3: Clinical presentation of arrhythmias • Part 1.4: Common Arrhythmias o Sub Part 1.4.1: Atrial fibrillation o Sub Part 1.4.2: Supraventricular tachycardia o Sub Part 1.4.3: Ventricular arrhythmias Introduction The heart can fail in genuinely two distinct ways, either through weakened contraction or through impaired relaxation and filling, and its normal rhythm can be disrupted in an equally wide variety of ways, from a benign, unnoticed irregularity to a genuinely life-threatening chaotic electrical storm. This opening Series of Cardiology II works through both of these
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS fundamental pathological states, heart failure and arrhythmia, building the theoretical foundation this course rests on. The aim of this Series is to equip you with an understanding of the pathophysiology, presentation, classification, and grading of systolic and diastolic heart failure, and the mechanisms, classification, and clinical presentation of cardiac arrhythmias, including the specific common arrhythmias of atrial fibrillation, supraventricular tachycardia, and ventricular arrhythmias. This Series opens with heart failure: systolic dysfunction, moves through heart failure: diastolic dysfunction and principles of cardiac arrhythmias, and closes with common arrhythmias. Series Learning Outcomes At the end of this Series, you should be able to: • SLO 1.1: describe the pathophysiology and clinical presentation of systolic heart failure • SLO 1.2: classify and grade heart failure • SLO 1.3: describe the pathophysiology and clinical presentation of diastolic heart failure • SLO 1.4: distinguish systolic from diastolic heart failure • SLO 1.5: describe the mechanisms and classification of cardiac arrhythmias • SLO 1.6: describe the clinical presentation of cardiac arrhythmias • SLO 1.7: describe atrial fibrillation and supraventricular tachycardia • SLO 1.8: describe ventricular arrhythmias 1.1 Heart Failure: Systolic Dysfunction 1.1.1 pathophysiology of systolic heart failure A failure of the heart's pumping capacity itself Systolic heart failure, also termed heart failure with reduced ejection fraction, results from impaired ventricular contractility, most commonly from ischaemic heart disease or dilated cardiomyopathy, reducing the proportion of blood ejected with each contraction, and the body's compensatory response, activating the sympathetic nervous system and the renin-angiotensin-aldosterone system, initially maintains adequate perfusion but, over time, genuinely worsens the underlying condition through progressive ventricular remodelling.
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS This neurohormonal activation, while adaptive in the short term following an acute insult, becomes genuinely maladaptive when sustained chronically, driving further myocardial damage, fluid retention, and progressive decline in cardiac function, a pathophysiological insight that directly underlies the specific pharmacological treatment strategies, deliberately targeting this compensatory pathway, discussed further in the management Series that follows later in this course. Fill in the blank: Systolic heart failure most commonly results from ischaemic heart disease or dilated ________. 1.1.2 clinical presentation of systolic heart failure Congestion behind a failing pump Systolic heart failure presents with symptoms reflecting fluid congestion both behind the failing left ventricle, producing breathlessness, orthopnoea, and paroxysmal nocturnal dyspnoea, and behind a failing right ventricle, producing peripheral oedema, raised jugular venous pressure, and hepatic congestion, with many patients demonstrating features of both presentations simultaneously given the frequent progression from isolated left-sided to combined biventricular failure over time. Examination findings include a displaced apex beat reflecting ventricular enlargement, a third heart sound reflecting rapid ventricular filling into a stiff, failing chamber, and, on auscultation of the chest, bilateral basal crackles reflecting pulmonary oedema, findings that together, alongside the symptom pattern already described, allow a confident clinical diagnosis to be reached before formal echocardiographic confirmation. Fill in the blank: A third heart sound reflects rapid ventricular filling into a stiff, ________ chamber. 1.1.3 classification and grading of heart failure Standardised frameworks for communicating severity Heart failure severity is graded using the New York Heart Association functional classification, ranging from class one, no limitation of physical activity, to class four, symptoms at rest, a widely used, simple framework allowing consistent communication of symptomatic severity between clinicians and tracking of change over time in an individual patient. Heart failure is further classified according to ejection fraction, measured on echocardiography, as heart failure with reduced ejection fraction, corresponding broadly to the systolic dysfunction discussed in this Part, heart failure with preserved ejection fraction, corresponding broadly to the
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS diastolic dysfunction discussed in the following Part, and heart failure with mildly reduced ejection fraction, an intermediate category recognised in more recent classification frameworks. Fill in the blank: New York Heart Association class four describes heart failure symptoms present at ________. Figure 1.1: A clinician examining jugular venous pressure and peripheral oedema during heart failure assessment. Pilot questions 1.1 1. Describe the pathophysiology of systolic heart failure. (Linked to SLO 1.1) 2. Explain why sustained neurohormonal activation becomes maladaptive in heart failure. (Linked to SLO 1.1) 3. Describe the symptoms and signs of left-sided versus right-sided heart failure. (Linked to SLO 1.1) 4. Describe the New York Heart Association functional classification. (Linked to SLO 1.2) 5. Distinguish heart failure with reduced, mildly reduced, and preserved ejection fraction. (Linked to SLO 1.2)
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.2 Heart Failure: Diastolic Dysfunction 1.2.1 pathophysiology of diastolic dysfunction A failure of relaxation, not contraction Diastolic heart failure, also termed heart failure with preserved ejection fraction, results from impaired ventricular relaxation and filling despite genuinely preserved contractile function, most commonly from longstanding hypertension causing left ventricular hypertrophy and increased chamber stiffness, or, less commonly, from hypertrophic or restrictive cardiomyopathy, discussed further in a later Series of this course. This impaired relaxation raises filling pressure required to achieve adequate ventricular filling, producing the same downstream congestive symptoms as systolic heart failure despite the ventricle's contractile function remaining genuinely normal on echocardiographic assessment, a pathophysiological distinction that, while conceptually clear, can genuinely complicate clinical diagnosis given the very similar symptomatic presentation the two conditions produce. Fill in the blank: Diastolic heart failure most commonly results from longstanding hypertension causing left ventricular ________. 1.2.2 clinical presentation and diagnosis of diastolic heart failure Similar symptoms, a genuinely different underlying mechanism Clinical presentation of diastolic heart failure closely mirrors that of systolic heart failure, breathlessness, orthopnoea, and peripheral oedema, meaning symptoms and signs alone genuinely cannot reliably distinguish between the two conditions, and confirming a preserved ejection fraction on echocardiography, alongside evidence of diastolic dysfunction from specific echocardiographic measurements, is essential to establish the diagnosis with confidence. Patients with diastolic heart failure are typically older, more commonly female, and more likely to have hypertension, atrial fibrillation, and other significant comorbidities compared with the typical systolic heart failure population, a demographic pattern that, while not diagnostic in itself, can genuinely raise clinical suspicion for this specific type of heart failure before formal echocardiographic confirmation is obtained. Fill in the blank: Patients with diastolic heart failure are typically older, more commonly ________, and have more comorbidities.
la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.2.3 distinguishing systolic from diastolic heart failure Why the distinction genuinely matters clinically Correctly distinguishing systolic from diastolic heart failure carries genuine treatment implications, since several of the specific pharmacological therapies with proven mortality benefit in systolic heart failure, covered in detail in a later management-focused Series, have not shown the same clear benefit in diastolic heart failure, meaning management of the latter condition focuses more heavily on symptom control and treating underlying contributing conditions such as hypertension. Echocardiography remains the definitive investigation distinguishing the two conditions, directly measuring ejection fraction and assessing diastolic function through specific parameters, and every patient presenting with a new diagnosis of heart failure should undergo this investigation before definitive treatment planning, given how directly the distinction between systolic and diastolic dysfunction shapes the most appropriate subsequent management approach. Fill in the blank: Echocardiography remains the definitive investigation distinguishing systolic from diastolic ________. Table 1.1: Comparing systolic and diastolic heart failure Feature Systolic heart failure Diastolic heart failure Ejection fraction Reduced Preserved Core mechanism Impaired contraction Impaired relaxation and filling Typical patient Often younger, ischaemic heart disease common Often older, female, hypertensive Pilot questions 1.2 1. Describe the pathophysiology of diastolic heart failure. (Linked to
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