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[Risk of stress-induced ventricular arrhythmias in hypertrophic cardiomyopathy]
Insights
Exercise tests reveal that ventricular arrhythmias are most common during pulmonary catheter insertion in hypertrophic obstructive cardiomyopathy (HOCM) patients. These arrhythmias, including pairs and tachycardias, often resolve spontaneously.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) and hypertrophic non-obstructive cardiomyopathy (HNCM) are distinct conditions.
- Hemodynamic assessment during exercise is crucial for managing these cardiomyopathies.
Purpose of the Study:
- To analyze the incidence and severity of ventricular arrhythmias during exercise testing in HOCM and HNCM patients.
- To correlate arrhythmias with specific phases of the exercise test protocol.
Main Methods:
- 200 exercise tests in 106 HOCM patients and 45 tests in 30 HNCM patients.
- Continuous ECG monitoring throughout a 4-phase exercise protocol including catheter insertion, rest, exercise, and post-exercise rest.
- Modified Lown classification for grading ventricular arrhythmias (VEB, pairs, salvos/tachycardias).
Main Results:
- The highest incidence of ventricular arrhythmias (75%) occurred during pulmonary wedge catheter insertion in HOCM patients.
- Ventricular pairs or tachycardias were observed in nearly 20% of HOCM exercise tests, with spontaneous termination.
- Ventricular arrhythmias persisted in 52% of HOCM patients during the post-exercise resting phase, with lower rates of pairs (5.5%) and tachycardias (2.5%).
Conclusions:
- Pulmonary catheter insertion is a significant trigger for ventricular arrhythmias in HOCM patients.
- Exercise testing can provoke arrhythmias in HOCM, necessitating careful monitoring.
- The majority of exercise-induced arrhythmias in HOCM are transient and self-limiting.
Abstract:
200 exercise tests in 106 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 45 exercise tests in 30 patients with hypertrophic non-obstructive cardiomyopathy (HNCM), primarily performed to assess the hemodynamic impairment during stepwise increased maximal exercise, were analysed with respect to incidence and severeness of ventricular arrhythmias by evaluating the continuously recorded ECG. The exercise tests were subdivided in 4 phases: 1. introduction of a Swan-Ganz pulmonary wedge catheter; 2. resting phase until constant hemodynamic basal values were reached; duration 5 to 51, mean 18 +/- 8 min; 3. exercise phase; bicycle ergometer exercise in supine position; increase in work load by steps of 25 Watts to the maximum which was defined by onset of angina pectoris, dyspnea or exhaustion; total duration 6 to 41, mean 18 +/- 6 min; 4. resting phase after exercise, duration 1 to 30, mean 5 +/- 3 min. Ventricular arrhythmias were classified in a modified Lown classification: 1. no ventricular ectopic beats (VEB); 2. single VEB, less than 0.5/min; 3. single VEB, more than 0.5/min; 4. ventricular pairs; 5. ventricular salvos or tachycardias (3 or more QRS complexes). In the total series of 200 exercise tests in patients with HOCM, the highest incidence of ventricular arrhythmias was found during insertion of the pulmonary wedge catheter, i.e., in 75% of the cases. In nearly 20% of the cases, ventricular pairs or tachycardias were observed. The longest tachycardia consisted of 17 QRS complexes. All tachycardias terminated spontaneously. During the following resting phase, ventricular arrhythmias were documented in 52% of the cases, with ventricular pairs, however, in only 11 (5.5%) and ventricular tachycardias in only 5 (2.5%) tests.(ABSTRACT TRUNCATED AT 250 WORDS)